67-56-1Relevant articles and documents
C-C Bond Cleavage of Acetonitrile by a Dinuclear Copper(II) Cryptate
Lu, Tongbu,Zhuang, Xiaomei,Li, Yanwu,Chen, Shi
, p. 4760 - 4761 (2004)
The dinuclear copper(II) cryptate [Cu2L](ClO4)4 (1) cleaves the C?C bond of acetonitrile at room temperature to produce a cyanide bridged complex of [Cu2L(CN)](ClO4)3·2CH3CN·4H2O (2). The cleavage mechanism is presented on the basis of the results of the crystal structure of 2, electronic absorption spectra, ESI-MS spectroscopy, and GC spectra of 1, respectively. Copyright
Kassel
, p. 493 (1936)
Photochemical and enzymatic synthesis of methanol from HCO3 - with dehydrogenases and zinc porphyrin
Amao, Yutaka,Watanabe, Tomoe
, p. 1544 - 1545 (2004)
Photochemical and enzymatic methanol synthesis from HCO3 - with formate dehydrogenase (FDH), aldehyde dehydrogenase (AldDH), and alcohol dehydrogenase (ADH) via the photoreduction of MV2+ using ZnTPPS photosensitization wa
Catalytic Activity of Nanosized CuO-ZnO Supported on Titanium Chips in Hydrogenation of Carbon Dioxide to Methyl Alcohol
Ahn, Ho-Geun,Lee, Hwan-Gyu,Chung, Min-Chul,Park, Kwon-Pil,Kim, Ki-Joong,Kang, Byeong-Mo,Jeong, Woon-Jo,Jung, Sang-Chul,Lee, Do-Jin
, p. 2024 - 2027 (2016)
In this study, titanium chips (TC) generated from industrial facilities was utilized as TiO2 support for hydrogenation of carbon dioxide (CO2) to methyl alcohol (CH3OH) over Cu-based catalysts. Nanosized CuO and ZnO catalysts were deposited on TiO2 support using a co-precipitation (CP) method (CuO-ZnO/TiO2), where the thermal treatment of TC and the particle size of TiO2 are optimized on CO2 conversion under different reaction temperature and contact time. Direct hydrogenation of CO2 to CH3OH over CuO-ZnO/TiO2 catalysts was achieved and the maximum selectivity (22%) and yield (18.2%) of CH3OH were obtained in the range of reaction temperature 210~240 °C under the 30 bar. The selectivity was readily increased by increasing the flow rate, which does not affect much to the CO2 conversion and CH3OH yield.
Comparative Study of Diverse Copper Zeolites for the Conversion of Methane into Methanol
Park, Min Bum,Ahn, Sang Hyun,Mansouri, Ali,Ranocchiari, Marco,van Bokhoven, Jeroen A.
, p. 3705 - 3713 (2017)
The characterization and reactive properties of copper zeolites with twelve framework topologies (MOR, EON, MAZ, MEI, BPH, FAU, LTL, MFI, HEU, FER, SZR, and CHA) are compared in the stepwise partial oxidation of methane into methanol. Cu2+ ion-exchanged zeolite omega, a MAZ-type material, reveals the highest yield (86 μmol g(cat.)?1) among these materials after high-temperature activation and liquid methanol extraction. The high yield is ascribed to the relatively high density of copper–oxo active species, which form in its three-dimensional 8-membered (MB) ring channels. In situ UV/Vis studies show that diverse copper species form in different zeolites after high-temperature activation, suggesting that there are no universally active species. Nonetheless, there are some dominant factors required for achieving high methanol yields: 1) highly dispersed copper–oxo species; 2) large amount of exchanged copper in small-pore zeolites; 3) moderately high temperature of activation; and 4) use of proton form zeolite precursors. Cu-omega and Cu-mordenite, with the proton form of mordenite as the precursor, yield methanol after activation in oxygen and reaction with methane at only 200 °C, that is, under isothermal conditions.
