- Manganese containing copper aluminate catalysts: Genesis of structures and active sites for hydrogenation of aldehydes
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Copper aluminate spinel (CuO.CuAl2O4) is the favoured Cr-free substitute for the copper chromite catalyst (CuO.CuCr2O4) in the industrial hydrogenation of aldehydes. New insights in the catalytic mechanism were obtained by systematically studying the structure and activity of these catalysts including effects of manganese as a catalyst component. The hydrogenation of butyraldehyde to butanol was studied as a model reaction and the active structure was characterised using X-ray diffraction, temperature programmed reduction, N2O chemisorption, EXAFS and XANES, including in-situ investigations. The active catalyst is a reduced spinel lattice that is stabilised by protons, with copper metal nanoparticles grown upon its surface. Incorporation of Mn into the spinel lattice has a profound effect on the spinel structure. Mn stabilises the spinel towards reduction of CuII to Cu0 by occupation of tetrahedral sites with Mn cations, but also causes decreased catalytic activity. Structural data, combined with the effect on catalysis, indicate a predominantly interface-based reaction mechanism, involving both the spinel and copper nanoparticle surface in protonation and reduction of the aldehyde. The electron reservoir of the metallic copper particles is regenerated by the dissociative adsorption and oxidation of H2 on the metal surface. The generated protons are stored in the spinel phase, acting as proton reservoir. Cu(I) species located within the spinel and identified by XANES are probably not involved in the catalytic cycle.
- D?rfelt, Christoph,Hammerton, Michelle,Martin, David,Wellmann, Alexander,Aletsee, Clara C.,Tromp, Moniek,K?hler, Klaus
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- Step mechanism of 1-butanol formation in the course of liquid-phase catalytic hydrogenation of 2-butyne-1,4-diol
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Exhaustive hydrogenation of 2-butyne-1,4-diol to 1,4-butanediol on suspended palladium and Raney nickel catalysts under atmospheric pressure at 40 C was studied with the aim to determine the mechanism of 1-butanol formation. The previously unknown pathway of 1-butanol synthesis is realized under these conditions. The content of 1-butanol precursors in hydrogenation catalyzates was estimated by gas-liquid chromatography. The graphic dependence of the content of the intermediates and 1-butanol on time was found. The possibility of increasing the hydrogenation selectivity on Raney Ni catalysts with respect to the target product was revealed.
- El'chaninov,Pyatnitsyna,El'chaninov
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- Transhalogenation Catalysed by Haloalkane Dehalogenases Engineered to Stop Natural Pathway at Intermediate
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Haloalkane dehalogenases (HLDs) are α/β-hydrolases that convert halogenated compounds to their corresponding alcohols. The overall kinetic mechanism proceeds via four steps: (i) binding of halogenated substrate, (ii) bimolecular nucleophilic substitution (SN2) leading to the cleavage of a carbon-halogen bond and the formation of an alkyl-enzyme intermediate, (iii) nucleophilic addition of a water molecule resulting in the hydrolysis of the intermediate to the corresponding alcohol and (iv) release of the reaction products – an alcohol, a halide ion and a proton. Although, the overall reaction has been reported as irreversible, several kinetic evidences from previous studies suggest the reversibility of the first SN2 chemical step. To study this phenomenon, we have engineered HLDs to stop the catalytic cycle at the stage of the alkyl-enzyme intermediate. The ability of the intermediate to exchange halides was confirmed by a stopped-flow fluorescence binding analysis. Finally, the transhalogenation reaction was confirmed with several HLDs and 2,3-dichloropropene in the presence of a high concentration of iodide. The formation of the transhalogenation product 3-iodo-2-chloropropene catalysed by five mutant HLDs was identified by gas chromatography coupled with mass spectrometry. Hereby we demonstrated the reversibility of the cleavage of the carbon-halogen bond by HLDs resulting in a transhalogenation. After optimization, the transhalogenation reaction can possibly find its use in biocatalytic applications. Enabling this reaction by strategically engineering the enzyme to stop at an intermediate in the catalytic cycle that is synthetically more useful than the product of the natural pathway is a novel concept. (Figure presented.).
- Beier, Andy,Damborsky, Jiri,Prokop, Zbynek
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- Hydrogen transfer reactions relevant to Guerbet coupling of alcohols over hydroxyapatite and magnesium oxide catalysts
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Hydrogenation and dehydrogenation reactions were performed over hydroxyapatite (Ca10(PO4)6(OH)2, HAP) and magnesia (MgO) to explore their role in the reaction network for the Guerbet coupling of ethanol to butanol. In particular, the dehydrogenation of benzyl alcohol at 633 K and the hydrogenation of ethene and acetone at 473 K using both H2 and ethanol as a hydrogen source were studied. The H2-D2 exchange reaction at room temperature and the Guerbet coupling of ethanol at 613-673 K in the presence of D2 were also performed. Although there was no consequence of adding D2 to the Guerbet coupling of ethanol in terms of rate or selectivity, incorporation of deuterium into product butanol was only observed over MgO. This was attributed to the rapid exchange of H2-D2 that can occur over MgO but not over HAP. Hydrogenation of acetone occurred with ethanol as a sacrificial hydrogen donor via an MPV-like reaction whereas hydrogenation with H2 was not observed. Hydrogenation of ethene with H2 or ethanol was not observed above background. Comparing the rate of benzyl alcohol dehydrogenation to the rate of ethanol coupling over HAP and MgO suggests that the MPV-like hydrogen transfer reaction over HAP is mostly responsible for generating intermediate acetaldehyde during the Guerbet reaction instead of direct dehydrogenation.
- Young, Zachary D.,Davis, Robert J.
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- Isotopic transient analysis of the ethanol coupling reaction over magnesia
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Isotopic transient analysis of ethanol coupling to butanol over MgO in a fixed-bed reactor at 673 K revealed a surface coverage of adsorbed ethanol equivalent to about 50% of the exposed MgO atomic pairs. DRIFTS of ethanol reaction at 673 K confirmed that the surface was populated primarily with adsorbed ethoxide and hydroxide, presumably from the dissociative adsorption of ethanol. The coverage of reactive intermediates leading to butanol was an order of magnitude lower than that of adsorbed ethanol, and about half the surface base sites counted by adsorption of CO2. The intrinsic turnover frequency for the coupling reaction at 673 K determined by isotopic transient analysis was 0.04 s-1, which is independent of any assumptions about the nature of the active sites. Although the ethanol coupling reaction appears to involve aldol condensation of an aldehyde intermediate, the high coverage of ethanol under steady-state conditions apparently inhibits unproductive CC coupling reactions that deactivate the catalyst at high temperature.
- Birky, Theodore W.,Kozlowski, Joseph T.,Davis, Robert J.
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- A green process for the production of butanol from butyraldehyde using alcohol dehydrogenase: Process details
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Depletion of energy sources has drawn attention towards production of bio-butanol by fermentation. However, the process is constrained by product inhibition which results in low product yield. Hence, a new strategy wherein butanol was produced from butyraldehyde using alcohol dehydrogenase and NADH as a cofactor was developed. Butyraldehyde can be synthesized chemically or through fermentation. The problem of cofactor regeneration during the reaction for butanol production was solved using substrate coupled and enzyme coupled reactions. The conventional reaction produced 35% of butanol without regeneration of cofactor using 300 μM NADH. The process of substrate coupled reaction was optimized to get maximum conversion. NADH (30 μM) and 100 μg per ml of alcohol dehydrogenase (320 U mg-1) could convert 17.39 mM of butyraldehyde to butanol using ethanol (ratio of butyraldehye to ethanol 1:4) giving a maximum conversion of 75%. The enzyme coupled reaction under the same conditions showed only 24% conversion of butyraldehyde to butanol using the glutamate dehydrogenase-l-glutamate enzyme system for the regeneration of cofactor. Hence, substrate coupled reaction is suggested as a better method over the enzyme coupled reaction for the cost effective production of butanol. This journal is the Partner Organisations 2014.
- Jadhav, Swati B.,Harde, Shirish,Bankar, Sandip B.,Granstroem, Tom,Ojamo, Heikki,Singhal, Rekha S.,Survase, Shrikant A.
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- Tuning the selectivities of Mg-Al mixed oxides for ethanol upgrading reactions through the presence of transition metals
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The effect of the presence of reduced Co and Ni (chosen as representative metals because of their good activity for dehydrogenation reactions) on the catalytic performance of basic mixed oxide (Mg-Al) for ethanol condensation is studied in this work. This effect has been studied both in absence and in presence of hydrogen, and considering the different steps of this complex reaction. Globally, best results were obtained with Co/MgAl, under reducing atmosphere, at mild temperature (below 600 K). At these conditons, 1-butanol production rates are up to eight times higher than the obtained with Mg-Al under inert atmosphere. Co has a marked activity in the dehydrogenation step, that prevails over its less relevant activity in aldolization and hydrogenation reactions. This result indicates the relevant role of this first reaction step. DRIFT spectroscopy analyses were carried out to support the experimental results and to identify the role of hydrogen and metals on the oligomerization and permanent adsorption processes, which can produce the deactivation of the catalyst.
