- Nickelocene-Lithium Aluminium Hydride, A New Effective Desulphurization Reagent
-
The carbon-sulphur bonds in thiols, sulphides, and thioacetals are reductively cleaved by nickelocene-lithium aluminium hydride.
- Chan, Man-Chor,Cheng, Kwok-Man,Li, Man Kong,Luh, Tien-Yau
-
-
Read Online
- REACTIONS OF ATOMIC MAGNESIUM IN THE BASIC STATE WITH ORGANIC CHLORINE DERIVATIVES AT LOW TEMPERATURES
-
Low-temperature solid-phase reactions of atomic magnesium in the basic state with a number of aliphatic monochlorine derivatives, chlorobenzene, carbon tetrachloride and 1,2-dichloroethane, have been investigated.The nature of the intermediate particles is discussed, the effect of the phase state of a frozen hydrocarbon on its reactivity examined, and the mechanisms of reactions with the participation of radicals and ion radicals proposed.
- Sergeev, G. B.,Smirnov, V. V.,Zagorsky, V. V.
-
-
Read Online
- Regioselective hydrogenation of alkenes over Pt-loaded zeolite BEA
-
The hydrogenation of dec-1-ene and of (E)-dec-5-ene has been studied over platinum/Na-BEA and non-zeolitic platinum catalysts. Provided that the solvent does not compete with the substrates for sorption in the zeolite, and that the external surface platinum is deactivated with a bulky phosphine, dec-1-ene is hydrogenated 18 times faster than (E)-dec-5-ene, whereas the ratio is only ca. 2 for platinum on non-microporous supports. This regioselectivity is explained by steric constraints imposed by the microporous structure of the zeolite. The hydrogenation rate over platinum/Na-BEA is much lower than that observed over the amorphous supported platinum catalysts; further, for the zeolite-based catalyst, approximately first-order kinetics are found compared with zero-order for the amorphous catalysts. Both effects can be explained in terms of alkene coverage of the Pt sites in the two types of catalyst.
- Creyghton, Edward J.,Grotenbreg, Robert A. W.,Downing, Roger S.,Van Bekkum, Herman
-
-
Read Online
- Catalytic Hydrogenation of Alkenes Using Zirconocene-Alkene Complexes
-
Hydrogenation reactions of alkenes were catalyzed by zirconium-alkene complex derivatives which were prepared from Cp2ZrCl2 (Cp = η5-C5H5) and n equiv. of RR'CHCH2M (M = MgX or Li).By the use of three or more equiv. of EtMgBr relative to Cp2ZrCl2, the product yield of hydrogenation of 1-decene was remarkably improved most likely due to the stabilization of the Zr(II) species.
- Takahashi, Tamotsu,Suzuki, Noriyuki,Kageyama, Motohiro,Nitto, Yu,Saburi, Masahiko,Negishi, Ei-ichi
-
-
Read Online
- Sono-emulsion electrosynthesis: Electrode-insensitive Kolbe reactions
-
The electro-oxidation of water-immiscible liquid aliphatic acids (RCO2H) leading to decarboxylation to afford a hyrocarbon (R-R) may be achieved using an emulsion formed via insonation so that the organic phase continuously extracts the products; in complete contrast to conventional monophasic electrolyses, the type and yield of products obtained from this biphasic Kolbe electrolysis are independent of the electrode material used.
- Wadhawan,Marken,Compton,Bull,Davies
-
-
Read Online
- Tripyrrolidinophosphoric acid triamide as an activator in samarium diiodide reductions
-
The electrochemical and spectrophotometric characterization of the complex formed from samarium diiodide and 4 equiv of tripyrrolidinophosphoric acid triamide (TPPA) is presented. Kinetic studies indicate that the SmI 2/TPPA complex possesses reactivity greater than the complex formed between samarium diiodide and 4 equiv of HMPA. Examples of the use of SmI 2/TPPA in synthesis are presented.
- McDonald, Chriss E.,Ramsey, Jeremy D.,Sampsell, David G.,Butler, Julie A.,Cecchini, Michael R.
-
-
Read Online
- Direct Iodination of Alkanes
-
(Matrix presented) A cheap and efficient iodination of hydrocarbons can be achieved by generating tert-butyl hypoiodite from iodine and sodium tert-butoxide. The alkane is reactant and solvent, and this metal-free process provides a clean solution for their direct iodination.
- Montoro, Raul,Wirth, Thomas
-
-
Read Online
- Fischer-Tropsch synthesis: effect of ammonia on product selectivities for a Pt promoted Co/alumina catalyst
-
The effects of co-fed ammonia in synthesis gas on the activity and product selectivities of a typical cobalt catalyst (0.5% Pt-25% Co/Al2O3) were investigated during the Fischer-Tropsch synthesis using a continuously stirred tank reactor (CSTR). The product selectivities were compared at a similar CO conversion level for various concentrations (10-1000 ppmv) of ammonia, as well as clean (un-poisoned) conditions. The addition of 10-1000 ppmv ammonia (concentration of ammonia with respect to the syngas feed) significantly decreased activity; the percentage of deactivation was similar (～40%) for the various concentrations of ammonia used. At similar CO conversions, the addition of ammonia caused an increase in olefin selectivity and the corresponding paraffin and alcohol selectivities were decreased compared to the ammonia free synthesis conditions. Olefin selectivity increased with increasing concentration of ammonia, and the paraffin and alcohol selectivities were decreased with increasing ammonia concentration. At similar CO conversions, ammonia addition exhibited a positive effect on hydrocarbon selectivity (i.e., lower light gas products and higher C5+) and also light gas product selectivities (C1-C4) were decreased and C5+ selectivity increased with increasing concentration of ammonia compared to ammonia free conditions.
- Rao Pendyala, Venkat Ramana,Shafer, Wilson D.,Jacobs, Gary,Martinelli, Michela,Sparks, Dennis E.,Davis, Burtron H.
-
-
Read Online
- Mechanistic studies of ethylene and α-olefin co-oligomerization catalyzed by chromium-PNP complexes
-
To explore the possibility of producing a narrow distribution of mid- to long-chain hydrocarbons from ethylene as a chemical feedstock, co-oligomerization of ethylene and linear α-olefins (LAOs) was investigated, using a previously reported chromium complex, [CrCl 3(PNPOMe)] (1, where PNPOMe = N,N-bis(bis(o-methoxyphenyl)phosphino)methylamine). Activation of 1 by treatment with modified methylaluminoxane (MMAO) in the presence of ethylene and 1-hexene afforded mostly C6 and C10 alkene products. The identities of the C10 isomers, assigned by detailed gas chromatographic and mass spectrometric analyses, strongly support a mechanism that involves five- and seven-membered metallacyclic intermediates comprised of ethylene and LAO units. Using 1-heptene as a mechanistic probe, it was established that 1-hexene formation from ethylene is competitive with formation of ethylene/LAO cotrimers and that cotrimers derived from one ethylene and two LAO molecules are also generated. Complex 1/MMAO is also capable of converting 1-hexene to C12 dimers and C18 trimers, albeit with poor efficiency. The mechanistic implications of these studies are discussed and compared to previous reports of olefin cotrimerization.
- Do, Loi H.,Labinger, Jay A.,Bercaw, John E.
-
-
Read Online
- Bioinspired Hollow Nanoreactor: Catalysts that Carry Gaseous Hydrogen for Enhanced Gas-Liquid-Solid Three-Phase Hydrogenation Reactions
-
For conventional gas-liquid-solid three-phase heterogeneous hydrogenation reactions, hydrogen must be dissolved into the solvent to be a participating reactant, restricting the reaction rates. In this study, we demonstrate that gaseous hydrogen could be directly involved in gas-liquid-solid hydrogenation reactions through a bioinspired hollow nanoreactor with superaerophilic surface to enhance the reaction rates. We produce Pd@meso-SiO2 hollow nanoreactor, whose external surface is modified with perfluorodecyltriethoxysilane (PFDTS). In aqueous solutions, H2 gas could be spread quickly on the surface and stored in the cavity of hollow spheres, and participated in hydrogenation reactions, thereby enhancing H2 concentration around Pd nanoparticles. In hydrogenation of olefin reactions, such three-phase interface allows rapid and direct transportation of H2 bubbles to the surface of Pd nanoparticles rather than through diffusion of dissolved H2 in liquid phase, leading to an enhanced catalytic rate. This strategy is expected to be useful for designing and developing new catalytic systems of gas-liquid-solid three-phase reaction.
