- Highly regioselective and active rhodium/bisphosphite catalytic system for isomerization-hydroformylation of 2-Butene
-
The formation of linear aldehyde from isomerization-hydroformylation of 2-butene represents an important subject and current task in industry. Both high activity and excellent regioselectivity were achieved in the rhodium-catalyzed 2-butene isomerization-hydroformylation with 2,2′- bis(dipyrrolylphosphinooxy)-1,1′-(±)-binaphthyl (1) as ligand. Bulky phosphite with electron-withdrawing pyrrol groups dramatically improved the selectivity of linear product, and a good yield of 90.5% aldehydes was obtained with an excellent linear aldehyde regioselectivity of 95.3% under optimized condition. Graphical Abstract: Bulky phosphite with electron-withdrawing pyrrol groups dramatically improved the selective of linear product, and an excellent yield of 90.5% aldehydes with 95.3% regioselectivity of linear aldehyde was obtained in the Rh-catalyzed isomerization- hydroformylation of 2-butene in the presence of ligand 1.[Figure not available: see fulltext.]
- Mo, Min,Yi, Tao,Zheng, Cong-Ye,Yuan, Mao-Lin,Fu, Hai-Yan,Li, Rui-Xiang,Chen, Hua
-
-
Read Online
- Nitrenium ions in N-chloro-α-amino acids decomposition?
-
This article deals with the kinetics of decomposition of four isomers: N - Cl-(L)-2-Aminohexanoic acid, N - Cl-(L)-Leucine, N - Cl-(L)-Isoleucine, and N - Cl-(L)-tert-Leucine, in mild acid and basic aqueous solution. An alternative mechanism for this process which takes place through a nitrenium-like ion transition state is proposed. This mechanism is in consonance with the experimental data and with those available from the literature.
- Armesto,Canle L.,Losada,Santaballa
-
-
Read Online
- Tungsten Complex Catalyzed Dehydrative Decarboxylation of 2,3-Dihydroxycarboxylic Acids
-
WOCl4 catalyzes dehydrative decarboxylation of 2,3-dihydrocarboxylic acids to enols, likely via β-lactone intermediates.Classical reagents for conversion of 3-hydroxycarboxylic acids to β-lactones fail with these substrates.
- Yu, Hye Kyung Bae,Schwartz, Jeffrey
-
-
Read Online
- Highly regioselective homogeneous isomerization-hydroformylation of 2-butene with water- and air-stable phosphoramidite bidentate ligand
-
Highly selective isomerization-hydroformylation of 2-butene was achieved with the presence of Rh(acac)(CO)2 and a phosphoramidite bidentate ligand which bearing 2,2′-dihydroxy-1,1′-binaphthyl backbone and N-indolyl substitute. The molar ratio of n- to isovaleraldehyde (217) is distinctly higher than the reported systems. NMR and IR revealed that the five-coordinate HRh(ligand)(CO)2 was an equatorial-equatorial configuration which contributed to the n-selectivity of valeraldehyde. The strong π-acceptor ability of ligand was suggested to play a key role in fast isomerization of 2-butene. Hydrolysis and oxidation experiments demonstrated that the ligand was water- and air-stable. Cyclic voltammetry measurement confirmed that this phosphoramidite ligand is more difficult to be oxidized, compared with the phosphine, phosphinite and phosphite ligands. Inspiringly, recycling experiments showed the catalytic system could work for at least 7 runs with unchanged selectivity.
- Tang, Songbai,Jiang, Yanxin,Yi, Jiwei,Duan, Xiaoxia,Fu, Haiyan,Li, Ruixiang,Yuan, Maolin,Chen, Hua,Yang, Chunji,Zheng, Xueli
-
-
Read Online
- Catalytic partial oxidation of cyclohexane in a single-gauze reactor
-
C6H12 catalytic partial oxidation in a single-gauze reactor produced ~ 85% selectivity to olefins and oxygenates at 25% C6H12 conversion and 100% oxygen conversion, with cyclohexene and 5-hexenal as the dominant products. Experiments were performed with a 90% platinum-10% rhodium single gauze (~ 90-μm wire diameter) at C6H12/O2 molar ratios of 0.4-5, flow rates of 1-3 std L/min, preheat temperatures of 100°-300°C, N2 dilution from 5% to the air composition, and 1.2-2 atm. The C6H12/O2 ratio was the most important variable for operation of the single-gauze reactor because temperatures, reactant conversions, and product selectivities all changed significantly as C6H12/O2 was varied. Low dilution favored olefin production while high dilution suppressed the homogeneous reactions necessary for oxygenate formation. Oxygenates were also favored by high flow rates and low inlet temperatures. Higher reactor pressures (≤ 2 atm) increased the yield of cyclohexene and 5-hexenal and allowed complete oxygen conversion. Cyclohexanone was produced with 5% selectivity at C6H12/O2 ~ 4. Reaction pathways for C6H12 partial oxidation were hypothesized, and the products were consistent with the proposed surface-assisted gas-phase sequences.
- O'Connor,Schmidt
-
-
Read Online
- Polymeric rhodium-containing catalysts in olefin hydroformylation
-
The main results obtained by studying hydroformylation of olefins on polymeric rhodium-containing catalysts are reviewed. Different types of N-containing polymeric ligands capable of hydroformylating under conditions of heterogeneous catalysis are considered. Possibilities of using water-soluble polymers containing quaternary ammonium groups are shown. The data on the influence of a polymeric matrix on the catalytic properties of the rhodium catalyst of olefin hydroformylation are presented.
- Slivinskii,Kolesnichenko
-
-
Read Online
- Copper mediated conversion of nitro compounds to aldehydes or ketones by dioxygen
-
Primary and secondary nitro compounds are easily transformed to aldehydes or ketones by dioxygen catalyzed by metallic copper.
- Balogh-Hergovich, Eva,Kaizer, Jozsef,Speier, Gabor
-
-
Read Online
- Delayed autocatalytic behavior of Mn(II) ions at a critical ratio: The effect of structural isomerism on permanganic oxidation of L-norleucine
-
The kinetics of the permanganic oxidation process of L-norleucine, L-leucine, L-isoleucine, and L-tert-leucine in strong acid medium has been investigated using a spectrophotometric technique. Conclusive evidences have proven autocatalytic activity of Mn(II) for these reactions in strong acid medium analogous to weak acid medium, but in the former, ratio of Mn(II) to amino acid concentration must reach a certain amount for autocatalytic phenomenon to emerge, which we call "critical ratio." This critical ratio depends on the nature of the amino acid employed. Thus considering "delayed autocatalytic behavior" of Mn(II) ions, rate equations satisfying observations for both catalytic and noncatalytic routes have been presented. Kinetic data in a noncatalytic pathway have been fitted to a biparametric equation including inductive, steric, and hyperconjugation correction effects, and it is determined that by shifting the side branch on a carbon chain toward an α-carbon atom (adjacent to amino acid's functional group) and also adding branches to the α-carbon atom, the reaction rate in the noncatalytic pathway decreases. Inductive and steric hindrance factors in amino acid's carbon chain are effective on processes' rate both in catalytic and noncatalytic pathways.
- Bahrami, Homayoon,Zahedi, Mansour
-
-
Read Online
- Combined synergetic and steric effects for highly selective hydrogenation of unsaturated aldehyde
-
Enhancing the selectivity to unsaturated alcohols for the hydrogenation of unsaturated aldehydes is of great importance and challenge. Herein, Pt-SnOx@ZIF-8 catalysts with combined synergetic and steric effects were designed for the hydrogenation of 2-pentenal. The selectivity to unsaturated alcohol was enhanced from 4.3% to 61.5% by the synergetic effect between SnOx and Pt active sites and was further enhanced to 80.9% by the steric effect of ZIF-8. In situ FTIR was used to investigate the surface reaction mode over the present catalysts. The results showed that SnOx acted as electrophilic sites for the adsorption and activation of the C[dbnd]O bond and the apertures of ZIF-8 oriented the C[dbnd]O adsorption on the active sites.
- Lan, Xiaocheng,Xue, Kaizhen,Wang, Tiefeng
-
-
Read Online
- Supported ionic liquid phase (SILP) catalyzed hydroformylation of 1-butene in a gradient-free loop reactor
-
The supported ionic liquid phase (SILP) catalysis technology was applied to gas-phase hydroformylation of 1-butene using sulfoxantphos 1 modified rhodium complexes. Kinetic experiments were performed in a fixed bed reactor and compared to a gradient-free gas-phase loop reactor (Berty type). The influence of substrate concentration, temperature and syngas pressure was determined. Data from fixed bed and Berty reactor were found to be in good agreement with respect to activation energy and reaction order. Ex-situ NMR studies of fresh and used SILP catalysts confirmed that the ligand remained intact after prolonged time on stream.
- Haumann, Marco,Jakuttis, Michael,Werner, Sebastian,Wasserscheid, Peter
-
-
Read Online
- Directed evolution of a pyruvate aldolase to recognize a long chain acyl substrate
-
The use of biological catalysts for industrial scale synthetic chemistry is highly attractive, given their cost effectiveness, high specificity that obviates the need for protecting group chemistry, and the environmentally benign nature of enzymatic procedures. Here we evolve the naturally occurring 2-keto-3-deoxy-6-phosphogluconate (KDPG) aldolases from Thermatoga maritima and Escherichia coli, into enzymes that recognize a nonfunctionalized electrophilic substrate, 2-keto-4-hydroxyoctonoate (KHO). Using an in vivo selection based on pyruvate auxotrophy, mutations were identified that lower the KM value up to 100-fold in E. coli KDPG aldolase, and that enhance the efficiency of retro-aldol cleavage of KHO by increasing the value of kcat/K M up to 25-fold in T. maritima KDPG aldolase. These data indicate that numerous mutations distal from the active site contribute to enhanced 'uniform binding' of the substrates, which is the first step in the evolution of novel catalytic activity.
- Cheriyan, Manoj,Walters, Matthew J.,Kang, Brian D.,Anzaldi, Laura L.,Toone, Eric J.,Fierke, Carol A.
-
-
Read Online
- Determination of aldehydic lipid peroxidation products with dabsylhydrazine by high-performance liquid chromatography
-
A high-performance liquid chromatographic method has been developed to measure adlehyde products of lipid peroxidation including n-alkanals, trans-2-alkenals, 4-hydroxy-2-nonenal, and malonaldehyde. The chromophoric reagent dabsylhydrazine reacts with various aldehydes produced from two different lipid peroxidation model systems: Fe2+/H2O2 and Fe3+/vitamin C oxidation of arachidonic and linoleic acids, respectively. The formed products were carefully characterized by IR, MS, and NMR spectral analysis and proved to be hydrazone rather than 2-pyrazoline or pyrrole derivatives. EI-MS of all the derivatized straight-chain aldehydes showed a characteristic (M - 28) fragment in the spectra with high consistency. Physicochemical properties including melting points are also described. The detection limits in the range of 11 pmol (5 ng) have been reached by using an NP Octadecyl C18 reversed-phase column. 4-Hydroxy-2-nonenal and hexanal were found to be the most abundant aldehydes in the lipid peroxidation systems described. The dose-response curve showed great linearity and exhibited good reproducibility of this procedure for quantitative estimation.