- Quesada, Jorge,Faba, Laura,Díaz, Eva,Ordó?ez, Salvador
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- Kinetics of complexation between cyclodextrin and alcohol by ultrasonic relaxation method: β-cyclodextrin solutions with 1-butanol and 2-methyl-2-propanol
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The ultrasonic absorption coefficients over frequency range from 1.0 to 220 MHz were measured in aqueous β-cyclodextrin solutions with 1-butanol and 2-methyl-2-propanol at 25 °C. A clear single relaxational absorption with a relaxation frequency from 5 to 20 MHz was observed in a solution with 1-butanol, while the relaxational absorption was found in a lower frequency range in a solution with 2-methyl-2-propanol. The cause of the relaxation was attributed to a perturbation of a chemical equilibrium associated with complexation between β-cyclodextrin (host) and alcohol (guest). The rate and equilibrium constants for the complexation were determined from the concentration dependence of the relaxation frequency for the solution with 1-butanol. The standard volume change of the reaction was also obtained from the maximum absorption per wavelength. These results were compared with those for complexation between β-cyclodextrin and 1-propanol, and were considered in relation to the alcohol molecular structure. It was found that the rate of complex formation is almost independent of the guest molecule, and, therefore, the equilibrium constant for the complexation is controlled by the rate of departure of the guest molecule from the host. From this fact, the rate parameters for a solution with 2-methyl-2-propanol were estimated, and the calculated ultrasonic relaxation parameter was compared with the experimental data.
- Nishikawa, Sadakatsu
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- Synthesis and Characterization of Ru-Loaded Anodized Aluminum Oxide for Hydrogenation Catalysis
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Anodized aluminum oxides (AAOs) are synthesized and used as catalyst support in combination with Ru as metal in hydrogenation catalysis. SEM and TEM analysis of the as-synthesized AAOs reveal uniform, ordered nanotubes with pore diameters of 18 nm, which are further characterized with Kr physisorption, XRD and FTIR spectroscopy. After impregnation of the AAOs with Ru, the presence of Ru nanoparticles inside the tubular pores is evidenced clearly for the first time via HAADF-STEM-EDX. The Ru?AAOs have been tested for catalytic activity, which showed high conversion and selectivity for the hydrogenation of toluene and butanal.
- Vandekerkhove, Annelies,Negahdar, Leila,Glas, Daan,Stassen, Ivo,Matveev, Serguei,Meeldijk, Johannes D.,Meirer, Florian,De Vos, Dirk E.,Weckhuysen, Bert M.
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- Multiproduct steady-state isotopic transient kinetic analysis of the ethanol coupling reaction over hydroxyapatite and magnesia
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The Guerbet coupling of ethanol into butanol was investigated using multiproduct steady-state isotopic transient kinetic analysis (SSITKA) in a comparative study between stoichiometric hydroxyapatite (HAP) and magnesia (MgO) catalysts at 613 and 653 K, respectively. The steady-state catalytic reactions were conducted in a gas-phase, fixed-bed, differential reactor at 1.3 atm total system pressure. Multiproduct SSITKA results showed that the mean surface residence time of reactive intermediates leading to acetaldehyde was significantly shorter than that of intermediates leading to butanol on both HAP and MgO. This finding may suggest that the dehydrogenation of ethanol to acetaldehyde is fast on these surfaces compared with C-C bond formation. If adsorbed acetaldehyde is a key reaction intermediate in the Guerbet coupling of ethanol into butanol, then SSITKA revealed that the majority of adsorbed acetaldehyde produced on the surface of MgO desorbs into the gas-phase, whereas the majority of adsorbed acetaldehyde on HAP likely undergoes sequential aldol-type reactions required for butanol formation. Adsorption microcalorimetry of triethylamine and CO2 showed a significantly higher number of acid and base sites on the surface of HAP compared with those on MgO. Diffuse reflectance infrared Fourier transform spectroscopy of adsorbed ethanol followed by stepwise temperature-programmed desorption revealed that ethoxide is more weakly bound to the HAP surface compared with MgO. A high surface density of acid-base site pairs along with a weak binding affinity for ethanol on HAP may provide a possible explanation for the increased activity and high butanol selectivity observed with HAP compared with MgO catalysts in the ethanol coupling reaction.
- Hanspal, Sabra,Young, Zachary D.,Shou, Heng,Davis, Robert J.
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- SINGLE-STAGE VAPOR-PHASE HYDROGENATION OF CROTONALDEHYDE TO n-BUTYL ALCOHOL.
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The commercial hydrogenation of crotonaldehyde to n-butyl alcohol is conducted in two stages. First the feedstock is 90-95% hydrogenated, then the product is rehydrogenated. Supported copper and nickel oxide catalysts are used. In order to carry out the single-stage vapor-phase hydrogenation of crotonaldehyde, work was performed on the preparation of a new, active catalyst with good mechanical strength; this was obtained by coprecipitation of copper compounds with other added metals from solutions of their salts, together with silica gel. The resulting catalyst mass was subjected to further treatment, including stages of syneresis, washing, drying, pelletizing, and activation. In the reported investigation, crotonaldehyde was hydrogenated on several catalyst specimens differing in chemical composition. The hydrogenations were performed at temperatures of 160, 180, and 200 C, liquid feedstock space velocities of 1. 2-2. 4 h** minus **1, and hydrogen space velocities of 1000 and 2000 h** minus **1. The composition of the liquid reaction products was determined by gas chromatography. Results obtained with the modified copper catalyst prepared under laboratory conditions are tabulated and compared with those obtained with commercial catalysts. It is shown that the modified catalyst has been more active than the commercial catalyst. This catalyst as prepared by the authors proved to have approximately twice the mechanical strength of the commercial catalyst.
- Morozova,Zhorov,Panchenkov
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- Influence of surface acid and base sites on the Guerbet coupling of ethanol to butanol over metal phosphate catalysts
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Hydroxyapatite (HAP; Ca10(PO4)6(OH)2) is a well-recognized catalyst for the Guerbet coupling of ethanol to butanol. In an effort to explore the role of the anion components of the catalyst, steady-state, gas phase catalytic coupling of ethanol to butanol was investigated at 633?K and atmospheric pressure over beta tricalcium phosphate (β-TCP; β-Ca3(PO4)2) and fluorine-substituted hydroxyapatite (FAP; Ca10(PO4)6F2). Both β-TCP and FAP catalysts were catalytically active for butanol formation, leading to ～35% selectivity at low conversion, suggesting that the PO43? group contributes to the active acid-base site pair for butanol formation during ethanol coupling over HAP. Co-feeding water, a product of ethanol coupling, revealed weaker inhibition of the rate over HAP relative to MgO, confirming the potential negative influence of strong base sites on coupling catalysts. Catalytic reactions of ethanol over Mg3(PO4)2, β-TCP, and Sr3(PO4)2 catalysts demonstrated the importance of Lewis acidity of the metal phosphates on the reaction. Relatively strong Lewis acid sites on the Mg3(PO4)2 surface (Mg2+ cations) favored undesired ethanol dehydration to ethene (36% selectivity) and diethyl ether (52% selectivity) whereas the Sr3(PO4)2 catalyst predominantly catalyzed ethanol dehydrogenation to acetaldehyde (91% selectivity) at a rate significantly higher than that observed over the other catalysts. Evidently, the β-TCP exposes intermediate-strength Lewis acid sites provided by surface Ca2+ cations that enable the material to effectively convert ethanol to butanol with 35% selectivity.
- Hanspal, Sabra,Young, Zachary D.,Prillaman, J. Tyler,Davis, Robert J.
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- Direct hydrogenation of biomass-derived butyric acid to n-butanol over a ruthenium-tin bimetallic catalyst
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Catalytic hydrogenation of organic carboxylic acids and their esters, for example, cellulosic ethanol from fermentation of acetic acid and hydrogenation of ethyl acetate is a promising possibility for future biorefinery concepts. A hybrid conversion process based on selective hydrogenation of butyric acid combined with fermentation of glucose has been developed for producing biobutanol. ZnO-supported Ru-Sn bimetallic catalysts exhibits unprecedentedly superior performance in the vapor-phase hydrogenation of biomass-derived butyric acid to n-butanol (>98% yield) for 3500 h without deactivation.
- Lee, Jong-Min,Upare, Pravin P.,Chang, Jong-San,Hwang, Young Kyu,Lee, Jeong Ho,Hwang, Dong Won,Hong, Do-Young,Lee, Seung Hwan,Jeong, Myung-Geun,Kim, Young Dok,Kwon, Young-Uk
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- Degradation of cyhalofop-butyl (CyB) by Pseudomonas azotoformans strain QDZ-1 and cloning of a novel gene encoding CyB-hydrolyzing esterase
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Cyhalofop-butyl (CyB) is a widely used aryloxyphenoxy propanoate (AOPP) herbicide for control of grasses in rice fields. Five CyB-degrading strains were isolated from rice field soil and identified as Agromyces sp., Stenotrophomonas sp., Aquamicrobium sp., Microbacterium sp., and Pseudomonas azotoformans; the results revealed high biodiversity of CyB-degrading bacteria in rice soil. One strain, P. azotoformans QDZ-1, degraded 84.5% of 100 mg L-1 CyB in 5 days of incubation in a flask and utilized CyB as carbon source for growth. Strain QDZ-1 could also degrade a wide range of other AOPP herbicides. An esterase gene, chbH, which hydrolyzes CyB to cyhalofop acid (CyA), was cloned from strain QDZ-1 and functionally expressed. A chbH-disrupted mutant dchbH was constructed by insertion mutation. Mutant dchbH could not degrade and utilize CyB, suggesting that chbH was the only esterase gene responsible for CyB degradation in strain QDZ-1. ChbH hydrolyzed all AOPP herbicides tested as well as permethrin. The catalytic efficiency of ChbH toward different AOPP herbicides followed the order quizalofop-P-ethyl ≈ fenoxaprop-P-ethyl > CyB ≈ fluazifop-P-butyl > diclofop-methyl ≈ haloxyfop-P-methyl; the results indicated that the chain length of the alcohol moiety strongly affected the biodegradability of the AOPP herbicides, whereas the substitutions in the aromatic ring had only a slight influence.
