- Hydroformylation of internal olefins to linear aldehydes with novel rhodium catalysts
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Unprecedented high activities and selectivities were observed in the hydroformylation of internal octenes to linear products using rhodium catalysts with rigid diphosphane ligands. Dibenzophosphole 1 and a phenoxaphosphane analogue with bite angles of 120 and 119°, respectively, are suited for this.
- Van Der Veen, Lars A.,Kamer, Paul C.J.,Van Leeuwen, Piet W. N. M.
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- Diastereoisomeric bisphosphite ligands in the hydroformylation of octenes: Rhodium catalysis and HP-NMR investigations
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Diastereoisomeric hydroformylation catalysts show differences for the catalyst preformation pathway and a strongly reduced n-octene hydroformylation activity for the (S,S,R)-isomer. The Royal Society of Chemistry.
- Selent, Detlef,Baumann, Wolfgang,Wiese, Klaus-Diether,Boerner, Armin
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- Efficient hydroformylation in dense carbon dioxide using phosphorus ligands without perfluoroalkyl substituents
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Rhodium catalysts modified with triphenylphosphine, triphenyl phosphite, and tris(2,4-ditrrt-butylphenyl) phosphite have been evaluated for their performance in the hydroformylation of 1octene using carbon dioxide as the solvent. It is demonstrated that these catalysts are very efficient for the hydroformylation in carbon dioxide, although they are not designed for use in this medium. In particular, the catalyst prepared in situ from dicarbonyl(2,4-pentanedione)rhodium(I) and tris(2,4-di-tert-butyl-phenyl) phosphite gave rise to an initial turnover frequency in excess of 3x 10 4 molaldehyde molRh h-1. Such a reaction rate is unprecedented for hydroformylation in supercritical carbon dioxide-rich reaction mixtures.
- Koeken, Ard C. J.,Benes, Nieck E.,Van Den Broeke, Leo J. P.,Keurentjes, Jos T. F.
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- Octene hydroformylation by using rhodium complexes tethered onto selectively functionalized mesoporous silica and in situ high pressure IR study
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SBA-15-based heterogeneous catalysts were applied to 1-octene hydroformylation. The turn over frequency over SBA-15/γ- aminopropylmethyldimethoxysilane (AEAPMDMS)/Rh catalyst with triphenylphosphine (TPP) ligand prepared by conventional post grafting method was higher than that of the homogeneous catalyst, (Rh(CH3COO)2)2 with TPP. The SBA-15/AEAPMDMS/Rh catalyst can be easily recycled without rhodium loss. The molar ratio of linear to branched nonyl aldehydes was remarkably enhanced over the heterogeneous catalysts. The selectively functionalized rhodium catalyst (SBA-15/Ph2Si(OEt)2/AEAPMDMS/Rh), in which rhodium was selectively tethered intra-pore of SBA-15, was beneficial for improving the selectivity to linear aldehyde. In situ high pressure FT-IR analysis suggested HRh(CO)2(PPh3)2 and HRh(CO)(PPh3)3 to be active species over the SBA-15/AEAPMDMS/Rh catalyst with TPP.
- Song, Ki-Chang,Baek, Ji Yeon,Bae, Jung A,Yim, Jin-Heong,Ko, Young Soo,Kim, Do Heui,Park, Young-Kwon,Jeon, Jong-Ki
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- Magnetically separable chicken feathers: A biopolymer based heterogeneous catalyst for the oxidation of organic substrates
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Magnetically separable poultry chicken feathers were found to be an efficient, green and heterogeneous catalyst for the oxidation of alcohols and sulfides to the corresponding carbonyl compounds and sulfoxides, respectively using t-butyl hydroperoxide (TBHP) as oxidant with complete selectivity and high conversions. The developed catalyst exhibited higher stability, activity and better recycling ability than the bare magnetic nanoparticles. The designed catalyst could readily be recovered using an external magnet without showing any significant leaching during the reaction.
- Patnam, Padma L.,Bhatt, Mukesh,Singh, Raghuvir,Saran, Sandeep,Jain, Suman L.
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- A facile method for promoting activities of ordered mesoporous silica-anchored Rh-P complex catalysts in 1-octene hydroformylation
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This work deals with the promotion of immobilized Rh catalyst activities in olefin hydroformylation by lengthening the alkyl spacers and choosing an active Rh precursor. The flexibility of long chain alkyls was used to free the motion of the anchored Rh c
- Zhou, Wei,He, Dehua
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- Rhodium-catalyzed biphasic hydroformylation of 4-octene using water-soluble calix[4]arene-phosphine ligands
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The hydroformylation of water-insoluble internal olefins has been realized in biphasic systems via the use of rhodium complexes of water-soluble calix[4]arene-phosphines. This catalytic system resulted in a good level of activity and reusability.
- Shirakawa,Shimizu,Sasaki
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- Hydroformylation activity of multinuclear rhodium complexes coordinated to dendritic iminopyridyl and iminophosphine scaffolds
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The synthesis of poly(propyleneimine)-iminopyridyl and iminophosphine rhodium(I) metallodendrimers, with rhodium coordinated to monodentate (N-donor) and chelating, heterobidentate (P,N) moieties respectively located on the periphery, has been accomplished in order to evaluate their potential as hydroformylation catalysts. Related mononuclear complexes were obtained in a similar manner to model the multinuclear complexes. The multinuclear rhodium(I) complexes were found to be effective catalyst precursors in the hydroformylation of 1-octene, achieving higher conversions, faster reaction rates and slightly enhanced catalytic activity when compared with analogous mononuclear rhodium complexes. Hydroformylation reactions using the tetra- and octanuclear rhodium complexes generally show a chemoselective formation of aldehydes, together with a small amount of isomerisation products.
- Antonels, Nathan C.,Moss, John R.,Smith, Gregory S.
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- Room-temperature production of bio-based aldehydes from vegetable oil-derived epoxide: via H2WO4?Al-MCM-41 as recyclable catalyst
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The oxidative cleavage of vegetable oils and their derivatives to produce bio-based aldehydes is a potentially useful process, although the aldehyde products are readily oxidized to carboxylic acids and thus seldom obtained in high yields. The present study developed a room-temperature method for the synthesis of bio-aldehydes via the oxidative cleavage of vegetable oil-derived epoxides, using H2WO4 as the catalyst, H2O2 as the oxidant, and t-BuOH as the solvent. Reactions were carried out at temperatures ranging from 25 to 35 °C for 3.5-10.5 h, and provided >99% conversion and >90% aldehyde yield. In particular, an approximately 97% yield was obtained at 25 °C after 10.5 h. As the reaction proceeded, the H2WO4 dissolved to form a W-containing anion. Several mesoporous Al-MCM-41 materials having different Si/Al ratios were hydrothermally synthesized and used as adsorbents to recover the catalyst by adsorbing these anions. The adsorption capacity of the Al-MCM-41 was found to increase with decreases in the Si/Al ratio. The Al-MCM-41 had little effect on the oxidative cleavage reaction at 25 °C, and thus could be directly added to the reaction system. The excellent anion adsorption performance of the Al-MCM-41 greatly improved the reusability of the H2WO4 catalyst. When using the Al-MCM-41 with the best adsorption performance, there was no significant decrease in the activity of the catalyst following five reuses.
- Peng, Libo,Xie, Qinglong,Nie, Yong,Liu, Xuejun,Lu, Meizhen,Ji, Jianbing
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- TEMPO oxidations with a silica-supported catalyst
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Silica-supported 1-hydroxy-2,2,6,6-tetramethylpiperidine (SG-TMP-OH) was successfully applied as a recyclable catalyst in the oxidation of various alcohols.
- Bolm, Carsten,Thomas, Fey
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- Mediated electrolysis of vicinal diols by neocuproine palladium catalysts
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Synthetic electrochemistry agrees well with the principles of sustainable chemistry, therefore it is considered as a more environmentally friendly approach than some current synthetic methods. Here, we present a new strategy for the chemoselective oxidation of vicinal diols, viz. the integration of neocuproine palladium catalysts and electrosynthesis. Benzoquinones are used as an effective mediator as the reduced species (hydroquinones) can be easily reoxidized at relative low potentials at an electrode surface. NeocuproinePd(OAc)2 efficiently works as a catalyst in an electrolysis reaction for vicinal diols at room temperature. This is a remarkable observation given the fact that aerobic oxidation reactions of alcohols typically need a more complex catalyst, i.e. [neocuproinePdOAc]2[OTf]2. In this article we describe the optimization of the electrolysis conditions for the neocuproinePd(OAc)2 catalyst to selectively oxidize diols. The suggested approach leads to conversion of alcohols with high yields and provides an interesting alternative to perform oxidation reactions under mild conditions by the aid of electrochemistry.
- Lybaert,Tehrani, K. Abbaspour,De Wael
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- Hydroformylation of 1-octene in the presence of cobalt alkylidynecarbonyl clusters
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The hydroformylation of 1-octene in the presence of Co3(CO)9(μ-CR) (R = H, Me, Ph, CO2Me, CO2Et, CO2Pr-i, CO2Bu-t, Cl, Br, OMe) alkylidynecarbonyl clusters, as well as triphenylphosphine derivatives of these complexes and heteronuclear Co2Ni compounds have been studied.The nature of the catalytically active species in hydroformylation, as well as the processes of their formation and transformation during the reaction, have been established by means of IR spectroscopy.The effects of the reaction conditions, the nature of the substituent at the apical carbon atom, the electron donating phosphine substituent, and the substituent in the metal cluster framework have been discussed. - Key words: 1-octene, hydroformylation; cobalt carbonyls.
- Tsoy, A. A.,Korneeva, G. A.,Kayumov, F. F.,Grudtsyn, Yu. D.,Slivinskii, E. V.,et al.
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- Reactivity of platinum stanna-closo-dodecaborate complexes: First hydroformylation studies
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The synthesis and characterization of two (dppp)Pt complexes with the stannaborate ligand SnB11H11 is described. In the case of the salt [Bu3MeN]2[(dppp)Pt (SnB11H11)2] the struc
- Wesemann, Lars,Hagen, Siegbert,Marx, Thiemo,Pantenburg, Ingo,Nobis, Markus,Driessen-Hoelscher, Birgit
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- Pd(II) loaded on diamine functionalized LDH for oxidation of primary alcohol using water as solvent
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Hybrid inorganic-organic materials which comprise organic functional groups tethered from layered double hydroxide surfaces are versatile, heterogeneous catalysts. This functional group can bind with palladium that provides catalytic activity superior to what can be obtained from homogeneous catalysts. This work reports synthesis of heterogeneous and recyclable Pd(II) (supported on diamine functionalized layered double hydroxide) catalyst for oxidation of primary alcohol using water as solvent and molecular O2 as a terminal oxidant. The organometallic-derived catalyst has been studied by XRD, FTIR, UV-vis DRS, solid-state NMR (13C, 29Si), XPS, TGDTA, SEM and EDX. Here the ligand N-[3-(trimethoxysilyl)-propyl] ethylenediamine (TPED) is covalently attached to the surface of LDH, which is shown by NMR spectroscopy. XPS results strongly suggest that it involves the formation of NPd coordination bonds. EDX confirmed that all the elements were present in the LDH/Pd(II) complex. The heterogeneous catalyst can be easily recovered and reused multiple times without significant loss of catalytic activity and selectivity, which is a better green alternative for practical applications.