- Wu, Hung-Yi,Lin, Jen-Kun
-
-
Read Online
- Aerosol formation in the cyclohexene-ozone system
-
Atmospheric oxidation of certain VOCs can yield products with low vapor pressure resulting in the partitioning of the products into the aerosol phase, producing secondary organic aerosol. As cyclohexene is known to produce aerosol upon photooxidation, it was used as a model system for the molecular identification of gas- and aerosol-phase products via derivatization and MS detection. Adipic acid, hydroxyglutaric acid, and hydroxyadipic acid were among the compounds identified in the aerosol phase. Pentanal was the predominant product in the gas phase at a molar yield of 17%. Possible explanations for the presence of relatively high vapor pressure compounds in the aerosol phase are presented.
- Seinfeld,Kalberer,Yu,Cocker,Flagan
-
-
Read Online
- Two-phase Hydroformylation of Buta-1,3-diene and Hydrocarbon Mixtures Containing Buta-1,3-diene
-
The two-phase hydroformylation of buta-1,3-diene with (HRh(CO)[P(m-C6H4SO3Na) 3]3) the Kuntz catalyst system with excess P(m-C6H4SO3Na)3) gives high yields of C5-monoaldehydes. Main product in this mixture is the reactive trans- and cis-pent-3-enal. In consecutive reactions the pent-3-enal is partially hydrogenated to n-pentanal, but also - favoured by the protolytic milieu of the two-phase reaction - aldol condensated to 2-propenylheptadienal. The hydrogenation product of the propenylheptadienal, 2-propylheptanol-1, is a good plasticizer alcohol with a wanted low vapour pressure. Especially promising is the two-phase hydroformylation of the unrefined C4-fraction of the naphtha pyrolysis: after a more than 95 per cent conversion of the buta-1,3-diene also more than 80 per cent of the n-but-1-ene in the C4-fraction is hydroformylated mainly to wanted n-pentanal. Less than 5-10% of the n-but-2-enes and the isobutene in the C4-fraction react under these conditions to oxo-products (2- and 3-methylbutanal). Acetylenic compounds in the C4-fraction are converted quantitatively into products.
- Fell, Bernhard,Hermanns, Peter,Bahrmann, Helmut
-
-
Read Online
- Asymmetric catalysis. Part 127: Enantioselective desymmetrization of 2- n-butyl-4,7-dihydro-1,3-dioxepin with (η6-arene)ruthenium(II) half-sandwich complexes
-
(η6-Arene)ruthenium half-sandwich complexes are highly active and stereoselective catalysts in the enantioselective desymmetrization of 2-n- butyl-4,7-dihydro-1,3-dioxepin to give 2-n-butyl-4,5-dihydro-1,3-dioxepin. Enantioselectivities up to 61% ee were achieved. The temperature and solvent dependence of the catalysis as well as the activation of the catalyst were investigated.
- Brunner, Henri,Prommesberger, Markus
-
-
Read Online
- Highly selective catalyst systems for the hydroformylation of internal olefins to linear aldehydes
-
Readily accessible and highly efficient: Substituted 2,2′-bis(diphenylphosphanylmethyl)-1,1′-binaphthyl (NAPHOS) ligands 1 can be readily prepared from 2,2′-bis(dichlorophosphanylmethyl)-1,1′-binaphthyl. Especially ligands with electron-withdrawing aryl substituents (for example, 3,4,5-F3C6H2 (instead of Ph), 1a) show a remarkable high activity and n:i selectivity in the rhodium-catalyzed hydroformylation of internal olefins (see scheme).
- Klein, Holger,Jackstell, Ralf,Wiese, Klaus-Diether,Borgmann, Cornelia,Beller, Matthias
-
-
Read Online
- Kinetics of the Reversible β-Scission of the Cyclopentyloxy Radical
-
The reaction of N-(cyclopentyloxy)pyridine-2-thione (6) with tributylstannane in benzene constitutes a clean experimental system for a kinetic study of the β-scission of the cyclopentyloxy radical (1).Product distributions are reported as a function of tributylstannane concentration over a temperature range of 6-80 deg C.The results are consistent with a mechanism involving a reversible β-scission.Arrhenius parameters for the β-scission of the cyclopentyloxy radical (1) are log A (s-1)=12.55+/-0.41 and Ea=6.26+/-0.54 kcal/mol, while those for the reverse reaction, the 1,5-exo cyclization of the 4-formylbutyl radical (2), are log A (s-1)=10.2+/-0.3 and Ea=6.88+/-0.46 kcal/mol.The observed equilibrium constants and activation parameters are compared with theoretical calculations including group-additivity equilibrium constants and AM1-UHF activation parameters.
- Beckwith, Athelstan L. J.,Hay, Benjamin P.
-
-
Read Online
- Generation of Alkoxyl Radicals from O-Alkyl Benzenesulphenates
-
Representative examples (1, 2, and 3) of primary, secondary, and tertiary alkyl benzenesulphenates, when treated with tributylstannane, generate alkoxy radicals which undergo characteristic β-scission or intramolecular addition reactions; the rate constants of these processes have been determined.
- Beckwith, Athelstan L.,Hay, Benjamin P.,Williams, Geoffrey M.
-
-
Read Online
- Ring Opening of Biomass-Derived Cyclic Ethers to Dienes over Silica/Alumina
-
We show that cyclic ethers, such 2-methyltetrahydrofuran (2-MTHF), can undergo dehydration to produce pentadienes over SiO2/Al2O3. The catalyst exhibited reversible deactivation due to coke deposition, with the yield to pentadienes decreasing from 68% to 52% at 623 K over 58 h time on stream. A reaction network for 2-MTHF dehydration was proposed on the basis of the results of space time studies. Pentadienes can be produced directly by a concerted hydride shift and dehydration of carbenium intermediates or indirectly through dehydration of pentanal and pentenol. Reaction kinetics studies were performed at temperatures ranging from 573 to 653 K and 2-MTHF partial pressures from 0.21 to 2.51 kPa. The apparent activation energy barrier for 2-MTHF conversion to pentadienes and the reaction rate order for ring opening were determined to be 74 kJ mol-1 and 0.24, respectively, indicating strong interaction between 2-MTHF and the SiO2/Al2O3 surface. Other solid acids such as γ-Al2O3, H-ZSM-5, and Al-Sn-Beta were found to be active for 2-MTHF dehydration to pentadienes. The rate of ring opening decreased in the order 2,5-dimethyltetrahydrofuran > 2-MTHF > tetrahydropyran > tetrahydrofuran. Over SiO2/Al2O3, the dehydration of 2,5-dimethyltetrahydrofuran resulted in 75% yield to hexadiene isomers. (Figure Presented).
- Kumbhalkar, Mrunmayi D.,Buchanan, J. Scott,Huber, George W.,Dumesic, James A.
-
-
Read Online
- HAPs release from wood drying
-
Hazardous Air Pollutant (HAP) profiles from drying softwood and hardwood flakes (for the manufacture of oriented strand board) are very similar, indicating that they originate through a common mechanism, the breakdown of wood tissue. Hence, the strategies employed to reduce VOC (volatile organic compound) emissions from hardwood can also be extended to decreasing HAPs from softwood. Drying aspen flakes in the field and in the laboratory gives rise to different VOC species, and direct extension of laboratory data to the field may prove difficult. Formaldehyde emissions from drying fresh aspen flakes are lower than those from stored material; the opposite effect occurs for methanol and the other aldehydes. HAPs evolved from drying pine flakes surge sharply at 5-10% moisture content during drying at 130-160 °C. Emissions of methanol, formaldehyde, pentanal, and hexanal all begin simultaneously, with the release of methanol and formaldehyde being the most sensitive to dryer temperature. Hence, the nature of the VOC mix is partly governed by the dryer temperature. Pine and aspen give rise to similar HAPs profiles during either drying or pressing flakes that are already dried.
- Otwell, Lawrence P.,Hittmeier, Michael E.,Hooda, Usha,Yan, Hui,Su, Wei,Banerjee, Sujit
-
-
Read Online
- Direct Production of Higher Oxygenates by Syngas Conversion over a Multifunctional Catalyst
-
Selective synthesis of higher oxygenates (linear α-alcohols and α-aldehydes, C2+OH) from syngas is highly attractive but remains challenging owing to the low C2+OH selectivity and low catalytic stability. Herein we introduce a multifunctional catalyst composed of CoMn and CuZnAlZr oxides that dramatically increased the oxygenates selectivity to 58.1 wt %, where more than 92.0 wt % of the produced oxygenates are C2+OH. Notably, the total selectivity to value-added chemicals including oxygenates and olefins reached 80.6 wt % at CO conversion of 29.0 % with high stability. The appropriate component proximity can effectively suppress the formation of the undesired C1 products, and the selectively propulsion of reaction network by synergetic effect of different components contributes to the enhanced selectivity to higher oxygenates. This work provides an alternative strategy for the rational design of new catalysts for direct conversion of syngas into higher oxygenates with co-production of olefins.
- Lin, Tiejun,Qi, Xingzhen,Wang, Xinxing,Xia, Lin,Wang, Caiqi,Yu, Fei,Wang, Hui,Li, Shenggang,Zhong, Liangshu,Sun, Yuhan
-
-
Read Online
- Photoepoxidation of Propylene at Elevated Pressures Sensitized by α-Diketones
-
The α-diketone sensitized photooxygenation of saturated propylene solutions (o-dichlorobenzene) at atmospheric pressure proceeds with high selectivity to propylene oxide.The effect of changing sensitizer concentration on the rate of epoxidation was determined for biacetyl, 1-phenyl-1,2-propanedione, and benzil.A small enhancement of the rate was achieved by using mixtures of biacetyl and 1-phenyl-1,2-propanedione.Pressurization of the reaction (140-185 psia) allowed the use of greater solution concentrations of propylene and oxygen and resulted in significant rateenhancement.In concentrated propylene solutions (3.2 M) the formation of epoxide decreased as oxidative cleavage to acetaldehyde and formaldehyde increased.Total propylene conversion remained relatively constant at these concentrations.
- Shepherd, James P.