- Nie, Zhi-Juan,Hang, Bao-Jian,Cai, Shu,Xie, Xiang-Ting,He, Jian,Li, Shun-Peng
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- Direct electrochemical addressing of immobilized alcohol dehydrogenase for the heterogeneous bioelectrocatalytic reduction of butyraldehyde to butanol
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Modified electrodes using immobilized alcohol dehydrogenase enzymes for the efficient electroreduction of butyraldehyde to butanol are presented as an important step for the utilization of CO2-reduction products. Alcohol dehydrogenase was immobilized, embedded in an alginate-silicate hybrid gel, on a carbon felt (CF) electrode. The application of this enzyme to the reduction of an aldehyde to an alcohol with the aid of the coenzyme nicotinamide adenine dinucleotide (NADH), in analogy to the final step in the natural reduction cascade of CO2 to alcohol, has been already reported. However, the use of such enzymatic reductions is limited because of the necessity of providing expensive NADH as a sacrificial electron and proton donor. Immobilization of such dehydrogenase enzymes on electrodes and direct pumping of electrons into the biocatalysts offers an easy and efficient way for the biochemical recycling of CO2 to valuable chemicals or alternative synthetic fuels. We report the direct electrochemical addressing of immobilized alcohol dehydrogenase for the reduction of butyraldehyde to butanol without consumption of NADH. The selective reduction of butyraldehyde to butanol occurs at room temperature, ambient pressure and neutral pH. Production of butanol was detected by using liquid-injection gas chromatography and was estimated to occur with Faradaic efficiencies of around 40%.
- Schlager,Neugebauer,Haberbauer,Hinterberger,Sariciftci
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- Insights into Ethanol Coupling over Hydroxyapatite using Modulation Excitation Operando Infrared Spectroscopy
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The coupling of biomass-derived ethanol to n-butanol is a topic of contemporary interest. Indeed, n-butanol can not only be used as a higher energy-density fuel additive, it is also a key component in perfumes and serves as a solvent for paints and dyes. Hydroxyapatite (HAP) emerged in the literature as a promising catalysts for this transformation, with n-butanol selectivity reaching ～75 percent at 10 percent ethanol conversion. However, the molecular-level mechanism for this reaction is still unclear and several mechanistic questions remain unanswered. Here, we use diffuse reflectance infrared Fourier Transform spectroscopy, coupled with mass spectrometry following a modulation excitation approach (ME-DRIFTS-MS) that enables us to better understand the dynamic processes involved. Our approach allows for a vibrational characterization of the active surface species and the formulation of a consistent mechanism. Based on our experimental observations, Ca2+/OH? can be put forward as the main active site for the aldol condensation. POH/OH? acid-base pair is proposed as the active site for the Meerwein-Ponndorf-Verley (MPV) direct hydrogen transfer of the aldol condensation product, crotonaldehyde.
- Wang, Shao-Chun,Cendejas, Melissa C.,Hermans, Ive
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- Boosting the guerbet reaction: A cooperative catalytic system for the efficient bio-ethanol refinery to second-generation biofuels
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The catalytic activity of anionic ruthenium complexes toward the transformation of bio-ethanol to 1-butanol and higher alcohols is found to be dependent on the imidazolium counterion. After the identification of a parallel reaction involving the catalyst in hydrogen evolution, conversion and selectivity are impressively boosted by the addition of p-benzoquinones as co-catalysts. The catalytic system avoids the side reaction and led to highly competitive conversions up to 88% (0.2 % mol ruthenium catalyst loading, 1.5 % mol benzoquinone loading). Butanol and higher alcohols are produced in yields up to 85% (overall selectivity 97%) as a mixture of valuable alcohols for advanced biofuel and lubricants applications. The catalytic system can be recycled and the reaction shows comparable efficiency on a real matrix (alcohol from wine production chain wastes) even in the presence of significant amounts of water, thus closing a hypothetic economic circle. A reaction mechanism is proposed for the most promising ruthenium complex working in cooperation with the most efficient co-catalyst: p-benzoquinone.
- Calcagno, Francesco,Cavani, Fabrizio,Cesari, Cristiana,Gagliardi, Anna,Lucarelli, Carlo,Mazzoni, Rita,Messori, Alessandro,Monti, Nicola,Rivalta, Ivan,Tabanelli, Tommaso,Zacchini, Stefano,Zanotti, Valerio
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- MOF-derived hcp-Co nanoparticles encapsulated in ultrathin graphene for carboxylic acids hydrogenation to alcohols
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Highly efficient conversion of carboxylic acids to valuable alcohols is a great challenge for easily corroded non-noble metal catalysts. Here, a series of few-layer graphene encapsulated metastable hexagonal closed-packed (hcp) Co nanoparticles were fabricated by reductive pyrolysis of metal-organic framework precursor. The sample pyrolyzed at 400 °C (hcp-Co@G400) presented outstanding performance and stability for converting a variety of functional carboxylic acids and its turnover frequency was one magnitude higher than that of conventional facc-centered cubic (fcc) Co catalysts. In situ DRIFTS spectroscopy of model reaction acetic acid hydrogenation and DFT calculation results confirm that carboxylic acid initially undergoes dehydroxylation to RCH2CO* followed by consecutive hydrogenation to RCH2CH2OH through RCH2COH*. Acetic acid prefers to vertically adsorb at hcp-Co (0 0 2) facet with a much lower adsorption energy than parallel adsorption at fcc-Co (1 1 1) surface, which plays a key role in decreasing the activation barrier of the rate-determining step of acetic acid dehydroxylation.
- Dong, Mei,Fan, Weibin,Gao, Xiaoqing,Zhu, Shanhui
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p. 201 - 211
(2021/06/03)
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- METHOD FOR PRODUCING BIO ALCOHOL FROM INTERMEDIATE PRODUCTS OF ANAEROBIC DIGESTION TANK
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The present invention relates to a method for producing a bio-alcohol by reacting a mixture of volatile fatty acid with methanol in 2 through 11 in a reactor in the presence of a 280 °C-membered alkaline earth metal catalyst or 400 °C transition metal catalyst formed based on a support.
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Paragraph 0057-0060; 0063; 0065-0066; 0068-0069; 0071
(2021/05/25)
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- Highly Modular Piano-Stool N-Heterocyclic Carbene Iron Complexes: Impact of Ligand Variation on Hydrosilylation Activity
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The piano-stool configuration combined with N-heterocyclic carbene (NHC) ligation constitutes an attractive scaffold for employing iron in catalysis. Here, we have expanded this scaffold by installing a pentamethyl cyclopentadienyl (Cp*) ligand as a strong electron donor compared to the traditionally used unsubstituted cyclopentadiene (Cp). Moreover, decarboxylation is introduced as a method to prepare these iron(II) NHC complexes, which avoids the isolation of air-sensitive free carbenes. In addition to the Cp/Cp? variation, the complexes have been systematically modulated at the NHC scaffold, the NHC wingtip groups, and the ancillary ligands in order to identify critical factors that govern the catalytic activity of the iron center in the hydrosilylation of aldehydes. These modulations reveal the importance of steric tailoring and optimization of electron density for high catalytic performance. The data demonstrate a critical role of the NHC scaffold with triazolylidenes imparting consistently higher activity than imidazolylidenes and a correlation between catalytic activity and steric rather than electronic factors. Moreover, the implementation of steric bulk is strongly dependent on the nature of the NHC and severely limited by the Cp? iron precursor. The best performing catalytic systems reach turnover frequencies, TOFmax's, of up to 360 h-1 at 60 °C. Mechanistic investigations by 1H NMR and in situ IR spectroscopies indicate a catalyst activation that involves CO release and aldehyde coordination to the [Fe(Cp)(NHC)I] fragment.
- Nylund, Pamela V. S.,Ségaud, Nathalie C.,Albrecht, Martin
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p. 1538 - 1550
(2021/05/29)
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- Method for producing a shaped catalyst body
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Provided herein is a novel process for producing shaped catalyst bodies in which a mixture having aluminum contents of Al±0 in the range from 80 to 99.8% by weight, based on the mixture used, is used to form a specific intermetallic phase, shaped catalyst bodies obtainable by the process of the invention, a process for producing an active catalyst fixed bed including the shaped catalyst bodies provided herein, the active catalyst fixed beds and also the use of these active catalyst fixed beds for the hydrogenation of organic hydrogenatable compounds or for formate degradation.
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Page/Page column 29-31
(2021/11/19)
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- Disproportionation of aliphatic and aromatic aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions
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Disproportionation of aldehydes through Cannizzaro, Tishchenko, and Meerwein–Ponndorf–Verley reactions often requires the application of high temperatures, equimolar or excess quantities of strong bases, and is mostly limited to the aldehydes with no CH2 or CH3 adjacent to the carbonyl group. Herein, we developed an efficient, mild, and multifunctional catalytic system consisting AlCl3/Et3N in CH2Cl2, that can selectively convert a wide range of not only aliphatic, but also aromatic aldehydes to the corresponding alcohols, acids, and dimerized esters at room temperature, and in high yields, without formation of the side products that are generally observed. We have also shown that higher AlCl3 content favors the reaction towards Cannizzaro reaction, yet lower content favors Tishchenko reaction. Moreover, the presence of hydride donor alcohols in the reaction mixture completely directs the reaction towards the Meerwein–Ponndorf–Verley reaction. Graphic abstract: [Figure not available: see fulltext.].