- Sahoo, Mitarani,Parida
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- Highly regioselective and active Rh-2,2′-bis(dipyrrolylphosphinooxy)- 1,1′-(±)-binaphthyl catalyst for hydroformylation of 2-octene
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Rhodium catalyst bearing 2,2′-bis(dipyrrolyphosphinooxy)-1,1′- (±)-binaphthyl (ligand 1) shows high regioselectivity and activity for the hydroformylation of 2-octene. The introduction of a pyrrolyl group in the ligand greatly improves the yield of the linear aldehyde. The regioselectivity is up to 97.5% under mild conditions (100 °C, 0.7 MPa H2/CO). Copyright
- Liu, Wenjing,Yuan, Maolin,Fu, Haiyan,Chen, Hua,Li, Ruixiang,Li, Xianjun
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- Integration of a phosphine ligand into an ionic liquid: A highly effective biphasic system for the Rh-catalyzed hydroformylation of 1-octene
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In classical biphasic ionic liquid (IL) catalysis, the use of a large amount of solvent IL is a major limitation, and usually leads to a waste of resources and relatively low reaction efficiency. So far, it has remained a challenge to establish a highly effective and long-life IL catalytic system that can utilize IL in a relatively efficient, green, and economical manner. Herein, a class of room-temperature phosphine-functionalized polyether guanidinium ionic liquids (RTP-PolyGILs) were synthesized using a simple ion exchange reaction of TPPTS with polyether guanidinium ionic liquids (PolyGILs) based on the notion of integrating phosphine ligand into the IL. These RTP-PolyGILs displayed the characteristics of the phosphine ligand and the solvent IL in both structure and properties, and could thus act not only as ligands to bind metal catalysts but also as catalyst carriers. By exploiting the dual functions of RTP-PolyGILs, we constructed a highly effective, green, and economical biphasic system for the Rh-catalyzed hydroformylation of 1-octene, and examined how the structures of the RTP-PolyGILs affected the activity, selectivity, and stability of the Rh catalysts. It was found that only a catalytic amount of RTP-PolyGILs (about 0.1-0.4 mol% 1-alkenes) was needed to give a high TOF of up to 2300 h-1, good aldehyde selectivity, long service life with a total turnover number (TTON) of up to 47000, and low Rh leaching of only 0.07-0.3 ppm.
- Jin, Xin,Feng, Jianying,Ma, Qingqing,Song, Hongbing,Liu, Qiangqiang,Xu, Bingying,Zhang, Mei,Li, Shumei,Yu, Shitao
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- Heterometallic catalysts. Cobalt carbonyl derivatives of lanthanides in catalysis of octene-1 hydroformylation
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The results of an investigation involving the catalysis of octene-1 hydroformylation with heterobimetallic catalysts, cobalt carbonyl derivatives of lanthanides, are reported.
- Beletskaya, I.P.,Magomedov, G.K.-I.,Voskoboinikov, A.Z.
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- Rhodium catalysed hydroformylation of alkenes using highly fluorophilic phosphines
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Highly fluorophilic phosphines incorporating at least one aromatic ring containing two directly attached perfluoroalkyl groups have been synthesised, their partition coefficients (organic phase : fluorous phase) measured and their electronic properties probed using 1JPtP data for their trans-[PtCl2L2] complexes. These phosphines have been used as modifying ligands for the rhodium catalysed hydroformylation of 1-octene in perfluorocarbon solvents. Catalyst activity, regioselectivity and the levels of rhodium leaching to the product phase vary with the substitution patterns of the modifying ligands that do not correlate with the electronic properties or partition coefficients of these ligands, but can be interpreted in terms of differences in the resting states of the catalysts. The Royal Society of Chemistry 2005.
- Adams, Dave J.,Bennett, James A.,Cole-Hamilton, David J.,Hope, Eric G.,Hopewell, Jonathan,Kight, Jo,Pogorzelec, Peter,Stuart, Alison M.
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- Realistic energy surfaces for real-world systems: An IMOMO CCSD(T):DFT scheme for rhodium-catalyzed hydroformylation with the 6-dppon ligand
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The hydroformylation of terminal alkenes is one of the most important homogeneously catalyzed processes in industry, and the atomistic understanding of this reaction has attracted enormous interest in the past. Herein, the whole catalytic cycle for rhodium-catalyzed hydroformylation with the 6-diphenylphosphinopyridine-(2H)-1-one (6-DPPon) ligand 1 was studied. This catalytic transformation is challenging to describe computationally, since two requirements must be met: 1) changes in the hydrogen-bond network must be modeled accurately and 2) bond-formation/bond-breaking processes in the coordination sphere of the rhodium center must be calculated accurately. Depending on the functionals used (BP86, B3LYP), the results were found to differ strongly. Therefore, the complete cycle was calculated by using highly accurate CCSD(T) computations for a PH3 model ligand. By applying an integrated molecular orbital plus molecular orbital (IMOMO) method consisting of CCSD(T) as high level and DFT as low-level method, excellent agreement between the two functionals was achieved. To further test the reliability of the calculations, the energetic-span model was used to compare experimentally derived and computed activation barriers. The accuracy of the new IMOMO method apparently makes it possible to predict the catalytic potential of real-world systems. Copyright
- Gellrich, Urs,Himmel, Daniel,Meuwly, Markus,Breit, Bernhard
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- Alkylated polyethyleneimine/polyoxometalate synzymes as catalysts for the oxidation of hydrophobic substrates in water with hydrogen peroxide
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Combinations of alkylated polyethylenimine and polyoxometalates yield water-soluble synzymes with hydrophobic regions that allowed the aqueous biphasic selective oxidation of very hydrophobic, water-insoluble substrates with hydrogen peroxide. With the alkylated PEI/{PO4[WO(O2)2]4}3- highly effective C-C bond cleavage of alkenes to aldheydes was observed. The synzymes have both tertiary and quaternary amine centers as shown by a combination of 15N-1H HMBC and XPS measurements. The existence of hydrophobic regions was concluded from the measurement of contact angles and a hypsochromic shift of a fluorescent probe. Copyright
- Haimov, Adina,Cohen, Hagai,Neumann, Ronny
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- Amphiphilic Resin-Supported Rhodium-Phosphine Catalysts for C-C Bond Forming Reactions in Water
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Amphiphilic resin-supported rhodium-phosphine complexes were prepared on polystyrene-poly(ethylene glycol) graft co-polymer (1% DVB cross-linked) beads. The immobilized rhodium complexes exhibited high catalytic activity in water to promote hydroformylation of 1-alkenes, [2+2+2] cyclotrimerization of internal alkynes forming benzene rings, and 1,4-addition of arylboronic acids.
- Uozumi, Yasuhiro,Nakazono, Maki
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- Highly sensitive and rapid detection of antibody catalysis by luminescent bacteria
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A highly sensitive, inexpensive, and facile bioluminescent assay for the detection of catalytic antibodies has been developed. This assay may be used for the early detection of antibody catalysis. The efficiency of this technique was exemplified by the use of the luminescent bacterium VhM42 for monitoring an antibody-catalyzed retroaldol fragmentation reaction with aldolase antibodies 38C2 and 24H6. (C) 2000 Elsevier Science Ltd.
- Shulman, Hagit,Eberhard, Anatol,Eberhard, Carolyn,Ulitzur, Shimon,Keinan, Ehud
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- Selectivity of rhodium-catalyzed hydroformylation of 1-octene during batch and semi-batch reaction using trifluoromethyl-substituted ligands
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The regioselectivity of catalysts generated in situ from dicarbonyl rhodium(I)(2,4-pentanedione) and trifluoromethyl-substituted triphenylphosphine ligands has been evaluated during the hydroformylation of 1-octene. The influence of batch or semi-batch operation, the solvent, and the number of trifluoromethyl substituents has been investigated. During batch operation in a supercritical carbon dioxide (CO2)-rich system the differential n:iso ratio increases from approximately 4 to a value of 12-16 at about 90-95% conversion for the catalyst based on bis[3,5-bis(trifluoromethyl)phenyl] phenylphosphine. For semi-batch conditions using hexane a constant n:iso ratio is obtained over a broad conversion range. Batch hydroformylation in neat 1-octene is faster than in a supercritical CO2-rich, one-phase system, with a similar overall selectivity as observed in the supercritical case. The results provide further directions for the development of ligands that are especially designed for the separation of homogeneous catalysts in continuously operated hydroformylation in ScCO2.
- Koeken, Ard C. J.,Van Vliet, Michiel C. A.,Van Den Broeke, Leo J. P.,Deelman, Berth-Jan,Keurentjes, Jos T. F.
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- Supported Cobalt Nanoparticles for Hydroformylation Reactions
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Hydroformylation of olefins has been studied in the presence of specific heterogeneous cobalt nanoparticles. The catalytic materials were prepared by pyrolysis of preformed cobalt complexes deposited onto different inorganic supports. Atomic absorption spectroscopy (AAS) measurements indicated a correlation of catalyst activity and cobalt leaching as well as a strong influence of the heterogeneous support on the productivity. These new, low-cost, easy-to-handle catalysts can substitute more toxic, unstable and volatile cobalt carbonyl complexes for hydroformylations on a laboratory scale.
- Hertrich, Maximilian Franz,Scharnagl, Florian Korbinian,Pews-Davtyan, Anahit,Kreyenschulte, Carsten Robert,Lund, Henrik,Bartling, Stephan,Jackstell, Ralf,Beller, Matthias
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- Cobalt N-heterocyclic carbene alkyl and acyl compounds: Synthesis, molecular structure and reactivity
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The N-heterocyclic-carbene containing cobalt carbonyl compound [Co(IMes)(CO)3(Me)] (IMes = 1,3-bis(2,4,6-trimethylphenyl)-imidazol- 2-ylidene), 1, has been synthesised by tertiary phosphine displacement from [Co(PPh3)(CO)3(Me)]. Subsequent carbonylation afforded the acyl derivative [Co(IMes)(CO)3(COMe)], 2. Similarly, the compound [Co(IMes)(CO)3(COEt)], 3, has been synthesised. The compounds 2 and 3 have been shown to react with dihydrogen to form the cobalt hydride compound [Co(IMes)(CO)3(H)], 4. The molecular structures of compounds 1 and 2 have been determined. The Royal Society of Chemistry 2006.
- Llewellyn, Simon A.,Green, Malcolm L. H.,Cowley, Andrew R.