-
-
Read Online
- Tuning Selectivity in Aliphatic C-H Bond Oxidation of N-Alkylamides and Phthalimides Catalyzed by Manganese Complexes
-
Site selective C-H oxidation of N-alkylamides and phthalimides with aqueous hydrogen peroxide catalyzed by manganese complexes is described. These catalysts are shown to exhibit substantially improved performance in product yields and substrate scope in comparison with their iron counterparts. The nature of the amide and imide group and of the N-alkyl moiety are shown to be effective tools in order to finely tune site selectivity between proximal (adjacent to the nitrogen) and remote C-H bonds on the basis of steric, electronic, and stereoelectronic effects. Moreover, formation of the α-hydroxyalkyl product in good yield and with excellent product chemoselectivity was observed in the reactions of the pivalamide and acetamide derivatives bearing an α-CH2 group, pointing again toward an important role played by stereoelectronic effects and supporting the hypothesis that these oxidations proceed via hydrogen atom transfer (HAT) to a high-valent manganese-oxo species. Good product yields and mass balances are obtained in short reaction times and under mild experimental conditions when relatively low loadings of an electron-rich manganese catalyst are used. The potential utility of these reactions for preparative purposes is highlighted in the site-selective oxidation of the pivalamide and phthalimide derivatives of substrates of pharmaceutical interest.
- Milan, Michela,Carboni, Giulia,Salamone, Michela,Costas, Miquel,Bietti, Massimo
-
-
Read Online
- Catalytic deprotection of acetals in basic solution with a self-assembled supramolecular "nanozyme"
-
(Formula Presented) Changing on the inside: Acetals are a commonly used protecting groups for aldehydes and ketones in organic synthesis because of their ease of installation and resistance to cleavage in neutral or basic solution. A self-assembled supramolecular assembly has been shown to catalyze the hydrolysis of acetals and ketals in basic solution (see scheme).
- Pluth, Michael D.,Bergman, Robert G.,Raymond, Kenneth N.
-
-
Read Online
- Modification of rhodium carbonyl catalysts for hydroformylation of 2-butenes by organophosphorus ligands
-
The influence of the nature of the organophosphorus ligand and the P/Rh molar ratio on the catalytic properties of rhodium caibonyl complexes in hydroformylation of 2-butencs was studied. The difference between phosphine and phosphite ligands during the formation of highly selective catalytic complexes was found. It was supposed that a decrease in the selectivity with respect to 2-methylbutanal is due to the isomerization of olefins under conditions of a decrease in the competitive capability of CO for coordination sites (the high P/Rh ratio, a decrease in the total pressure of the synthesis-gas).
- Kolesnichenko,Markova,Teleshev,Slivinskii
-
-
Read Online
- Oxidative cleavage of vic-diols to aldehydes with dioxygen catalyzed by Ru(PPh3)3Cl2 on active carbon
-
Formula presented A variety of vic-diols were first successfully cleaved to the corresponding aldehydes with dioxygen catalyzed by Ru(PPh3)3Cl2 on active carbon in fair to good yields. For example, treatment of 1,2-octandiol and 1,2-cyclooctanediol with dioxygen in the presence of Ru(PPh3)3Cl2/C in PhCF3 at 60°C for 15 h produced heptanal and 1,8-octanedial in 77% and 76% yields, respectively.
- Takezawa, Eiichiro,Sakaguchi, Satoshi,Ishii, Yasutaka
-
-
Read Online
- Studies on the oxidation of α-amino acids by N-bromo oxidants: Kinetics of the reaction of bromide ion with N-bromoacetamide
-
The rate of oxidation of amino acids (AA) by N-Bromoacetamide (NBA) was studied in aqueous buffered medium at 35°C. The rate of disappearance of (NBA) is catalyzed by the Br- produced from the reduction of NBA. Analysis of the autocatalyzed reaction gives the kinetic data for the oxidation of bromide ion by NBA. The results suggest that the protonated NBA reacts with Br- to form Br2 which rapidly oxidizes amino acids. The rate constant for the reaction between protonated NBA and Br- at 35°C is estimated. 1996 John Wiley & Sons, Inc.
- Ramachandran,Easwaramoorthy,Malim Maniraj
-
-
Read Online
- Discovery of Anti-TNBC Agents Targeting PTP1B: Total Synthesis, Structure-Activity Relationship, in Vitro and in Vivo Investigations of Jamunones
-
Twenty-three natural jamunone analogues along with a series of jamunone-based derivatives were synthesized and evaluated for their inhibitory effects against breast cancer (BC) MDA-MB-231 and MCF-7 cells. The preliminary structure-activity relationship revealed that the length of aliphatic side chain and free phenolic hydroxyl group at the scaffold played a vital role in anti-BC activities and the methyl group on chromanone affected the selectivity of molecules against MDA-MB-231 and MCF-7 cells. Among them, jamunone M (JM) was screened as the most effective anti-triple-negative breast cancer (anti-TNBC) candidate with a high selectivity against BC cells over normal human cells. Mechanistic investigations indicated that JM could induce mitochondria-mediated apoptosis and cause G0/G1 phase arrest in BC cells. Furthermore, JM significantly restrained tumor growth in MDA-MB-231 xenograft mice without apparent toxicity. Interestingly, JM could downregulate phosphatidylinositide 3-kinase (PI3K)/Akt pathway by suppressing protein-tyrosine phosphatase 1B (PTP1B) expression. These findings revealed the potential of JM as an appealing therapeutic drug candidate for TNBC.
- Hu, Caijuan,Li, Guoxun,Mu, Yu,Wu, Wenxi,Cao, Bixuan,Wang, Zixuan,Yu, Hainan,Guan, Peipei,Han, Li,Li, Liya,Huang, Xueshi
-
-
Read Online
- Rapid Identification and Quantification of Linear Olefin Isomers by Online Ozonolysis-Single Photon Ionization Time-of-Flight Mass Spectrometry
-
The specific locations of the double bonds in linear olefins can facilitate olefin catalytic synthetic reactions to improve the quality of target olefin products. We developed a simple and efficient approach based on single photon ionization time-of-flight mass spectrometry (SPI-TOFMS) combined with online ozonolysis to identify and quantify the linear olefin double bond positional isomers. The online ozonolysis cleaved the olefins at the double bond positions that led to formation of corresponding characteristic aldehydes. The aldehydes were then detected by SPI-TOFMS to achieve unique spectrometric "fingerprints" for each linear olefin to successfully identify the isomeric ones. To accurately quantify the isomeric components in olefin mixtures, an algorithm was proposed to quantify three isomeric olefin mixtures based on characteristic ion intensities and their equivalent ionization coefficients. The relative concentration errors for the olefin components were lower than 2.5% while the total analysis time was less than 2 min. These results demonstrate that the online ozonolysis SPI-TOFMS has the potential for real-time monitoring of catalytic olefin synthetic reactions.
- Xie, Yuanyuan,Chen, Ping,Hua, Lei,Hou, Keyong,Wang, Yongchao,Wang, Haiyan,Li, Haiyang
-
-
Read Online
- Propanol formation from CO2 and C2H4 with H2 over Au/TiO2: Effect of support and K doping
-
The direct conversion of CO2 with C2H4 and H2 into propanol was investigated over K-promoted Au/TiO2-r (rutile) and Au/TiO2-a (anatase) catalysts at 473 K and 523 K. For both catalytic systems, the propanol selectivity increased with rising K loading, while the conversion of CO2 decreased. Both effects of the promoter diminished at 523 K. However, irrespective of K loading and reaction temperature, K-Au/TiO2-r materials showed higher propanol selectivity than K-Au/TiO2-a. In addition, the non-desired conversion of ethylene into ethane over the rutile-based catalysts decreased with rising temperature from 473 K to 523 K, while an increase was observed for the anatase-based materials. Taking into account the results of HAADF-STEM analysis, the metal-support interaction influencing both size and distribution of Au species was assumed to be a reason for the support effect on the target and side reactions.
- Ahlers, Stefan J.,Kraehnert, Ralph,Kreyenschulte, Carsten,Pohl, Marga-Martina,Linke, David,Kondratenko, Evgenii V.
-
-
Read Online
- Products of the gas-phase reactions of O3 with alkenes
-
The products of the gas-phase reactions of O3 with 1-pentene, 1-hexene, 1-heptene, 1-octene, 2,3-dimethyl-1-butene, cyclopentene, and 1-methyl-cyclohexene have been investigated at room temperature and 740 Torr total pressure of air in the presence of cyclohexane or n-octane to scavenge OH radicals. Products were identified and quantified by gas chromatography and in situ Fourier transform infrared absorption spectroscopy. The presence of cyclohexene, showed the formation of OH radicals from these O3 reactions. The carbonyl products were identified and quantified. -from Authors
- Atkinson,Tuazon,Aschmann
-
-
Read Online
- Properties and applications of sodium (5-methyl-2-alkyl-1,3-dioxane-5-yl)-carboxylate synthesized with nanosolid superacid
-
A series of novel sodium (5-methyl-2-alkyl-1,3-dioxane-5-yl) carboxylate surfactants were synthesized using nanosolid superacid SO2-4 /Fe2O3 as a catalyst and characterized by 1H NMR, IR and elemental analysis. The critical micelle concentration (CMC) of surfactants was determined and the results showed that the CMC values were less than 2.0× 10-3 mol/L. Other relevant surface properties (Krafft point, emulsion stability, foam ability, degradability) were also evaluated. It was suggested that with respect to emulsion formation, foam stability and the range of application temperature, compared with traditional surfactants, the new surfactants could give better results and showed better properties when used as an emulsifier in emulsion polymerization. In addition, the surfactants were stable under neutral and alkaline conditions, and could form solid under acid condition. The solid will generate the original surfactants for reuse with alkali. Sodium (5-methyl-2-alkyl-1,3-dioxane-5-yl) carboxylate is likely to be a new type of 'environmentally friendly' surfactant.
- Yuan, Lin,Jia, Guo Kai,Li, Zhong Yan,Zhang, Min,Yuan, Xian You
-
-
Read Online
- Ligand-modified rhodium catalysts on porous silica in the continuous gas-phase hydroformylation of short-chain alkenes-catalytic reaction in liquid-supported aldol products
-
Ligand-modified Rh complexes were physically adsorbed on the surface of porous silica. The resulting materials were subjected to the continuous gas-phase hydroformylation of C2 and C4 alkenes. The ligands used for catalyst modification were bidentate phosphorus ligands known from the literature, namely, sulfoxantphos (1) and a benzopinacol-based bulky diphosphite 2. The tested catalyst materials were active and, in particular, selective as in comparable homogeneous liquid-phase experiments. Long-term stability experiments over 1000h on stream showed minor deactivation. A significant increase in the catalyst mass after the reaction was detected by weighing and thermogravimetric analysis. By using headspace-GC-MS, the mass increase could be attributed to high-boiling compounds, which are formed insitu during the catalytic reaction itself and accumulate inside the pores of the support. Evidence is given that the initially physisorbed catalyst complexes dissolve in the high-boiling aldol side-products, which are suitable solvents for the active catalyst species and provide a liquid-phase environment held by capillary forces on the support. It's all in the pores! Ligand-modified Rh complexes are physically adsorbed onto the surface of porous silica and the resulting solid materials are subjected to continuous gas-phase hydroformylation of C2 and C4 alkenes. The catalyst materials were surprisingly active and, in particular, exhibited similar selectivity to liquid-phase reactions.