Spontaneous hydrolysis of ionized phosphate monoesters and diesters and the proficiencies of phosphatases and phosphodiesterases as catalysts
Wolfenden, Richard,Ridgway, Caroline,Young, Gregory
, p. 833 - 834 (1998)
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Facile synthesis of ZnO particles: Via benzene-assisted co-solvothermal method with different alcohols and its application
Maneechakr, Panya,Karnjanakom, Surachai,Samerjit, Jittima
, p. 73947 - 73952 (2016)
In this study, ZnO particles with different morphologies were synthesized by a novel co-solvothermal method using benzene. The prepared samples were characterized by Brunauer-Emmett-Teller (BET) measurements, X-ray diffractometry (XRD), scanning electron microscopy coupled with an energy dispersive X-ray detector (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectrometry (XPS), and H2-temperature programmed reduction (H2-TPR). The results showed that the molecular sizes and carbon numbers of the alcohols used in the reaction and the addition of benzene had a great effect on the morphologies, textural properties, and crystalline structures of the material products in our reaction system. Different ZnO morphologies, such as spherical coral-like, carnation-like, rose-like, and plate-like structures, were obtained using methanol, ethanol, propanol, and butanol, respectively. Moreover, Cu particles loaded on ZnO with different morphologies were also investigated for the hydrogenation of CO2 to CH3OH. High catalytic activity and selectivity (82.8%) for CH3OH formation were obtained using ZnO prepared from methanol with Cu doping (Cu/ZnO-Me).
Efficient ionic liquid-based platform for multi-enzymatic conversion of carbon dioxide to methanol
Zhang, Zhibo,Muschiol, Jan,Huang, Yuhong,Sigurdardóttir, Sigyn Bj?rk,Von Solms, Nicolas,Daugaard, Anders E.,Wei, Jiang,Luo, Jianquan,Xu, Bao-Hua,Zhang, Suojiang,Pinelo, Manuel
, p. 4339 - 4348 (2018)
Low yields commonly obtained during enzymatic conversion of CO2 to methanol are attributed to low CO2 solubility in water. In this study, four selected ionic liquids with high CO2 solubility were separately added to the multi-enzyme reaction mixture and the yields were compared to the pure aqueous system (control). In an aqueous 20% [CH][Glu] system, yield increased ca. 3.5-fold compared to the control (ca. 5-fold if NADH regeneration was incorporated). Molecular dynamics simulation revealed that CO2 remains for longer in a productive conformation in the enzyme in the presence of [CH][Glu], which explains the marked increase of yield that was also confirmed by isothermal titration calorimetry-lower energy (ΔG) binding of CO2 to FDH. The results suggest that the accessibility of CO2 to the enzyme active site depends on the absence/presence and nature of the ionic liquid, and that the enzyme conformation determines CO2 retention and hence final conversion.
Comparative study of hydrotalcite-derived supported Pd2Ga and PdZn intermetallic nanoparticles as methanol synthesis and methanol steam reforming catalysts
Ota, Antje,Kunkes, Edward L.,Kasatkin, Igor,Groppo, Elena,Ferri, Davide,Poceiro, Beatriz,Navarro Yerga, Rufino M.,Behrens, Malte
, p. 27 - 38 (2012)
An effective and versatile synthetic approach to produce well-dispersed supported intermetallic nanoparticles is presented that allows a comparative study of the catalytic properties of different intermetallic phases while minimizing the influence of differences in preparation history. Supported PdZn, Pd2Ga, and Pd catalysts were synthesized by reductive decomposition of ternary Hydrotalcite-like compounds obtained by co-precipitation from aqueous solutions. The precursors and resulting catalysts were characterized by HRTEM, XRD, XAS, and CO-IR spectroscopy. The Pd2+ cations were found to be at least partially incorporated into the cationic slabs of the precursor. Full incorporation was confirmed for the PdZnAl-Hydrotalcite-like precursor. After reduction of Ga- and Zn-containing precursors, the intermetallic compounds Pd2Ga and PdZn were present in the form of nanoparticles with an average diameter of 6 nm or less. Tests of catalytic performance in methanol steam reforming and methanol synthesis from CO2 have shown that the presence of Zn and Ga improves the selectivity to CO2 and methanol, respectively. The catalysts containing intermetallic compounds were 100 and 200 times, respectively, more active for methanol synthesis than the monometallic Pd catalyst. The beneficial effect of Ga in the active phase was found to be more pronounced in methanol synthesis compared with steam reforming of methanol, which is likely related to insufficient stability of the reduced Ga species in the more oxidizing feed of the latter reaction. Although the intermetallic catalysts were in general less active than a Cu-/ZnO-based material prepared by a similar procedure, the marked changes in Pd reactivity upon formation of intermetallic compounds and to study the tunability of Pd-based catalysts for different reactions.