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- Stereoelectronic effects in a homologous series of bidentate cyclic phosphines. A clear correlation of hydroformylation catalyst activity with ring size
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The homologous series of diphosphines (CH2) n-1P(CH2)3P(CH2)n-1 where n = 5 (L5), 6 (L6), or 7 (L7) have been synthesized from the corresponding PhP(CH
- Haddow, Mairi F.,Middleton, Ann J.,Orpen, A. Guy,Pringle, Paul G.,Papp, Rainer
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- Rhodium(I) Ferrocenylcarbene Complexes: Synthesis, Structural Determination, Electrochemistry, and Application as Hydroformylation Catalyst Precursors
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New examples of the rare class of rhodium(I) ferrocenyl Fischer carbene complexes 1-8, [Rh(LL)Cl{C(XR)Fc}] [LL = cod, (CO)2, (CO, PR3) (R = Ph, Cy or OPh), and (CO, AsPh3); XR = OEt or NHnPr] were prepared, and the electronic effects of coligands and alkoxy vs aminocarbene substituents were investigated by spectroscopic and electrochemical methods. The molecular structures of complexes 1, 2, and 4-6 were confirmed by single-crystal X-ray diffraction. The use of the complexes 1-8 as homogeneous catalysts for the hydroformylation of 1-octene was demonstrated, and the influence of the carbene substituents and coligands on the activity and regioselectivity of the catalysts evaluated. Finally, the stability of the Rh-Ccarbene bond of complex 1 under hydroformylation conditions was confirmed with 13C NMR experiments.
- Ramollo, G. Kabelo,López-Gómez, María J.,Liles, David C.,Matsinha, Leah C.,Smith, Gregory S.,Bezuidenhout, Daniela I.
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- Ordered mesoporous materials as solid supports for rhodium-diphosphine catalysts with remarkable hydroformylation activity
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A rhodium-diphosphine complex based on Xantphos-type ligands was anchored on mesoporous silica SBA-15, and the material showed remarkably high catalytic activity in the hydroformylation of 1-octene, even exceeding its homogeneous analogue under certain conditions.
- Marras, Fabrizio,Wang, Jia,Coppens, Marc-Olivier,Reek, Joost N. H.
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- Linear amphiphilic TEMPO-grafted poly(ether sulfone) as polymeric interfacial catalyst: Synthesis, self-assembly behavior, and application
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In this study, we report the development of a novel recyclable polymer-supported interfacial catalyst for Montanari oxidation. The catalyst was prepared by immobilization of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) on poly(ether sulfone) (PES) bridged by imidazole groups and characterized by 1H nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, elemental analysis, contact angle measurement, and transmission electron microscopy (TEM). This well-designed polymer was self-assembled into nanoaggregates in CH2Cl2. It was then used as Pickering emulsifier in Montanari oxidation system (NaClO/NaBr/immobilized TEMPO) for selective oxidation of different alcohols, which exhibited higher activity due to the enhanced mass transfer through microreactor mechanism. Moreover, this polymeric interfacial catalyst was pH-sensitive and could be easily recycled by adding small amount of acid, and subsequent cycles of alcohol oxidation showed no loss on either conversion or selectivity. This study represents an innovative approach for developing polymeric interfacial catalyst.
- Chen, Liang,Tang, Jun,Zhang, Qi,Wang, Jianli
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- Porous polymerized organocatalysts rationally synthesized from the corresponding vinyl-functionalized monomers as efficient heterogeneous catalysts
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Porous polymerized organocatalysts (PPOs) have been successfully synthesized from the corresponding vinyl-functionalized monomers under solvothermal conditions. These PPOs have high surface areas, large pore volumes, hierarchical porosity, and good stability. Utilized as a typical organocatalyst, the porous polymerized 2,2,6,6-tetramethylpiperidine-1-oxyl (PPO-TEMPO) with stable free radicals shows high activities and excellent recyclabilities in selective oxidations of a variety of alcohols to the corresponding aldehydes or ketones. This synthesis method may open a new door for developing heterogeneous catalysts with high activity and good recyclability in the future.
- Huangfu, Ying,Sun, Qi,Pan, Shuxiang,Meng, Xiangju,Xiao, Feng-Shou
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- Reaction Activity and Selectivity as a Function of Solution Ionic Strength in Oct-1-ene Hydroformylation with Sulfonated Phosphines
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Salt concentration has a considerable influence on the activity and selectivity of water-soluble hydroformylation catalysts derived from Rh(acac)(CO)2 and the sulfonated phosphine, P3; addition of Na2SO4 or Na2HPO4 to the catalysts enhances the both the rate and selectivity of the hydroformylation reaction.
- Ding, Hao,Hanson, Brian E.
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- Synthesis of an Azaphosphatriptycene and Its Rhodium Carbonyl Complex
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A 10-aza-9-phosphatriptycene is accessible on a gram scale, in three laboratory steps from commercially available precursors. Infrared spectroscopy of a rhodium(I) carbonyl complex bearing this ligand reflects the weak σ-donor/strong π-acceptor character of the phosphine; the solid-state structure reveals moderate steric demand. This ligand supports highly active catalysts for the hydroformylation of cyclic alkenes.
- Cao, Yu,Napoline, Jonathan W.,Bacsa, John,Pollet, Pamela,Soper, Jake D.,Sadighi, Joseph P.
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- High pressure infrared and nuclear magnetic resonance studies of the rhodium-sulfoxantphos catalysed hydroformylation of 1-octene in ionic liquids
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The rhodium-sulfoxantphos catalysed hydroformylation of 1-octene in 1-n-butyl-3-methylimidazoliuni hexafluorophosphate (BMI·PF6) as a room temperature ionic liquid was monitored in situ by high pressure IR (HP-IR) and NMR (HP-NMR). Similar ee (bis-equatorial) and ea (equatorial-apical) (diphosphine)Rh(CO)2H catalytic species, as observed in organic solvents, are formed in the BMI·PF6 ionic liquid. The ratio of the ee and ea isomers is influenced by both the temperature and syngas pressure. An increase in hydrogen partial pressure has no effect on the activity of the system during the reaction performed in BMI:PF6, while some hydroformylation systems using xanthene backbone ligands in conventional organic solvents can be sensitive to hydrogen partial pressure.
- Silva, Silvana M.,Bronger, Raymond P. J.,Freixa, Zoraida,Dupont, Jairton,Van Leeuwen, Piet W. N. M.
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- Rhodium-NHC-complexes as potent catalysts in the hydroformylation of 1-octene
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We present an overview of eight different rhodium-N-heterocyclic carbene (NHC) complexes 1-8 and their catalytic activity and selectivity in hydroformylation of 1-octene. It could be shown that activity can be increased by going from electron-rich NHC- to electron-poor NHC-ligands. However, no increase in the selectivity could be achieved by introducing bulky substituents to the NHCs.
- Bortenschlager, Martin,Schütz, Jan,Von Preysing, Denise,Nuyken, Oskar,Herrmann, Wolfgang A.,Weberskirch, Ralf
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- Continuous, selective hydroformylation in supercritical carbon dioxide using an immobilised homogeneous catalyst
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A continuous process for the selective hydroformylation of higher olefins in supercritical carbon dioxide (scCO2) is presented; the catalyst shows high selectivity and activity over several hours and no decrease in performance was observed over several days.
- Meehan,Sandee,Reek,Kamer,Van Leeuwen,Poliakoff
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- New phosphorus ligands for the rhodium-catalyzed isomerization/hydroformylation of internal octenes
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Going up! n-Selectivity and activity can be increased simultaneously in hydroformylation by the use of novel hybrid ligands such as 1 containing O-acylphosphite groups. For the first time these ligands deliver impressively n-selective rhodium-catalyzed hy
- Selent, Detlef,Hess, Dieter,Wiese, Klaus-Diether,Roettger, Dirk,Kunze, Christine,Boerner, Armin
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- Silica gel supported ferric nitrate: A convenient oxidizing reagent
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A silica gel supported ferric nitrate was prepared by co-grinding Fe(NO3)3.9H2O with silica gel in appropriate amounts. The reagent was used in equimolar quantity to oxidize various alcohols to corresponding aldehydes with complete selectivity. Similarly it successfully oxidizes various Hantzsch-type 1,4-dihydropyridines.
- Khadilkar, Bhushan,Borkar, Shobha
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- Novel active dirhodium complexes for the low pressure hydroformylation reaction. Unexpected inhibiting effect of high partial pressures of hydrogen
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The complex tBu)2(CO)2(PPh3)2> was shown to be an active precursor for the low pressure hydroformylation of terminal alkenes in the presence of an excess of triphenylphosphine.Preliminary kinetic studies have shown that as usual has CO an inhibiting efect, but unexpectedly the reaction was also inhibited by high H2/CO rations.
- Kalck, Philippe,Peres, Yolande,Queau, Rene,Molinier, Jacques,Escaffre, Pascale,et al.
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- N-Acetyl-N,N-dipyrid-2-yl (cyclooctadiene) rhodium (I) and iridium (I) complexes: Synthesis, X-ray structures, their use in hydroformylation and carbonyl hydrosilylation reactions and in the polymerization of diazocompounds
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The synthesis of novel N-acetyl-N,N-dipyrid-2-yl complexes of RhI and IrI, i.e. [RhCl(CH3CONPy2)(COD)] (1) and [IrCl(CH3CONPy2)(COD)] (2), respectively, is described. Upon prolonged treatment in CH2Cl2 at room temperature, complex 1 is transformed into a cationic Rh-complex, i.e. [Rh(CH3CONPy2)(COD)+RhCl2(COD)-] (1a). Compound 1a crystallizes in the monoclinic space group P21/c, complex 2 crystallizes in the triclinic space group P over(1, ?). Compound 1 was investigated for its catalytic activity in the hydroformylation of cyclooctene as well as of 1-octene. In addition, 1 was used in various carbonyl hydrosilylation reactions of both aldehydes and ketones. There, turn-over numbers up to 50 000 and yields in the range of 85-100% were observed. Finally, compound 1 was successfully used for the polymerization of N2CHCOOEt yielding highly stereoregular poly(ethoxycarbonylcarbene) with Mw = 67 000 g/mol and a polydispersity index (PDI) of 2.59.
- Bantu, Bhasker,Wurst, Klaus,Buchmeiser, Michael R.
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- Continuous flow homogeneous catalysis using supercritical fluids
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The continuous flow hydroformylation of 1-octene catalysed by Rh/[RMIM][Ph2PC6H4SO3] (R = 1-propyl, 1-pentyl or 1-octyl) dissolved only in the steady state reaction mixture and using scCO2 as a transport vector for both substrates and products gives rates up to 160-240 catalyst turnovers h-1 with low rhodium leaching over a 12 h period at a total pressure of 125-140 bar.
- Webb, Paul B.,Cole-Hamilton, David J.
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- Sol-Gel Ormosils Doped with TEMPO as Recyclable Catalysts for the Selective Oxidation of Alcohols
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Organically modified silicas doped with TEMPO prepared via the sol-gel method are highly recyclable catalysts of the selective Montanari-Anelli oxidation of 1-nonanol; They show a notable "positive feedback" effect of matrix alkylation on the catalyst activity which is typical of doped sol-gel materials and markedly differentiates the behaviour of these materials from that of analogous silica-supported TEMPO.