- Sharifi, Sina,Sharifi, Hannah,Koza, Darrell,Aminkhani, Ali
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p. 803 - 808
(2021/07/20)
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- Synthesis, Structure, and Catalytic Hydrogenation Activity of [NO]-Chelate Half-Sandwich Iridium Complexes with Schiff Base Ligands
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A series of N,O-coordinate iridium(III) complexes with a half-sandwich motif bearing Schiff base ligands for catalytic hydrogenation of nitro and carbonyl substrates have been synthesized. All iridium complexes showed efficient catalytic activity for the hydrogenation of ketones, aldehydes, and nitro-containing compounds using clean H2 as reducing reagent. The iridium catalyst displayed the highest TON values of 960 and 950 in the hydrogenation of carbonyl and nitro substrates, respectively. Various types of substrates with different substituted groups afforded corresponding products in excellent yields. All N,O-coordinate iridium(III) complexes 1-4 were well characterized by IR, NMR, HRMS, and elemental analysis. The molecular structure of complex 1 was further characterized by single-crystal X-ray determination.
- Lv, Wen-Rui,Li, Rong-Jian,Liu, Zhen-Jiang,Jin, Yan,Yao, Zi-Jian
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p. 8181 - 8188
(2021/05/26)
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- carba Nicotinamide Adenine Dinucleotide Phosphate: Robust Cofactor for Redox Biocatalysis
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Here we report a new robust nicotinamide dinucleotide phosphate cofactor analog (carba-NADP+) and its acceptance by many enzymes in the class of oxidoreductases. Replacing one ribose oxygen with a methylene group of the natural NADP+ was found to enhance stability dramatically. Decomposition experiments at moderate and high temperatures with the cofactors showed a drastic increase in half-life time at elevated temperatures since it significantly disfavors hydrolysis of the pyridinium-N?glycoside bond. Overall, more than 27 different oxidoreductases were successfully tested, and a thorough analytical characterization and comparison is given. The cofactor carba-NADP+ opens up the field of redox-biocatalysis under harsh conditions.
- D?ring, Manuel,Sieber, Volker,Simon, Robert C.,Tafertshofer, Georg,Zachos, Ioannis
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supporting information
p. 14701 - 14706
(2021/05/13)
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- Deactivation Mechanism of Palladium Catalysts for Ethanol Conversion to Butanol
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Abstract: A Pd/Al2O3 catalyst (Pd = 0.1 wt%) for ethanol conversion to butanol deactivates within 10 h of service, despiteits high initial activity at 275°C. Probable deactivation mechanisms wereexplored, including poisoning ofPd/Al2O3 due to adsorption ofby-products on Pd, sintering of Pd phases, leaching of Pd from the catalyst,changes in the Pd electronic state, changes in the catalyst’s porous structure,and blockage of Al2O3 activesites. The Pd/Al2O3 deactivationwas found to be mainly caused by CO molecules that evolved during sidereactions. These molecules can either block Pd active sites due to the formationof strong Pd–CO complexes, or enter a CO disproportionation reaction to formcarbon deposits on Pd phases. The knowledge gained from this study can be usedfor the targeted modification ofPd/Al2O3 and the creation ofselective systems operating stably in the presence of by-products.
- Ezzhelenko,Nikolaev,Chistyakov,Chistyakova,Tsodikov
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p. 504 - 515
(2021/05/07)
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- COMPOSITION OF CATALYSTS FOR CONVERSION OF ETHANOL TO N-BUTANOL AND HIGHER ALCOHOLS
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A method of producing a catalyst comprises forming a decomposed material comprising a decomposed hydrotalcite, a decomposed hydrocalumite, or a combination of both, combining the decomposed material with a mixture to form a catalyst mixture, and heating the catalyst mixture to convert the metal salt to a metal oxide. The mixture comprises a metal salt and a chelating agent, and the resulting metal oxide combined with the decomposed material forms the catalyst.
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Paragraph 0103-0121
(2021/05/21)
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- Transition metals promoting Mg-Al mixed oxides for conversion of ethanol to butanol and other valuable products: Reaction pathways
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This paper is focused on the catalytic synthesis of butanol from ethanol in a microflow reactor at a constant weight hour space velocity (4.5 h?1) and different reaction temperatures (280, 300 and 350 °C). The reaction was catalysed by Mg-Al mixed oxides (i) pure and (ii) with added transition metals such as Co, Ni, Cu, Mn and Cr (synthesis by coprecipitation). The solid materials were deeply characterised. Other products, such as ethylene, 1,1-diethoxyethane, ethyl acetate, 1-hexanol, etc. were also determined and the reaction pathway for their formation was examined. The metals Cr and Mn did not increase the catalyst activity, which was quite low (maximum 19% at 350 °C). However, the metals Co and Ni positively influenced butanol formation, while Cu positively influenced ethyl acetate formation. Moreover, ethanol conversion increased with increasing temperature, but at the same time the selectivity to butanol decreased.
- Frolich, Karel,Hájek, Martin,Ka?párek, Ale?,Kocík, Jaroslav,Mück, Jáchym,Ti?ler, Zdeněk
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- SELECTIVE PRODUCTION OF METHANOL AND ETHANOL FROM CO HYDROGENATION
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A method for producing methanol and ethanol is disclosed. The method can include contacting a gaseous stream comprising carbon monoxide (CO) and hydrogen (H22) with a crystalline cobalt molybdenum catalyst under conditions suitable to produce a products stream comprising methanol and ethanol from the CO and H22.
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Paragraph 0036-0037
(2021/02/12)
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- Probing the Interface between Encapsulated Nanoparticles and Metal-Organic Frameworks for Catalytic Selectivity Control
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Encapsulating metal nanoparticles (NPs) in metal-organic frameworks (MOFs) to control catalytic selectivity has recently attracted great attention; however, an understanding of the NP-MOF interface is lacking. In this work, we used spectroscopy to investi
- Lo, Wei-Shang,Chou, Lien-Yang,Young, Allison P.,Ren, Chenhao,Goh, Tian Wei,Williams, Benjamin P.,Li, Yang,Chen, Sheng-Yu,Ismail, Mariam N.,Huang, Wenyu,Tsung, Chia-Kuang
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- Preparation and catalytic performance of NiO-MnO2/Nb2O5-TiO2 for one-step synthesis of 2-ethylhexanol from n-butyraldehyde
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One-pot synthesis of 2-ethylhexanol(2EHO) from n-butyraldehyde is of commercialimportance. The promotion of 2EHO selectivity requires suppressing direct hydrogenation of n-butyraldehyde. In this work, a series of NiO-MOx/Nb2O5-TiO2 catalysts were prepared and utilized by means of reduction-in-reaction technique, aiming at delaying the formation of metal sites and suppressing the direct hydrogenation. NiO-MnO2/Nb2O5-TiO2 with a Ni/Mn mass ratio of 10 and NiO-MnO2 loading of 14.3 wt% shows the best catalytic performance; 2-EHO selectivity could reach 90.0% at a complete conversion of n-butyraldehyde. Furthermore the catalyst could be used for four times without a substantial change in its catalytic performance.
- An, Hualiang,Li, Sibo,Wang, Yanji,Zhang, Jiaxun,Zhao, Xinqiang
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- Effects of Support on the Formation and Activity of Gold Catalysts for Ethanol Conversion to Butanol
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Abstract: Using a combination of physicochemical methods, such as TEM, SEM, EDS, XPS,NH3–TPD, and N2 adsorption,the study investigates the structure of a number of supports(Al2O3,SiO2, TiO2,ZrO2, and C) and of Au/support catalyst samples (Au =0.5%). The concentration of highly active 2–4 nm gold particles in Au catalystsis influenced by the support’s texture; this concentration increases in thefollowing order: Au/TiO2 2 22O3. The acidity ofAu catalysts is influenced by the support’s nature; this acidity decreases inthe following order: Al2O3 >TiO2 > ZrO2 >SiO2 >> Au/C. At 275°C, a carbon support isinactive in ethanol conversion to butanol. In the presence of oxide supports,the target reaction occurs at a relatively low rate by a bimolecular condensation mechanism. OverAu/Al2O3,Au/SiO2, Au/TiO2, orAu/ZrO2, the reaction occurs more rapidly by analdol condensation mechanism. At anethanol conversion of 14–18%, the butanol selectivity increases in the followingorder: Au/C(0) 2 (0.4%) 2 (1.5%) 2(2%) 2O3 (78%). Thehigh efficiency of Au/Al2O3 stemsfrom the high density of the Aln+–O2– sites located onthe support’s surface, and of the coordination-unsaturatedAu0(KH) atoms located on the surface of 2–4 nmgold particles. [Figure not available: see fulltext.]
- Chistyakov, A. V.,Chistyakova, P. A.,Ezzhelenko, D. I.,Konkova, T. V.,Liberman, E. Yu.,Nikolaev, S. A.,Tsodikov, M. V.