Self-sufficient and exclusive oxygenation of methane and its source materials with oxygen to methanol via metgas using oxidative bi-reforming
Olah, George A.,Prakash, G. K. Surya,Goeppert, Alain,Czaun, Miklos,Mathew, Thomas
, p. 10030 - 10031 (2013)
A combination of complete methane combustion with oxygen of the air coupled with bi-reforming leads to the production of metgas (H2/CO in 2:1 mole ratio) for exclusive methanol synthesis. The newly developed oxidative bi-reforming allows direct oxygenation of methane to methanol in an overall economic and energetically efficient process, leaving very little, if any, carbon footprint or byproducts.
Spinel-Structured ZnCr2O4 with Excess Zn Is the Active ZnO/Cr2O3 Catalyst for High-Temperature Methanol Synthesis
Song, Huiqing,Laudenschleger, Daniel,Carey, John J.,Ruland, Holger,Nolan, Michael,Muhler, Martin
, p. 7610 - 7622 (2017)
A series of ZnO/Cr2O3 catalysts with different Zn:Cr ratios was prepared by coprecipitation at a constant pH of 7 and applied in methanol synthesis at 260-300 °C and 60 bar. The X-ray diffraction (XRD) results showed that the calcined catalysts with ratios from 65:35 to 55:45 consist of ZnCr2O4 spinel with a low degree of crystallinity. For catalysts with Zn:Cr ratios smaller than 1, the formation of chromates was observed in agreement with temperature-programmed reduction results. Raman and XRD results did not provide evidence for the presence of segregated ZnO, indicating the existence of Zn-rich nonstoichiometric Zn-Cr spinel in the calcined catalyst. The catalyst with Zn:Cr = 65:35 exhibits the best performance in methanol synthesis. The Zn:Cr ratio of this catalyst corresponds to that of the Zn4Cr2(OH)12CO3 precursor with hydrotalcite-like structure obtained by coprecipitation, which is converted during calcination into a nonstoichiometric Zn-Cr spinel with an optimum amount of oxygen vacancies resulting in high activity in methanol synthesis. Density functional theory calculations are used to examine the formation of oxygen vacancies and to measure the reducibility of the methanol synthesis catalysts. Doping Cr into bulk and the (10-10) surface of ZnO does not enhance the reducibility of ZnO, confirming that Cr:ZnO cannot be the active phase. The (100) surface of the ZnCr2O4 spinel has a favorable oxygen vacancy formation energy of 1.58 eV. Doping this surface with excess Zn charge-balanced by oxygen vacancies to give a 60% Zn content yields a catalyst composed of an amorphous ZnO layer supported on the spinel with high reducibility, confirming this as the active phase for the methanol synthesis catalyst.
Dodge
, p. 89 (1930)
A novel low-temperature methanol synthesis method from CO/H2/CO2 based on the synergistic effect between solid catalyst and homogeneous catalyst
Zhao, Tian-Sheng,Zhang, Kun,Chen, Xuri,Ma, Qingxiang,Tsubaki, Noritatsu
, p. 98 - 104 (2010)
The activity of a binary catalyst in alcoholic solvents for methanol synthesis from CO/H2/CO2 at low temperature was investigated in a concurrent synthesis course. Experiment results showed that the combination of homogeneous potassium formate catalyst and solid copper-magnesia catalyst enhanced the conversion of CO2-containing syngas to methanol at temperature of 423-443 K and pressure of 3-5 MPa. Under a contact time of 100 g h/mol, the maximum conversion of total carbon approached the reaction equilibrium and the selectivity of methanol was 99%. A reaction pathway involving esterification and hydrogenolysis of esters was postulated based on the integrative and separate activity tests, along with the structural characterization of the catalysts. Both potassium formate for the esterification as well as Cu/MgO for the hydrogenolysis were found to be crucial to this homogeneous and heterogeneous synergistically catalytic system. CO and H2 were involved in the recycling of potassium formate.