- Ciriminna, Rosaria,Bolm, Carsten,Fey, Thomas,Pagliaro, Mario
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- Mechanistic insights into a supramolecular self-assembling catalyst system: Evidence for hydrogen bonding during rhodium-catalyzed hydroformylation
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The structural integrity and flexibility provided by intermolecular hydrogen bonds leads to the outstanding properties of the 6- diphenylphosphinopyridin-(2H)-1-one ligand (see scheme) in the rhodium-catalyzed hydroformylation of terminal alkenes, as demonstrated by the combination of spectroscopic methods and DFT computations. Hydrogen bonds were also detected in a competent intermediate of the catalytic cycle. Copyright
- Gellrich, Urs,Seiche, Wolfgang,Keller, Manfred,Breit, Bernhard
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- Hydroformylation of Oct-1-ene with Extremely High Rates using Rhodium Catalysts containing Bulky Phosphites
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A rhodium complex containing tris(o-tert-butyl-p-methylphenyl) phosphite as a ligand catalyses the hydroformylation of oct-1-ene with good selectivity and extremely high rates; the rate constant, which is pseudo first-order in and 1/, shows that the reaction of hydrogen is the rate determining step.
- Rooy, Annemiek van,Orij, Edwin N.,Kamer, Paul C. J.,Aardweg, Fred van den,Leeuven, Piet W. N. M. van
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- Preparation of Polymer Supported Phosphine Ligands by Metal Catalyzed Living Radical Copolymerization and Their Application to Hydroformylation Catalysis
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A series of well-defined polystyrene-supported tertiary phosphine ligands were prepared by copper-catalyzed atom transfer radical polymerization (ATRP), involving direct copolymerization of styrene and 4-diphenylphosphinostyrene (or 4-styryldiphenylphosphine, SDPP). Copolymerization of the two monomers at different molar ratios showed a decreasing level of control as the SDPP molar fraction (fSDPP) increased. A satisfactory level of control was achieved for fSDPP≤0.25 such that there was a constant concentration of growing living chains , and linear Mn growth with conversion and low dispersity. Copper-free polymers with different chain lengths were prepared and tested as polymeric ligands in the rhodium-catalyzed hydroformylation of 1-octene. The polymeric ligands yielded higher linear/branched selectivity and lower activity relative to PPh3 at the same P/Rh ratio. The selectivity increased slightly as a function of the polymer chain length.
- Cardozo, Andres F.,Manoury, Eric,Julcour, Carine,Blanco, Jean-Francois,Delmas, Henri,Gayet, Florence,Poli, Rinaldo
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- Room temperature ambient pressure (RTAP)-hydroformylation in water using a self-assembling ligand
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We herein demonstrate a hydroformylation at room temperature and ambient pressure (RTAP) using our Rh/6-DPPon (1) system in aqueous media. The hydrogen bonding network of the ligand backbone stays intact, exemplified by the excellent regioselectivity for the linear aldehyde. Various substrates with different functional groups (with some prone to hydrolysis) are stable under the applied conditions and can undergo hydroformylation resulting in good yields. Copyright
- Straub, Alexander T.,Otto, Marina,Usui, Ippei,Breit, Bernhard
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- Functionalized-1,3,4-oxadiazole ligands for the ruthenium-catalyzed Lemieux-Johnson type oxidation of olefins and alkynes in water
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Three arene-ruthenium(II) complexes bearing alkyloxy(5-phenyl-1,3,4-oxadiazol-2-ylamino)(4-trifluoromethylphenyl)methyl ligands were quantitatively obtained through the reaction of (E)-1-(4-trifluoromethylphenyl)-N-(5-phenyl-1,3,4-oxadiazol-2-yl)-methanimine with the ruthenium precursor [RuCl2(η6-p-cymene)]2 in a mixture of the corresponding alcohol and CH2Cl2 at 50 °C. The obtained complexes were fully characterized by elemental analysis, infrared, NMR and mass spectrometry. Solid-state structures confirmed the coordination of the 1,3,4-oxadiazole moiety to the ruthenium center via their electronically enriched nitrogen atom at position 3 in the aromatic ring. These complexes were evaluated as precatalysts in the Lemieux-Johnson type oxidative cleavage of olefins and alkynes in water at room temperature with NaIO4 as oxidizing agent. Good to full conversions of olefins into the corresponding aldehydes were measured, but low catalytic activity was observed in the case of alkynes. In order to get more insight into the mechanism, three analogue arene-ruthenium complexes were synthesized and tested in the oxidative cleavage of styrene. The latter tests clearly demonstrated the importance of the hemilabile alkyloxy groups, which may form more stable (N,O)-chelate intermediates and increase the efficiency of the cis-dioxo-ruthenium(VI) catalyst.
- Hkiri, Shaima,Touil, Soufiane,Samarat, Ali,Sémeril, David
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- Spongy titanosilicate promotes the catalytic performance and reusability of WO3 in oxidative cleavage of methyl oleate
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A tungsten containing catalyst catalyzed oxidative cleavage of methyl oleate (MO) by employing H2O2 as an oxidant and is known as an efficient approach for preparing high value-added chemicals, however, the tungsten leaching problem remains unresolved. In this work, a binary catalyst consisting of tungsten oxide (WO3) and spongy titanosilicate (STS) zeolite is proposed for MO oxidative cleavage. The function of STS in this catalyst is investigated. On the one hand, STS converts MO to 9,10-epoxystearate (MES), which further forms nonyl aldehyde (NA) and methyl azelaaldehydate (MAA) with the catalysis of WO3. In this way, MO oxidation and hydrolysis that generates unwanted diol product 9,10-dihydroxystearate (MDS) decreases obviously. On the other hand, STS decomposes peroxide and promotes the conversion of soluble peroxotungstate to insoluble polytungstate. Meanwhile, these tungsten species are allowed to precipitate on its surface instead of remaining in the liquid phase owing to its relative large specific area. Therefore, tungsten leaching can be reduced from 37.0% to 1.2%. Due to the cooperation of WO3 and STS, 94.4% MO conversion and oxidative cleavage product selectivity of 63.1% are achieved, and the WO3-STS binary catalyst maintains excellent catalytic performance for 8 recycling reactions.
- Huang, Zuoxin,Lin, Min,Peng, Xinxin,Shu, Xingtian,Xia, Changjiu,Xin, Shihao,Zhang, Yao,Zheng, Aiguo,Zhu, Bin
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p. 5135 - 5144
(2022/02/25)
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- Biobased Aldehydes from Fatty Epoxides through Thermal Cleavage of β-Hydroxy Hydroperoxides**
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The ring-opening of epoxidized methyl oleate by aqueous H2O2 has been studied using tungsten and molybdenum catalysts to form the corresponding fatty β-hydroxy hydroperoxides. It was found that tungstic acid and phosphotungstic acid gave the highest selectivities (92–93 %) towards the formation of the desired products, thus limiting the formation of the corresponding fatty 1,2-diols. The optimized conditions were applied to a range of fatty epoxides to give the corresponding fatty β-hydroxy hydroperoxides with 30–80 % isolated yields (8 examples). These species were fully characterized by 1H and 13C NMR spectroscopy and HPLC-HRMS, and their stability was studied by differential scanning calorimetry. The thermal cleavage of the β-hydroxy hydroperoxide derived from methyl oleate was studied both in batch and flow conditions. It was found that the thermal cleavage in flow conditions gave the highest selectivity towards the formation of aldehydes with limited amounts of byproducts. The aldehydes were both formed with 68 % GC yield, and nonanal and methyl 9-oxononanoate were isolated with 57 and 55 % yield, respectively. Advantageously, the overall process does not require large excess of H2O2 and only generates water as a byproduct.
- De Dios Miguel, Thomas,Duc Vu, Nam,Lemaire, Marc,Duguet, Nicolas
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p. 379 - 386
(2020/11/30)
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- ALDEHYDE GENERATION VIA ALKENE HYDROFORMYLATION
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Aldehyde generation includes providing a first input stream, a second input, and an alkene substrate to a reactor system. The first input stream includes a catalyst, a ligand, and an organic solvent. The second input stream includes a mixture of carbon monoxide (CO) and hydrogen gas (H2). The alkene substrate is in either gaseous form or liquid form, the liquid form of the alkene substrate being provided with the first input stream, the gaseous form of the alkene substrate being provided with the second input stream. The reactor system includes a first reactor and a second reactor, where the second reactor is gas permeable and positioned within the first reactor.
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Paragraph 0035; 0079-0081
(2021/09/26)
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- Micellar Catalysis for Sustainable Hydroformylation
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It is here reported a fully sustainable and generally applicable protocol for the regioselective hydroformylation of terminal alkenes, using cheap commercially available catalysts and ligands, in mild reaction conditions (70 °C, 9 bar, 40 min). The process can take advantages from both micellar catalysis and microwave irradiation to obtain the linear aldehydes as the major or sole regioisomers in good to high yields. The substrate scope is largely explored as well as the application of hydroformylation in tandem with intramolecular hemiacetalization thus demonstrating the compatibility with a broad variety of functional groups. The reaction is efficient even in large scale and the catalyst and micellar water phase can be reused at least 5 times without any impact in reaction yields. The efficiency and sustainability of this protocol is strictly related to the in situ transformation of the aldehyde into the corresponding Bertagnini's salt that precipitates in the reaction mixture avoiding organic solvent mediated purification steps to obtain the final aldehydes as pure compounds.
- Calamante, Massimo,Dei, Filippo,Maramai, Samuele,Migliorini, Francesca,Petricci, Elena
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p. 2794 - 2806
(2021/05/03)
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- Atomically dispersed Rh on hydroxyapatite as an effective catalyst for tandem hydroaminomethylation of olefins
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Tandem hydroaminomethylation is an efficient and green route for one-pot synthesis of amines directly from olefins. Herein, heterogeneous hydroxyapatite (HAP) supported single-atom Rh catalyst was prepared and used for tandem hydroaminomethylation of olefins. Characterization techniques confirmed the atomic dispersion of Rh species on HAP. Up to 99% conversion of 1-hexene with high selectivity to the desired amines (93.2%) was obtained over 0.5Rh1/HAP catalyst. Mechanism study demonstrated that the first hydroformylation step during the tandem catalytic process was rate-determining. Compared with the Rh nanoparticles on other oxide supports (Mg3Al, MgO and Al2O3), the atomically dispersed Rh sites on HAP ensured the high hydroformylation activity, thereby guaranteed the outstanding catalytic performance for the total tandem process. Furthermore, various corresponding amines can be obtained with satisfactory yields over 0.5Rh1/HAP catalyst from a wide scope of olefins or amines substrates.
- Gun, Gong,Li, Liusha,Li, Xiao,Lin, Tiejun,Qin, Tingting,Zhong, Liangshu
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- Expanding the Biocatalytic Toolbox with a New Type of ene/yne-Reductase from Cyclocybe aegerita
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This study introduces a new type of ene/yne-reductase from Cyclocybe aegerita with a broad substrate scope including aliphatic and aromatic alkenes/alkynes from which aliphatic C8-alkenones, C8-alkenals and aromatic nitroalkenes were the preferred substrates. By comparing alkenes and alkynes, a ~2-fold lower conversion towards alkynes was observed. Furthermore, it could be shown that the alkyne reduction proceeds via a slow reduction of the alkyne to the alkene followed by a rapid reduction to the corresponding alkane. An accumulation of the alkene was not observed. Moreover, a regioselective reduction of the double bond in α,β-position of α,β,γ,δ-unsaturated alkenals took place. This as well as the first biocatalytic reduction of different aliphatic and aromatic alkynes to alkanes underlines the novelty of this biocatalyst. Thus with this study on the new ene-reductase CaeEnR1, a promising substrate scope is disclosed that describes conceivably a broad occurrence of such reactions within the chemical landscape.