- Schoenweiz, Andreas,Debuschewitz, Jonas,Walter, Simon,Woelfel, Rene,Hahn, Hanna,Dyballa, Katrin M.,Franke, Robert,Haumann, Marco,Wasserscheid, Peter
-
-
Read Online
- Synthesis of Adipic Acid, 1,6-Hexanediamine, and 1,6-Hexanediol via Double-n-Selective Hydroformylation of 1,3-Butadiene
-
A method for the synthesis of the industrially relevant monomers adipic acid, 1,6-hexanediol (HDO), and 1,6-hexanediamine (HMD) via isomerizing hydroformylation of 1,3-butadiene is described. The aldehyde intermediates are protected in situ as acetals to avoid hydrogenation to pentanal. Adipic aldehyde diacetal is obtained in good yields, and the first examples for the conversion toward adipic acid, 1,6-hexanediol, and 1,6-hexanediamine are shown.
- Mormul, Jaroslaw,Breitenfeld, Jan,Trapp, Oliver,Paciello, Rocco,Schaub, Thomas,Hofmann, Peter
-
-
Read Online
- Products of the Gas-Phase Reactions of a Series of 1-Alkenes and 1-Methylcyclohexene with the OH Radical in the Presence of NO
-
The products of the gas-phase reactions of the OH radical with 1-pentene, 1-hexene, 1-heptene, 1-octene, 2,3-dimethyl-1-butene, and 1-methylcyclohexene have been investigated in the presence of NO at room temperature and 740 Torr total pressure of air. Products were identified and quantified by gas chromatography and in situ Fourier transform infrared absorption spectroscopy. The carbonyl products identified and their yields were as follows: from 1-pentene, butanal (0.73 +/- 0.09) and HCHO (0.88 +/- 0.11); from 1-hexene, pentanal (0.46 +/- 0.07) and HCHO (0.57 +/- 0.08); from 1-heptene, hexanal (0.30 +/- 0.04) and HCHO (0.49 +/- 0.06); from 1-octene, heptanal (0.21 +/- 0.03) and HCHO (0.39 +/- 0.06); from 2,3-dimethyl-1-butene, acetone (0.27 +/- 0.04), 3-methyl-2-butanone, (0.45 +/- 0.06), and HCHO (0.50 +/- 0.04); and from 1-methylcyclohexene, 5-acetylpentanal (0.31 +/- 0.08). These product yield data suggest that the intermediate β-hydroxyalkoxy radicals undergo isomerization and/or reaction with O2 in competition with decomposition, and the decrease in the carbonyl and HCHO yields with increasing carbon number in the 1-alkenes 1-pentene through 1-octene suggests that isomerization of the intermediate β-hydroxyalkoxy radical is occurring.
- Atkinson, Roger,Tuazon, Ernesto C.,Aschmann, Sara M.
-
-
Read Online
- Rational design of stereoselectivity in the class II pyruvate aldolase BphI
-
BphI, a pyruvate-specific class II aldolase, catalyzes the reversible carbon-carbon bond formation of 4-hydroxy-2-oxoacids up to eight carbons in length. During the aldol addition catalyzed by BphI, the S-configured stereogenic center at C4 is created via attack of a pyruvate enolate intermediate on the si face of the aldehyde carbonyl of acetaldehyde to form 4(S)-hydroxy-2-oxopentanoate. Replacement of a Leu-87 residue within the active site of the enzyme with polar asparagine and bulky tryptophan led to enzymes with no detectable aldolase activity. These variants retained decarboxylase activity for the smaller oxaloacetate substrate, which is not inhibited by excess 4-hydroxy-2-oxopentanoate, confirming the results from molecular modeling that Leu-87 interacts with the C4-methyl of 4(S)-hydroxy-2-oxoacids. Double variants L87N;Y290F and L87W;Y290F were constructed to enable the binding of 4(R)-hydroxy-2-oxoacids by relieving the steric hindrance between the 5-methyl group of these compounds and the hydroxyl substituent on the phenyl ring of Tyr-290. The resultant enzymes were shown to exclusively utilize only 4(R)- and not 4(S)-hydroxy-2-oxopentanoate as the substrate. Polarimetric analysis confirmed that the double variants are able to synthesize 4-hydroxy-2-oxoacids up to eight carbons in length, which were the opposite stereoisomer compared to those produced by the wild-type enzyme. Overall the kcat/K m values for pyruvate and aldehydes in the aldol addition reactions were affected 10-fold in the double variants relative to the wild-type enzyme. Thus, stereocomplementary class II pyruvate aldolases are now available to create chiral 4-hydroxy-2-oxoacid skeletons as synthons for organic reactions.
- Baker, Perrin,Seah, Stephen Y. K.
-
-
Read Online
- Magnetic Polystyrene Nanosphere Immobilized TEMPO: A Readily Prepared, Highly Reactive and Recyclable Polymer Catalyst in the Selective Oxidation of Alcohols
-
The 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical immobilized on the magnetic polystyrene nanospheres (MPNs) was used as a recyclable catalyst in the oxidation of various alcohols. The new and simply prepared heterogeneous TEMPO/MPNs exhibits both similar versatility and efficiency to homogeneous TEMPO under basic Montanari conditions. The excellent stability of the MPNs enables the TEMPO/MPNs to be recycled more than 20times without significant leaching of immobilized TEMPO radicals or degradation of Fe3O4 nanoparticles. Moreover, the magnetic response ensures the rapid separation and quantitative recycling of TEMPO/MPNs by simple magnetic decantation.
- Zheng, Zhi,Wang, Jianli,Zhang, Miao,Xu, Lixin,Ji, Jianbing
-
-
Read Online
- Green, homogeneous oxidation of alcohols by dimeric copper(II) complexes
-
Three pyrazole derivatives, 3,5-dimethyl-1H-pyrazole (DMPz) (I), 3-methyl-5-phenyl-1H-pyrazole (MPPz) (II), and 3,5-diphenyl-1H-pyrazole (DPPz) (III), were prepared via reacting semicarbazide hydrochloride with the acetylacetone, 1-phenylbutane-1,3-dione, and 1,3-diphenylpropane-1,3-dione, respectively. Complexes 1–3 were isolated by reacting CuCl2·2H2O with I–III, respectively, and characterized by CHNS elemental analyses, FT-IR, UV-Vis, 1H and 13C NMR, EPR spectra, and TGA/DTA. Molecular structures of the pyrazole derivatives I–III and copper(II) complexes 2 and 3 were studied through single-crystal XRD analysis to confirm their molecular structures. Overlapping of hyperfine splitting in the EPR spectra of the dimeric copper(II) complexes 1–3 indicates that both copper centers do not possess the same electronic environment in solution. The copper(II) complexes are dimeric in solid state as well as in solution and catalyze the oxidation of various primary and secondary alcohols selectively. Catalysts 1–3 show more than 92% product selectivity toward ketones during the oxidation of secondary alcohols. Surprisingly primary alcohols, which are relatively difficult to oxidize, produce carboxylic acid as a major product (48%–90% selectivity) irrespective of catalytic systems. The selectivity for carboxylic acid rises with decreasing the carbon chain length of the alcohols. An eco-friendly and affordable catalytic system for oxidation of alcohols is developed by the utilization of H2O2, a green oxidant, and water, a clean and greener solvent, which is a notable aspect of the study.
- Maurya, Abhishek,Haldar, Chanchal
-
p. 885 - 904
(2020/12/18)
-
- SBA15-supported nano-ruthenium catalyst for the oxidative cleavage of alkenes to aldehydes under flow conditions
-
SBA15-supported ruthenium nanoparticles were prepared and employed as catalytic system for the oxidative cleavage of olefins under flow conditions. Design of experiments was adopted to optimize the reaction parameters and was instrumental to develop a fast and robust method for producing aldehydes from alkenes. Utilizing a simple flow set-up, the process provided high conversions in only few minutes with 0.5% mol of ruthenium under mild reaction conditions and high flow rates.
- Di Michele, Alessandro,Giovagnoli, Stefano,Filipponi, Paolo,Venturoni, Francesco,Gioiello, Antimo
-
-
- MANUFACTURING METHOD FOR THE ALDEHYDE BY HYDROFORMYLATION REACTION
-
A phosphine ligand represented by chemical formula 1. Transition metal catalyst A hydroformylation catalyst composition comprising a solvent and a solvent. Provided is a process for preparing aldehydes by hydroformylation using olefinic compounds and formaldehyde to produce aldehydes.
- -
-
Paragraph 0079-0081; 0083-0084; 0101
(2021/07/13)
-
- Method for synthesizing valeraldehyde
-
The invention discloses a method for synthesizing valeraldehyde, which is characterized by comprising the following steps: adding a catalyst and an organic solvent into a reaction kettle, adding n-butene in a closed state, and introducing a mixed gas of CO and H2; heating the reaction kettle for reaction; wherein the catalyst is an N-heterocyclic carbene cobalt complex. Compared with the prior art, the N-heterocyclic carbene cobalt complex can be prepared by using a direct and rapid method, meanwhile, reagents with strong toxicity are not used, and the conditions are mild, so that the N-heterocyclic carbene cobalt complex is a good alternative reaction system of a phosphine ligand catalytic system; the method is simple in synthesis process and low in cost, and has a relatively high industrial application prospect.