Continuous supercritical low-temperature methanol synthesis with n-butane as a supercritical fluid
Reubroycharoen, Prasert,Bao, Jun,Zhang, Yi,Tsubaki, Noritatsu
, p. 790 - 791 (2008)
A process of supercritical low-temperature methanol synthesis from syngas containing CO2 was carried out at 443 K and 60 bar. The 2-butanol and n-butane was used as catalytic solvent and supercritical medium, respectively. The results showed that the total carbon conversion, especially the CO 2 conversion of the methanol synthesis was increased significantly under the supercritical condition. Copyright
Molybdenum-Bismuth Bimetallic Chalcogenide Nanosheets for Highly Efficient Electrocatalytic Reduction of Carbon Dioxide to Methanol
Sun, Xiaofu,Zhu, Qinggong,Kang, Xinchen,Liu, Huizhen,Qian, Qingli,Zhang, Zhaofu,Han, Buxing
, p. 6771 - 6775 (2016)
Methanol is a very useful platform molecule and liquid fuel. Electrocatalytic reduction of CO2 to methanol is a promising route, which currently suffers from low efficiency and poor selectivity. Herein we report the first work to use a Mo-Bi bimetallic chalcogenide (BMC) as an electrocatalyst for CO2 reduction. By using the Mo-Bi BMC on carbon paper as the electrode and 1-butyl-3-methylimidazolium tetrafluoroborate in MeCN as the electrolyte, the Faradaic efficiency of methanol could reach 71.2 % with a current density of 12.1 mA cm-2, which is much higher than the best result reported to date. The superior performance of the electrode resulted from the excellent synergistic effect of Mo and Bi for producing methanol. The reaction mechanism was proposed and the reason for the synergistic effect of Mo and Bi was discussed on the basis of some control experiments. This work opens a way to produce methanol efficiently by electrochemical reduction of CO2.
Characterization of modified Fischer-Tropsch catalysts promoted with alkaline metals for higher alcohol synthesis
Cosultchi, Ana,Perez-Luna, Miguel,Morales-Serna, Jose Antonio,Salmon, Manuel
, p. 368 - 377 (2012)
Two series of Cu/Co/Cr modified Fischer-Tropsch catalyst promoted with Zn or Mn and an alkaline metal (Me: Li, Na, K, Rb, Cs) were prepared by co-precipitation method and tested for high alcohol synthesis (HAS) at one hour on-stream and at two temperatures, 300 and 350 °C. The results indicate that the best selectivity toward high alcohols depends on temperature and catalysts composition and is obtained as follows: a) at 300 °C over catalysts without Zn and containing K, Na and Rb; b) at 350 °C over catalysts without Zn and containing K; c) at 350 °C over catalysts containing Zn as well as Li and Cs.
ACID-CATALYZED HYDROLYSIS OF 2-METHOXYPROPENAL
Fedoronko, Michal,Petrusova, Maria,Tvaroska, Igor
, p. 85 - 94 (1983)
2-Methoxypropenal in acid media undergoes general acid-catalyzed hydrolysis with formation of 2-oxopropanal.The kinetics of this reaction were studied, the rate constants established, and a reaction mechanism is suggested.Hydrolysis of 2-methoxypropenal is governed by a mechanism of the vinyl ether type, and the presence of the aldehyde group causes a decrease in the reaction rate.The analogy of the acid-catalyzed hydrolysis of 2-methoxypropenal to that of a vinyl ether was shown by the solvent isotope-effect, kD/kH=0.41, and the value of the Broensted exponent, α=0.60.The activation parameters found and quantum-chemical calculations of charge distribution in 2-methoxypropenal and other model compounds were also utilized to explain the mechanism of the acid-catalyzed hydrolysis of the title compound.
Carbon Dioxide Conversion to Methanol over Size-Selected Cu4 Clusters at Low Pressures
Liu, Cong,Yang, Bing,Tyo, Eric,Seifert, Soenke,Debartolo, Janae,Von Issendorff, Bernd,Zapol, Peter,Vajda, Stefan,Curtiss, Larry A.