- Karrer, Dominik,Gand, Martin,Rühl, Martin
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p. 2191 - 2199
(2021/02/26)
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- Bio-derived nanosilica-anchored Cu(II)-organoselenium complex as an efficient retrievable catalyst for alcohol oxidation
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A new copper(II) complex supported onto rice-husk-derived nanosilica was prepared from 2,6-bis((phenylselanyl)methyl)pyridine, salicylaldehyde and copper acetate monohydrate, Cu(OAc)2·H2O. The as-synthesized complex Cu(II)SeNSe@imine-nanoSiO2 (Complex I) was extensively characterized with FT-IR, powder XRD, SEM-EDX, solid-state UV-Vis, ESR, XPS, TGA and BET surface area analysis. The catalytic activity of the complex was explored for alcohol oxidation reactions using H2O2 as oxidant and acetonitrile as solvent. For comparison, we have also prepared an analogous homogeneous catalyst (Complex II) and characterized it with FT-IR, UV-Vis, LC-MS and ESR analyses. Its catalytic activity was also screened to the same reaction. The immobilized catalyst showed better efficiency with 75%–95% isolated yield compared with the homogeneous one for alcohol oxidation with at least five times recyclability without profound loss in activity.
- Gogoi, Rajjyoti,Borah, Geetika
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- Synthesis of α,β-unsaturated epoxy ketones utilizing a bifunctional sulfonium/phosphonium ylide
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Herein, a new protocol for rapid synthesis of α,β-unsaturated epoxy ketones utilizing a bifunctional sulfonium/phosphonium ylide is described. This approach comprises two sequential chemoselective reactions between sulfonium and phosphonium ylides and two distinct aldehydes, which allows for the rapid construction of a variety of unsymmetric α,β-unsaturated epoxy ketones. This methodology allows the rapid construction of the core reactive functionality of a family of lipid peroxidation products, the epoxyketooctadecenoic acids, but can be further broadly utilized as a useful synthon for the synthesis of natural products, particularly those derived from oxidized fatty acids. Accordingly, a protocol utilizing this approach to synthesize the epoxyketooctadecenoic acid family of molecules is described.
- Eskandari, Roozbeh,Hess, Jeremy P.,Tochtrop, Gregory P.
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supporting information
p. 7136 - 7139
(2021/07/28)
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- Methyl-modified cage-type phosphorus ligand and preparation method thereof Preparation method and application thereof
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The invention discloses a methyl-modified cage-type phosphorus ligand, a preparation method and application thereof, in particular to a synthesis design, wherein methyl is further introduced on a phenyl ring of triphenylphosphine, and a methyl-modified cage-type phosphorus ligand is synthesized, and when a methyl meta-substituted cage-type phosphorus ligand is used as a hydroformylation reaction catalyst the proportion of n-structural aldehyde and isomeric aldehyde is 2.6. TOF-1 The methyl-substituted cage-type phosphorus ligand is excellent in performance, stable in property and recyclable, has excellent substrate applicability in the hydroformylation catalytic reaction, has a good industrial application prospect, and has very important significance in metal organic catalysis.
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Paragraph 0075-0084; 0087-0088
(2021/09/15)
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- Dibismuthanes in catalysis: From synthesis and characterization to redox behavior towards oxidative cleavage of 1,2-diols
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A family of aryl dinuclear bismuthane complexes has been successfully synthesized and characterized. The two bismuth centers are bonded to various xanthene-type backbones, which differ in ring-size and flexibility, resulting in complexes with different intramolecular Bi?Bi distances. Moreover, their pentavalent Bi(v) analogues have also been prepared and structurally characterized. Finally, the synergy between bismuth centers in catalysis has been studied by applying dinuclear bismuthanes5-8to the catalytic oxidative cleavage of 1,2-diols. Unfortunately, no synergistic effects were observed and the catalytic activities of dinuclear bismuthanes and triphenylbismuth are comparable.
- Magre, Marc,Kuziola, Jennifer,N?thling, Nils,Cornella, Josep
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supporting information
p. 4922 - 4929
(2021/06/16)
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- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
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As is well known, CO2 is an attractive renewable C1 resource and H2 is a cheap and clean reductant. Combining CO2 and H2 to prepare building blocks for high-value-added products is an attractive yet challenging topic in green chemistry. A general and selective rhodium-catalyzed hydroformylation of alkenes using CO2/H2 as a syngas surrogate is described here. With this protocol, the desired aldehydes can be obtained in up to 97% yield with 93/7 regioselectivity under mild reaction conditions (25 bar and 80 °C). The key to success is the use of a bifunctional Rh/PTA catalyst (PTA: 1,3,5-triaza-7-phosphaadamantane), which facilitates both CO2 hydrogenation and hydroformylation. Notably, monodentate PTA exhibited better activity and regioselectivity than common bidentate ligands, which might be ascribed to its built-in basic site and tris-chelated mode. Mechanistic studies indicate that the transformation proceeds through cascade steps, involving free HCOOH production through CO2 hydrogenation, fast release of CO, and rhodium-catalyzed conventional hydroformylation. Moreover, the unconventional hydroformylation pathway, in which HCOOAc acts as a direct C1 source, has also been proved to be feasible with superior regioselectivity to that of the CO pathway.
- Hua, Kaimin,Liu, Xiaofang,Wei, Baiyin,Shao, Zilong,Deng, Yuchao,Zhong, Liangshu,Wang, Hui,Sun, Yuhan
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supporting information
p. 8040 - 8046
(2021/11/01)
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- Insight into decomposition of formic acid to syngas required for Rh-catalyzed hydroformylation of olefins
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Formic acid (FA) is one kind of important bulk chemicals, which is recognized as a sustainable and eco-friendly energy carrier to transport H2 via dehydrogenation or CO via decarbonylation. Expectantly, FA upon decomposition into H2 and CO could be used as the syngas alternative for hydroformylation. In this paper, the behaviors of FA to release H2 as well as CO following the distinct pathways were carefully investigated for the first time, and then established a new hydroformylation protocol free of syngas. It was found that the atmospheric hydroformylation of olefins with formic acid (FA) as syngas alternative was smoothly fulfilled over Xantphos (L1) modified Rh-catalyst under mild conditions (80 °C, Rh concentration 1 mol %, 14 h), resulting in >90% conversion of the olefins along with the high selectivity to the target aldehydes (>93%). By using FA as syngas source, the side-reaction of olefin-hydrogenation was greatly depressed. The in situ FT-IR and the high-pressure 1H NMR spectroscopic analyses were applied to reveal how FA behaves dually as CO surrogate and hydrogen source over L1-Rh(acac)(CO)2 catalytic system, based on which the deeply insight into the catalytic mechanism of hydroformylation of olefins with FA as syngas alternative was offered.
- Liu, Lei,Chen, Xiao-Chao,Yang, Shu-Qing,Yao, Yin-Qing,Lu, Yong,Liu, Ye
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p. 406 - 415
(2020/12/07)
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- Reactive Species and Reaction Pathways for the Oxidative Cleavage of 4-Octene and Oleic Acid with H2O2over Tungsten Oxide Catalysts
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Oxidative cleavage of carbon-carbon double bonds (C-C) in alkenes and fatty acids produces aldehydes and acids valued as chemical intermediates. Solid tungsten oxide catalysts are low cost, nontoxic, and selective for the oxidative cleavage of C-C bonds with hydrogen peroxide (H2O2) and are, therefore, a promising option for continuous processes. Despite the relevance of these materials, the elementary steps involved and their sensitivity to the form of W sites present on surfaces have not been described. Here, we combine in situ spectroscopy and rate measurements to identify significant steps in the reaction and the reactive species present on the catalysts and examine differences between the kinetics of this reaction on isolated W atoms grafted to alumina and on those exposed on crystalline WO3 nanoparticles. Raman spectroscopy shows that W-peroxo complexes (W-(η2-O2)) formed from H2O2 react with alkenes in a kinetically relevant step to produce epoxides, which undergo hydrolysis at protic surface sites. Subsequently, the CH3CN solvent deprotonates diols to form alpha-hydroxy ketones that react to form aldehydes and water following nucleophilic attack of H2O2. Turnover rates for oxidative cleavage, determined by in situ site titrations, on WOx-Al2O3 are 75% greater than those on WO3 at standard conditions. These differences reflect the activation enthalpies (ΔH?) for the oxidative cleavage of 4-octene that are much lower than those for the isolated WOx sites (36 ± 3 and 60 ± 6 kJ·mol-1 for WOx-Al2O3 and WO3, respectively) and correlate strongly with the difference between the enthalpies of adsorption for epoxyoctane (ΔHads,epox), which resembles the transition state for epoxidation. The WOx-Al2O3 catalysts mediate oxidative cleavage of oleic acid with H2O2 following a mechanism comparable to that for the oxidative cleavage of 4-octene. The WO3 materials, however, form only the epoxide and do not cleave the C-C bond or produce aldehydes and acids. These differences reflect the distinct site requirements for these reaction pathways and indicate that acid sites required for diol formation are strongly inhibited by oleic acids and epoxides on WO3 whereas the Al2O3 support provides sites competent for this reaction and increase the yield of the oxidative cleavage products.
- Yun, Danim,Ayla, E. Zeynep,Bregante, Daniel T.,Flaherty, David W.
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p. 3137 - 3152
(2021/04/06)
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- The effect of the position of cross-linkers on the structure and microenvironment of PPh3moiety in porous organic polymers
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Three trivinyl functionalization triphenylphosphine (3vPPh3)-based porous organic ligands (3vPPh3-POLs) with cross-linkers in different positions were obtained through solvothermal polymerization. By simply changing the position of the cross-linkers (vinyl groups) attached to the PPh3monomer, the resulting porous organic polymer (POP) materials acquired diverse hierarchical porous structures, and the microenvironment of POPs was sequently regulated. Among the three 3vPPh3-POLs, the BET surface areas ranged from 168 to 1583 m2g?1, while the proportion of micropores changed from 0.0% to 52.0%. Benefiting from the unique structure, Rh ions could be coordinated and dispersed as a single site inm-3vPPh3-POL to form HRh(CO)2(PPh3-POL)2species, which endowed the Rh/m-3vPPh3-POL catalyst with an activity similar to that in the homogeneous system, anl/bratio (the ratio of the linear aldehyde to the branched aldehyde) approximately as high as 10, and stability for a duration of more than 500 h in the hydroformylation of 1-octene.