- Li, Zhaohua,Zhu, Zhongpeng,Cao, Changyan,Jiang, Lei,Song, Weiguo
-
-
Read Online
- Zero valent iron complexes as base partners in frustrated Lewis pair chemistry
-
The prototypical iron(0) complex [Fe(CO)3(PMe3)2] (1) forms a frustrated Lewis pair (FLP) with B(C6F5)3 (BCF). In this FLP, the iron complex acts as the Lewis base partner, and the borane as the Lewis acid partner. This FLP is able to cleave H-H, H-Cl, H-O and H-S bonds in H2, HCl, H2O and HSPh. The FLP 1/BCF is shown to catalyze the hydrogenation of alkenes under mild conditions, where terminal alkenes are preferentially reduced. Mechanistic studies using D2 gas suggest that a branched intermediate in an alkene insertion cycle or an ionic cycle is favored for this catalytic reaction.
- Fraser, Craig,Tinnermann, Hendrik,Young, Rowan D.
-
-
Read Online
- Supported ionic liquid phase rhodium nanoparticle hydrogenation catalysts
-
Rh(0) nanoparticles (ca. 4 nm) dispersed in an ionic liquid (1-n-butyl-3-methylimidazolium tetrafluoroborate) were immobilized within a silica network, prepared by the sol-gel method. The effect of the sol-gel catalyst (acid or base) on the encapsulated ionic liquid and Rh(0) content, on the silica morphology and texture, and on the catalyst alkene hydrogenation activity was investigated. The Rh(0) content in the resulting xerogels (ca. 0.1 wt% Rh/SiO2) was shown to be independent of the sol-gel process. However, acidic conditions afforded higher contents of encapsulated ionic liquid and xerogels with larger pore diameters, which in turn might be responsible for the higher catalyst activity in hydrogenation of the alkenes. The Royal Society of Chemistry.
- Gelesky, Marcos A.,Chiaro, Sandra S. X.,Pavan, Flavio A.,Dos Santos, Joao H. Z.,Dupont, Jairton
-
-
Read Online
- An excellent nickel boride catalyst for the selective hydrogenation of olefins
-
Nickel boride prepared on borohydride exchange resin (BER) in methanol is an excellent catalyst for the selective hydrogenation of olefins. Thus, monosubstituted olefins and norbornene were hydrogenated quantitatively at 0°C in 1 hour in the presence of disubstituted olefins and trisubstituted α,β-unsaturated acid derivatives, the disubstituted olefins in turn were hydrogenated at 65°C in 1 hour without affecting trisubstituted olefins, benzene, and heteroaromatic compounds.
- Choi, Jaesung,Yoon, Nung Min
-
-
Read Online
- Platinum nanoparticles on carbon nanomaterials with graphene structure as hydrogenation catalysts
-
Carbon nanomaterials with graphene structure (single- and multiwall nanotubes and nanofibers) after oxidizing by a mixture of sulfuric and nitric acids and presumable introducing of carboxyl groups can be used as carrying agents of hydrogenation catalysts. Platinum in a concentration which should not exceed 10 wt % can be fixed using H2PtCl6 as a precursor in presence of an organic base. Catalysts based on these nanomaterials with the average size of platinum particles 6-8 nm exceed in activity the Pt/C catalyst with the size of platinum particles 65-70 nm, but are inferior to catalysts based on fullerene black with the average size of platinum particles 3-4 nm.
- Kushch,Kujunko,Tarasov
-
-
Read Online
- Highly Selective Heterogeneous Palladium-Catalyzed Hydrogenations Using Triethoxysilane and Water
-
Treatment of alkenes or alkynes at ambient temperature with triethoxysilane and 5 mol percent of palladium(II) acetate in a mixture of tetrahydrofuran and water affords the corresponding hydrogenated products.Excellent chemoselectivities and stereoselectivities can be abtained using this process.
- Tour, James M.,Cooper, Joel P.,Pendalwar, Shekhar L.
-
-
Read Online
- Transition-metal nanoparticles in imidazolium ionic liquids: Recycable catalysts for biphasic hydrogenation reactions
-
1-n-Butyl-3-methylimidazolium hexafluorophosphate room-temperature ionic liquid is not only suitable as a medium for the preparation and stabilization of iridium nanoparticles but also ideal for the generation of recyclable biphasic catalytic systems for hydrogenation reactions. Thus, Ir(0) nanoparticles with a mean diameter of 2 nm have been prepared by reduction of Ir(I) dissolved in the ionic liquid with H2. This catalytic solution can be reused several times for the biphasic hydrogenation of olefins under mild reaction conditions. Copyright
- Dupont, Jairton,Fonseca, Gledison S.,Umpierre, Alexandre P.,Fichtner, Paulo F. P.,Teixeira, Sergio R.
-
-
Read Online
- Direct synthesis of hydrogen peroxide over Pd/C catalyst prepared by selective adsorption deposition method
-
A new catalyst design based on selective adsorption deposition method was developed to achieve high reaction performance in the direct synthesis of hydrogen peroxide. The activity of the unprecedented Pd/C catalyst was superior to that of the conventionally prepared Pd/C catalysts, and the initial H2O2 productivity and H2 selectivity reached as high as 8606 mmol H2O2/g Pd.h and 95.1%, respectively. This excellent activity may result from the intrinsic structural and electronic features of the active sites, i.e., the extremely small and monodispersed Pd nanoparticles with a high Pd2+/Pd0 ratio, which were realized by combining the selective adsorption of metal precursor cations on a negatively charged activated carbon surface and the subsequent homogeneous surface deposition of palladium hydroxide by the hydroxide ions that are slowly generated upon urea decomposition. The catalytic activity was significantly affected by the oxygen groups of the activated carbon support. The carboxyl groups do not efficiently suppress the unfavorable H-OOH dissociation but rather accelerate the H2O2 hydrolysis by forming hydrogen bonds with H2O2. Moreover, a sharp decrease in the reaction rates of H2O2 hydrogenation and direct synthesis of H2O2 was observed with the increase in the number of carboxyl groups on the activated carbon surface. This loss of activity, as confirmed by acid treatment and olefin hydrogenation experiments, implies that the carboxyl groups in close proximity to the active sites have a detrimental effect by hindering or poisoning the active sites.
- Lee, Seungsun,Jeong, Hwiram,Chung, Young-Min
-
-
Read Online
- Formation of a Pt12 cluster by single-atom control that leads to enhanced reactivity: Hydrogenation of unreactive olefins
-
A platinum subnanocluster catalyst composed of 12 atoms was synthesized using a phenylazomethine dendrimer, which can assemble twelve PtCl4 units by stepwise complexation, followed by reduction to Pt0. Unreactive olefins that were not activated by conventional 2 nm Pt nanoparticles were successfully hydrogenated by the subnanocluster. EWG=electron-withdrawing group. Copyright
- Takahashi, Masaki,Imaoka, Takane,Hongo, Yushi,Yamamoto, Kimihisa
-
-
Read Online
- Characterization of the complex formed between samarium diiodide and the dehydro dimer of HMPA (diHMPA)
-
A new ligand that facilitates samarium diiodide-mediated reductions has been developed. Addition of a solution of samarium diiodide to the dehydro dimer of hexamethylphosphoramide results in a purple complex which is an excellent reductant for a variety of organic functionalities. The complex was characterized by the kinetics of reduction of 1-bromodecane, visible spectroscopy, and cyclic voltammetry.
- McDonald, Chriss E.,Ramsey, Jeremy D.,Grant, James A.,Howerter, Kelly A.
-
-
Read Online
- Highly selective hydrogenation of Α-pinene in aqueous medium using PVA-stabilized Ru nanoparticles
-
Polyvinyl alcohol (PVA)-stabilized ruthenium nanoparticles in water were synthesized and characterized by transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and confocal laser scanning microscope (CLSM). The Ru-PVA catalyst was highly effective for the hydrogenation of α-pinene, exhibiting higher selectivity for cis-pinane as well as high conversion. The selectivity could reach approximately 99%. The catalyst phase could be recycled at least eight times without obvious loss in the catalytic activity and selectivity. Furthermore, both the preparation of catalyst and hydrogenation of α-pinene were under mild experimental conditions. Using water as the reaction medium and PVA as the stabilizing agent made the hydrogenation process environmentally friendly. This catalytic system may also be used to convert a range of cyclenes and long chain alkenes, in particular aromatic compounds to corresponding hydrogenated products.