, p. 8676 - 8679 (2015)
The activation of CO2 and its hydrogenation to methanol are of much interest as a way to utilize captured CO2. Here, we investigate the use of size-selected Cu4 clusters supported on Al2O3 thin films for CO2 reduction in the presence of hydrogen. The catalytic activity was measured under near-atmospheric reaction conditions with a low CO2 partial pressure, and the oxidation state of the clusters was investigated by in situ grazing incidence X-ray absorption spectroscopy. The results indicate that size-selected Cu4 clusters are the most active low-pressure catalyst for catalytic CO2 conversion to CH3OH. Density functional theory calculations reveal that Cu4 clusters have a low activation barrier for conversion of CO2 to CH3OH. This study suggests that small Cu clusters may be excellent and efficient catalysts for the recycling of released CO2.
Selective Photoreduction of Carbon Dioxide to Methanol on Titanium Dioxide Photocatalysts in Propylene Carbonate Solution
Kuwabata, Susumu,Uchida, Hiroyuki,Ogawa, Akihiro,Hirao, Shigeki,Yoneyama, Hiroshi
, p. 829 - 830 (1995)
Methanol is selectively photosynthesised from carbon dioxide using TiO2 photocatalysts in propylene carbonate containing propan-2-ol as a hole scavenger.
Effect of Γ-alumina nanorods on CO hydrogenation to higher alcohols over lithium-promoted CuZn-based catalysts
Choi, SuMin,Kang, YoungJong,Kim, SangWoo
, p. 188 - 196 (2018)
To achieve high catalytic activities and long-term stability to produce higher alcohols via CO hydrogenation, the catalytic activities were tuned by controlling the loading amounts of γ-alumina nanorods and Al3+ ions added to modify Cu-Zn catalysts promoted with Li. The selectivity of higher alcohols and the CO conversion to higher alcohols over a Li-modified Cu0.45Zn0.45Al0.1 catalyst supported on 10% nanorods were 1.8 and 2.7 times higher than those with a Cu-Zn catalyst without nanorods and Al3+ ions, respectively. The introduction of the thermally and chemically stable γ-Al2O3 nanorod support and of Al3+ to the modified catalysts improves the catalytic activities by decreasing the crystalline size of CuO and increasing the total basicity. Along with the nanorods, a refractory CuAl2O4 formed by the thermal reaction of CuO and Al3+ enhances the long-term stability by increasing the resistance to sintering of the catalyst.
CO2 Conversion into Methanol Using Granular Silicon Carbide (α6H-SiC): A Comparative Evaluation of 355 nm Laser and Xenon Mercury Broad Band Radiation Sources
Gondal, Mohammed Ashraf,Ali, Mohammed Ashraf,Dastageer, Mohamed Abdulkader,Chang, Xiaofeng
, p. 108 - 117 (2013)
Granular silicon carbide (α6H-SiC) was investigated as a photo-reduction catalyst for CO2 conversion into methanol using a 355 nm laser from the third harmonic of pulsed Nd:YAG laser and 500 W collimated xenon mercury (XeHg) broad band lamp. The reaction cell was filled with distilled water, α6H-SiC granules and pressurized with CO2 gas at 50 psi. Maximum molar concentration of methanol achieved was 1.25 and 0.375 mmol/l and the photonic efficiencies of CO2 conversion into methanol achieved were 1.95 and 1.16 % using the laser and the XeHg lamp respectively. The selectivity of methanol produced using the laser irradiation was 100 % as compared to about 50 % with the XeHg lamp irradiation. The band gap energy of silicon carbide was estimated to be 3.17 eV and XRD demonstrated that it is a highly crystalline material. This study demonstrated that commercially available granular silicon carbide is a promising photo-reduction catalyst for CO 2 into methanol. Graphical Abstract: Gas Chromatograms of reaction products collected at 30-120 min irradiation in the presence of 355 nm laser having 40 mJ/pulse energy. The inset shows the comparison of retention time of GC peaks with the methanol standard and it is at 2.46 min.[Figure not available: see fulltext.]