- Ji, Guangjun,Li, Cunyao,Xiao, Dong,Wang, Guoqing,Sun, Zhao,Jiang, Miao,Hou, Guangjin,Yan, Li,Ding, Yunjie
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p. 9165 - 9174
(2021/04/16)
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- Selective Production of Linear Aldehydes and Alcohols from Alkenes using Formic Acid as Syngas Surrogate
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Performing carbonylation without the use of carbon monoxide for high-value-added products is an attractive yet challenging topic in sustainable chemistry. Herein, effective methods for producing linear aldehydes or alcohols selectively with formic acid as both carbon monoxide and hydrogen source have been described. Linear-selective hydroformylation of alkenes proceeds smoothly with up to 88 % yield and >30 regioselectivity in the presence of single Rh catalyst. Strikingly, introducing Ru into the system, the dual Rh/Ru catalysts accomplish efficient and regioselective hydroxymethylation in one pot. The present processes utilizing formic acid as syngas surrogate operate simply under mild condition, which opens a sustainable way for production of linear aldehydes and alcohols without the need for gas cylinders and autoclaves. As formic acid can be readily produced via CO2 hydrogenation, the protocols represent indirect approaches for chemical valorization of CO2.
- Chen, Junjun,Hua, Kaimin,Liu, Xiaofang,Deng, Yuchao,Wei, Baiyin,Wang, Hui,Sun, Yuhan
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p. 9919 - 9924
(2021/05/31)
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- Directing Selectivity to Aldehydes, Alcohols, or Esters with Diphobane Ligands in Pd-Catalyzed Alkene Carbonylations
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Phenylene-bridged diphobane ligands with different substituents (CF3, H, OMe, (OMe)2, tBu) have been synthesized and applied as ligands in palladium-catalyzed carbonylation reactions of various alkenes. The performance of these ligands in terms of selectivity in hydroformylation versus alkoxycarbonylation has been studied using 1-hexene, 1-octene, and methyl pentenoates as substrates, and the results have been compared with the ethylene-bridged diphobane ligand (BCOPE). Hydroformylation of 1-octene in the protic solvent 2-ethyl hexanol results in a competition between hydroformylation and alkoxycarbonylation, whereby the phenylene-bridged ligands, in particular, the trifluoromethylphenylene-bridged diphobane L1 with an electron-withdrawing substituent, lead to ester products via alkoxycarbonylation, whereas BCOPE gives predominantly alcohol products (n-nonanol and isomers) via reductive hydroformylation. The preference of BCOPE for reductive hydroformylation is also seen in the hydroformylation of 1-hexene in diglyme as the solvent, producing heptanol as the major product, whereas phenylene-bridged ligands show much lower activities in this case. The phenylene-bridged ligands show excellent performance in the methoxycarbonylation of 1-octene to methyl nonanoate, significantly better than BCOPE, the opposite trend seen in hydroformylation activity with these ligands. Studies on the hydroformylation of functionalized alkenes such as 4-methyl pentenoate with phenylene-bridged ligands versus BCOPE showed that also in this case, BCOPE directs product selectivity toward alcohols, while phenylene-bridge diphobane L2 favors aldehyde formation. In addition to ligand effects, product selectivities are also determined by the nature and the amount of the acid cocatalyst used, which can affect substrate and aldehyde hydrogenation as well as double bond isomerization.
- Aitipamula, Srinivasulu,Britovsek, George J. P.,Nobbs, James D.,Tay, Dillon W. P.,Van Meurs, Martin
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p. 1914 - 1925
(2021/06/28)
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- Iron-Catalyzed C-C Single-Bond Cleavage of Alcohols
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An iron-catalyzed deconstruction/hydrogenation reaction of alcohols through C-C bond cleavage is developed through photocatalysis, to produce ketones or aldehydes as the products. Tertiary, secondary, and primary alcohols bearing a wide range of substituents are suitable substrates. Complex natural alcohols can also perform the transformation selectively. A investigation of the mechanism reveals a procedure that involves chlorine radical improved O-H homolysis, with the assistance of 2,4,6-collidine.
- Liu, Wei,Wu, Qiang,Wang, Miao,Huang, Yahao,Hu, Peng
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supporting information
p. 8413 - 8418
(2021/11/01)
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- Direct oxidative carboxylation of terminal olefins to cyclic carbonates by tungstate assisted-tandem catalysis
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Tungstate catalysts are well established for olefin epoxidation reactions, while their catalytic activity for CO2 insertion in epoxides is a more recent discovery. This dual reactivity of tungstate prompted the present development of a catalytic tandem process for the direct conversion of olefins into the corresponding cyclic organic carbonates (COCs). Each of the two steps was studied in the presence of the ammonium tungstate ionic liquid catalyst-[N8,8,8,1]2[WO4]-obtained via a benign procedure starting from ammonium methylcarbonate ionic liquids. The catalytic epoxidation first step was optimised on 1-decene as model substrate, using H2O2 as benign oxidant, [N8,8,8,1]2[WO4] as catalyst and phosphoric acid as promoter affording quantitative conversion with 92% selectivity towards decene oxide. Unfortunately, the addition of CO2 from the start (auto-tandem catalysis) gave low yields of decene carbonate (10%). On the contrary, the addition of 1 atm CO2 and tetrabutyl ammonium iodide after completion of the epoxidation first step without any intermediate work-up (assisted-tandem catalysis) afforded a 94% yield in decene carbonate. The protocol could be scaled up to a 10 gram scale. The scope of the reaction was demonstrated for primary aliphatic olefins with different alkyl chain lengths (C6-C16), while cyclic and aromatic activated olefins such as cyclohexene and styrene suffered from the formation of undesired overoxidation products in the first step.
- Calmanti, Roberto,Perosa, Alvise,Selva, Maurizio
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p. 7609 - 7619
(2021/10/12)
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- Rh-catalyzed highly regioselective hydroformylation to linear aldehydes by employing porous organic polymer as a ligand
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In this work, we developed a new structural porous organic polymer containing biphosphoramidite unit, which can be used as a solid bidentate phosphorous ligand for rhodium-catalyzed solvent-free higher olefins hydroformylation. The resultant catalyst demonstrated unprecedently high regioselectivity to linear aldehydes and could be readily recovered for successive reuses with good stability in both catalytic activity and regioselectivity. This journal is
- Wang, Zhaozhan,Yang, Yong
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p. 29263 - 29267
(2020/10/06)
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- Bimetallic Paddlewheel-type Dirhodium(II,II) Acetate and Formamidinate Complexes: Synthesis, Structure, Electrochemistry, and Hydroformylation Activity
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Classical hydroformylation catalysts use mononuclear rhodium(I) complexes as precursors; however, very few examples of bimetallic systems have been reported. Herein, we report fully substituted dirhodium(II,II) complexes (C1-C6) containing acetate and diphenylformamidinate bridging ligands (L1-L4). The structure and geometry around these paddlewheel-type, bimetallic cores were confirmed by single-crystal X-ray diffraction. The complexes C3-C6 show electrochemical redox reactions, with the expected reduction (Rh24+/3+) and two oxidation (Rh24+/5+ and Rh25+/6+) electron transfer processes. Furthermore, the bimetallic complexes were evaluated as catalyst precursors for the hydroformylation of 1-octene, with the acetate-containing complexes (C1 and C2) showing near quantitative conversion (>99%) of 1-octene, excellent activity and chemoselectivity toward aldehydes (>98%), with moderate regioselectivity toward linear products. Replacement of the acetate with diphenylformamidinate ligands (complexes C3-C6) yielded moderate-to-good chemoselectivity and regioselectivity, favoring linear aldehydes.
- Casimiro, Anna,De Doncker, Stephen,Kotze, Izak A.,Ngubane, Siyabonga,Smith, Gregory S.
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p. 12928 - 12940
(2020/09/15)
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- Hydroformylation of higher olefins in aqueous biphasic medium using rhodium-sulfoxantphos catalyst: Activity and selectivity study
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Hydroformylation of higher olefins such as 1-hexene, 1-octene, 1-decene and 1-dodecene has been studied in an aqueous biphasic medium using water-soluble Rh-sulfoxantphos complex catalyst. The effect of temperature, presence of various co-solvents and concentration of co-solvent on the reaction rate and chemo and regioselectivity was investigated. N-Methyl pyrrolidone (NMP) was found to be the best co-solvent, which enhances the rate dramatically (4-96 fold) as compared to the reactions in aqueous-organic biphasic medium for hydroformylation of higher olefins. Catalyst recycle study was performed to check the leaching of metal in organic phase.
- Pagar, Nitin S.,Deshpande, Raj M.
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p. 2061 - 2066
(2020/09/01)
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- One-pot synthesis of aldoximes from alkenes: Via Rh-catalysed hydroformylation in an aqueous solvent system
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Aldoxime synthesis directly starting from alkenes was successfully achieved through the combination of hydroformylation and subsequent condensation of the aldehyde intermediate with aqueous hydroxylamine in a one-pot process. The metal complex Rh(acac)(CO)2 and the water-soluble ligand sulfoxantphos were used as the catalyst system, providing high regioselectivities in the initial hydroformylation. A mixture of water and 1-butanol was used as an environmentally benign solvent system, ensuring sufficient contact of the aqueous catalyst phase and the organic substrate phase. The reaction conditions were systematically optimised by Design of Experiments (DoE) using 1-octene as a model substrate. A yield of 85% of the desired linear, terminal aldoxime ((E/Z)-nonanal oxime) at 95% regioselectivity was achieved. Other terminal alkenes were also converted successfully under the optimised conditions to the corresponding linear aldoximes, including renewable substrates. Differences of the reaction rate have been investigated by recording the gas consumption, whereby turnover frequencies (TOFs) >2000 h-1 were observed for 4-vinylcyclohexene and styrene, respectively. The high potential of aldoximes as platform intermediates was shown by their subsequent transformation into the corresponding linear nitriles using aldoxime dehydratases as biocatalysts. The overall reaction sequence thus allows for a straightforward synthesis of linear nitriles from alkenes with water being the only by-product, which formally represents an anti-Markovnikov hydrocyanation of readily available 1-alkenes.
- Gr?ger, H.,Guntermann, A.,Hinzmann, A.,Jolmes, T.,Panke, D.,Plass, C.,R?sler, J.,Seidensticker, T.,Terhorst, M.,Vogt, D.,Vorholt, A. J.
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supporting information
p. 7974 - 7982
(2020/11/30)
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- Catalytic Selective Oxidation of Primary and Secondary Alcohols Using Nonheme [Iron(III)(Pyridine-Containing Ligand)] Complexes
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The selective oxidation of different primary and secondary alcohols to carbonyl compounds by hydrogen peroxide was found to be catalyzed in conversion ranging from good to excellent by an iron(III) complex of a pyridine-containing macrocyclic ligand (Pc-L), without the need of any additive. The choice of the counteranion (Cl, Br, OTf) appeared to be of fundamental importance and the best results in terms of selectivity (up to 99 %) and conversion (up to 98 %) were obtained using the well-characterized [Fe(III)(Br)2(Pc-L)]Br complex, 4c. Magnetic moments in solid-state, also confirmed in solution ([D6]DMSO) by Evans NMR method, were calculated and point out to an iron metal center in the high spin state of 5/2. The crystal structure shows that the iron(III) center is coordinated by the four nitrogen atoms of the macrocycle and two bromide anions to form a distorted octahedral coordination environment. The catalytic oxidation of benzyl alcohol in acetonitrile was found occurring with better conversions and selectivities than in other solvents. The reaction proved to be quite general, tolerating aromatic and aliphatic alcohols, although very low yields were obtained for terminal aliphatic alcohols. Preliminary mechanistic studies are in agreement with a catalytic cycle promoted by a high-spin iron complex.