- Wang, Xiaoyan,Yu, Fengli,Xie, Congxia,Yu, Shitao
-
-
Read Online
- Platinum nanoparticles supported on ionic liquid-modified-silica gel: Hydrogenation catalysts
-
Platinum nanoparticles (ca. 2.3 nm) dispersed in ionic liquids and functionalized ionic liquids were supported within a silica network by the sol-gel method. The effect of the sol-gel catalyst (acid or base) on the encapsulated ionic liquid and on the platinum content was studied, and the silica morphology, the texture of the support material, and the hydrogenation activity were investigated. The Pt(0) content in the resulting xerogels (ca. 0.2 wt% Pt/SiO2) was shown to be independent of the sol-gel process. The acidic conditions resulted in xerogels with larger pore diameters, which in turn might be responsible for the higher catalytic activity in hydrogenation of the alkenes and arenes obtained with the heterogeneous catalyst (Pt(0)/SiO 2).
- Foppa, Lucas,Dupont, Jairton,Scheeren, Carla W.
-
-
Read Online
- Samarium-catalyzed electrochemical reduction of organic halides
-
Electroreduction of a series of organic halides including chloro- and fluoroderivatives bearing various functional groups is effected in good yields in the presence of a ctalytical amount of SmCl3. Reactions are carried out in DMF in a single-compartment cell fitted with a consumable magnesium anode.
- Hebri,Dunach,Perichon
-
-
Read Online
- Mechanistic study of the SmI2/H2O/amine-mediated reduction of alkyl halides: Amine base strength (pKBH+) dependent rate
-
The kinetics of the SmI2/H2O/amine-mediated reduction of 1-chlorodecane has been studied in detail. The rate of reaction is first order in amine and 1-chlorodecane, second order in SmI2, and zero order in H2O. Initial rate studies of more than 20 different amines show a correlation between the base strength (pKBH+) of the amine and the logarithm of the observed initial rate, in agreement with Bronsted catalysis rate law. To obtain the activation parameters, the rate constant for the reduction was determined at different temperatures (0 to +40 °C, ΔH? = 32.4 ± 0.8 KJ mol-1, ΔS? = -148 ± 1 J K-1 mol-1, and ΔG? 298K = 76.4 ± 1.2 kJ mol-1). Additionally, the 13C kinetic isotope effects (KIE) were determined for the reduction of 1-iododecane and 1-bromodecane. Primary 13C KIEs (k 12/k13, 20 °C) of 1.037 ± 0.007 and 1.062 ± 0.015, respectively, were determined for these reductions. This shows that cleavage of the carbon-halide bond occurs in the rate-determining step. A mechanism of the SmI2/H2O/amine-mediated reduction of alkyl halides is proposed on the basis of these results.
- Dahlen, Anders,Hilmersson, Goeran
-
-
Read Online
- Phase-separable catalysis using room temperature ionic liquids and supercritical carbon dioxide
-
A new phase-separable catalysis concept is demonstrated using supercritical carbon dioxide and the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate for hydrogenation of alkenes and carbon dioxide.
- Liu,Abrams,Baker,Tumas
-
-
Read Online
- A metal-organic framework immobilised iridium pincer complex
-
An iridium pincer complex has been immobilised in the metal-organic framework NU-1000 using a technique called solvent assisted ligand-incorporation (SALI). The framework proved to be stable under the conditions required to activate the iridium complex and spectroscopic investigations showed formation of the catalytically active iridium dihydride. The Ir-pincer modified NU-1000 is an active catalyst for the condensed phase hydrogenation of a liquid alkene (1-decene and styrene) and shows enhanced activity with respect to a homogeneous analogue. Additionally, the Ir-pincer immobilised inside NU-1000 operated as an efficient heterogenous catalyst under flow conditions.
- Rimoldi, Martino,Nakamura, Akitake,Vermeulen, Nicolaas A.,Henkelis, James J.,Blackburn, Anthea K.,Hupp, Joseph T.,Stoddart, J. Fraser,Farha, Omar K.
-
-
Read Online
- Silyl Chalconium Ions: Synthesis, Structure and Application in Hydrodefluorination Reactions
-
The synthesis of two series of silylated chalconium borates, 9 and 10, which are based on the peri-naphthyl and peri-acenaphthyl framework, is reported (chalcogen (Ch): O, S, Se, Te). NMR investigations of the selenium- and tellurium-containing precursor silanes 3 d–f and 8 d, f revealed a significant through-space J-coupling between the chalcogen nuclei and the Me2SiH group. Experimental and computational results typify the synthesized cations 9 and 10 as chalconium ions. The imposed ring strain weakens the Si?Ch linkage compared to acyclic chalconium ions. This attenuation of the Si?Ch bond strength is more pronounced in the acenaphthene series. Surprisingly, the Si?O bonds in oxonium ions 9 a and 10 a are the weakest Si?Ch linkage in both series. The synthesized silyl chalconium borates are active in hydrodefluorination reactions of alkyl fluorides with silanes. A cooperative activation of the silane by the Lewis acidic (silicon) and by the Lewis basic side (chalcogen) is suggested.
- Kordts, Natalie,Künzler, Sandra,Rathjen, Saskia,Sieling, Thorben,Gro?ekappenberg, Henning,Schmidtmann, Marc,Müller, Thomas
-
-
Read Online
- A New Route to an Active Form of Nickel. Transfer Hydrogenation of Alkenes and Carbonyl Compounds with 2-Propanol
-
A new procedure for the transfer hydrogenation of alkenes and carbonyl compounds have been developed using an activated form of metallic nickel prepared by the thermal decomposition of nickel diisopropoxide in boiling 2-propanol.Monosubstituted alkenes undergo carbon-carbon double-bond migration more quickly than reduction; the 2-alkene produced is then reduced to alkane.Ketones are reduced in high yields, provided that acetone formed during the process is removed continuously.Unsaturated ketones are first converted to saturated ketones andthen to alcohols, so by a careful control of the reaction course it is possible to stop the reaction at the first stage.Finally a comparison with the transfer hydrogenation of ketones, catalyzed by alkali metal isopropoxides in 2-propanol, has been performed.
- Boldrini, Gian Paolo,Savoia, Diego,Tagliavini, Emilio,Trombini, Claudio,Umani-Ronchi, Achille
-
-
Read Online
- Controlling the Lewis Acidity and Polymerizing Effectively Prevent Frustrated Lewis Pairs from Deactivation in the Hydrogenation of Terminal Alkynes
-
Two strategies were reported to prevent the deactivation of Frustrated Lewis pairs (FLPs) in the hydrogenation of terminal alkynes: reducing the Lewis acidity and polymerizing the Lewis acid. A polymeric Lewis acid (P-BPh3) with high stability was designed and synthesized. Excellent conversion (up to 99%) and selectivity can be achieved in the hydrogenation of terminal alkynes catalyzed by P-BPh3. This catalytic system works quite well for different substrates. In addition, the P-BPh3 can be easily recycled.
- Geng, Jiao,Hu, Xingbang,Liu, Qiang,Wu, Youting,Yang, Liu,Yao, Chenfei
-
p. 3685 - 3690
(2021/05/31)
-
- Designing of Highly Active and Sustainable Encapsulated Stabilized Palladium Nanoclusters as well as Real Exploitation for Catalytic Hydrogenation in Water
-
Abstract: Encapsulated nanoclusters based on palladium, 12-tunstophosphoric acid and silica was designed by simple wet impregnation methodology. The catalyst was found to be very efficient towards cyclohexene hydrogenation up to five catalytic runs with substrate/catalyst ratio of 4377/1 at 50?°C as well as for alkene, aldehyde, nitro and halogen compounds. Graphic Abstract: Silica encapsulated Pd nanoclusters stabilized by 12-tungstophosphoric acid is proved to be sustainable and excellent for water mediated hydrogenation reaction with very high catalyst to substrate ratio as well as TON.[Figure not available: see fulltext.]
- Patel, Anish,Patel, Anjali
-
p. 803 - 820
(2020/08/12)
-
- Ambient Hydrogenation and Deuteration of Alkenes Using a Nanostructured Ni-Core–Shell Catalyst
-
A general protocol for the selective hydrogenation and deuteration of a variety of alkenes is presented. Key to success for these reactions is the use of a specific nickel-graphitic shell-based core–shell-structured catalyst, which is conveniently prepared by impregnation and subsequent calcination of nickel nitrate on carbon at 450 °C under argon. Applying this nanostructured catalyst, both terminal and internal alkenes, which are of industrial and commercial importance, were selectively hydrogenated and deuterated at ambient conditions (room temperature, using 1 bar hydrogen or 1 bar deuterium), giving access to the corresponding alkanes and deuterium-labeled alkanes in good to excellent yields. The synthetic utility and practicability of this Ni-based hydrogenation protocol is demonstrated by gram-scale reactions as well as efficient catalyst recycling experiments.