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p. 748 - 761
(2021/08/03)
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- CO hydrogenation over K-Co-MoSx catalyst to mixed alcohols: A kinetic analysis
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Higher alcohol synthesis (HAS) from syngas is one of the most promising approaches to produce fuels and chemicals. Our recent investigation on HAS showed that potassium-promoted cobalt-molybdenum sulfide is an effective catalyst system. In this study, the intrinsic kinetics of the reaction were studied using this catalyst system under realistic conditions. The study revealed the major oxygenated products are linear alcohols up to butanol and methane is the main hydrocarbon. The higher alcohol products (C3+) followed an Anderson-Schultz-Flory distribution while the catalyst suppressed methanol and ethanol formation. The optimum reaction conditions were estimated to be at temperature of 340°C, pressure of 117?bar, gas hourly space velocity of 27?000?mL?g–1h–1 and H2/CO molar feed ratio of 1. A kinetic network has been considered and kinetic parameters were estimated by nonlinear regression of the experimental data. The results indicated an increasing apparent activation energy of alcohols with the length of alcohols except for ethanol. The lower apparent activation energy of alcohols compared with hydrocarbon evidenced the efficiency of this catalyst system to facilitate the formation of higher alcohols.
- Negahdar, Leila,Xi, Xiaoying,Zeng, Feng,Winkelman,Heeres, Hero Jan,Palkovits, Regina
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supporting information
p. 419 - 427
(2020/11/30)
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- Upgrading of Ethanol to n-Butanol via a Ruthenium Catalyst in Aqueous Solution
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The upgrading of ethanol to n-butanol via the Guerbet reaction in aqueous media has been developed. This system allows for the upgrading of ethanol to n-butanol in up to a 28% yield and 57% selectivity, at only 80 °C. This system is also able to tolerate the same feedstock ratio found in fermentation broth (water to ethanol ratio of 90:10), albeit a decrease in yield and selectivity (20% yield of n-butanol, 48% selectivity). Smaller amounts of longer-chain alcohols are also formed.
- Dibenedetto, Tarah A.,Jones, William D.
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supporting information
p. 1884 - 1888
(2021/06/30)
-
- PROCESSES FOR PRODUCING ALCOHOLS FROM BIOMASS AND FURTHER PRODUCTS DERIVED THEREFROM
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Processes for producing alcohols from biomass are provided. The processes utilize supercritical methanol to depolymerize biomass with subsequent conversion to a mixture of alcohols. In particular the disclosure relates to continuous processes which produce high yields of alcohols through recycling gases and further employ dual reactor configurations which improve overall alcohol yields. Processes for producing higher ethers and olefins from the so-formed alcohols, through alcohol coupling and subsequent dehydration are also provided. The resulting distillate range ethers and olefins are useful as components in liquid fuels, such as diesel and jet fuel.
- -
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Paragraph 0539-0540
(2021/11/26)
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- Improving the Catalytic Stability of Ni/TiO2 for Ethanol Guerbet Condensation: Influence of Second Metal Component
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Abstract: Ethanol Guerbet condensation (EGC) is a green process for preparing n-butanol and the development of highly effective solid catalysts is still the bottleneck of this reaction. In this work, a series of multifunctional catalysts Ni–X/TiO2 (X = Ru, Pt, Ir, Au, Cu, Mn, Co, Fe) were prepared by a co-impregnation method in order to improve the catalytic performance, especially the stability. It was found that the addition of the second metal component changed the acidity and alkalinity of Ni/TiO2 catalyst. What is more, acid site number affected ethanol conversion while alkali site number affected n-butanol selectivity. Among the Ni–X/TiO2 catalysts, Ni–Cu/TiO2 showed the best catalytic performance. The effects of preparation conditions on the catalytic performance of Ni–Cu/TiO2 were investigated and the results showed that the suitable preparation conditions were as follows: a Ni/Cu mass ratio of 59 : 1, a Ni–Cu loading of 12.5 wt %, a calcination temperature of 450°C, a calcination time of 2 h, a reduction temperature of 400°C, and a reduction time of 4?h. At a 10 wt % of catalyst loading, a reaction temperature of 210°C and a reaction time of 10 h, the ethanol conversion and the selectivity of n-butanol were 47.9 and 44.4%, respectively. Moreover, the stability of Ni–Cu/TiO2 catalyst was greatly improved due to the interaction between Ni and Cu as compared with the Ni/TiO2 catalyst: the catalytic activity of Ni–Cu/TiO2 did not decline significantly for reuse in three cycles.
- An, Hualiang,Han, Xiaoxu,Li, Shuaiqi,Wang, Yanji,Zhao, Xinqiang
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p. 632 - 640
(2021/09/28)
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- Interfacial Sites in Ag Supported Layered Double Oxide for Dehydrogenation Coupling of Ethanol to n-Butanol
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Upgrading of ethanol to n-butanol through dehydrogenation coupling has received increasing attention due to the wide application of n-butanol. But the enhancement of ethanol dehydrogenation and followed coupling to produce high selectivity to n-butanol is still highly desired. Our previous work has reported an acid-base-Ag synergistic catalysis, with Ag particles supported on Mg and Al-containing layered double oxides (Ag/MgAl-LDO). Here, Ag-LDO interfaces have been manipulated for dehydrogenation coupling of ethanol to n-butanol by tailoring the size of Ag particles and the interactions between Ag and LDO. It has been revealed that increasing the population of surface Ag sites at Ag-LDO interfaces promotes not only the dehydrogenation of ethanol to acetaldehyde but also the subsequent aldol condensation of generated acetaldehyde. A selectivity of up to 76 % to n-butanol with an ethanol conversion of 44 % has been achieved on Ag/LDO with abundant interfacial Ag sites, much superior to the state-of-the-art catalysts.
- Zhang, Jian,Shi, Kai,Zhu, Yanru,An, Zhe,Wang, Wanning,Ma, Xiaodan,Shu, Xin,Song, Hongyan,Xiang, Xu,He, Jing
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p. 1095 - 1103
(2021/02/01)
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- Indirect reduction of CO2and recycling of polymers by manganese-catalyzed transfer hydrogenation of amides, carbamates, urea derivatives, and polyurethanes
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The reduction of polar bonds, in particular carbonyl groups, is of fundamental importance in organic chemistry and biology. Herein, we report a manganese pincer complex as a versatile catalyst for the transfer hydrogenation of amides, carbamates, urea derivatives, and even polyurethanes leading to the corresponding alcohols, amines, and methanol as products. Since these compound classes can be prepared using CO2as a C1 building block the reported reaction represents an approach to the indirect reduction of CO2. Notably, these are the first examples on the reduction of carbamates and urea derivatives as well as on the C-N bond cleavage in amides by transfer hydrogenation. The general applicability of this methodology is highlighted by the successful reduction of 12 urea derivatives, 26 carbamates and 11 amides. The corresponding amines, alcohols and methanol were obtained in good to excellent yields up to 97%. Furthermore, polyurethanes were successfully converted which represents a viable strategy towards a circular economy. Based on control experiments and the observed intermediates a feasible mechanism is proposed.
- Liu, Xin,Werner, Thomas
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p. 10590 - 10597
(2021/08/20)
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- Conversion of succinic acid over Ni and Co catalysts
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Liquid-phase hydrogenation of succinic acid (SA) over supported Ni and Co catalysts was investigated at 200 °C and 6 MPa of H2. Reduced and passivated catalysts with the same surface metal density (2.5 atoms of metal per nm2 of support) were prepared by incipient wetness impregnation. The catalysts were characterized by X-ray diffraction (XRD), N2 adsorption, X-ray photoelectron spectroscopy (XPS), temperature-programmed reduction (TPR), CO-chemisorption, and temperature-programmed desorption of NH3 (TPD-NH3). The Ni and Co catalysts supported over SiO2 showed different product distribution, due to the adsorption of the SA over the surface of catalysts, determined by DFT calculations. The Co/SiO2, Co/SiO2-Al2O3, and Co/Al2O3 catalysts showed different product distribution, which was correlated with total acidity from TPD-NH3 results. In general, the Co catalysts promoted the hydrogenation process; however, the highest total acidity showed by Co/Al2O3 also promoted the dehydration process. Finally, the initial rate follows the trend according to the dispersion determined by CO-chemisorption.
- Rojas, Mabel,Zarate, Ximena,Canales, Roberto I.,Dongil, Ana Belen,Pazo, Cesar,Saavedra-Torres, Mario,Escalona, Néstor
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p. 165 - 176
(2020/05/14)
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- First row transition metals on the ethanol Guerbet reaction: Products distribution and structural behavior of mixed metal oxides as catalysts
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Described is the transformation of ethanol into 1-butanol, acetaldehyde and other products by the Guerbet reaction (GR) over mixed metal oxides (MMOs) as catalysts. The MMOs, in which Mg2+ was partially (20 mol%) substituted by Fe2+, Co2+, Ni2+, Cu2+, and Zn2+, were obtained from hydrotalcite precursors and the reactions conducted in a fixed bed flow reactor. EPR was used to observe oxygen vacancies after the catalytic reactions, which may be related to the ethanol reactivity due to the basicity enhancement of the catalyst. Carbon deposition, mostly filamentous, was observed in all catalysts and a trend between the metal-carbon bond energy and the percentage of deposited carbon was established. This correlation and the catalyst product distribution can be useful to tailor new catalysts. Using four parameters, ethanol conversion, 1-butanol and side-product selectivities and percentage of carbon deposition, Zn20MMO proved to be the best choice for GR.
- Boscolo, Mauricio,Metzker, Gustavo,Mora Vargas, Jorge Andres,Perrone, Olavo Micali,Siqueira, Marcos Rechi,Varanda, Laudemir Carlos,de Lima, Livia Padilha
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- Investigating hydrogenation and decarbonylation in vapor-phase furfural hydrotreating over Ni/SiO2 catalysts: Propylene production
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Furfural can be mass-produced from lignocellulose biomass and can be a platform chemical for producing valuable chemicals. In this study, we examine Ni/SiO2 catalysts for the conversion of furfural under a hydrogen atmosphere. The reactivity an
- Chen, Szu-Hua,Tseng, Ya-Chun,Yang, Sheng-Chiang,Lin, Shawn D.