- -
-
Paragraph 0030; 0032-0052
(2021/03/11)
-
- 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)
-
- Solvent-free oxidation of straight-chain aliphatic primary alcohols by polymer-grafted vanadium complexes
-
Oxidovanadium(IV) complexes [VO(tertacac)2] (1), [VO(dipd)2] (2), and [VO(phbd)2] (3) were synthesized by reacting [VO(acac)2] with 2,2,6,6-tetramethyl-3,5-hepatanedione, 1,3-diphenyl-1,3-propanedione, and 1-phenyl-1,3-butanedione, respectively. Imidazole-modified Merrifield resin was used for the heterogenization of complexes 1–3. During the process of heterogenization, the V4+ center in complex 2 converts into V5+, whereas the other two complexes 1 and 3 remain in the oxidovanadium(IV) state in the polymer matrix. Theoretically, calculated IPA values of 1–3 suggest that 2 is prone to oxidation compared with 1 and 3, which was also supported by the absence of EPR lines in 5. Polymer-supported complexes Ps-Im-[VIVO(tertacac)2] (4), Ps-Im-[VVO2(dipd)2] (5), and Ps-Im-[VIVO(phbd)2] (6) were applied for the solvent-free heterogenous oxidation of a series of straight-chain aliphatic alcohols in the presence of H2O2 at 60°C and showed excellent substrate conversion specially for the alcohols with fewer carbon atoms. Higher reaction temperature improves the substrate conversion significantly for the alcohols containing more carbon atoms such as 1-pentanol, 1-hexanol, and 1-heptanol while using optimized reaction conditions. However, alcohols with fewer carbon atoms seem less affected by reaction temperatures higher than the optimized temperature. A decreasing trend in the selectivity(%) of carboxylic acid was observed with increasing carbon atoms among the examined alcohols, whereas the selectivity towards aldehydes increased. The order of efficiency of the supported catalysts is 4 > 6 > 5 in terms of turnover frequency (TOF) values and substrate conversion, further supported by theoretical calculations.
- Chaudhary, Nikita,Haldar, Chanchal,Kachhap, Payal
-
-
- Synthesis of Chiral Amines via a Bi-Enzymatic Cascade Using an Ene-Reductase and Amine Dehydrogenase
-
Access to chiral amines with more than one stereocentre remains challenging, although an increasing number of methods are emerging. Here we developed a proof-of-concept bi-enzymatic cascade, consisting of an ene reductase and amine dehydrogenase (AmDH), to afford chiral diastereomerically enriched amines in one pot. The asymmetric reduction of unsaturated ketones and aldehydes by ene reductases from the Old Yellow Enzyme family (OYE) was adapted to reaction conditions for the reductive amination by amine dehydrogenases. By studying the substrate profiles of both reported biocatalysts, thirteen unsaturated carbonyl substrates were assayed against the best duo OYE/AmDH. Low (5 %) to high (97 %) conversion rates were obtained with enantiomeric and diastereomeric excess of up to 99 %. We expect our established bi-enzymatic cascade to allow access to chiral amines with both high enantiomeric and diastereomeric excess from varying alkene substrates depending on the combination of enzymes.
- Fossey-Jouenne, Aurélie,Jongkind, Ewald P. J.,Mayol, Ombeline,Paul, Caroline E.,Vergne-Vaxelaire, Carine,Zaparucha, Anne
-
-
- Chromium-Catalyzed Production of Diols From Olefins
-
Processes for converting an olefin reactant into a diol compound are disclosed, and these processes include the steps of contacting the olefin reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the diol compound. While being contacted, the olefin reactant and the supported chromium catalyst can be irradiated with a light beam at a wavelength in the UV-visible spectrum. Optionally, these processes can further comprise a step of calcining at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
- -
-
Paragraph 0111
(2021/03/19)
-
- Method for preparing aldehyde compounds by oxidative cleavage of carbon-carbon bonds of terminal alkene compounds
-
The invention discloses a method for preparing aldehyde compounds by oxidizing and breaking carbon-carbon bonds of terminal alkene compounds. The method comprises the following steps: adding an alkene-terminated compound, an additive and a nitrogen-doped mesoporous carbon-loaded monatomic catalyst into a fatty primary alcohol solvent, putting into a pressure container, sealing, introducing oxygen source gas with a certain pressure, controlling the pressure of the oxygen source gas to be 0.1-1MPa and the reaction temperature to be 80-150 DEG C, and obtaining a reaction product, namely the aldehyde compound. The nitrogen-doped mesoporous carbon-loaded monatomic catalyst adopted by the invention is high in activity, the highest separation yield of the aldehyde compound as a reaction product reaches 99%, the method is wide in application range, the reaction conditions are easy to control, the catalyst can be recycled, the post-treatment is simple, and the method is suitable for industrial production.
- -
-
Paragraph 0079-0080; 0089-0090
(2021/06/06)
-
- Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
-
The function of ammonium salts on the epoxidation performance over Ti-BEA zeolite was investigated in detail. Experiments of alkene epoxidation, side reactions of epoxide and decomposition of H2O2 with or without ammonium salts were designed, and the UV-Vis spectroscopy was employed to analyze the structure of Ti-hydroperoxo species. It is revealed that the ammonia (or amines) dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3?H2O (NH3/Ti>1) or NaOH bond with the Ti-η2(OOH)-R species and generate salt-like Ti-η2(OO)-M+ species, resulting in the deactivation of Ti active center. While for ammonium salts, e.g. NH4Cl, the limited dissociation degree along with the acidic environment help the Ti active center to maintain in highly active. In short, this work provides a practical Ti active center tuning method for Ti-BEA zeolite, as well as a thorough understanding of its Ti-hydroperoxo species.
- Liang, Xiaohang,Liu, Dan,Luo, Yibin,Peng, Xinxin,Shu, Xingtian,Xia, Changjiu
-
-
- Method for synthesizing fluorescent dye intermediate aldehyde by hydroformylation of 1,3-diene compound
-
The invention discloses a method for synthesizing a fluorescent dye intermediate aldehyde by hydroformylation of 1,3-diene compound. The method comprises the following steps: S1, sequentially adding 0.01 mmol (1 mol%) of [Rh(cod)Cl]2, 0.1 mmol of a phosphine ligand(P/Rh=10/1) and 1 mmol of diene into a reaction flask, adding 1 ml of a solvent DMF, putting the reaction flask into a high-pressure reaction kettle, after the reaction is finished, transferring a mixed solution into a 25 mL glass bottle with 200 microliters of n-tridecane as an internal standard by using a rubber head dropper, and detecting; and S2, determining the product yield and the structure through a gas chromatograph and a nuclear magnetic resonance spectrum, wherein the obtained olefin conversion rate is larger than 99%, the aldehyde yield ranges from 61% to 99%, and the regioselectivity of the product aldehyde ranges from 70/30 to 100/0. According to the method disclosed by the invention, the separation and purification steps of aldehyde products are simplified, and the substrate of the dialkene hydroformylation reaction is excellent in universality.
- -
-
Paragraph 0053-0054; 0056-0057
(2021/08/07)
-
- Preparation of novel biphenyl tetradentate phosphite ligand and application of novel biphenyl tetradentate phosphite ligand in mixed/etherified C4 hydroformylation reaction
-
The invention discloses a preparation method of a novel biphenyl tetradentate phosphite ligand 2, 2 ', 6, 6'-tetra [(1, 1 'biphenyl-2, 2'-diyl) phosphite]-3, 3 ', 5, 5'- tetra-tert-butyl -1, 1- 'biphenyl and derivatives thereof. The novel biphenyl tetradentate phosphite ligand has a structure as shown in general formula I, wherein a substituent R in the general formula I can be a cyclic phosphinestructure. Meanwhile, the invention discloses an application in a mixed/etherified C4 (butene) hydroformylation reaction system taking a novel biphenyl tetradentate phosphite ligand as a ligand.
- -
-
Paragraph 0071-0075
(2020/11/23)
-
- Highly active and durable WO3/Al2O3catalysts for gas-phase dehydration of polyols
-
Gas-phase glycerol dehydration over WO3/Al2O3catalysts was investigated. WO3loading on γ-Al2O3significantly affected the yield of acrolein and the catalyst with 20 wt% WO3loading showed the highest activity. The WO3/Al2O3catalyst with 20 wt% WO3loading showed higher activity and durability than the other supported WO3catalysts and zeolites. The number of Br?nsted acid sites and mesopores of the WO3/Al2O3catalyst did not decrease after the reaction, suggesting that glycerol has continuous access to Br?nsted acid sites inside the mesopores of WO3/Al2O3, thereby sustaining a high rate of formation of acrolein. Dehydration under O2flow further increased the durability of the WO3/Al2O3catalyst, enabling the sustainable formation of acrolein. In addition, the WO3/Al2O3catalyst with 20 wt% WO3loading showed high activity for the dehydration of various polyols to afford the corresponding products in high yield.
- Aihara, Takeshi,Asazuma, Katsuya,Miura, Hiroki,Shishido, Tetsuya
-
p. 37538 - 37544
(2020/10/19)
-
- Continuous gas-phase hydroformylation of but-1-ene in a membrane reactor by supported liquid-phase (SLP) catalysis
-
Process intensification is a cornerstone to achieve a significant reduction in energy consumption and CO2emissions in the chemical industry. In this context, a monolithic membrane reactor combining homogeneous catalytic gas-phase hydroformylation of but-1-ene with in situ product removal is here presented. The homogeneous supported ionic liquid-phase (SILP) catalyst consists of a Rh-biphephos complex dissolved in 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [C2C1Im][NTf2] and immobilized on a mesoporous silicon carbide monolith. The resulting monolith is catalytically active and selective towards linear aldehyde formation, but the accumulation of aldehyde products and high boilers in the ionic liquid leads to slow catalyst deactivation. This accumulation is suppressed when bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate is used as alternative solvent, where only marginal aldehyde accumulation and aldol formation occur. A polydimethylsiloxane (PDMS) membrane coating of the monolith increases the aldehyde-alkene ratio by an enrichment factor of 2.2 in the permeate gas compared to the retentate gas from the reactor simplifying further downstream processing. The monolithic membrane reactor loaded with SILP or SLP catalysts presents a scalable, versatile platform to achieve process intensification for diverse hydroformylation reactions as well as related gas-phase reactions.
- Fehrmann, Rasmus,Franke, Robert,Haumann, Marco,Hecht, Corinna,José Garciá-Suárez, Eduardo,Logemann, Morten,Marinkovic, Jakob Maximilian,Riisager, Anders,Sch?rner, Markus,Wessling, Matthias
-
p. 5691 - 5700
(2020/10/21)
-
- Method for preparing aldehyde by olefin hydroformylation
-
The invention relates to a method for preparing aldehyde through olefin hydroformylation. The method comprises the steps: enabling alpha-olefin and synthesis gas to enter a hydroformylation reactor; carrying out a contact reaction on alpha-olefin and synthesis gas with a catalyst to generate an aldehyde-containing product, wherein the catalyst comprises a main catalyst and a co-catalyst, the maincatalyst is a complex catalyst and comprises a rhodium complex and a phosphine ligand, the phosphine ligand is tris[2,4-di-tert-butylphenyl]phosphite, and the co-catalyst is a nickel-palladium bimetallic phosphinate. The method has the advantages of high normal-to-abnormal ratio in the product, good selectivity and yield, mild reaction conditions and the like.