- Beller, Matthias,Feng, Lu,Gao, Jie,Jackstell, Ralf,Jagadeesh, Rajenahally V.,Liu, Yuefeng,Ma, Rui
-
supporting information
p. 18591 - 18598
(2021/06/28)
-
- Chemo- And regioselective hydroformylation of alkenes with CO2/H2over a bifunctional catalyst
-
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
-
supporting information
p. 8040 - 8046
(2021/11/01)
-
- A New Protocol for Catalytic Reduction of Alkyl Chlorides Using an Iridium/Bis(benzimidazol-2′-yl)pyridine Catalyst and Triethylsilane
-
The reduction of alkyl chlorides using triethylsilane is investigated. Primary, secondary, tertiary, and benzylic C-Cl bonds are effectively converted into C-H bonds using an [IrCl(cod)] 2/2,6-bis(benzimidazol-2′-yl)pyridine catalyst system. This catalyst system is quite simple since the tridentate N-ligand can be easily prepared in one step from commercially available reagents.
- Fukuyama, Takahide,Hamada, Yuki,Ryu, Ilhyong
-
p. 3404 - 3408
(2021/07/14)
-
- Enantiopure 2,9-Dideuterodecane – Preparation and Proof of Enantiopurity
-
(R,R)- and (S,S)-(2,9-2H2)-n-Decane were prepared regio- and stereospecifically in 25–26 % yield over five steps from commercially available enantiopure (R)- and (S)-propylene oxide, respectively. The synthetic procedure involved nucleophilic displacement of (R)- and (S)-4-toluenesulfonic acid 1-methyl-4-pentenyl ester with LiAlD4 to furnish the respective (5-2H)-1-hexenes. Subsequent olefin metathesis and reduction of the double bond furnished the title compounds. The optical purity of (R,R)- and (S,S)-(2,9-2H2)-n-decane could not be determined by chromatography or polarimetry. Therefore, (R,R)- and (R,S)-(5-2H)-3-hydroxy-2-hexanone were prepared from their respective hexenes by Wacker oxidation, followed by enantioselective α-hydroxylation. The enantiopurity could then be determined by NMR spectroscopy because the stereospecifically deuterated hydroxyketones showed separated signals for the subterminal carbon atom (C-5) in the 13C NMR spectrum.
- Christoffers, Jens,Eru?ar, Gülsera,Fsadni, Miriam H.,Golding, Bernard T.,Mitschke, Nico,Roberts, Amy R.,Sadeghi, Majid M.,Wilkes, Heinz
-
p. 3854 - 3863
(2021/08/24)
-
- Highly active cobalt complex catalysts used for alkene hydrosilylation
-
A series of nitrogen phosphine ligands were synthesized, and the hydrosilylation reaction of alkenes catalyzed using MCl2 in the presence of these ligands was investigated. FeCl2/1(N1, N1, N2, N2-Tetrakis[(diphenylphosphino)methyl]ethane-1,2-diamine) showed low catalytic activity. MnCl2/1, CrCl3/1 and NiCl2/1 showed some catalytic activity. The CoCl2/N,P-ligand catalyst system showed high activity as well as excellent selectivity (The selectivity of the β-adduct was ~100%.) in the hydrosilylation reaction. CoCl2/1 showed the highest catalytic activity (~ >99.9% conversion of 1-octene). Additionally, no α-adduct, dehydrogenative silylation product and octane were detected.
- Liu, Yu,Li, Jiayun,Bai, Ying,Peng, Jiajian
-
-
- A General Approach to Intermolecular Olefin Hydroacylation through Light-Induced HAT Initiation: An Efficient Synthesis of Long-Chain Aliphatic Ketones and Functionalized Fatty Acids
-
Herein, an operationally simple, environmentally benign and effective method for intermolecular radical hydroacylation of unactivated substrates by employing photo-induced hydrogen atom transfer (HAT) initiation is described. The use of commercially available and inexpensive photoinitiators (Ph2CO and NHPI) makes the process attractive. The olefin hydroacylation protocol applies to a wide array of substrates bearing numerous functional groups and many complex structural units. The reaction proves to be scalable (up to 5 g). Different functionalized fatty acids, petrochemicals and naturally occurring alkanes can be synthesized with this protocol. A radical chain mechanism is implicated in the process.
- Guin, Joyram,Paul, Subhasis
-
p. 4412 - 4419
(2021/02/05)
-
- Palladium nanoparticles stabilized by novel choline-based ionic liquids in glycerol applied in hydrogenation reactions
-
Palladium nanoparticles stabilized by choline-based ionic liquids in glycerol were prepared from Pd(II) precursors by simply heating at 80 °C under argon; in this process, the water present in the ionic liquid was found to be responsible for the reduction of Pd(II) into zero-valent palladium species. Palladium nanoparticles were fully characterized in both liquid phase and solid state. The as-prepared metal nanoparticles exhibited remarkable catalytic activity in hydrogenation processes for a significant variety of functional groups (alkenes, alkynes, nitro derivatives, benzaldehydes, aromatic ketones).
- Garg, Garima,Foltran, Stéphanie,Favier, Isabelle,Pla, Daniel,Medina-González, Yaocihuatl,Gómez, Montserrat
-
-
- Hydrogenation reaction method
-
The invention relates to a hydrogenation reaction method, and belongs to the technical field of organic synthesis. The hydrogenation reaction method provided by the invention comprises the following steps: carrying out a hydrogen transfer reaction on a hydrogen acceptor compound, pinacol borane and a catalyst in a solvent in the presence of proton hydrogen, so that the hydrogen acceptor compound is subjected to a hydrogenation reaction; the catalyst is one or more than two of a palladium catalyst, an iridium catalyst and a rhodium catalyst; the hydrogen acceptor compound comprises one or morethan two functional groups of carbon-carbon double bonds, carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogentriple bonds and epoxy. The method is mild in reaction condition, easy to operate, high in yield, short in reaction time, wide in substrate application range, suitable for carbon-carbon double bonds,carbon-carbon triple bonds, carbon-oxygen double bonds, carbon-nitrogen double bonds, nitrogen-nitrogen double bonds, nitryl, carbon-nitrogen triple bonds and epoxy functional groups, good in selectivity and high in reaction specificity.
- -
-
Paragraph 0034; 0185-0188
(2020/05/14)
-
- Generalized Chemoselective Transfer Hydrogenation/Hydrodeuteration
-
A generalized, simple and efficient transfer hydrogenation of unsaturated bonds has been developed using HBPin and various proton reagents as hydrogen sources. The substrates, including alkenes, alkynes, aromatic heterocycles, aldehydes, ketones, imines, azo, nitro, epoxy and nitrile compounds, are all applied to this catalytic system. Various groups, which cannot survive under the Pd/C/H2 combination, are tolerated. The activity of the reactants was studied and the trends are as follows: styrene'diphenylmethanimine'benzaldehyde'azobenzene'nitrobenzene'quinoline'acetophenone'benzonitrile. Substrates bearing two or more different unsaturated bonds were also investigated and transfer hydrogenation occurred with excellent chemoselectivity. Nano-palladium catalyst in situ generated from Pd(OAc)2 and HBPin extremely improved the TH efficiency. Furthermore, chemoselective anti-Markovnikov hydrodeuteration of terminal aromatic olefins was achieved using D2O and HBPin via in situ HD generation and discrimination. (Figure presented.).
- Wang, Yong,Cao, Xinyi,Zhao, Leyao,Pi, Chao,Ji, Jingfei,Cui, Xiuling,Wu, Yangjie
-
supporting information
p. 4119 - 4129
(2020/08/10)
-
- Anionic Amphiphilic Cyclodextrins Bearing Oleic Grafts for the Stabilization of Ruthenium Nanoparticles Efficient in Aqueous Catalytic Hydrogenation
-
Oleic succinyl β-cyclodextrin was proved to be efficient for the stabilization of ruthenium nanoparticles (NPs) in aqueous medium. These NPs were characterized by FTIR spectroscopy and transition electron microscopy (TEM). The catalytic activity of these NPs was evaluated in the aqueous hydrogenation of petrosourced and biosourced unsaturated compounds such as benzene and furfural derivatives. The catalytic system can be easily recycled and reused up to nine runs without any loss of activity and selectivity, demonstrating its robustness.