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- Furfural hydrodeoxygenation (HDO) over silica-supported metal phosphides – The influence of metal–phosphorus stoichiometry on catalytic properties
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The gas-phase hydrodeoxygenation (HDO) of furfural, a model compound for bio-based conversion, was investigated over transition metal phosphide catalysts. The HDO activity decreases in the order Ni2P ≈ MoP > Co2P ≈ WP ? Cu3P > Fe2P. Nickel phosphide phases (e.g., Ni2P, Ni12P5, Ni3P) are the most promising catalysts in the furfural HDO. Their selectivity to the gasoline additives 2-methylfuran and tetrahydro-2-methylfuran can be adjusted by varying the P/Ni ratio. The effect of P on catalyst properties as well as on the reaction mechanism of furfural HDO were investigated in depth for the first time. An increase of the P stoichiometry weakens the furan-ring/catalyst interaction, which contributes to a lower ring-opening and ring-hydrogenation activity. On the other hand, an increasing P content does lead to a stronger carbonyl/catalyst interaction, i.e., to a stronger η2(C, O) adsorption configuration, which weakens the C1[sbnd]O1 bond (Scheme 1) in the carbonyl group and enhances the carbonyl conversion. Phosphorus species can also act as Br?nsted acid sites promoting C1[sbnd]O1 (Scheme 1) hydrogenolysis of furfuryl alcohol, hence contributing to higher production of 2-methylfuran.
- Lan, Xuefang,Pestman, Robert,Hensen, Emiel J.M.,Weber, Thomas
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p. 181 - 193
(2021/02/27)
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- Method for recycling byproducts in synthesis of diphenyl sulfide compound
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The invention provides a method for recycling byproducts in synthesis of a diphenyl sulfide compound. The byproducts comprise alkyl alcohol and dimethyl disulfide. The method comprises the steps of (1) mixing the byproducts in synthesis of the diphenyl sulfide compound with a sodium nitrite aqueous solution, adding concentrated hydrochloric acid for reaction, and obtaining alkyl nitrite and dimethyl disulfide; and (2) mixing the products obtained in the step (1) with copper powder, adding an aniline compound for reaction, carrying out desolvation treatment on the obtained reaction solution toobtain a diphenyl sulfide compound and byproducts, and returning the byproducts to the step (1). According to the recycling method, the byproducts do not need to be separated, the byproducts serve asraw materials to be directly applied to synthesis of the diphenyl sulfide compound, the process steps are simple and safe, cyclic utilization of the materials is achieved, and the raw material cost ofindustrial production of the diphenyl sulfide compound and the treatment cost of industrial three wastes are remarkably reduced.
- -
-
Paragraph 0067; 0071-0073
(2021/03/30)
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- Chromium-Catalyzed Production of Diols From Olefins
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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)
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- One-pot synthesis of 2-alkyl cycloketones on bifunctional Pd/ZrO2 catalyst
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2-Alkyl cycloketones are essential chemicals and intermediates for synthetic perfumes and pesticides, which are conventionally produced by multistep process including aldol condensation, separation and hydrogenation. In present work, a batch one-pot cascade approach using aldehydes and cycloketones as the raw materials, and a bifunctional Pd/ZrO2 catalyst was developed for the synthesis of 2-alkyl cycloketones, e.g., cyclohexanone and cycloheptanone. Very high aldehydes (except for paraldehyde with large steric hindrance) conversion and high yields for 2-alkyl cycloketones (e.g., 99 % of conversion for n-butanal and 76 wt.% of yield for 2-butyl cyclohexanone) were obtained at mild temperature of 140 °C. After 10 cycles of reuse, Pd/ZrO2 catalyst showed slight deactivation (ca. 5 % conversion and 10 % yield losses), due to the coke on the catalyst. However, the performance of the catalyst was completely recovered after an oxidative regeneration.
- Xue, Weiyang,Gu, Bin,Wu, Huiling,Liu, Mengyang,He, Songbo,Li, Jingmei,Rong, Xin,Sun, Chenglin
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- Transition Metal-Free Direct Hydrogenation of Esters via a Frustrated Lewis Pair
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"Frustrated Lewis pairs"(FLPs) continue to exhibit unique reactivity for the reduction of organic substrates, yet to date, the catalytic hydrogenation of an ester functionality has not been demonstrated. Here, we report that iPr3SnNTf2 (1-NTf2; Tf = SO2CF3) is a more potent Lewis acid than the previously studied iPr3SnOTf; in an FLP with 2,4,6-collidine/2,6-lutidine (col/lut), this translates to faster H2 activation and the catalytic hydrogenolysis of an ester bond by a main-group compound, furnishing alcohol and ether (minor) products. The reaction outcome is sensitive to the steric and electronic properties of the substrate; CF3CO2Et and simple formates (HCO2Me and HCO2Et) are catalytically reduced, whereas related esters CF3CO2nBu and CH3CO2Et show only stoichiometric reactivity. A computational case study on the hydrogenation of CF3CO2Et and CH3CO2Et reveals that both share a common mechanistic pathway; however, key differences in the energies of a Sn-acetal intermediate and transition states emerge, favoring CF3CO2Et reduction. The alcohol products reversibly inhibit 1-NTf2/lut via formation of resting-state species 1-OR/[1·(1-OR)]+[NTf2]- however, the extra energy required to regenerate 1-NTf2/lut exacerbates the unfavorable reduction energy profile for CH3CO2Et, ultimately preventing turnover. These findings will assist the design of future main-group catalysts for ester hydrogenation, with improved performance.
- Sapsford, Joshua S.,Csókás, Dániel,Turnell-Ritson, Roland C.,Parkin, Liam A.,Crawford, Andrew D.,Pápai, Imre,Ashley, Andrew E.
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p. 9143 - 9150
(2021/07/31)
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- Interworking ligand, hydroformylation catalyst and preparation method of dihydric alcohol
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The invention discloses an interworking ligand, a hydroformylation catalyst and a preparation method of dihydric alcohol. The interworking ligand comprises a ligand unit I and a ligand unit II, has the characteristics of a bidentate phosphine ligand, and is high in catalytic activity and good in stability; and when the catalyst is used for preparing dihydric alcohol from olefin, linear alcohol can be obtained through a one-step method, and the content of by-products in a traditional series process is reduced. The method has the advantages of simple and convenient process, low cost and energy consumption, good production safety, high product quality and the like, and is particularly suitable for large-scale industrial production.
- -
-
Paragraph 0061; 0069-0070; 0091-0092; 0093-0094
(2021/07/09)
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- Hydrodeoxygenation of C4-C6 sugar alcohols to diols or mono-alcohols with the retention of the carbon chain over a silica-supported tungsten oxide-modified platinum catalyst
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The hydrodeoxygenation of erythritol, xylitol, and sorbitol was investigated over a Pt-WOx/SiO2 (4 wt% Pt, W/Pt = 0.25, molar ratio) catalyst. 1,4-Butanediol can be selectively produced with 51% yield (carbon based) by erythritol hydrodeoxygenation at 413 K, based on the selectivity over this catalyst toward the regioselective removal of the C-O bond in the -O-C-CH2OH structure. Because the catalyst is also active in the hydrodeoxygenation of other polyols to some extent but much less active in that of mono-alcohols, at higher temperature (453 K), mono-alcohols can be produced from sugar alcohols. A good total yield (59%) of pentanols can be obtained from xylitol, which is mainly converted to C2 + C3 products in the literature hydrogenolysis systems. It can be applied to the hydrodeoxygenation of other sugar alcohols to mono-alcohols with high yields as well, such as erythritol to butanols (74%) and sorbitol to hexanols (59%) with very small amounts of C-C bond cleavage products. The active site is suggested to be the Pt-WOx interfacial site, which is supported by the reaction and characterization results (TEM and XAFS). WOx/SiO2 selectively catalyzed the dehydration of xylitol to 1,4-anhydroxylitol, whereas Pt-WOx/SiO2 promoted the transformation of xylitol to pentanols with 1,3,5-pentanetriol as the main intermediate. Pre-calcination of the reused catalyst at 573 K is important to prevent coke formation and to improve the reusability.
- Betchaku, Mii,Cao, Ji,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi,Yabushita, Mizuho
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supporting information
p. 5665 - 5679
(2021/08/16)
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- Predicting the hydrolytic breakdown rates of organophosphorus chemical warfare agent simulants using association constants derived from hydrogen bonded complex formation events
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Organophosphorus (OP) chemical warfare agents (CWAs) represent an ongoing global threat, through either purposeful environmental release or the need to dispose of historic stockpiles. This presents a need for the development of novel decontamination technologies. Due to the toxic nature and legal limitations placed on OP CWAs, the use of appropriate OP simulants that mimic the reactivity but not the toxicity of the agents themselves is vital to decontamination studies. Herein, we show that association constants derived from non-specific hydrogen bonded complexation events may be used as parameters within models to predict simulant reactivity. We also discuss the limitations that should be placed on such data.