- Caselli, Alessandro,Gallo, Emma,Panza, Nicola,Rizzato, Silvia,Tseberlidis, Giorgio,di Biase, Armando
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supporting information
p. 6635 - 6644
(2020/10/30)
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- Donor-Flexible Bis(pyridylidene amide) Ligands for Highly Efficient Ruthenium-Catalyzed Olefin Oxidation
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An exceptionally efficient ruthenium-based catalyst for olefin oxidation has been designed by exploiting N,N′-bis(pyridylidene)oxalamide (bisPYA) as a donor-flexible ligand. The dynamic donor ability of the bisPYA ligand, imparted by variable zwitterionic and neutral resonance structure contributions, paired with the redox activity of ruthenium provided catalytic activity for Lemieux–Johnson-type oxidative cleavage of olefins to efficiently prepare ketones and aldehydes. The ruthenium bisPYA complex significantly outperforms state-of-the-art systems and displays extraordinary catalytic activity in this oxidation, reaching turnover frequencies of 650 000 h?1 and turnover numbers of several millions.
- Albrecht, Martin,Salzmann, Kevin,Segarra, Candela
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supporting information
p. 8932 - 8936
(2020/04/22)
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- In-Situ generation of surface-active HCo(CO)y like intermediate from gold supported on ion-promoted Co3O4 for induced hydroformylation-hydrogenation of alkenes to alcohols
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In this study, a greener and stable surface-active cobalt-carbonyl like specie [HCo(CO)y] was generated via H2 and CO spillover by gold on ion-promoted cobalt oxide. The supports and catalysts syntheses were based on inverse micelle and deposition-precipitation methods, respectively. The temperature-programmed reduction was used for optimization to obtain the best supports. The catalysts with activity (Co3O4 3O4 3O4 and Au loadings 10 percent 3O4 catalyst more active than the others and displayed excellent alcohol chemoselectivity with varying regioselectivity under milder reaction conditions. The reaction was assumed to take place via the formation of [HCo(CO)y] specie, as the active catalytic site of the catalyst. The enhanced catalytic performance was also ascribed to the low-temperature reducibility and surface basicity of the nanomaterials. The stability of the catalyst was evaluated by recycling, with its mesostructure retained after four cycles.
- Akinnawo, Christianah A.,Meijboom, Reinout,Mogudi, Batsile M.,Oseghale, Charles O.
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- Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
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Aliphatic aldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphatic aldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon less homologous carbonyl compounds, the reduction of the same key intermediates followed by an oxidation produced one-carbon more homologous carbonyl compounds.
- Yoo, Jae Won,Seo, Youngran,Park, Jong Beom,Kim, Young Gyu
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- Supramolecular Catalysis of the oxa-Pictet–Spengler Reaction with an Endohedrally Functionalized Self-Assembled Cage Complex
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An endohedrally functionalized self-assembled Fe4L6 cage complex can catalyze oxa-Pictet—Spengler cyclizations of tryptophols and various aldehyde derivatives, showing strong rate accelerations and size-selectivity. Selective molecular recognition of substrates controls the reactivity, and the cage is capable of binding and activating multiple different species along the multistep reaction pathway. The combination of a functionalized active site, size-selective reactivity, and multistep activation, all from a single host molecule, illustrates the biomimetic nature of the catalysis.
- Harman, W. Hill,Hooley, Richard J.,Ngai, Courtney,Sanchez-Marsetti, Colomba M.
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supporting information
p. 23505 - 23509
(2020/10/21)
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- Boosting the hydrolytic stability of phosphite ligand in hydroformylation by the construction of superhydrophobic porous framework
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The development of a catalyst that delivers high activities and selectivities with excellent durability is of great importance. Numerous efficient catalysts suffer from the inherent hydrolysis liabilities, plaguing their practical applications. Herein, we show that this challenge can be tackled by constructing them into superhydrophobic porous frameworks, as exemplified by a water-sensitive phosphite ligand, tris(2-tert-butylphenyl) phosphite. The efficiency and long-term stability of the developed system are remarkably high in the hydroformylation of internal olefins after metalation with Rh species, superior to the corresponding homogeneous analogues. The significantly boosted hydrolytic stability allows for catalytic transformations using water as a green solvent, which not only facilitates the isolation of the products, but also furnishes the aldehydes with higher regioselectivities for the desired linear form in comparison with that operated under benchmark conditions using toluene as a reaction medium. Given these promising results, we anticipate the strategy advanced herein will form the basis for constructive perspectives in the enhancement of the water resistance of catalysts and the development of high performance hydroformylation catalysts.
- Tang, Yongquan,Dong, Ke,Wang, Sai,Sun, Qi,Meng, Xiangju,Xiao, Feng-Shou
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- HYDROFORMYLATION METHOD AND CATALYST USING RHODIUM-RUTHENIUM DUAL METAL AND TETRADENTATE PHOSPHINE LIGAND
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A homogeneous catalytic reaction method and a catalyst for isomerization and hydroformylation of long-chain internal olefins are disclosed. A rhodium-ruthenium metal complex is used as a catalyst; and the ligands are tetradentate phosphine ligands. By means of the catalytic system, homogeneous internal olefin isomerization aid hydroformylation can be performed under a certain temperature and pressure to obtain aldehyde products having high normal to iso ratios. The present invention is applicable to not only long-chain internal olefins (≥C8) but also internal olefins having a carbon number less than 8.
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Paragraph 0033-0035; 0036-0038; 0039-0041; 0044
(2019/11/19)
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- A new air-stable and reusable tetraphosphine ligand for rhodium-catalyzed hydroformylation of terminal olefins at low temperature
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Tetraphosphine and bisphosphine ligands were synthesized, characterized and employed in Rh-catalyzed hydroformylation of 1-octene and 1-hexene. Conversion of over 97.7% and aldehyde yield of 94.1% were achieved at 60°C, 20?bar. This remarkable performance could also be retained at lower temperature (i.e. 40°C) by prolonging the reaction time. The tetraphosphine ligand-modified Rh catalyst could be reused for at least seven successive runs with catalytic activity and selectivity almost unchanged; the catalyst was separated from the products and recycled directly in homogeneous hydroformylation, indicating that the catalyst might have good stability. 31P NMR and high-resolution mass spectral characterization hinted that the reason for the reusability of the catalyst might be that the tetraphosphine ligand is relatively air-stable and is probably slowly oxidized during the recycling runs. The tetraphosphine ligand has four phosphorus atoms to be partially oxidized and could still coordinate with the Rh center via the unoxidized phosphorus atoms to stabilize the catalyst, based on the multiple chelating modes of the tetraphosphine ligand. Hence, the catalytic activity and selectivity could be retained for a certain number of runs.
- Zhou, Fanding,Zhang, Lin,Wu, Qianhui,Guo, Fuya,Tang, Songbai,Xu, Bin,Yuan, Maolin,Fu, Haiyan,Li, Ruixiang,Zheng, Xueli,Chen, Hua
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- Encapsulated liquid nano-droplets for efficient and selective biphasic hydroformylation of long-chain alkenes
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Aqueous nano-droplets of homogeneous Rh-TPPTS catalyst encapsulated within the cavity of hollow silica nanospheres were fabricated for biphasic hydroformylation of long-chain alkenes, which showed significant reaction rate enhancement effects and improved aldehyde selectivity.
- Zhang, Xiaoli,Wei, Juan,Zhang, Xiaoming
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supporting information
p. 14134 - 14138
(2019/09/18)
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- Olefin hydroformylation and kinetic studies using mono- and trinuclear N,O-chelate rhodium(I)-aryl ether precatalysts
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Rh(I)-salicylaldimine-triazole mononuclear (6) and trinuclear (7) complexes based on an aryl-ether scaffold were investigated as precatalysts in the rhodium-catalysed hydroformylation of the terminal olefin, 1-octene, and internal olefins, 7-tetradecene and 4-octene. The complexes generally show good catalytic activity in the hydroformylation of 1-octene at temperatures ranging from 75 °C to 95 °C and syngas pressures of 20 to 40 bar. The precatalysts have excellent stability and could be reused several times using organic solvent nanofiltration under optimum conditions of 85 °C and 40 bar. Kinetic studies using catalyst precursor 6 were investigated by evaluating the effect of temperature, syngas total pressure and catalyst loading on the rate of hydroformylation. The activation energy for the hydroformylation of 1-octene was calculated to be 62 kJ mol?1 and the experimental rate constants were found to be in good agreement with the predicted rate data obtained using a modified fundamental mechanism-based rate model.
- Siangwata, Shepherd,Breckwoldt, Nicholas C.C.,Goosen, Neill J.,Smith, Gregory S.
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- Metal-free mechanochemical oxidations in Ertalyte jars
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The authors acknowledge Form-Tech Scientific for the loan of the FTS-1000 Shaker Mill apparatus (Form-Tech Scientific, Canada, https://formtechscientific.com/). Authors are grateful to MIUR (Italy, PRIN project: multifunctional polymer composites based on grown materials). A. P. is grateful to MIUR for “Finanziamento delle Attività Base di Ricerca (FABR 2017)“.
- Porcheddu, Andrea,Delogu, Francesco,De Luca, Lidia,Fattuoni, Claudia,Colacino, Evelina
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supporting information
p. 1786 - 1794
(2019/08/07)
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- Copper Nanoparticles Immobilized on Nanocellulose: A Novel and Efficient Heterogeneous Catalyst for Controlled and Selective Oxidation of Sulfides and Alcohols
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In this work, we have described the versatility of low metal loading copper nanoparticles immobilized on nanocellulose for the controlled and selective oxidation of sulfides to sulfoxides and primary alcohols to aldehydes using green oxidant at room temperature. Aromatic, aliphatic and heterocyclic sulfides were oxidized to their corresponding sulfoxides with high yields without formation of over oxidized sulfones. Similarly, benzylic, allylic and aliphatic alcohols were selectively oxidized to aldehydes without traces of carboxylic acids in good to excellent yields.
- Dutta, Apurba,Chetia, Mitali,Ali, Abdul A.,Bordoloi, Ankur,Gehlot, Praveen S.,Kumar, Arvind,Sarma, Diganta
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p. 141 - 150
(2018/12/13)
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- An Engineered Alcohol Oxidase for the Oxidation of Primary Alcohols
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Structure-guided directed evolution of choline oxidase has been carried out by using the oxidation of hexan-1-ol to hexanal as the target reaction. A six-amino-acid variant was identified with a 20-fold increased kcat compared to that of the wild-type enzyme. This variant enabled the oxidation of 10 mm hexanol to hexanal in less than 24 h with 100 % conversion. Furthermore, this variant showed a marked increase in thermostability with a corresponding increase in Tm of 20 °C. Improved solvent tolerance was demonstrated with organic solvents including ethyl acetate, heptane and cyclohexane, thereby enabling improved conversions to the aldehyde by up to 30 % above conversion for the solvent-free system. Despite the evolution of choline oxidase towards hexan-1-ol, this new variant also showed increased specific activities (by up to 100-fold) for around 50 primary aliphatic, unsaturated, branched, cyclic, benzylic and halogenated alcohols.