- Cocq, Aurélien,Léger, Bastien,No?l, Sébastien,Bricout, Hervé,Djeda?ni-Pilard, Florence,Tilloy, Sébastien,Monflier, Eric
-
p. 1013 - 1018
(2019/12/27)
-
- Preparation of flavin-containing mesoporous network polymers and their catalysis
-
Riboflavin tetramethacrylate (RFlTMA) was prepared as a flavin monomer and copolymerized with ethylene glycol dimethacrylate (EGDMA) under polymerization-induced phase separation conditions. The resulting flavin-containing mesoporous network polymer, poly(RFlTMA-co-EGDMA), was found to be a more effective catalyst than riboflavin tetraacetate (RFlTA), a soluble analogue, for aerobic hydrogenation of olefins despite its heterogeneity, which allowed for its multiple recovery and reuse through simple filtrations and washings without loss in catalytic activity. In addition, the polymeric flavin was demonstrated to be utilized also as an effective photocatalyst in the oxidation of benzyl alcohols.
- Arakawa, Yukihiro,Sato, Fumiaki,Ariki, Kenta,Minagawa, Keiji,Imada, Yasushi
-
supporting information
(2020/02/15)
-
- Conception of Nanosized Membrane Reactors for Hydrogenation with Accumulated Hydrogen
-
Abstract: Results are summarized from studies to develop the concept of next-generation nanosized membrane reactors (NMRs) in which hydrogenation reactions are run in pores of varying diameter using hydrogen preadsorbed in mono- and multilayer oriented carbon nanotubes with graphene walls (OCNTGs) formed on the inner surface of pores of ceramic membranes. A comparative analysis is performed of the morphology of such carbon nanostructures as graphenes, OCNTGs, and pyrocarbon nanocrystallites (PNCs), and morphology is studied via X-ray diffraction analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and transmission electron microscopy (TEM). It is shown that only OCNTGs are capable of accumulating and storing hydrogen. The mechanism of hydrogen adsorption and the laws governing adsorption in this nanostructure are discussed. Results from the noncatalytic hydrogenation of decene-1 and naphthalene in NMRs with hydrogen adsorbed in OCNTGs are analyzed, and the kinetics and activation energies for these reactions are determined. The effect of the substrate on which graphene nanostructures are synthesized is estimated through a comparative analysis of the mechanisms of hydrogen adsorption in OCNTGs and cylindrical and planar graphene nanostructures (CPGNSes) formed on zeolites. The concept of NRMs is formulated, the directions of developing the concept are discussed. These include devising ways to create of catalytically active metal-containing sites in the NMR structure and the effect of the steric factor of the nanoreactor configuration on the selective hydrogenation of different organic substrates.
- Soldatov, A. P.
-
p. 663 - 677
(2020/04/24)
-
- Exploring Opportunities for Platinum Nanoparticles Encapsulated in Porous Liquids as Hydrogenation Catalysts
-
The unusual combination of characteristics observed for porous liquids, which are typically associated with either porous solids or liquids, has led to considerable interest in this new class of materials. However, these porous liquids have so far only been investigated for their ability to separate and store gases. Herein, the catalytic capability of Pt nanoparticles encapsulated within a Type I porous liquid (Pt@HS-SiO2 PL) is explored for the hydrogenation of several alkenes and nitroarenes under mild conditions (T=40 °C, PH2=1 atm). The different intermediates in the porous liquid synthesis (i.e., the initial Pt@HS-SiO2, the organosilane-functionalized intermediate, and the final porous liquid) are employed as catalysts in order to understand the effect of each component of the porous liquid on the catalysis. For the hydrogenation of 1-decene, the Pt@HS-SiO2 PL catalyst in ethanol has the fastest reaction rate if normalized with respect to the concentration of Pt. The reaction rate slows if the reaction is completed in a “neat” porous liquid system, probably because of the high viscosity of the system. These systems may find application in cascade reactions, in particular, for those with mutually incompatible catalysts.
- Hemming, Ellen B.,Masters, Anthony F.,Maschmeyer, Thomas
-
p. 7059 - 7064
(2020/03/24)
-
- Hydrogenation of Alkenes Catalyzed by a Non-pincer Mn Complex
-
Hydrogenation of substituted styrenes and unactivated aliphatic alkenes by molecular hydrogen has been achieved using a Mn catalyst with a non-pincer, picolylphosphine ligand. This is the second reported example of alkene hydrogenation catalyzed by a Mn complex. Mechanistic studies showed that a Mn hydride formed by H2 activation in the presence of a base is the catalytically active species. Based on experimental and DFT studies, H2 splitting is proposed to occur via a metal-ligand cooperative pathway involving deprotonation of the CH2 arm of the ligand, leading to pyridine dearomatization.
- Rahaman, S. M. Wahidur,Pandey, Dilip K.,Rivada-Wheelaghan, Orestes,Dubey, Abhishek,Fayzullin, Robert R.,Khusnutdinova, Julia R.
-
p. 5912 - 5918
(2020/10/30)
-
- One-pot synthesis of aldoximes from alkenes: Via Rh-catalysed hydroformylation in an aqueous solvent system
-
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.
-
supporting information
p. 7974 - 7982
(2020/11/30)
-
- Cationic Iridium/Chiral Bisphosphine-Catalyzed Enantioselective Hydroacylation of Ketones
-
A facile and convenient synthesis of the chiral phthalide framework catalyzed by cationic iridium was developed. The method utilized cationic iridium/bisphosphine-catalyzed asymmetric intramolecular carbonyl hydroacylation of 2-keto benzaldehydes to furnish the corresponding optically active phthalide products in good to excellent enantioselectivities (up to 98% ee). The mechanistic studies using a deuterium-labelled substrate suggested that the reaction involved an intramolecular carbonyl insertion mechanism to iridium hydride intermediate. In addition, we investigated the kinetic isotope effect (KIE) of intramolecular hydroacylation with deuterated substrate and determined that the C?H activation step is not included in the turnover-limiting step.
- Shirai, Tomohiko,Iwasaki, Tomoya,Kanemoto, Kazuya,Yamamoto, Yasunori
-
supporting information
p. 1858 - 1862
(2020/06/02)
-
- Catalytic deoxygenation of bio-based 3-hydroxydecanoic acid to secondary alcohols and alkanes
-
This work comprises the selective deoxygenation of bio-derivable 3-hydroxydecanoic acid to either linear alkanes or secondary alcohols in aqueous phase and H2-atmosphere over supported metal catalysts. Among the screened catalysts, Ru-based systems were identified to be most active. By tailoring the catalyst, the product selectivity could be directed to either secondary alcohols or linear alkanes. In the absence of a Br?nsted acidic additive, 2-nonanol and 3-decanol were accessible with a yield of 79% and 6% respectively, both of which can be used in food and perfume industries as flavoring agents and fragrances. To produce alkanes, we successfully synthesized a bifunctional Ru/HZSM-5 catalyst. The acidic zeolite support facilitated the dehydration of the intermediary formed alcohols to alkenes, while the following hydrogenation occurred at the Ru centers. Thus, full 3-hydroxydecanoic acid deoxygenation to nonane and decane, which are both well-established as diesel and jet fuels, was achieved with up to 72% and 12% yield, respectively.
- Artz, Jens,Brosch, Sebastian,Golchert, Christiane,Hergesell, Adrian H.,Mensah, Joel B.,Palkovits, Regina
-
supporting information
p. 3522 - 3531
(2020/08/28)
-
- Iron-catalyzed protodehalogenation of alkyl and aryl halides using hydrosilanes
-
A simple and efficient iron-catalyzed protodehalogenation of alkyl and aryl halides using phenylhydrosilane is disclosed. The reaction utilizes FeCl3 without the requirement of ligands. Unactivated alkyl and aryl halides were successfully reduced in good yields; sterically hindered tertiary halides were also reduced including the less reactive chlorides. The scalability of this methodology was demonstrated by a gram-scale synthesis with a catalyst loading as low as 0.5 mol%. Notably, disproportionation of phenylsilane leads to diphenylsilane that further reduces the halides. Preliminary mechanistic studies revealed a non-radical pathway and the source of hydrogen is PhSiH3via deuterium labeling studies. Our methodology represents simplicity and provides a good alternative to typical tin, aluminum and boron hydride reagents.
