116-09-6Relevant articles and documents
High-stable CuPd-Cu2O/Ti-powder catalyst for low-temperature gas-phase selective oxidation of alcohols
Liu, Kun,Chen, Zhaoxiang,Zou, Peipei,Wang, Yuanyuan,Dai, Liyi
, p. 54 - 58 (2015)
Abstract The oxidation of alcohols to carbonyl compounds in gas-phase is of great importance in organic chemistry and industrial process. Herein, the catalyst CuPd-Cu2O/Ti-powder is prepared by depositing Cu(NO3)2 and Pd(NO3)2 on Ti powder support followed by in-situ activation in reaction stream, which delivers high-performance for the gas-phase oxidation of alcohols. Compared with Cu/Ti-powder and Pd/Ti-powder, CuPd-Cu2O/Ti-powder exhibits higher stability and activity in alcohol oxidation reaction. The catalyst is characterized by XRD, XPS, TEM and ICP. The results indicate that CuPd(alloy)-Cu2O formed during the reaction contributes to the high activity and stability.
Flash Photolysis Study of the UV Spectrum and Kinetics of Reactions of the Acetonylperoxy Radical
Bridier, Isabelle,Veyret, Bernard,Lesclaux, Robert,Jenkin, Michael E.
, p. 2993 - 2997 (1993)
The flash-photolysis-UV-absorption method was used to study the UV spectrum and the kinetics of the CH3C(O)CH2O2 radical formed in the presence of oxygen via the reaction between Cl atoms and acetone.Results were analysed in the light of the results of th
High-pressure fast-pyrolysis, fast-hydropyrolysis and catalytic hydrodeoxygenation of cellulose: Production of liquid fuel from biomass
Venkatakrishnan, Vinod Kumar,Degenstein, John C.,Smeltz, Andrew D.,Delgass, W. Nicholas,Agrawal, Rakesh,Ribeiro, Fabio H.
, p. 792 - 802 (2014)
A lab-scale, high-pressure, continuous-flow fast-hydropyrolysis and vapor-phase catalytic hydrodeoxygenation (HDO) reactor has been successfully designed, built and tested with cellulose as a model biomass feedstock. We investigated the effects of pyrolysis temperature on high-pressure cellulose fast-pyrolysis, hydrogen on high-pressure cellulose fast-hydropyrolysis, reaction pressure (27 bar and 54 bar) on our reactor performance and candidate catalysts for downstream catalytic HDO of cellulose fast-hydropyrolysis vapors. In this work, a liquid chromatography-mass spectrometry (LC-MS) method has been developed and utilized for quantitative characterization of the liquid products. The major compounds in the liquid from cellulose fast-pyrolysis (27 bar, 520 °C) are levoglucosan and its isomers, formic acid, glycolaldehyde, and water, constituting 51 wt%, 11 wt%, 8 wt% and 24 wt% of liquid respectively. Our results show that high pressures of hydrogen do not have a significant effect on the fast-hydropyrolysis of cellulose at 480 °C but suppress the formation of reactive light oxygenate species like glycolaldehyde and formic acid at 580 °C. The formation of permanent gases (CO, CO2, CH4) and glycolaldehyde and formic acid increased with increasing pyrolysis temperature in the range of 480 °C-580 °C in high-pressure cellulose fast-pyrolysis, in the absence of hydrogen. Candidate HDO catalysts Al 2O3, 2% Ru/Al2O3 and 2% Pt/Al 2O3 resulted in extents of deoxygenation of 20%, 22% and 27%, respectively, but led to carbon loss to gas phase as CO and CH4. These catalysts provide useful insights for other candidate HDO catalysts for improving the extent of deoxygenation with higher carbon recovery in the liquid product.
Catalytic performance of Pt/AlPO4 catalysts for selective hydrogenolysis of glycerol to 1,3-propanediol in the vapour phase
Priya, Samudrala Shanthi,Kumar, Vanama Pavan,Kantam, Mannepalli Lakshmi,Bhargava, Suresh K.,Chary, Komandur V. R.