- Heath, Rachel S.,Birmingham, William R.,Thompson, Matthew P.,Taglieber, Andreas,Daviet, Laurent,Turner, Nicholas J.
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p. 276 - 281
(2019/01/04)
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- Solid Base Bi24O31Br10(OH)δ with Active Lattice Oxygen for the Efficient Photo-Oxidation of Primary Alcohols to Aldehydes
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The selective oxidation of primary alcohols to aldehydes by O2 instead of stoichiometric oxidants (for example, MnVII, CrVI, and OsIV) is an important but challenging process. Most heterogeneous catalytic systems (thermal and photocatalysis) require noble metals or harsh reaction conditions. Here we show that the Bi24O31Br10(OH)δ photocatalyst is very efficient in the selective oxidation of a series of aliphatic (carbon chain from C1 to C10) and aromatic alcohols to their corresponding aldehydes/ketones under visible-light irradiation in air at room temperature, which would be challenging for conventional thermal and light-driven processes. High quantum efficiencies (71 % and 55 % under 410 and 450 nm irradiation) are reached in a representative reaction, the oxidation of isopropanol. We propose that the outstanding performance of the Bi24O31Br10(OH)δ photocatalyst is associated with basic surface sites and active lattice oxygen that boost the dehydrogenation step in the photo-oxidation of alcohols.
- Dai, Yitao,Ren, Pengju,Li, Yaru,Lv, Dongdong,Shen, Yanbin,Li, Yongwang,Niemantsverdriet, Hans,Besenbacher, Flemming,Xiang, Hongwei,Hao, Weichang,Lock, Nina,Wen, Xiaodong,Lewis, James P.,Su, Ren
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p. 6265 - 6270
(2019/03/07)
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- Tandem IBX-Promoted Primary Alcohol Oxidation/Opening of Intermediate β,γ-Diolcarbonate Aldehydes to (E)-γ-Hydroxy-α,β-enals
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A tandem IBX-promoted oxidation of primary alcohol to aldehyde and opening of intermediate β,γ-diolcarbonate aldehyde to (E)-γ-hydroxy-α,β-enal has been developed. Remarkably, the carbonate opening delivered exclusively (E)-olefin and no over-oxidation of γ-hydroxy was observed. The method developed has been extended to complete the stereoselective total synthesis of both (S)- and (R)-coriolides and d-xylo- and d-arabino-C-20 guggultetrols.
- Kumari, Anupama,Gholap, Sachin P.,Fernandes, Rodney A.
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p. 2278 - 2290
(2019/06/17)
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- CO2-switchable Pickering emulsions: Efficient and tunable interfacial catalysis for alcohol oxidation in biphasic systems
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CO2-responsive Pickering emulsions were fabricated on the basis of polymeric nanoaggregates with adjustable surface wettability. The static Pickering emulsion system provides an efficient and sustainable platform for in situ separation and reuse of catalysts in biphasic reactions.
- Tang, Jun,Cao, Shixiong,Wang, Jianli
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supporting information
p. 11079 - 11082
(2019/09/20)
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- Valorization of Methyl Azelaaldehydate – A Vegetable Oil Based Platform Molecule for the Synthesis of Monomers through Stetter Reaction
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The valorization of vegetable oil-derived methyl azelaaldehydate (methyl 9-oxo-nonanoate) to monomers was studied through NHC-catalysed Stetter reaction. Among the Michael acceptors tested, dimethyl fumarate gave the highest selectivity (97 %) for the corresponding Stetter adduct, thus limiting the competing benzoin condensation.
- Charvieux, Aubin,Duc Vu, Nam,Duguet, Nicolas,Lemaire, Marc
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supporting information
p. 1251 - 1256
(2019/01/24)
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- Method for preparing nonanal by selective oxidation of erucic acid or ester thereof
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A method for preparing nonanal by selective oxidation of erucic acid or ester thereof is disclosed. A catalyst is a manganese complex of an isosteviol derivative. The method comprises the steps of: adding a solvent, erucic acid or an ester thereof, the catalyst and a cocatalyst to a reaction vessel, introducing oxygen, keeping the pressure of the reaction vessel at 0.2 to 0.7 MPa, the reaction temperature at 100 to 170 DEG C and the reaction time of 60 to 300 minutes, so as to obtain nonanal. Compared with the prior art, free radicals generated by decomposition of the co-catalyst tert-butyl hydroperoxide reacts with oxygen to form oxygen free radicals, the catalyst, that is, the manganese complex of the isosteviol derivative acts with a double bond of erucic acid or ester thereof to enablethe double bond to have higher reactivity, and the activated double bond reacts with the oxygen free radicals to form nonanal. The method of the invention is mild in reaction conditions, friendly toenvironment, good in nonanal selectivity and high in yield.
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Paragraph 0036; 0048; 0051
(2019/04/18)
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- Gem-Dialkyl Effect in Diphosphine Ligands: Synthesis, Coordination Behavior, and Application in Pd-Catalyzed Hydroformylation
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A series of palladium complexes with C3-bridged bidentate bis(diphenylphosphino)propane ligands with substituents of varying steric bulk at the central carbon have been synthesized. The size of the gem-dialkyl substituents affects the C-C-C bond angles within the ligands and consequently the P-M-P ligand bite angles. A combination of solid-state X-ray diffraction (XRD) and density functional theory (DFT) studies has shown that an increase in substituent size results in a distortion of the 6-membered metal-ligand chair conformation toward a boat conformation, to avoid bond angle strain. The influence of the gem-dialkyl effect on the catalytic performance of the complexes in palladium-catalyzed hydroformylation of 1-octene has been investigated. While hydroformylation activity to nonanal decreases with increasing size of the gem-dialkyl substituents, a change in chemoselectivity toward nonanol via reductive hydroformylation is observed.
- Aitipamula, Srinivasulu,Britovsek, George J. P.,Nobbs, James D.,Romain, Charles,Tay, Dillon W. P.,Van Meurs, Martin,White, Andrew J. P.
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p. 663 - 671
(2020/01/02)
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- A Redox Strategy for Light-Driven, Out-of-Equilibrium Isomerizations and Application to Catalytic C-C Bond Cleavage Reactions
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We report a general protocol for the light-driven isomerization of cyclic aliphatic alcohols to linear carbonyl compounds. These reactions proceed via proton-coupled electron-transfer activation of alcohol O-H bonds followed by subsequent C-C β-scission of the resulting alkoxy radical intermediates. In many cases, these redox-neutral isomerizations proceed in opposition to a significant energetic gradient, yielding products that are less thermodynamically stable than the starting materials. A mechanism is presented to rationalize this out-of-equilibrium behavior that may serve as a model for the design of other contrathermodynamic transformations driven by excited-state redox events.
- Ota, Eisuke,Wang, Huaiju,Frye, Nils Lennart,Knowles, Robert R.
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supporting information
p. 1457 - 1462
(2019/01/25)
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- Biocatalytic N-Alkylation of Amines Using Either Primary Alcohols or Carboxylic Acids via Reductive Aminase Cascades
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The alkylation of amines with either alcohols or carboxylic acids represents a mild and safe alternative to the use of genotoxic alkyl halides and sulfonate esters. Here we report two complementary one-pot systems in which the reductive aminase (RedAm) from Aspergillus oryzae is combined with either (i) a 1° alcohol/alcohol oxidase (AO) or (ii) carboxylic acid/carboxylic acid reductase (CAR) to affect N-alkylation reactions. The application of both approaches has been exemplified with respect to substrate scope and also preparative scale synthesis. These new biocatalytic methods address issues facing alternative traditional synthetic protocols such as harsh conditions, overalkylation and complicated workup procedures.
- Ramsden, Jeremy I.,Heath, Rachel S.,Derrington, Sasha R.,Montgomery, Sarah L.,Mangas-Sanchez, Juan,Mulholland, Keith R.,Turner, Nicholas J.
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p. 1201 - 1206
(2019/01/21)
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- Anisole: A further step to sustainable hydroformylation
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Hydroformylation, also known as the "oxo" process, is a major industrial process that employs rhodium or cobalt catalysts in solution; therefore the solvent of this process is a critical issue for its sustainability. Although several innovative solutions have been proposed recently, traditional fossil-derived solvents dominate the scenario for this reaction. In this paper, we studied a series of solvents considered more sustainable in recent ranks in the hydroformylation of a series of olefins. Anisole, a solvent with an impressive sustainability rank and very scarcely exploited in hydroformylation, proved to be an excellent alternative for this reaction.
- Delolo, Fábio G.,Dos Santos, Eduardo N.,Gusevskaya, Elena V.
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supporting information
p. 1091 - 1098
(2019/03/12)
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- Integration of phosphine ligands and ionic liquids both in structure and properties-a new strategy for separation, recovery, and recycling of homogeneous catalyst
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The major limitation of classic biphasic ionic liquid (IL) catalysis is the heavy use of solvent ILs, which not only violates green chemistry principles but also even worsens catalytic efficiency. So it has always been a challenge finding ways to use ILs more efficiently, economically, and greenly to construct highly effective and long term stable IL catalytic systems. In this work, we synthesized a class of room temperature phosphine-functionalized polyether guanidinium ionic liquids (RTP-PolyGILs) by a convenient ion exchange reaction of polyether guanidinium ionic liquids (PolyGILs) with phosphine-sulfonate ligands based on the concept of the integration of both the phosphine ligand and IL. The resulting RTP-PolyGILs existed as liquids at room temperature and possessed dual functions of both the phosphine ligand and solvent IL; therefore they could both form catalysts by complexing with transition metals and act as catalyst carriers, thus achieving the integration of phosphine ligands with ILs both in structure and properties. Based on the unique properties of these multi-functional integrated RTP-PolyGILs, we constructed a highly effective homogeneous catalysis-biphasic separation (HCBS) system for Rh-catalyzed hydroformylation of higher olefins using only a catalytic amount of RTP-PolyGILs (equivalent to 0.025-0.4 mol% of 1-alkenes). Our HCBS system could be flexibly regulated with regard to catalytic performance (activity and linear selectivity) by changing the structure or type of the sulfonated ligand anion on RTP-PolyGILs. Specifically, it presented a TOF value of 3000-26000 h-1 and a linear selectivity of 68%-98% (corresponding to the l/b ratio of 2.2-37.5) with a total turnover number (TTON) of 11000-45000 and an extremely low Rh leaching of only 0.02-0.4 ppm. Therefore, the HCBS system can effectively combine the advantages of both homogeneous (high activity and good selectivity) and biphasic catalysis (easy catalyst separation). We additionally extended the application of the HCBS system to the hydrogenation of olefins to demonstrate the universality of the RTP-PolyGILs in catalytic reactions.
- Jin, Xin,Feng, Jianying,Song, Hongbing,Yao, Jiajun,Ma, Qingqing,Zhang, Mei,Yu, Cong,Li, Shumei,Yu, Shitao
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p. 3583 - 3596
(2019/07/10)
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