- Chu, Dominique F.,Clark, Ewan R.,Ellaby, Rebecca J.,Hiscock, Jennifer,Pépés, Antigoni
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- Electrochemical Reduction of Carbon Dioxide to 1-Butanol on Oxide-Derived Copper
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The electroreduction of carbon dioxide using renewable electricity is an appealing strategy for the sustainable synthesis of chemicals and fuels. Extensive research has focused on the production of ethylene, ethanol and n-propanol, but more complex C4 molecules have been scarcely reported. Herein, we report the first direct electroreduction of CO2 to 1-butanol in alkaline electrolyte on Cu gas diffusion electrodes (Faradaic efficiency=0.056 %, j1-Butanol=?0.080 mA cm?2 at ?0.48 V vs. RHE) and elucidate its formation mechanism. Electrolysis of possible molecular intermediates, coupled with density functional theory, led us to propose that CO2 first electroreduces to acetaldehyde-a key C2 intermediate to 1-butanol. Acetaldehyde then undergoes a base-catalyzed aldol condensation to give crotonaldehyde via electrochemical promotion by the catalyst surface. Crotonaldehyde is subsequently electroreduced to butanal, and then to 1-butanol. In a broad context, our results point to the relevance of coupling chemical and electrochemical processes for the synthesis of higher molecular weight products from CO2.
- Chen, Stuart Tze-Jin,García-Muelas, Rodrigo,López, Núria,Martín, Antonio J.,Pérez-Ramírez, Javier,Pablo-García, Sergio,Peng, Yujie,Per, Edwin Yu Xuan,Ting, Louisa Rui Lin,Veenstra, Florentine L. P.,Yeo, Boon Siang
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supporting information
p. 21072 - 21079
(2020/09/11)
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- Mechanistic Insights into Electroreductive C-C Coupling between CO and Acetaldehyde into Multicarbon Products
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Production of valuable multicarbon (C3+) products through the electrochemical CO2 and CO reduction reactions (CO2RR and CORR) is desirable; however, mechanistic understanding that enables C-C coupling beyond the self-coupling of CO to valuable products is lacking. In this work, we elucidate the C-C coupling mechanism between CO and acetaldehyde, a reactive intermediate in both CO2RR and CORR, via combined isotopic labeling and in situ spectroscopic investigations. CO attacks the carbonyl carbon of acetaldehyde in the coupling, and the carbon in CO ends up in the hydroxymethyl group (-CH2OH) of the produced 1-propanol. While the coupling between CO and acetaldehyde does occur when the CORR is conducted with added acetaldehyde, only a minor fraction (up to 36%) of 1-propanol is from this pathway, and the majority of it is produced in the CORR by the self-coupling among CO. The adsorbed methylcarbonyl is proposed as the likely intermediate where the reaction pathway bifurcates to C2 and C3 products; i.e., it could either be hydrogenated to acetaldehyde and ethanol or couple with CO leading to the formation of 1-propanol.
- Chang, Xiaoxia,Malkani, Arnav,Xu, Bingjun,Yang, Xuan
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p. 2975 - 2983
(2020/03/10)
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- Continuous-Flow Amide and Ester Reductions Using Neat Borane Dimethylsulfide Complex
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Reductions of amides and esters are of critical importance in synthetic chemistry, and there are numerous protocols for executing these transformations employing traditional batch conditions. Notably, strategies based on flow chemistry, especially for amide reductions, are much less explored. Herein, a simple process was developed in which neat borane dimethylsulfide complex (BH3?DMS) was used to reduce various esters and amides under continuous-flow conditions. Taking advantage of the solvent-free nature of the commercially available borane reagent, high substrate concentrations were realized, allowing outstanding productivity and a significant reduction in E-factors. In addition, with carefully optimized short residence times, the corresponding alcohols and amines were obtained in high selectivity and high yields. The synthetic utility of the inexpensive and easily implemented flow protocol was further corroborated by multigram-scale syntheses of pharmaceutically relevant products. Owing to its beneficial features, including low solvent and reducing agent consumption, high selectivity, simplicity, and inherent scalability, the present process demonstrates fewer environmental concerns than most typical batch reductions using metal hydrides as reducing agents.
- ?tv?s, Sándor B.,Kappe, C. Oliver
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p. 1800 - 1807
(2020/02/27)
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- One-pot synthesis of 1,3-butanediol by 1,4-anhydroerythritol hydrogenolysis over a tungsten-modified platinum on silica catalyst
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Chemical production of 1,3-butanediol from biomass-derived compounds was first reported by 1,4-anhydroerythritol hydrogenolysis over a Pt-WOx/SiO2 catalyst. The reaction proceeded by ring opening hydrogenolysis of 1,4-anhydroerythritol followed by selective removal of secondary OH groups in 1,2,3-butanetriol, and an overall 1,3-butanediol yield up to 54% was then obtained. The performance of the Pt-WOx/SiO2 catalyst for 1,4-anhydroerythritol hydrogenolysis was closely correlated with that for glycerol hydrogenolysis to 1,3-propanediol. The optimized Pt-WOx/SiO2 (Pt: 4 wt% and W: 0.94 wt%) catalyst showed 57% yield of 1,3-propanediol.
- Asano, Takehiro,Liu, Lujie,Nakagawa, Yoshinao,Tamura, Masazumi,Tomishige, Keiichi
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supporting information
p. 2375 - 2380
(2020/05/14)
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- Phosphine-free pincer-ruthenium catalyzed biofuel production: High rates, yields and turnovers of solventless alcohol alkylation
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Phosphine-free pincer-ruthenium carbonyl complexes based on bis(imino)pyridine and 2,6-bis(benzimidazole-2-yl) pyridine ligands have been synthesized. For the β-alkylation of 1-phenyl ethanol with benzyl alcohol at 140 °C under solvent-free conditions, (Cy2NNN)RuCl2(CO) (0.00025 mol%) in combination with NaOH (2.5 mol%) was highly efficient (ca. 93% yield, 372?000 TON at 12?000 TO h-1). These are the highest reported values hitherto for a ruthenium based catalyst. The β-alkylation of various alcohol combinations was accomplished with ease which culminated to give 380?000 TON at 19?000 TO h-1 for the β-alkylation of 1-phenyl ethanol with 3-methoxy benzyl alcohol. DFT studies were complementary to mechanistic studies and indicate the β-hydride elimination step involving the extrusion of acetophenone to be the overall RDS. While the hydrogenation step is favored for the formation of α-alkylated ketone, the alcoholysis step is preferred for the formation of β-alkylated alcohol. The studies were extended for the upgradation of ethanol to biofuels. Among the pincer-ruthenium complexes based on bis(imino)pyridine, (Cy2NNN)RuCl2(CO) provided high productivity (335 TON at 170 TO h-1). Sterically more open pincer-ruthenium complexes such as (Bim2NNN)RuCl2(CO) based on the 2,6-bis(benzimidazole-2-yl) pyridine ligand demonstrated better reactivity and gave not only good ethanol conversion (ca. 58%) but also high turnovers (ca. 2100) with a good rate (ca. 710 TO h-1). Kinetic studies indicate first order dependence on concentration of both the catalyst and ethanol. Phosphine-free catalytic systems operating with unprecedented activity at a very low base loading to couple lower alcohols to higher alcohols of fuel and pharmaceutical importance are the salient features of this report. This journal is
- Das, Babulal,Das, Kanu,Kumar, Akshai,Srivastava, Hemant Kumar,Yasmin, Eileen
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p. 8347 - 8358
(2020/12/31)
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- Effect of Promoter M (M = Au, Ag, Cu, Ce, Fe, Ni, Co, Zn) on the Activity of Pd–M/Al2O3 Catalysts of Ethanol Conversion into α-Alcohols
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Abstract: Pd/Al2O3 and Pd–M/Al2O3 catalysts (M = Au, Ag, Cu, Ce, Fe, Ni, Co, Zn) were obtained by ion exchange and impregnation. Pd/Al2O3 had high initial activity in the conversion of ethanol into α-alcohols, but lost 90% of its activity after 10 h of operation because of deactivation caused by the chemisorption of the by-product (CO) on Pd atoms. Modification of Pd with gold or silver led to an increase in the rate of Pd deactivation. As a result, the Pd–Au and Pd–Ag systems were less active and stable. In contrast, the Pd–Fe, Pd–Co, Pd–Ni, Pd–Cu, Pd–Zn, and Pd–Ce systems exhibited higher resistance to CO poisoning than Pd and demonstrated high activity and stability. The observed tendencies in the catalytic action of the mono- and bimetallic systems were explained within the framework of the d band model proposed by Hammer and Norskov. Pd–Cu/Al2O3 was most effective in the target process; it is not poisoned by CO and allows ethanol conversion into α-alcohols at 95% selectivity, while the time of its stable operation is at least 100 h. The structure of the Pd–Cu catalytic system was studied by TEM, EDA, XPS, TPR-H2, and TPD-NH3. A model of active catalyst sites was proposed.
- Chistyakov, A. V.,Chistyakova, P. A.,Ezzhelenko, D. I.,Krotova, I. N.,Nikolaev, S. A.,Tsodikov, M. V.
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p. 894 - 902
(2020/12/31)
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- 1-D manganese(ii)-terpyridine coordination polymers as precatalysts for hydrofunctionalisation of carbonyl compounds
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Reductive catalysis with earth-abundant metals is currently of increasing importance and shows potential in replacing precious metal catalysis. In this work, we revealed catalytic hydroboration and hydrosilylation of ketones and aldehydes achieved by a structurally defined manganese(ii) coordination polymer (CP) as a precatalyst under mild conditions. The manganese-catalysed methodology can be applied to a range of functionalized aldehydes and ketones with turnover numbers (TON) of up to 990. Preliminary results on the regioselective catalytic hydrofunctionalization of styrenes by the Mn-CP catalyst are also presented.