Continuous precipitation of Cu/ZnO/Al2O3 catalysts for methanol synthesis in microstructured reactors with alternative precipitating agents
Simson, Georg,Prasetyo, Eko,Reiner, Stefanie,Hinrichsen, Olaf
, p. 1 - 12 (2013)
Ternary Cu/ZnO/Al2O3 catalyst systems were systematically prepared by innovative synthesis routes in microstructured synthesis setups, allowing to study different types of micromixers. The coprecipitation in the slit plate and valve-assisted mixers was operated continuously under exact control of pH, temperature, concentration and ageing time. Due to the enhanced surface to volume ratio in microstructured reactors, a precise temperature control and efficient mixing of the reactants are enabled. The precipitation was performed with sodium, ammonium and potassium carbonate as well as sodium hydroxide. To evaluate the potential of the novel synthesis routes, reference samples in a conventional batch process were prepared. The catalysts were synthesized according to the constant pH method with a molar ratio of 60:30:10 for copper, zinc and aluminum. The synthesis routes applied have a significant influence on the structures of hydroxycarbonate precursors and on the catalytic activity in methanol synthesis. XRD patterns of hydroxycarbonate precursors from the synthesis in micromixers, especially using ammonium carbonate as precipitating agent, display high crystallinity and sharp reflections of malachite and rosasite. Cu/ZnO/Al2O3 catalysts prepared in continuously operated micromixers in general show higher specific copper surface areas than catalysts prepared in conventional batch processes. The highest methanol productivity of all prepared catalyst systems was observed with the catalyst precipitated in the slit plate mixer with ammonium carbonate.
Stable amorphous georgeite as a precursor to a high-activity catalyst
Kondrat, Simon A.,Smith, Paul J.,Wells, Peter P.,Chater, Philip A.,Carter, James H.,Morgan, David J.,Fiordaliso, Elisabetta M.,Wagner, Jakob B.,Davies, Thomas E.,Lu, Li,Bartley, Jonathan K.,Taylor, Stuart H.,Spencer, Michael S.,Kiely, Christopher J.,Kelly, Gordon J.,Park, Colin W.,Rosseinsky, Matthew J.,Hutchings, Graham J.
, p. 83 - 87 (2016)
Copper and zinc form an important group of hydroxycarbonate minerals that include zincian malachite, aurichalcite, rosasite and the exceptionally rare and unstable - and hence little known and largely ignored - georgeite. The first three of these minerals are widely used as catalyst precursors for the industrially important methanol-synthesis and low-temperature water-gas shift (LTS) reactions, with the choice of precursor phase strongly influencing the activity of the final catalyst. The preferred phase is usually zincian malachite. This is prepared by a co-precipitation method that involves the transient formation of georgeite; with few exceptions it uses sodium carbonate as the carbonate source, but this also introduces sodium ions - a potential catalyst poison. Here we show that supercritical antisolvent (SAS) precipitation using carbon dioxide (refs 13, 14), a process that exploits the high diffusion rates and solvation power of supercritical carbon dioxide to rapidly expand and supersaturate solutions, can be used to prepare copper/zinc hydroxycarbonate precursors with low sodium content. These include stable georgeite, which we find to be a precursor to highly active methanol-synthesis and superior LTS catalysts. Our findings highlight the value of advanced synthesis methods in accessing unusual mineral phases, and show that there is room for exploring improvements to established industrial catalysts.
The partial oxidation of methane to methanol with nitrite and nitrate melts
Lee, Bor-Jih,Kitsukawa, Shigeo,Nakagawa, Hidemoto,Asakura, Shukuji,Fukuda, Kenzo
, p. 679 - 682 (1998)
The effect of reduced oxygen species on the partial oxidation of methane to methanol was examined with nitrite melts. The experimental results support the suggestion that the formation of methanol or C2 compounds depends on different reduced oxygen species, as observed in our previous work using nitrate melts. It has been suggested that the partial oxidation of methane proceeds to CH3OH or C2 compounds via parallel pathways. This suggestion was verified by increasing the oxygen concentration to carry out the partial oxidation of methane in 25 mol% NaNO3 - 75 mol% KNO3 melts. A methanol selectivity of 8.2% and a methanol yield of 0.43% were observed with CH4/O2 = 15/1 at 575 °C, whereas with CH4/O2 = 7/1 methanol selectivity and yield increased to 23.7% and 1.1%, respectively. The results further confirm the contribution of the superoxide ion O2- on methanol formation.