, p. 51893 - 51903 (2014)
Hydrogenolysis of glycerol to 1,3-propanediol was investigated in the vapour phase over a series of Pt/AlPO4 catalysts with platinum loadings ranging from 0.5 to 3 wt%. The catalysts were prepared by a wet impregnation method and characterized by various techniques such as X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), BET surface area, Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and CO-chemisorption methods. Ex situ pyridine adsorbed FTIR analysis and temperature programmed desorption (TPD) of NH3 were employed to investigate the acidic properties of the catalysts. Further, the effect of reaction temperature, hydrogen flow rate, glycerol concentration and various contents of platinum (0.5 to 3 wt%) have been investigated to find the optimum reaction conditions. Superior performance with almost 100% conversion of glycerol and above 35% selectivity to 1,3-propanediol was obtained over 2 wt% Pt/AlPO4 at 260 °C and atmospheric pressure. The influence of acidity of the catalyst and its correlation to the catalytic performance (selectivity and conversion) has been studied. The high strength of weak acidic sites and Bronsted acidity of the catalyst measured by NH3-TPD and Pyr-FTIR were concluded to play a key role in selective formation of 1,3-propanediol. XRD, TEM and CO-chemisorption studies revealed that platinum was well dispersed on AlPO4 which further contributed to higher catalytic activity for glycerol hydrogenolysis. This journal is
Selective transformation of glycerol into 1,2-propanediol on several Pt/ZnO solids: Further insight into the role and origin of catalyst acidity
Montes,Boutonnet,J?r?s,Marinas,Marinas,Urbano
, p. 246 - 258 (2015)
Microemulsion technique allowed us to synthesize different ZnO solids with similar particle sizes and textural properties. Platinum was subsequently incorporated by deposition-precipitation and impregnation methods and solids tested for glycerol selective transformation into 1,2-PDO. Incorporation of platinum led to the creation of new (mainly Lewis) acid sites. A good correlation between conversion and acidity of Pt/ZnO solids was obtained. Interestingly, despite exhibiting some acidity, supports alone were inactive in the process which evidenced the role of the metal in dehydration of glycerol into acetol. Furthermore, as the reaction proceeded some chlorine coming from the precursor (H2PtCl6) was leached which led to the disappearance of the strongest acid sites, associated to side reactions (catalytic cracking) thus resulting in an increase in selectivity to 1,2-PDO. Eventual formation of Pt-Zn alloy upon reduction of the systems at ca. 400°C was beneficial to 1,2-PDO selectivity.
The selective continuous flow synthesis of lower alcohols from polyols-a mechanistic interpretation of the results
Van Ryneveld, Esti,Mahomed, Abdul S.,Van Heerden, Pieter S.,Green, Mike J.,Holzapfel, Cedric,Friedrich, Holger B.
, p. 832 - 837 (2014)
In an endeavour to understand the hydrogenolysis pathway of glycerol to lower alcohols over Ni on Al2O3 and SiO2 catalysts, the role of the intermediates (1,2-propanediol (1,2-PDO), 1,3-propanediol (1,3-PDO), ethylene glycol (EG) and ethanol) was investigated. Under the reaction conditions employed in this study, it was clear that the hydrogenolysis of the C-C and C-O bonds of glycerol takes place to a lesser extent as compared to dehydrogenation and dehydration which are seen as the dominating initial steps. Ethanol was produced in high selectivities (~67%) with 1,2-propanediol as feed and 1-propanol (1-PO, ~80%) was the main product obtained when 1,3-propanediol was used as feed. Ethylene glycol gave methanol and methane as products, whereas ethanol gave methane and CO2 as major products.
Double-cuvette ISES: In situ estimation of enantioselectivity and relative rate for catalyst screening
Dey, Sangeeta,Karukurichi, Kannan R.,Shen, Weijun,Berkowitz, David B.