- Pilli, Ramadevi,Balakrishnan, Venkadesh,Chandrasekaran, Revathi,Rasappan, Ramesh
-
supporting information
p. 1749 - 1753
(2019/02/20)
-
- Rethinking Basic Concepts-Hydrogenation of Alkenes Catalyzed by Bench-Stable Alkyl Mn(I) Complexes
-
An efficient additive-free manganese-catalyzed hydrogenation of alkenes to alkanes with molecular hydrogen is described. This reaction is atom economic, implementing an inexpensive, earth-abundant nonprecious metal catalyst. The most efficient precatalyst is the bench-stable alkyl bisphosphine Mn(I) complex fac-[Mn(dippe)(CO)3(CH2CH2CH3)]. The catalytic process is initiated by migratory insertion of a CO ligand into the Mn-alkyl bond to yield an acyl intermediate which undergoes rapid hydrogenolysis to form the active 16e Mn(I) hydride catalyst [Mn(dippe)(CO)2(H)]. A range of mono- A nd disubstituted alkenes were efficiently converted into alkanes in good to excellent yields. The hydrogenation of 1-alkenes and 1,1-disubstituted alkenes proceeds at 25 °C, while 1,2-disubstituted alkenes require a reaction temperature of 60 °C. In all cases, a catalyst loading of 2 mol % and a hydrogen pressure of 50 bar were applied. A mechanism based on DFT calculations is presented, which is supported by preliminary experimental studies.
- Weber, Stefan,St?ger, Berthold,Veiros, Luis F.,Kirchner, Karl
-
p. 9715 - 9720
(2019/10/14)
-
- Aggregation-induced Substrate Specificity in Aerobic Reduction of Olefins with Ultrasound Gel Catalyst of Synthetic Flavin
-
A riboflavin derivative bearing octadecanoyl functionalities 1 a gelatinizes a variety of organic solvents upon brief ultrasonication in an organic fluid. The rate of gelation with 1 a can be externally and precisely controlled by tuning the sonication time and type of solvent. The present ultrasound gel exhibits unprecedented substrate specificity for the catalytic aerobic reduction of olefins, which can be performed with hydrazine at ambient temperature and atmospheric pressure in air. The reaction rates of 1-dodecene (2), allylbenzene (3), and o-allylphenol (4) with the ultrasound gel 1 a catalyst is in the order of 2?3>4, the substrate specificity of which is in contrast to the almost non-specificity with the non-gelled catalyst 1 b bearing butanoyl functionalities, and entirely inverse specificity with a flavin-dendrimer association catalyst (234). Based on kinetic studies, the aggregation effects on the substrate specificity have been ascribed to the specific inclusion of aliphatic olefins into the enzyme-like artificial cavities of the gel catalysts.
- Kawamorita, Soichiro,Fujiki, Misa,Li, Zimeng,Kitagawa, Takahiro,Imada, Yasushi,Naota, Takeshi
-
p. 878 - 884
(2019/01/14)
-
- Hydrogenation of hydrophobic substrates catalyzed by gold nanoparticles embedded in Tetronic/cyclodextrin-based hydrogels
-
Hydrogenation of alkenes, alkynes and aldehydes was investigated under biphasic conditions using Au nanoparticles (AuNP) embedded into combinations of α-cyclodextrin (α-CD) and a poloxamine (Tetronic90R4). Thermo-responsive AuNP-containing α-CD/Tetronic90R4 hydrogels are formed under well-defined conditions of concentration. The AuNP displayed an average size of ca. 7 nm and a narrow distribution, as determined by TEM. The AuNP/α-CD/Tetronic90R4 system proved to be stable over time. Upon heating above the gel-to-sol transition temperature, the studied catalytic system allowed hydrogenation of a wide range of substrates such as alkenes, alkynes and aldehydes under biphasic conditions. Upon repeated heating/cooling cycles, the Au NP/α-CD/Tetronic90R4 catalytic system could be recycled several times without a significant decline in catalytic activity.
- Chevry,Menuel,Léger,No?l,Monflier,Hapiot
-
p. 9865 - 9872
(2019/07/04)
-
- Integration of phosphine ligands and ionic liquids both in structure and properties-a new strategy for separation, recovery, and recycling of homogeneous catalyst
-
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
-
p. 3583 - 3596
(2019/07/10)
-
- Dehalogenative Deuteration of Unactivated Alkyl Halides Using D2O as the Deuterium Source
-
The general dehalogenation of alkyl halides with zinc using D2O or H2O as a deuterium or hydrogen donor has been developed. The method provides an efficient and economic protocol for deuterium-labeled derivatives with a wide substrate scope under mild reaction conditions. Mechanistic studies indicated that a radical process is involved for the formation of organozinc intermediates. The facile hydrolysis of the organozinc intermediates provides the driving force for this transformation.
- Xia, Aiyou,Xie, Xin,Hu, Xiaoping,Xu, Wei,Liu, Yuanhong
-
p. 13841 - 13857
(2019/10/17)
-
- A Free-Radical Reduction and Cyclization of Alkyl Halides Mediated by FeCl2
-
Iron mediated catalytic reactions are of great interest in the field of organic synthesis because they are economic and naturally abundant. However, the use of iron catalyst in the field of free radical cyclization or reduction of alkyl halides remains limited. Here we describe the use of an unprecedented combination of iron and zinc in the reduction and 5-exo-trig radical cyclization of alkyl halides under mild condition in the absence of added ligands or additives. The method is distinguished by its wide scope, functional group tolerance and the use of 1,4-cyclohexadiene as the source of hydrogen, which aids easy purification.
- Pulikottil, Feba Thomas,Pilli, Ramadevi,Murugesan, Vetrivelan,Krishnan, Chandu G.,Rasappan, Ramesh
-
p. 2438 - 2442
(2019/04/30)
-
- Involving Single-Atom Silver(0) in Selective Dehalogenation by AgF under Visible-Light Irradiation
-
The dehalogenation-arylation and the hydrodehalogenation of various types of organic halides are selectively realized using AgF and visible light without any organic additives under mild conditions. Single-atom silver(0) (denoted as SAAg) serves as the catalytically active center, and the TOF of SAAg reaches 6000 h-1. This elusive activity of Ag is beyond that expected from its ionic, nano, or bulk forms.
- Wu, Wenli,Cui, Enxin,Zhang, Yun,Zhang, Chen,Zhu, Feng,Tung, Chen-Ho,Wang, Yifeng
-
p. 6335 - 6341
(2019/07/04)
-
- Potassium Yttrium Ate Complexes: Synergistic Effect Enabled Reversible H2 Activation and Catalytic Hydrogenation
-
A potassium yttrium benzyl ate complex was generated simply by mixing an yttrium amide and potassium benzyl. The benzyl ate complex could undergo peripheral deprotonation to produce a cyclometalated complex or hydrogenation to give a hydride ate complex. The latter hydride ate complex features a (KH)2 structure protected by two yttrium amide complexes. The synergistic effect between potassium hydride and the amide ligand enables the complex to deprotonate a methyl C-H bond. The combination of intramolecular deprotonation of the hydride ate complex and hydrogenation of the cyclometalated complex constitutes a reversible H2 activation process. Using this process involving formal addition and elimination of H2, we accomplished the catalytic hydrogenation of alkenes, alkynes, and imines.
- Zhai, Dan-Dan,Du, Hui-Zhen,Zhang, Xiang-Yu,Liu, Yu-Feng,Guan, Bing-Tao
-
p. 8766 - 8771
(2019/09/30)
-
- Molybdenum Oxide-Modified Iridium Catalysts for Selective Production of Renewable Oils for Jet and Diesel Fuels and Lubricants
-
Supported inverse metal-metal oxide catalysts have received significant research interest owing to their effective hydrodeoxygenation (HDO) activity toward biomass substrates, but the high cost of the reported catalysts poses a challenge for commercialization. We present the synthesis of a series of metal-metal oxide catalysts, Ir-MOx/SiO2 (M = Re, Mo, W, V, or Nb) and M′-MoOx/SiO2 (M = Rh, Ru, Pt, or Pd) and their HDO performance on multifuran (high carbon) substrates to produce renewable jet and diesel fuels and lubricant base oils. A MoOx-modified Ir/SiO2 catalyst with a Mo/Ir ratio of 0.13 (Ir-MoOx/SiO2) exhibits the highest product yield (78-96%) under mild reaction conditions. Controlled experiments using probe substrates reveal that furan ring hydrogenation and C-O hydrogenolysis of saturated and unsaturated furan rings occur in a sequential manner. The carbon atom adjacent to the furan or saturated furan ring of substrates or intermediate compounds undergoes slow C-C bond scission, resulting in a small fraction of lighter alkanes. Catalyst characterization suggests that Ir is reduced to a fully metallic state to dissociate hydrogen for hydrogenation. Intact MoOx, partly covering the Ir metal surface, promotes ring opening, hydrogenolysis of etheric and alcoholic C-O bonds, and hydrogenation of Ca? O bonds. This study highlights the potential of low-cost metal-metal oxide catalysts with low loading of oxophilic metals to enable cost-competitive production of bioproducts and demonstrates applicability of these catalysts on other substrates, including fatty acids, fatty esters, and lipids.