Carbon dioxide hydrogenation to methanol over Cu/ZrO2/CNTs: Effect of carbon surface chemistry
Wang, Guannan,Chen, Limin,Sun, Yuhai,Wu, Junliang,Fu, Mingli,Ye, Daiqi
, p. 45320 - 45330 (2015)
Methanol synthesis from CO2 hydrogenation in a fixed-bed plug flow reactor was investigated over Cu-ZrO2 catalysts supported on CNTs bearing various functional groups. The highest methanol activity (turnover frequency 1.61 × 10-2 s-1, space time yield 84.0 mg gcat-1 h-1) was obtained over the Cu/ZrO2/CNTs catalyst (CZ/CNT-3) with CNTs functionalized by nitrogen-containing groups and Cu loading only about 10.3 wt% under the reaction conditions of 260 °C, 3.0 MPa, V(H2):V(CO2):V(N2) = 69:23:8 and GHSV of 3600 h-1. The catalysts were fully characterized by N2 physisorption, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), H2-temperature-programmed reduction (H2-TPR) and temperature-programmed desorption of H2 (H2-TPD) techniques. The excellent performance of CZ/CNT-3 is attributed to the presence of nitrogen-containing groups on the CNTs surface, which increase the dispersion of copper oxides, promote their reduction, decreases the crystal size of Cu, and enhances H2 and CO2 adsorption capability, thus leading to good catalytic performance towards methanol synthesis. This journal is
Hydrogenation of Esters by Manganese Catalysts
Li, Fu,Li, Xiao-Gen,Xiao, Li-Jun,Xie, Jian-Hua,Xu, Yue,Zhou, Qi-Lin
, (2022/01/13)
The hydrogenation of esters catalyzed by a manganese complex of phosphine-aminopyridine ligand was developed. Using this protocol, a variety of (hetero)aromatic and aliphatic carboxylates including biomass-derived esters and lactones were hydrogenated to primary alcohols with 63–98% yields. The manganese catalyst was found to be active for the hydrogenation of methyl benzoate, providing benzyl alcohol with turnover numbers (TON) as high as 45,000. Investigation of catalyst intermediates indicated that the amido manganese complex was the active catalyst species for the reaction. (Figure presented.).
Synthesis of phenol from degraded lignin using synergistic effect of iron-oxide based catalysts: Oxidative cracking ability and acid-base properties
Fumoto, Eri,Ishimaru, Hiroya,Masuda, Takao,Nakasaka, Yuta,Sato, Shinya,Yoshikawa, Takuya
, (2022/02/05)
The effects of ZrO2 and TiO2 incorporated into Fe2O3 matrix on oxidative cracking of degraded lignin and on the acid-base properties were investigated. After lignin degradation, cracking into lower-molecular-weight products was greatest using ZrO2-FeOX. Reactivity of the lattice oxygen was evaluated using H2-TPR, which revealed that the reactivity was improved. Thus, ZrO2-FeOX promoted oxidative decomposition of lignin to oligomers. In the cracking of 2-methoxyphenol, TiO2-FeOX and ZrO2-FeOX resulted in a 5- to 6-fold greater yield of phenol than the yield over Fe2O3. According to Mulliken population analysis, the charge density difference between Fe-O increased by ca. 12% in TiO2-FeOX and ZrO2-FeOX as compared with Fe2O3. This result suggests that addition of TiO2 and ZrO2 improved the acid-base properties of the catalyst, which promoted demethoxylation of 2-methoxyphenol. Thus, ZrO2-FeOX enhanced oxidative decomposition using its lattice oxygen that converted degraded lignin into lower molecule oligomers, followed by demethoxylation to produce phenol.
Catalytic Partial Oxidation of Methane
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Paragraph 0056; 0066; 0072, (2021/10/30)
Systems and methods are provided for direct conversion of methane and/or ethane to methanol. The methods can include exposing methane to an oxidant, such as O2, in a solvent at conditions that are supercritical for the solvent while having a temperature of 310° C. or less, or about 300° C. or less, or about 290° C. or less. The solvent can correspond to an electron donor solvent that, when in a supercritical state, can complex with O2. By forming a complex with the O2, the supercritical electron donor solvent can facilitate conversion of alkane to methanol at short residence times while reducing or minimizing further oxidation of the methanol to other products.