- -
-
Paragraph 0032-0034; 0040-0045
(2020/07/15)
-
- Selective hydrogenation of 2-pentenal using highly dispersed Pt catalysts supported on ZnSnAl mixed metal oxides derived from layered double hydroxides
-
A highly dispersed Pt catalyst supported on ZnSnAl mixed metal oxides (MMO), with Pt in single-atom and small nanoclusters, was produced by the induction of lattice-confined Sn sites in layered double hydroxides (LDHs) and used in the selective hydrogenation of 2-pentenal. Compared with the Pt/Al2O3, Pt-SnOx/Al2O3 and MgSnAl-MMO supported Pt catalysts, the optimized ZnSnAl-MMO supported Pt catalyst gave a higher selectivity to 2-pentenol (82.2%) at 28.5% conversion of 2-pentenal. Based on catalytic evaluation results and catalyst characterization with XRD, Pyridine-IR, H2-TPR, XPS, and HAADF-STEM, it was found that the combined effects of Sn and Zn species promoted the performance of the Pt catalyst by favoring the activation of the CO bond. In addition, due to the size effect and electronic effect on the Pt species, the highly dispersed Pt induced by the lattice-confined Sn sites in ZnSnAl-LDH enhanced the catalytic activity of Pt/Zn(1Sn)(Al)O/Al2O3 by 2.7 times compared with Pt-SnOx/Zn(Al)O/Al2O3.
- Ali, Babar,Lan, Xiaocheng,Wang, Huanjun,Wang, Shiqing,Wang, Tiefeng
-
p. 1106 - 1116
(2020/03/11)
-
- Butadiene hydroformylation to adipaldehyde with Rh-based catalysts: Insights into ligand effects
-
Rh-catalyzed hydroformylation of butadiene to adipaldehyde is a promising alternative route for producing valuable C6 compounds such as adipic acid and hexamethylenediamine. Fundamental insights into reaction pathways, aimed at enhancing adipaldehyde yield, were obtained from temporal concentration profiles and in situ ReactIR studies of butadiene hydroformylation on Rh complexes at 80 °C and 14 bar syngas (molar CO/H2 = 1) pressure in a batch reactor. Specifically, the effects of operating conditions and eight commercially available ligands on activity and selectivity were systematically investigated. It was found that the adipaldehyde selectivity is independent of the ligand/Rh ratio, rhodium concentration, butadiene concentration and syngas pressure, but significantly dependent on the type of ligand used. For example, while the DIOP ligand provided an adipaldehyde yield of ～40% with butadiene as a substrate, the 6-DPPon ligand gave a maximum adipaldehyde yield of ～93% with 4-pentenal as substrate. Furthermore, the adipaldehyde selectivity correlates well with the natural bite angle of the various ligands. ReactIR studies suggest that the preferential formation of the stable rhodium η3-crotyl complex with the various Rh complexes may be the main reason for the low adipaldehyde selectivity.
- Yu, Si-min,Snavely, William K.,Chaudhari, Raghunath V.,Subramaniam, Bala
-
-
- Reductive Electrochemical Activation of Molecular Oxygen Catalyzed by an Iron-Tungstate Oxide Capsule: Reactivity Studies Consistent with Compound i Type Oxidants
-
The reductive activation of molecular oxygen catalyzed by iron-based enzymes toward its use as an oxygen donor is paradigmatic for oxygen transfer reactions in nature. Mechanistic studies on these enzymes and related biomimetic coordination compounds designed to form reactive intermediates, almost invariably using various "shunt" pathways, have shown that high-valent Fe(V)=O and the formally isoelectronic Fe(IV) =O porphyrin cation radical intermediates are often thought to be the active species in alkane and arene hydroxylation and alkene epoxidation reactions. Although this four decade long research effort has yielded a massive amount of spectroscopic data, reactivity studies, and a detailed, but still incomplete, mechanistic understanding, the actual reductive activation of molecular oxygen coupled with efficient catalytic transformations has rarely been experimentally studied. Recently, we found that a completely inorganic iron-tungsten oxide capsule with a keplerate structure, noted as {Fe30W72}, is an effective electrocatalyst for the cathodic activation of molecular oxygen in water leading to the oxidation of light alkanes and alkenes. The present report deals with extensive reactivity studies of these {Fe30W72} electrocatalytic reactions showing (1) arene hydroxylation including kinetic isotope effects and migration of the ipso substituent to the adjacent carbon atom ("NIH shift"); (2) a high kinetic isotope effect for alkyl C - H bond activation; (3) dealkylation of alkylamines and alkylsulfides; (4) desaturation reactions; (5) retention of stereochemistry in cis-alkene epoxidation; and (6) unusual regioselectivity in the oxidation of cyclic and acyclic ketones, alcohols, and carboxylic acids where reactivity is not correlated to the bond disassociation energy; the regioselectivity obtained is attributable to polar effects and/or entropic contributions. Collectively these results also support the conclusion that the active intermediate species formed in the catalytic cycle is consistent with a compound I type oxidant. The activity of {Fe30W72} in cathodic aerobic oxidation reactions shows it to be an inorganic functional analogue of iron-based monooxygenases.
- Bugnola, Marco,Shen, Kaiji,Haviv, Eynat,Neumann, Ronny
-
p. 4227 - 4237
(2020/05/05)
-
- Homogeneous catalytic oxidation of alkenes employing mononuclear vanadium complex with hydrogen peroxide
-
Abstract: Homogeneous liquid-phase oxidation of alkenes (allylbenzene, cis-cyclooctene, 4-chlorostyrene, styrene, 2-norbornene, 1-methyl cyclohexene, indene, lemonine, and 1-hexene) were catalyzed by using vanadium complex [VO(hyap)(acac)2] in existence of H2O2. The complex [VO(hyap)(acac)2] was formed as a crystal by the reaction of [VO(acac)2] and 2-hydroxyacetophenone (hyap) in the presence of methanol by refluxing the reaction mixture. Various analytical and spectroscopic techniques, namely FTIR, ESI–MS, UV–Vis, single-crystal XRD, and EPR, were used to analyze and optimize the structure of the complexes. Graphic abstract: [Figure not available: see fulltext.].
- Maurya, Abhishek
-
p. 3261 - 3269
(2020/07/14)
-
- Phosphine ligand, preparation method and application thereof
-
The invention provides a preparation method of a phosphine ligand and application of the phosphine ligand in catalyzing olefin hydroformylation reaction. A structural formula of the phosphine ligand is shown as the specification, wherein R, R1, R2 and R3 are selected from C1-C40 alkyl, alkenyl, alkynyl, and phenyl, substituted phenyl, naphthyl, anthryl, phenanthryl or other aromatic ring and aromatic heterocyclic substituents with higher carbon number. The preparation method of the phosphine ligand comprises the following step: carrying out one-step reaction on an isochroman salt and trisilylphosphine under the promotion of villiaumite. The phosphine ligand has strong stability and coordination ability, and can be well coordinated with cobalt, rhodium and other metals, the obtained complex can be used for hydroformylation reaction of terminal olefin, internal olefin, trisubstituted olefin and tetrasubstituted olefin, the catalyst dosage is small, the reaction conditions are mild, andthe yield and selectivity of aldehyde products are very high.
- -
-
Paragraph 0063-0065
(2020/07/13)
-
- The formyloxyl radical: Electrophilicity, C-H bond activation and anti-Markovnikov selectivity in the oxidation of aliphatic alkenes
-
In the past the formyloxyl radical, HC(O)O, had only been rarely experimentally observed, and those studies were theoretical-spectroscopic in the context of electronic structure. The absence of a convenient method for the preparation of the formyloxyl radical has precluded investigations into its reactivity towards organic substrates. Very recently, we discovered that HC(O)O is formed in the anodic electrochemical oxidation of formic acid/lithium formate. Using a [CoIIIW12O40]5- polyanion catalyst, this led to the formation of phenyl formate from benzene. Here, we present our studies into the reactivity of electrochemically in situ generated HC(O)O with organic substrates. Reactions with benzene and a selection of substituted derivatives showed that HC(O)O is mildly electrophilic according to both experimentally and computationally derived Hammett linear free energy relationships. The reactions of HC(O)O with terminal alkenes significantly favor anti-Markovnikov oxidations yielding the corresponding aldehyde as the major product as well as further oxidation products. Analysis of plausible reaction pathways using 1-hexene as a representative substrate favored the likelihood of hydrogen abstraction from the allylic C-H bond forming a hexallyl radical followed by strongly preferred further attack of a second HC(O)O radical at the C1 position. Further oxidation products are surmised to be mostly a result of two consecutive addition reactions of HC(O)O to the CC double bond. An outer-sphere electron transfer between the formyloxyl radical donor and the [CoIIIW12O40]5- polyanion acceptor forming a donor-acceptor [D+-A-] complex is proposed to induce the observed anti-Markovnikov selectivity. Finally, the overall reactivity of HC(O)O towards hydrogen abstraction was evaluated using additional substrates. Alkanes were only slightly reactive, while the reactions of alkylarenes showed that aromatic substitution on the ring competes with C-H bond activation at the benzylic position. C-H bonds with bond dissociation energies (BDE) ≤ 85 kcal mol-1 are easily attacked by HC(O)O and reactivity appears to be significant for C-H bonds with a BDE of up to 90 kcal mol-1. In summary, this research identifies the reactivity of HC(O)O towards radical electrophilic substitution of arenes, anti-Markovnikov type oxidation of terminal alkenes, and indirectly defines the activity of HC(O)O towards C-H bond activation.
- Iron, Mark A.,Khenkin, Alexander M.,Neumann, Ronny,Somekh, Miriam
-
p. 11584 - 11591
(2020/11/23)
-
- High iso Aldehyde Selectivity in the Hydroformylation of Short-Chain Alkenes
-
The hydroformylation of propene to give predominantly iso-butanal has been achieved; class-leading selectivity is possible even at higher temperatures that deliver fast conversion. Racemic rhodium complexes of bidentate phospholane phosphites derived from tropos-biphenols and unusual solvent systems are the key to the selectivity observed.
- Iu, Leo,Fuentes, José A.,Janka, Mesfin E.,Fontenot, Kevin J.,Clarke, Matthew L.
-
supporting information
p. 2120 - 2124
(2019/01/25)
-
- Visible-light mediated C-C bond cleavage of 1,2-diols to carbonyls by cerium-photocatalysis
-
We describe a photocatalytic method for the cleavage of vicinal diols to aldehydes and ketones. The reaction is catalyzed by blue light and a cerium-catalyst and the scope includes aryl as well as alkyl substituted diols. The simple protocol which works under air and at room temperature enables the valorization of abundant diols.