- Liu, Sibao,Zheng, Weiqing,Fu, Jiayi,Alexopoulos, Konstantinos,Saha, Basudeb,Vlachos, Dionisios G.
-
p. 7679 - 7689
(2019/08/20)
-
- Hexadecane Conversion on an Alumina–Nickel Catalyst
-
Abstract: The conversion of hexadecane on a 4% Ni/Al2O3 catalyst in a temperature range of 20–300°C was studied using IR spectroscopy and catalytic methods. It was found that the dehydrogenation of hexadecane occurred at 20–100°C with the subsequent formation of aromatic products, but the rates of these processes were very low. As the reaction temperature was increased to 200°C, the 4% Ni/Al2O3 catalyst exhibited a maximum activity and high selectivity for the formation of 1-hexadecene, and aromatic compounds and cracking products were present in the reaction products. As the reaction temperature was further increased, the catalytic activity significantly decreased. This was due to the fact that polyaromatic deposits gradually accumulated on the catalyst surface in a temperature range of 200–300°C.
- Chesnokov,Chichkan,Paukshtis,Chesalov, Yu. A.,Krasnov
-
p. 439 - 445
(2019/09/04)
-
- Rhodium-Catalyzed Alkenylation of Toluene Using 1-Pentene: Regioselectivity to Generate Precursors for Bicyclic Compounds
-
Rhodium catalysts for arene alkenylation reported by our group (e.g., Science 2015, 348, 421; J. Am. Chem. Soc. 2017, 139, 5474; J. Am. Chem. Soc. 2018, 140, 17007) have demonstrated selectivity for 1-aryl alkenes over y-aryl alkenes (y > 1). This selectivity is notable because 1-aryl alkenes or 1-aryl alkanes cannot be generated using acid-based Friedel-Crafts arene alkylation or acidic zeolite catalysts. Herein, we report the extension of Rh arene alkenylation catalysis to generate 1-tolyl-1-pentenes, which are potential precursors for bicyclic compounds. The olefin concentration, copper(II) oxidant identity and concentration, reaction temperature, and rhodium concentration for the alkenylation of toluene with 1-pentene have been optimized using [Rh(Η2-C2H4)2(μ-OAc)]2 as the catalyst precursor. The rhodium-based catalysis achieves up to 12(1):1 anti-Markovnikov selectivity for 1-tolyl-1-pentenes over 2-tolyl-2-pentenes and is selective for alkenylation in the meta and para positions.
- Liebov, Nichole S.,Zhu, Weihao,Chen, Junqi,Webster-Gardiner, Michael S.,Schinski, William L.,Gunnoe, T. Brent
-
p. 3844 - 3851
(2019/10/16)
-
- H-Transfer reactions of internal alkenes with tertiary amines as H-donors on carbon supported noble metals
-
A hydride transfer reaction with tertiary amines was observed in the presence of noble metals on a carbon support. Hydride transfer had been documented previously in terms of activated allyl-type carbon-carbon double bonds containing carbonyl derivatives in the presence of triethyl amine (conjugate reduction). The proposed mechanism is a hydride transfer reaction in which the metal serves as the reaction partner of the hydrido-metal iminium adduct formation. The saturation of a non-activated internal double bond containing compound, such as methyl oleate and trans-5-decene as substrates, was observed for the first time in this work. The pre-reduced catalyst samples showed high activity; in the presence of Pd/C, Pt/C and Rh/C partial to complete conversion was detected at 140 °C in a p-xylene solvent without molecular hydrogen. Higher molecular weight byproducts of the amines were formed, while in the case of the substrates negligible amounts of unreacted but double bond migrated species were present. There is a possibility of usage of alkyl amines other than triethylamine; thus use of tributyl-, tripentyl-, trihexylamine and N,N-diisopropylethylamine, as well as cyclic 1-ethylpyrrolidine and 1-ethylpiperidine, was investigated. Cyclic amines and diisopropyl derivatives as H sources produced the highest conversion, while amines with longer alkyl chains showed minor activity. As a clear indication of H-donation, the formation of unsaturated amine species such as 1-ethyl-pyrrole and pyridine was observed.
- Yang, Guoju,Bauer, Thomas J.,Haller, Gary L.,Baráth, Eszter
-
supporting information
p. 1172 - 1177
(2018/02/21)
-
- Selective Hydrogenation of Carboxylic Acids to Alcohols or Alkanes Employing a Heterogeneous Catalyst
-
The chemoselective hydrogenation of carboxylic acids to either alcohols or alkanes is reported, employing a heterogeneous bimetallic catalyst consisting of rhenium and palladium supported on graphite. α-Chiral carboxylic acids were hydrogenated without loss of optical purity. The catalyst displays a reverse order of reactivity upon hydrogenation of different carboxylic functions with esters being less reactive than amides and carboxylic acids. This allows for chemoselective hydrogenation of an acid in the presence of an ester or an amide function.
- Ullrich, Johannes,Breit, Bernhard
-
p. 785 - 789
(2018/02/14)
-
- Sodium borohydride-nickel chloride hexahydrate in EtOH/PEG-400 as an efficient and recyclable catalytic system for the reduction of alkenes
-
An efficient, safe and one-pot convenient catalytic system has been developed for the reduction of alkenes using NaBH4-NiCl2·6H2O in EtOH/PEG-400 under mild conditions. In this catalytic system, a variety of alkenes (including trisubstituted alkene α-pinene) were well reduced and the Ni catalyst could be recycled.
- Li, Kaoxue,Liu, Chuanchao,Wang, Kang,Ren, Yang,Li, Fahui
-
p. 7761 - 7764
(2018/03/01)
-
- Preparation of MOF Confined Ag Nanoparticles for the Highly Active, Size Selective Hydrogenation of Olefins
-
Catalysts with both high activity and good selectivity for hydrogenation of olefins to alkanes are of interest. Herein, MOF confined ultrafine Ag NPs (Ag@HKUST-1) were synthesized by double-solvent approach using HKUST-1 as the template and support. HKUST-1 with narrow cage size distribution (0.5 to 0.9 nm) confined the growth of Ag NPs, while the uniform pores prohibited the entrance of olefins with the molecular size lager than 5.0 ?, which endow the Ag@HKUST-1 with high catalytic activity and size selectivity for hydrogenation reaction. The hydrogenation of eight kinds of olefins with different molecular size (1-hexene, cyclohexene, 1-octene, cyclooctene, styrene, 1-decene, 1, 1-diphenylethylene, and 1-dodecene) catalyzed by Ag@HKUST-1 confirmed this hypothesis. The olefins with molecular smaller than 5.0 ? were efficiently converted to the corresponding alkanes, whereas those greater than 5.0 ? exhibited extremely low conversation. The catalyst also exhibited high recycle stability in the hydrogenation of styrene.
- Chen, Wen-Jing,Cheng, Bin-Hai,Sun, Qing-Ting,Jiang, Hong
-
p. 3659 - 3665
(2018/08/07)
-
- Kinetics and chemoselectivity studies of hydrogenation reactions of alkenes and alkynes catalyzed by (benzoimidazol-2-ylmethyl)amine palladium(II) complexes
-
A series of (benzoimidazol-2-ylmethyl)amine palladium(II) complexes have been employed as catalysts in the homogeneous hydrogenation of alkenes and alkynes under mild conditions. A correlation between the catalytic activity and the nature of the ligand was established. Kinetic studies of the hydrogenation reactions of styrene established pseudo-first-order dependence on styrene substrate. On the other hand, partial orders with respect to H2 and catalyst concentrations were obtained. The nature of the solvent used influenced the hydrogenation reactions, where coordinating solvents resulted in lower catalytic activities. Kinetics and mechanistic studies performed were consistent with the formation of palladium monohydride intermediates as the active species.
- Tshabalala, Thandeka A.,Ojwach, Stephen O.