, p. 8610 - 8611 (2005)
Described is a new method for the screening of an array of catalysts, in situ, to estimate enantioselectivity and relative rates. We term this approach "double-cuvette ISES (in situ enzymatic screening)". The Co(III)-salen mediated hydrolytic kinetic resolution (HKR) of (±)-propylene oxide is used as a model reaction to demonstrate proof of principle. In two parallel cuvettes, a lower CHCl3-based organic layer is loaded with the epoxide and the chiral salen catalyst. Aqueous reporting layers, containing distinct "reporting enzymes" and their nicotinamide cofactors, are layered above the organic layers. The 1,2-propanediol enantiomers formed by the chiral catalyst diffuse into the aqueous layer and are oxidized there by the reporting enzymes at rates dependent upon the diol concentration, the R:S ratio of the diol, and the enantioselectivity of the reporting enzymes. A focused chiral salen library was constructed from seven chiral 1,2-diamines, derived from amino acid, terpenoid, and carbohydrates skeletons, and seven salicylaldehyde derivatives. Double-cuvette ISES identified a couple of interesting combinatorial hits in this salen array, wherein either the sense or magnitude of enantioselection for a given chiral diamine depends significantly upon the choice of "salicylaldehyde" partner. A comparison of predicted ee's and relative rates using this new screening tool with those independently measured is provided. Copyright
Two radical-dependent mechanisms for anaerobic degradation of the globally abundant organosulfur compound dihydroxypropanesulfonate
Ang, Ee Lui,Cao, Peng,Chen, Jiawei,Li, Yaxin,Lin, Lianyun,Liu, Jiayi,Liu, Yangping,Liu, Yanhong,Lu, Qiang,Teng, Lin,Wei, Yifeng,Xu, Runyao,Yin, Jinyu,Yuchi, Zhiguang,Zhai, Weixiang,Zhang, Yan,Zhao, Huimin,Zheng, Yuchun
, p. 15599 - 155608 (2020)
2(S)-dihydroxypropanesulfonate (DHPS) is a microbial degradation product of 6-deoxy-6-sulfo-d-glucopyranose (sulfoquinovose), a component of plant sulfolipid with an estimated annual production of 1010 tons. DHPS is also at millimolar levels in highly abundant marine phytoplankton. Its degradation and sulfur recycling by microbes, thus, play important roles in the biogeochemical sulfur cycle. However, DHPS degradative pathways in the anaerobic biosphere are not well understood. Here, we report the discovery and characterization of two O2-sensitive glycyl radical enzymes that use distinct mechanisms for DHPS degradation. DHPS-sulfolyase (HpsG) in sulfate- and sulfite-reducing bacteria catalyzes C–S cleavage to release sulfite for use as a terminal electron acceptor in respiration, producing H2S. DHPS-dehydratase (HpfG), in fermenting bacteria, catalyzes C–O cleavage to generate 3-sulfopropionaldehyde, subsequently reduced by the NADH-dependent sulfopropionaldehyde reductase (HpfD). Both enzymes are present in bacteria from diverse environments including human gut, suggesting the contribution of enzymatic radical chemistry to sulfur flux in various anaerobic niches.
Chemoselective aerobic oxidation of unprotected diols catalyzed by Pd-(NHC) (NHC = N-heterocyclic carbene) complexes
Bettucci, Lorenzo,Bianchini, Claudio,Oberhauser, Werner,Hsiao, Tsun-Hung,Lee, Hon Man
, p. 63 - 72 (2010)
Neutral Pd(X)(η3-allyl) (X = Cl, OAc (acetate)) complexes bearing mono-coordinating NHC ligands have been synthesized, characterized and employed to catalyze the aerobic oxidation of unprotected 1,2- and 1,3-diols selectively to hydroxy ketones. A comparison of the catalytic performance of these precursors with a reference system has shown that the precursor with the ligands N,N′-bis(adamantyl)imidazol-2-ylidene and chloride is the most efficient for the chemoselective oxidation of 1,2-diols is concerned. High-pressure 1H NMR (HPNMR) experiments in combination with catalytic batch reactions have provided valuable information on the activation of the precursor as well as on the stability of the catalysts.
Influence of the carrier and composition of active phase on physicochemical and catalytic properties of CuAg/ oxide catalysts for selective hydrogenolysis of glycerol
Samson,Zelazny,Grabowski,Ruggiero-Mikolajczyk,liwa,Pamin,Kornas,Lachowska
, p. 9295 - 9306 (2015)
The aim of the present study is to investigate the influence of the support and composition of the active bimetallic phase on both the physicochemical and catalytic properties of catalysts for use in glycerol hydrogenolysis reaction. Two series of catalysts with different amounts of copper oxide and/or silver supported on Al2O3 or TiO2 oxides were prepared. To determine the physicochemical properties of the catalysts, the following techniques were used: Brunauer-Emmett-Teller, reactive N2O adsorption, X-ray diffraction, and temperature-programmed reduction TPR-H2. Physicochemical characterization revealed that addition of silver modifies the redox properties of the catalysts containing copper oxide and influences their specific surface area. It was found that the type of carrier determines the catalytic activity and selectivities for desired products, strongly influencing their distribution. The Al2O3-supported catalysts were much more selective for 1,2-propanediol, whereas 1-propanol was the main reaction product for the titania-supported catalysts. The best catalysts (6Cu/Al and 2Cu/Ti) achieved 38 % glycerol conversion with 71 % selectivity for 1,2-propanediol and 44 % conversion with 62 % selectivity for 1-propanol, respectively.