- Schwarz, Johanna,K?nig, Burkhard
-
supporting information
p. 486 - 488
(2019/01/10)
-
- Production and testing of technical catalysts based on MnO2 for the abatement of aromatic volatile compounds at the laboratory and pilot plant scales
-
Shaping is a crucial step to produce technical catalysts that remains as some sort of dark art for catalytic researchers in academia. This contribution discusses aspects concerning the fabrication of technical catalysts based on MnO2 powders ai
- Baldovino-Medrano, Víctor Gabriel,Kartheuser, Beno?t,Gaigneaux, Eric M.
-
-
- Hydrodealkenylative C(sp3)–C(sp2) bond fragmentation
-
Chemical synthesis typically relies on reactions that generate complexity through elaboration of simple starting materials. Less common are deconstructive strategies toward complexity—particularly those involving carbon-carbon bond scission. Here, we introduce one such transformation: the hydrodealkenylative cleavage of C(sp3)–C(sp2) bonds, conducted below room temperature, using ozone, an iron salt, and a hydrogen atom donor. These reactions are performed in nonanhydrous solvents and open to the air; reach completion within 30 minutes; and deliver their products in high yields, even on decagram scales. We have used this broadly functionality tolerant transformation to produce desirable synthetic intermediates, many of which are optically active, from abundantly available terpenes and terpenoid-derived precursors. We have also applied it in the formal total syntheses of complex molecules.
- Smaligo, Andrew J.,Swain, Manisha,Quintana, Jason C.,Tan, Mikayla F.,Kim, Danielle A.,Kwon, Ohyun
-
p. 681 - 685
(2019/06/11)
-
- Polymer-anchored mononuclear and binuclear CuII Schiff-base complexes: Impact of heterogenization on liquid phase catalytic oxidation of a series of alkenes
-
Liquid phase catalytic oxidation of a number of alkenes, for example, cyclohexene, cis-cyclooctene, styrene, 1-methyl cyclohexene and 1-hexene, was performed using polymer-anchored copper (II) complexes PS-[Cu (sal-sch)Cl] (5), PS-[Cu (sal-tch)Cl] (6), PS-[CH2{Cu (sal-sch)Cl}2] (7) and PS-[CH2{Cu (sal-tch)Cl}2] (8). Neat complexes [Cu (sal-sch)Cl] (1), [Cu (sal-tch)Cl] (2), [CH2{Cu (sal-sch)Cl}2] (3) and [CH2{Cu (sal-tch)Cl}2] (4) were isolated by reacting CuCl2·2H2O with [Hsal-sch] (I), [Hsal-tch] (II), [H2bissal-sch] (III) and [H2bissal-tch] (IV), respectively, in refluxing methanol. Complexes 1–4 have been covalently anchored in Merrifield resin through the amine nitrogen of the semicarbazide or thiosemicarbazide moiety. A number of analytical, spectroscopic and thermal techniques, such as CHNS analysis, Fourier transform-infrared, UV–Vis, PMR, 13C-NMR, electron paramagnetic resonance, scanning electron microscopy, energy-dispersive X-ray analysis, thermogravimetric analysis, atomic force microscopy, atomic absorption spectroscopy, and electrospray ionization-mass spectrometry, were used to analyze and establish the molecular structure of the ligands (I)–(IV) and complexes (1)–(8) in solid state as well as in solution state. Grafted complexes 5–8 were employed as active catalysts for the oxidation of a series of alkenes in the presence of hydrogen peroxide. Copper hydroperoxo species ([CuIII (sal-sch)-O-O-H]), which is believed to be the active intermediate, generated during the catalytic oxidation of alkenes, are identified. It was found that supported catalysts are very economical, green and efficient in contrast to their neat complexes as well as most of the recently reported heterogeneous catalysts.
- Maurya, Abhishek,Kesharwani, Neha,Kachhap, Payal,Mishra, Vivek Kumar,Chaudhary, Nikita,Haldar, Chanchal
-
-
- Transition metal-free hydrodefluorination of acid fluorides and organofluorines by Ph3GeH promoted by catalytic[Ph3C][B(C6F5)4]
-
It has been shown that the germane Ph3GeH converts aryl and aliphatic acid fluorides directly to their corresponding aldehydes without over-reduction via the conversion of Ph3GeH to the germylium cation[Ph3Ge]+ by a catalytic amount of the tritylium salt[Ph3C][B(C6F5)4]. Here, no transition metal catalyst is required and there is no decarbonylation of the acid fluoride, which are advantages over existing methods. The fluorine atoms can also be abstracted from organofluorine compounds using this method.
- Hayatifar, Ardalan,Borrego, Alejandro,Bosek, David,Czarnecki, Matthew,Derocher, Gabriel,Kuplicki, Adam,Lytle, Erik,Padilla, Jonas,Paroly, Charles,Tubay, Gillian,Vyletel, Jackson,Weinert, Charles S.
-
supporting information
p. 10852 - 10855
(2019/09/18)
-
- Kinetics and Mechanism of the Oxidative Conversion of n-Amyl Alcohol to Valeric Acid on a Modified Zeolite Catalyst
-
The catalytic activity of natural and synthetic mordenites modified with Cu2+, Zn2+, and Pd2+ cations via ion exchange was studied in the oxidative conversion of n-amyl alcohol to valeric acid under the action of oxygen. It is established that the highest activity and selectivity in this reaction is exhibited by mordenite hydrothermally synthesized from kaolinite and containing 3.0 wt % Cu2+, 0.1 wt % Pd2+, and 2.0 wt % Zn2+. The kinetics of this catalytic reaction is studied. Based on the experimental data, a possible stepwise mechanism is proposed, and a theoretically grounded kinetic model of the process is developed.
- Aliev,Bakhmanov,Agaev,Agaev, V. Sh.,Shabanova,Safarov
-
p. 656 - 662
(2018/04/12)
-
- Double tooth phosphine ligand and its application in the hydroformylation reaction (by machine translation)
-
The invention discloses a double-phosphine ligand, its general structure is represented by the formula; in the above formula, Ph is phenyl, a, b, c, d, e, f, g, h are the same or different, selected from H, R, OR, NR2 , NO2 Or cyano, R is alkyl or substituted alkyl. The double-phosphine ligand and the transition metal complex to make the metal - phosphine ligand complex can be used for the hydroformylation reaction catalyst, has high activity and linear selectively, in particular based on selected from transition metal Co, Rh complex; and catalytic reaction the amount of phosphine ligand is greatly reduced. The invention of the double-phosphine ligand easy synthesis, low cost of raw materials. (by machine translation)
- -
-
Paragraph 0049-0055
(2018/10/19)
-
- Encapsulation of Crabtree's Catalyst in Sulfonated MIL-101(Cr): Enhancement of Stability and Selectivity between Competing Reaction Pathways by the MOF Chemical Microenvironment
-
Crabtree's catalyst was encapsulated inside the pores of the sulfonated MIL-101(Cr) metal–organic framework (MOF) by cation exchange. This hybrid catalyst is active for the heterogeneous hydrogenation of non-functionalized alkenes either in solution or in the gas phase. Moreover, encapsulation inside a well-defined hydrophilic microenvironment enhances catalyst stability and selectivity to hydrogenation over isomerization for substrates bearing ligating functionalities. Accordingly, the encapsulated catalyst significantly outperforms its homogeneous counterpart in the hydrogenation of olefinic alcohols in terms of overall conversion and selectivity, with the chemical microenvironment of the MOF host favouring one out of two competing reaction pathways.
- Grigoropoulos, Alexios,McKay, Alasdair I.,Katsoulidis, Alexandros P.,Davies, Robert P.,Haynes, Anthony,Brammer, Lee,Xiao, Jianliang,Weller, Andrew S.,Rosseinsky, Matthew J.
-
supporting information
p. 4532 - 4537
(2018/03/26)
-
- Efficient Vanadium-Catalyzed Aerobic C?C Bond Oxidative Cleavage of Vicinal Diols
-
The aerobic oxidative C?C bond cleavage of vicinal diols catalyzed by vanadium amino triphenolates is described. Our results show that C?C bond cleavage can be performed in different solvents, under an air or oxygen atmosphere, with a large variety of glycols (cyclic or linear, with aromatic or aliphatic substituents) affording the corresponding carbonyl derivatives with high chemoselectivity. Reactions can be performed with as little as 10 ppm of catalyst reaching TON up to 81,000 and TOFs of up to 4150 h?1. A reaction mechanism, rationalized by density functional theory calculations, is also proposed. (Figure presented.).
- Amadio, Emanuele,González-Fabra, Joan,Carraro, Davide,Denis, William,Gjoka, Blerina,Zonta, Cristiano,Bartik, Kristin,Cavani, Fabrizio,Solmi, Stefania,Bo, Carles,Licini, Giulia
-
supporting information
p. 3286 - 3296
(2018/05/30)
-
- Bidentate phosphine ligand and application thereof in hydroformylation reaction
-
The invention discloses a bidentate phosphine ligand. A structural formula of the bidentate phosphine ligand is shown in a following formula, wherein Ph is phenyl; a, b, c, d, e, f, g and h are the same or different, and are selected from H, R or Ar; R is alkyl or substituted alkyl; Ar is aryl or substituted aryl. A metal-phosphine ligand prepared from the bidentate phosphine ligand and transitionmetals is a catalyst for the hydroformylation reaction, has high activity and linear selectivity, and is a complex from transition metals Co (cobalt) and Rh (rhodium); the usage amount of phosphine ligand in the catalysis reaction is greatly reduced. The bidentate phosphine ligand has the advantages that the synthesizing is easy, and the cost of the raw materials is low. The formula is shown in the attached figure.
- -
-
Paragraph 0045-0051; 0060; 0065
(2018/12/02)
-
- Visible-Light-Driven Photocatalytic Oxidation of Organic Chlorides Using Air and an Inorganic-Ligand Supported Nickel-Catalyst Without Photosensitizers
-
Engineering photoredox-triggered chemical transformation via visible light has been an emerging area in organic synthesis. However, most of the well-established photocatalysts are based upon either transition metal complexes involved with noble metals and organic ligands or photosensitive organic dyes, the development of pure inorganic molecular photocatalysts that could provide better stability and durability is greatly retarded. Herein we discover that the Anderson polyoxometalate (POM) Na4[NiMo6O18(OH)6] (1), which consists of pure inorganic framework built from a central NiII core supported by six MoVIO6 inorganic scaffold/ligands, can be used as a powerful photocatalyst. Upon irradiation with visible light (>400 nm), the compound can catalyze, in high efficiency, a wide range of reactions, including the oxidative cross-coupling reaction of chlorides with amines, as well as oxidation of chlorides using molecular oxygen, affording various imines, aldehydes, and ketones, respectively in high selectivity and good yields. Owing to the robust inorganic framework, this catalyst exhibits excellent stability during the catalysis and reusability with little loss of the catalytic activity, thus providing an alternative without use of complicated organic ligands and expensive noble metal-based photosensitizers.