- Johnson, Jahvon,Li, Sihan,Mo, Zixuan,Neary, Michelle C.,Zeng, Haisu,Zhang, Guoqi,Zheng, Shengping
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supporting information
p. 2610 - 2615
(2020/03/05)
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- Combined KOH/BEt3Catalyst for Selective Deaminative Hydroboration of Aromatic Carboxamides for Construction of Luminophores
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The selective catalytic C-N bond cleavage of amides into value-added amine products is a desirable but challenging transformation. Molecules containing iminodibenzyl motifs are prevalent in pharmaceutical molecules and functional materials. Here we established a combined KOH/BEt3 catalyst for deaminative hydroboration of acyl-iminodibenzyl derivatives, including nonheterocyclic carboxamides, to the corresponding amines. This novel transition-metal-free methodology was also applied to the construction of Clomipramine and luminophores.
- Li, Jinshan,Wang, Jiali,Yang, Jianguo,Yao, Wubing,Zhong, Aiguo
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supporting information
p. 8086 - 8090
(2020/11/03)
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- METHOD FOR PRODUCING ALCOHOL
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PROBLEM TO BE SOLVED: To provide a method for producing selectively alcohol from carboxylic acid under mild conditions. SOLUTION: In the presence of a catalyst with M1 and M2 as metal species supported on a support, a substrate is reduced to produce a corresponding alcohol. (M1 is Rh, Pt, Ru, Ir, or Pd; M2 is Sn, V, Mo, W, or Re; the support is ZrO2, hydroxyapatite, Nb2O5, fluoroapatite, or hydrotalcite; the substrate is the formula 1a, 1b, or 1c). SELECTED DRAWING: None COPYRIGHT: (C)2020,JPO&INPIT
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Paragraph 0101-0108; 0113; 0117-0119; 0122-0124; 0129-0130
(2020/11/26)
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- MgO?SiO2 Catalysts for the Ethanol to Butadiene Reaction: The Effect of Lewis Acid Promoters
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MgO?SiO2 samples, having the composition of natural talc (NT), were obtained by co-precipitation (CP) and wet kneading (WK) methods. The materials were used as catalysts of the ethanol-to-1,3-butadiene reaction. ZnO, Ga2O3 and In2O3 were tested as promoters. The catalyst WK gave the highest 1,3-Butadiene (BD) yield among the non-promoted catalysts because of the high specific surface area and strong basicity. Results suggested that over the neat WK catalyst the acetaldehyde coupling to crotonaldehyde was the rate-determining process step. Formation of crotyl alcohol intermediate was substantiated to proceed by the hydrogen transfer reaction between crotonaldehyde and ethanol. The crotyl alcohol intermediate becomes dehydrated to BD or, in a disproportionation side reaction, it forms crotonaldehyde and butanol. The promoter was found to increase the surface concentration of the reactant and reaction intermediates, thereby increases the rates of conversion and BD formation. The order of promoting efficiency was Zn>In>Ga.
- Szabó, Blanka,Novodárszki, Gyula,Pászti, Zoltán,Domján, Attila,Valyon, József,Hancsók, Jen?,Barthos, Róbert
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p. 5686 - 5696
(2020/09/22)
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- Effect of Promoter Nature on Synthesis Gas Conversion to Alcohols over (K)MeMoS2/Al2O3 Catalysts
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The influence of the promoter nature and of a modifier in (K)(Me)MoS2/Al2O3 (Me=Fe, Co, Ni) catalysts on the conversion and selectivity of products of synthesis gas conversion to alcohols and jnl oxygenates was investigated. Relationships between promoter nature, hydrocarbon chain length and selectivity in the formed alcohols were established. Electronic structure of a promoter atom in an active site (AS) was found to strongly affect selectivity of alcohol formation. Promotion of the S-edge by Fe, Co or Ni suppressed hydrogen activation, which resulted in a lower synthesis gas conversion. Promotion of the M-edge by Fe, Co, or Ni entailed the formation of double vacancies which are active sites of synthesis gas conversion. Potassium affected the oxophilicity of Mo atoms and reduced Co/Ni-promoted MoS AS. It decreased the probability of C?O bond breaking in the adsorbed intermediate and shifted selectivity from the formation of alkyl towards alkoxide fragments over these catalysts.
- Maximov, Vladimir V.,Permyakov, Eugenii A.,Dorokhov, Viktor S.,Wang, Anjie,Kooyman, Patricia J.,Kogan, Victor M.
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p. 1443 - 1452
(2020/02/11)
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- Catalytic upgrading of ethanol to butanol over a binary catalytic system of FeNiOx and LiOH
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Catalytic conversion of ethanol to butanol is vital to bridge the gap between huge amounts of ethanol production, the limited blending ratio of ethanol in gasoline, and the outstanding performance of butanol. In this work, a highly active binary catalytic system of FeNiOx and LiOH was developed for upgrading of ethanol to butanol. After 24 h reaction at 493 K, the selectivity to butanol reached 71% with >90% high carbon alcohols at 28% ethanol conversion, which was comparable to the performance of some noble metal homogeneous catalysts.
- Li, Xianquan,Li, Xinsheng,Liu, Shimin,Pang, Jifeng,Wang, Junhu,Wang, Zhinuo,Zhang, Tao,Zheng, Mingyuan
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p. 672 - 678
(2020/01/28)
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- SATURATED HOMOETHER MANUFACTURING METHOD FROM UNSATURATED CARBONYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for manufacturing saturated homoether from an unsaturated carboxyl compound at good efficiency. SOLUTION: There is provided a manufacturing method of saturated homoether using an unsaturated carboxyl compound and hydrogen as raw materials, and a catalyst in which a metal is carried on an acidic catalyst carrier. The metal of the catalyst is for example palladium, and the carrier of the catalyst is alumina, silica, silica-alumina, or the like. The unsaturated carbonyl compound as the raw material is 2-butenal, 2-ethyl-2-hexenal, 2-ethyl-2-butenal, 2-hexenal, and manufactured saturated homoether is dibuthylether, bis(2-ethylhexyl)ether, bis(2-ethylbuty)ether, dihexylether, or the like. SELECTED DRAWING: None COPYRIGHT: (C)2020,JPO&INPIT
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Paragraph 0045-0046
(2020/05/14)
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- Single-reactor conversion of ethanol to 1-/2-butenes
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A simplified processes for producing desired chemicals such as butenes from feedstock mixtures containing ethanol. In one set of embodiments this is performed in a single step, wherein a feed containing ethanol in a gas phase is passed over an acidic metal oxide catalyst having a transition metal dispersion of at least 5% on a metal oxide support. The ethanol content of the feedstock mixture may vary from 10 to 100 percent of the feed and in those non-eat applications the ethanol feed may contain water.
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Page/Page column 9
(2020/06/03)
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- Synthesis of α,β- and β-Unsaturated Acids and Hydroxy Acids by Tandem Oxidation, Epoxidation, and Hydrolysis/Hydrogenation of Bioethanol Derivatives
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We report a reaction platform for the synthesis of three different high-value specialty chemical building blocks starting from bio-ethanol, which might have an important impact in the implementation of biorefineries. First, oxidative dehydrogenation of ethanol to acetaldehyde generates an aldehyde-containing stream active for the production of C4 aldehydes via base-catalyzed aldol-condensation. Then, the resulting C4 adduct is selectively converted into crotonic acid via catalytic aerobic oxidation (62 % yield). Using a sequential epoxidation and hydrogenation of crotonic acid leads to 29 % yield of β-hydroxy acid (3-hydroxybutanoic acid). By controlling the pH of the reaction media, it is possible to hydrolyze the oxirane moiety leading to 21 % yield of α,β-dihydroxy acid (2,3-dihydroxybutanoic acid). Crotonic acid, 3-hydroxybutanoic acid, and 2,3-dihydroxybutanoic acid are archetypal specialty chemicals used in the synthesis of polyvinyl-co-unsaturated acids resins, pharmaceutics, and bio-degradable/ -compatible polymers, respectively.
- Faria, Jimmy,Komarneni, Mallik R.,Li, Gengnan,Pham, Tu,Resasco, Daniel E.,Ruiz, Maria P.,Santhanaraj, Daniel
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supporting information
p. 7456 - 7460
(2020/03/23)
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- Efficient one-pot conversion of furfural into 2-methyltetrahydrofuran using non-precious metal catalysts
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2-methyltetrahydrofuran, a biomass-derived chemical, is an important solvent with broad applications in organic chemistry. In this study, one-pot conversion of furfural into 2-methyltetrahydrofuran over non-precious metal catalysts was achieved by two-stage packing in a single reactor. The first stage converted furfural into 2-methylfuran over Co-based catalysts, and the second stage converted 2-methylfuran into 2-methyltetrahydrofuran over Ni-based catalysts. In order to reveal the reaction pathway and mechanism of this process, the hydrogenation reactions of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol were also carefully investigated. It is discovered that the conversion of furfural into 2-methylfuran could be catalyzed by Lewis acid sites, which was confirmed by a correlation between 2-methylfuran production rate and Lewis acid site density. Also, a mechanism on the direct conversion of furfural into 2-methylfuran without forming furfuryl alcohol as the intermediate is proposed. The experimental results of 2-methylfuran, furfuryl alcohol, and tetrahydrofurfuryl alcohol hydrogenation/hydrodeoxygenation over various catalysts provided valuable information on the future design of 2-methyltetrahydrofuran catalyst.
- Jia, Xinxin,Li, Cuiqing,Liu, Ping,Song, Yongji,Sun, Luyang,Wang, Hong,Zhang, Chen,Zhang, Wei
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