-
supporting information
p. 148 - 155
(2018/08/23)
-
- Structurally uniform 1-hexene, 1-octene, and 1-decene oligomers: Zirconocene/MAO-catalyzed preparation, characterization, and prospects of their use as low-viscosity low-temperature oil base stocks
-
An original approach to α-olefin oligomerization as well as novel thermally stable zirconocene catalysts for use in such reactions has been elaborated. The method reported allows the achievement of fractions of lightweight α-olefin oligomers up to 90% yields without considerable formation of byproducts like internal alkenes, alkanes, and higher oligomers. Trimers, tetramers, and pentamers of 1-hexene, 1-octene, and 1-decene were isolated as individual compounds and were hydrogenated. Viscosity characteristics of the isolated saturated and unsaturated hydrocarbons have been studied at various temperatures. The isolated saturated oligomers of 1-octene and 1-decene outperform the traditional electrophilic oligomerization products in terms of viscosity indexes, pour points, and low-temperature viscosity.
- Nifant'ev, Ilya E.,Vinogradov, Alexander A.,Vinogradov, Alexey A.,Sedov, Igor V.,Dorokhov, Viktor G.,Lyadov, Anton S.,Ivchenko, Pavel V.
-
-
- Emollients and cosmetic compositions based on specific branched hydrocarbons
-
A cosmetic or pharmaceutical composition is provided. The composition contains a mixture of oils prepared by Kolbe electrolysis of branched chain fatty acids and mixtures of branched chain fatty acids with straight chain fatty acids. The fatty acids containing from 3 to 26 carbon atoms. The oils are a mixture of oils with different spreading rates (spreading cascade).
- -
-
Page/Page column 10
(2018/05/16)
-
- Cross-coupling reaction of alkyl halides with alkyl grignard reagents catalyzed by cp-iron complexes in the presence of 1,3-butadiene
-
Iron-catalyzed cross-coupling reaction of alkyl halides with alkyl Grignard reagents by the combined use of cyclopentadienyl ligand and 1,3-butadiene additive is described. The reaction smoothly proceeds at room temperature using unactivated alkyl bromides and fluorides via non-radical mechanism, which is in sharp contrast with hitherto known Fe-catalyzed cross-coupling reactions of alkyl halides.
- Iwasaki, Takanori,Shimizu, Ryohei,Imanishi, Reiko,Kuniyasu, Hitoshi,Kambe, Nobuaki
-
supporting information
p. 763 - 766
(2018/05/29)
-
- Reevaluation of the Palladium/Carbon-Catalyzed Decarbonylation of Aliphatic Aldehydes
-
An improved method for the decarbonylation of aliphatic aldehydes by using a commercially available Pd/C catalyst is described. The reaction conditions are suitable for linear, cyclic, or sterically demanding substrates, as they afford the corresponding alkanes in yields of up to 99%. In addition, this Pd/C-catalyzed method exhibits good functional-group tolerance. A comparison of previously reported methods with the present one showed that the reaction conditions play a crucial role in the outcome of the reaction. The method can also be applied in a two-step reaction sequence for the synthesis of industrially important compounds.
- Ajda?i?, Vladimir,Nikoli?, Andrea,Kerner, Michael,Wipf, Peter,Opsenica, Igor M.
-
supporting information
p. 1781 - 1785
(2018/08/12)
-
- Hydrofunctionalization of olefins to value-added chemicals: Via photocatalytic coupling
-
A green strategy was developed for the synthesis of various value-added chemicals using methanol, acetonitrile, acetic acid, acetone and ethyl acetate as the hydrogen source by coupling them with olefins over heterogeneous photocatalysts. A radical coupling mechanism was proposed for the hydrofunctionalization of olefins with methanol to higher aliphatic alcohols over the Pt/TiO2 catalyst as the model reaction. C-H bond cleavage and C-C bond formation between photogenerated radicals and terminal olefins were accomplished in a single reaction at high efficiency. Our approach is atomically economical with high anti-Markovnikov regioselectivity and promising application potential under mild reaction conditions.
- Fan, Yonghui,Li, Shenggang,Bao, Jingxian,Shi, Lei,Yang, Yanzhang,Yu, Fei,Gao, Peng,Wang, Hui,Zhong, Liangshu,Sun, Yuhan
-
supporting information
p. 3450 - 3456
(2018/08/06)
-
- Rhodium-Complex-Catalyzed Hydroformylation of Olefins with CO2and Hydrosilane
-
A rhodium-catalyzed one-pot hydroformylation of olefins with CO2, hydrosilane, and H2has been developed that affords the aldehydes in good chemoselectivities at low catalyst loading. Mechanistic studies indicate that the transformation is likely to proceed through a tandem sequence of poly(methylhydrosiloxane) (PMHS) mediated CO2reduction to CO and a conventional rhodium-catalyzed hydroformylation with CO/H2. The hydrosilylane-mediated reduction of CO2in preference to aldehydes was found to be crucial for the selective formation of aldehydes under the reaction conditions.
- Ren, Xinyi,Zheng, Zhiyao,Zhang, Lei,Wang, Zheng,Xia, Chungu,Ding, Kuiling
-
supporting information
p. 310 - 313
(2016/12/30)
-
- Aminopyridine-Borane Complexes as Hydrogen Atom Donor Reagents: Reaction Mechanism and Substrate Selectivity
-
Lewis base-borane complexes are shown to be potent hydrogen atom donors in radical chain reduction reactions. Results obtained in 1H, 11B, and 13C NMR measurements and kinetic experiments support a complex reaction mechanism involving the parent borane as well as its initial reaction products as active hydrogen atom donors. Efficient reduction reactions of iodides, bromides, and xanthates in apolar solvents rely on initiator systems generating oxygen-centered radicals under thermal conditions and pyridine-borane complexes carrying solubilizing substituents. In contrast to tin hydride reagents, the pyridine-boranes reduce xanthates faster than the corresponding iodides.
- Barth, Florian,Achrainer, Florian,Pütz, Alexander M.,Zipse, Hendrik
-
p. 13455 - 13464
(2017/10/05)
-
- Unsaturated-compound hydrogenation nanocatalysts based on palladium and platinum particles immobilized in pores of mesoporous aromatic frameworks
-
Heterogeneous catalysts for the hydrogenation of unsaturated hydrocarbons have been synthesized on the basis of palladium and platinum nanoparticles immobilized in pores of mesoporous aromatic frameworks, which represent a new class of carbon supports with a diamond-like ordered structure. The resulting materials have been characterized by transmission electron microscopy, IR spectroscopy, and NMR spectroscopy. It has been shown that the catalyst activity in the hydrogenation reaction depends on the substrate molecule size and adsorbability on the surface of nanoparticles. Catalytic activity has been studied in the hydrogenation of a number of unsaturated compounds at temperatures of 60 and 80°C and pressures of 1.0 and 3.0 MPa.
- Kulikov,Terenina,Kryazheva, I. Yu.,Karakhanov
-
p. 222 - 229
(2017/04/07)
-
- In Situ Generation and Immobilization of an Activated Rh Complex Catalyst in a Metal–Organic Framework for Hydrogenation at Low H2 Pressure
-
Hydrogenation reactions under low-pressure H2 atmosphere are highly relevant from the safety viewpoint, because H2 gas is highly flammable in air and explosions can be triggered by spark, heat, or sunlight. In this work, an Rh complex/MOF hybrid was synthesized and used as catalyst for the hydrogenation of alkene substrates. Thanks to the activation of the Rh complex catalyst during the immobilization process and the intrinsic gas-condensation property of MOFs, the resulting composite showed much higher catalytic activity than the complex catalyst itself. Moreover, the composite can maintain its catalytic activity even at low H2 pressures that cannot support the reaction with the complex catalyst alone. Furthermore, in contrast to the complex catalyst, the composite maintained its catalytic activity even without solvent, and thus provides an environmentally friendly approach to catalysis.
- Takashima, Yohei,Fukuhara, Yoshimasa,Sato, Yasushi,Tsuruoka, Takaaki,Akamatsu, Kensuke
-
p. 5344 - 5349
(2017/12/04)
-
- Acid-tolerant cyclodextrin-based ruthenium nanoparticles for the hydrogenation of unsaturated compounds in water
-
A water-soluble β-cyclodextrin polymer synthesized by crosslinking β-cyclodextrin with epichlorohydrin and glycidyltrimethylammonium chloride allowed the stabilization of ruthenium nanoparticles not only in basic aqueous medium but also in acidic medium. The aqueous ruthenium colloidal suspensions obtained with this polymer were active as catalysts for the hydrogenation of a large variety of unsaturated compounds including aromatic or fatty acids. The recycling of this catalytic system was attested through ten consecutive runs without loss of stability and activity, demonstrating its robustness.
- No?l, Sébastien,Bourbiaux, Dolorès,Tabary, Nicolas,Ponchel, Anne,Martel, Bernard,Monflier, Eric,Léger, Bastien
-
p. 5982 - 5992
(2017/12/26)
-