- Yu, Han,Wang, Jingjing,Zhai, Yongyan,Zhang, Mengqi,Ru, Shi,Han, Sheng,Wei, Yongge
-
p. 4274 - 4279
(2018/09/10)
-
- Selective aerobic oxidation of halides and amines with an inorganic-ligand supported zinc catalyst
-
A practical, efficient and environmentally benign catalytic protocol for the oxidative cross-coupling reaction of halides with amines, oxidative self-coupling of amines and oxidation of halides was developed with inorganic-ligand supported ZnPOM (NH4)4[ZnMo6O18(OH)6] using molecular oxygen. This method mainly utilizes an inorganic polymolybdate ligand to support the Zn2+ ion, avoiding the use of complicated organic ligands.
- Wang, Jingjing,Zhai, Yongyan,Wang, Ying,Yu, Han,Zhao, Wenshu,Wei, Yongge
-
supporting information
p. 13323 - 13327
(2018/10/15)
-
- Method for producing aldehydes through olefin hydroformylation reaction
-
The invention relates to a method for producing aldehydes through an olefin hydroformylation reaction, and mainly solves the problems that in the prior art, olefins or olefins containing side-chain radicals are poor in reactivity, and a catalytic system is not stable under weak acidic conditions. The method for producing the aldehydes through the olefin hydroformylation reaction comprises the step that under the conditions that the temperature is 60-130 DEG C and the reaction pressure is 1.0-6.0 MPa, an aldehyde serves as a solvent, olefin hydroformylation is catalyzed with a rhodium compound, a phosphorus compound containing o-methyl and phenyl groups, a hard base pentavalent phosphorus-containing oxide and a bidentate phosphite ester compound to synthesize the aldehydes; according to the technical scheme, the olefin is at least one of isobutene, cis-2-butene, 2,5-dihydrofuran, 1-butene, propylene and ethylene, the problem is well solved, and the olefin can be used for the process of producing the aldehydes through the olefin hydroformylation reaction.
- -
-
Paragraph 0027; 0028; 0029; 0030
(2017/04/03)
-
- Method for synthesis of aldehydes by hydroformylation of alkenes on one same set of production equipment
-
The invention relates to a method for synthesis of aldehydes by hydroformylation of alkenes on one same set of production equipment, and mainly aims to solve the problem of reaction activity decreasing and catalyst poisoning caused by cross of catalyst ligands in the switching process of different catalysts in the prior art. According to the method, at 60-130 DEG C under the reaction pressure of 1.0-6.0MPa in the switching process of different hydroformylation catalysts, a ruthenium compound is added, so that a rhodium compound, a phosphine compound and a bidentate phosphite composition can catalyze the hydroformylation for synthesis of different aldehydes; the alkenes are at least one of isobutene, cis-2-Butene, trans-2-Butene, 1-Butene, propylene and ethylene, by use of the method, the problem of reaction activity decreasing and catalyst poisoning can be well solved, and the method can be used for synthesis of the aldehydes by hydroformylation of the alkenes on one same set of production equipment.
- -
-
Paragraph 0030; 0031; 0032; 0033
(2017/08/26)
-
- 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)
-
- Mechanism and Product Distribution of the O3-Initiated Degradation of (E)-2-Heptenal, (E)-2-Octenal, and (E)-2-Nonenal
-
The O3-molecule initiated degradation of three 2-alkenals (E)-2-heptenal, (E)-2-octenal, and (E)-2-nonenal has been investigated in a 1080 L quartz-glass environmental chamber at 298 ± 2 K and atmospheric pressure of synthetic air using in situ FTIR spectroscopy to monitor the reactants and products. The experiments were performed in the absence of an OH scavenger. The molar yields of the primary products formed were glyoxal (49 ± 4) % and pentanal (34 ± 3) % from the reaction of (E)-2-heptenal with O3, glyoxal (41 ± 3) % and hexanal (39 ± 3) % from the reaction of (E)-2-octenal with O3, and glyoxal (45 ± 3) % and heptanal (46 ± 3) % from the reaction of (E)-2-nonenal with O3. The residual bands in the infrared product spectra for each of the studied reactions are attributed to 2-oxoaldehyde compounds. Based on the observed products, a general mechanism for the ozonolysis reaction of long chain unsaturated aldehydes is proposed, and the results are compared with the available literature data.
- Gaona Colmán, Elizabeth,Blanco, María B.,Barnes, Ian,Wiesen, Peter,Teruel, Mariano A.
-
p. 5147 - 5155
(2017/07/24)
-
- A TEMPO-like nitroxide combined with an alkyl-substituted pyridine: An efficient catalytic system for the selective oxidation of alcohols with iodine
-
An efficient method for the oxidation of alcohols to aldehydes or ketones in a two-phase CH2Cl2/NaHCO3 (aq.) system, using iodine and catalytic amounts of 4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxyl and 2,4,6-trimethylpyridine, was developed. The performance of the method was demonstrated by the selective oxidation of 37 variously substituted alcohols in ≥90% yield, including the gram-scale synthesis of the important chemical 2,5-diformylfuran from biomass-derived 5-hydroxylmethylfurfural.
- Kashparova, Vera P.,Klushin, Victor A.,Zhukova, Irina Yu.,Kashparov, Igor S.,Chernysheva, Daria V.,Il'chibaeva, Irina B.,Smirnova, Nina V.,Kagan, Efim Sh.,Chernyshev, Victor M.
-
supporting information
p. 3517 - 3521
(2017/10/05)
-
- BISPHOSPHITES HAVING 2,4-DIMETHYLPHENYL UNITS AND USE THEREOF AS LIGANDS IN HYDROFORMYLATION
-
The invention relates to bisphosphites having 2,4-dimethylphenyl units and a method for the preparation thereof. Furthermore, the invention relates to the use of the compounds as ligands in a ligand-metal complex. The compound, and also the complex, may be used as a catalytically active composition in hydroformylation reactions.
- -
-
Paragraph 0095-00100
(2017/08/01)
-
- Highly efficient aqueous phase chemoselective hydrogenation of α,β-unsaturated aldehydes catalysed by phosphine-decorated polymer immobilized IL-stabilized PdNPs
-
Phosphino-decorated polymer immobilised ionic liquid phase stabilised palladium nanoparticles (PdNP@PPh2-PIILP) and their PEGylated counterparts (PdNP@PPh2-PEGPIILP) are remarkably active and exceptionally selective catalysts for the aqueous phase hydrogenation of α,β-unsaturated aldehydes, ketones, esters and nitriles with PdNP@PPh2-PEGPIILP giving complete conversion and 100% selectivity for reduction of the CC bond, under mild conditions. This is the most selective PdNP-based system to be reported for the aqueous phase hydrogenation of this class of substrates.
- Doherty,Knight,Backhouse,Abood,Alshaikh,Fairlamb,Bourne,Chamberlain,Stones
-
supporting information
p. 1635 - 1641
(2017/06/05)
-
- Properties and applications of sodium 2-alkyl-5-(ethoxycarbonyl)-1,3-dioxane-5-carboxylate synthesized with nano-sulfonated carbon
-
A series of novel sodium 2-alkyl-5-(ethoxycarbonyl)-1,3-dioxane-5-carboxylate surfactants were synthesized in high yield using nanosolid superacid sulfonated carbon as a catalyst and characterized by 1H NMR, IR and elemental analysis. Critical micelle concentration (CMC) of the surfactants was determined and the results showed that the CMC values were less than 1.0 × 10-3 mol/L. Other relevant surface properties were also evaluated, such as emulsion stability, foam ability and degradability. In relation to emulsion formation, foam stability and the range of application of temperature, the new surfactants showed better properties than traditional surfactants when used as an emulsifier in emulsion polymerization. Moreover, the surfactants were stable under alkaline and neutral conditions, and degraded into raw materials under acid condition. Convenient synthesis process with high yield and superior properties promisingly make the title compounds to be a type of 'environmentally friendly' surfactants.
- Yuan, Lin,Li, Zhong Yan,Zhang, Min,Yuan, Xian You,Zhu, Xiao Qing
-
p. 2201 - 2205
(2017/01/28)
-
- N-Pyrrolylphosphines as ligands for highly regioselective rhodium-catalyzed 1-butene hydroformylation: Effect of water on the reaction selectivity
-
The hydroformylation of 1-butene catalyzed by Rh(acac)(CO)2 with an excess of N-pyrrolylphosphine ligands, L = P(NC4H4)3, PPh2(NC4H4) or PPh(NC4H4)2, was investigated under constant pressure of synthesis gas (4-10 bar, H2/CO = 1) and 2 bar of 1-butene at temperatures ranging from 50 to 80 °C. N-Pyrrolylphosphine ligands facilitated excellent selectivity towards aldehydes and regioselectivity towards linear aldehydes. The application of a higher temperature, the presence of a small amount of water, and a [L]/[Rh] ratio of ca. 13 resulted in the achievement of the highest n/iso values in a short time. A further increase in selectivity was achieved after the addition of water to the reaction mixture. The catalytic performance of the studied systems showed an increase in selectivity (n/iso) with the increase of the number of pyrrolyl groups in phosphine: (P(NC4H4)3 > PPh(NC4H4)2 > PPh2(NC4H4)) > PPh3.
- Alsalahi,Grzybek,Trzeciak
-
p. 3097 - 3103
(2017/08/14)
-
- Ruthenium on Carbon Catalysed Carbon-Carbon Cleavage of Aryl Alkyl Ketones and Aliphatic Aldehydes in Aqueous Media
-
A new ruthenium on carbon-catalysed carbon–carbon (C?C) cleavage reaction of aryl alkyl ketone derivatives in water in the presence of CaO under atmospheric oxygen conditions has been developed. Corresponding benzoic acid derivatives were produced from various aryl alkyl ketones in excellent yields. CaO acts as an adsorbent of CO and CO2 to maintain a sufficient concentration of oxygen around the catalyst required for effective progress of the reaction. It was also revealed that aliphatic aldehydes were generated from the alkyl moiety of aryl alkyl ketones over the course of the reaction. The aliphatic aldehyde derivatives undergo either an oxidation to the corresponding aliphatic carboxylic acids or a further continuous C?C cleavage reaction to form aliphatic aldehydes with loss of one carbon along with the formation of CO and CO2. (Figure presented.).
- Hattori, Tomohiro,Okami, Hiroki,Ichikawa, Tomohiro,Mori, Shigeki,Sawama, Yoshinari,Monguchi, Yasunari,Sajiki, Hironao
-
supporting information
p. 3490 - 3495
(2017/09/06)
-
