616-38-6Relevant articles and documents
Direct synthesis of dimethyl carbonate from methanol and carbon dioxide over Ga2O3/Ce0.6Zr0.4O2 catalysts: Effect of acidity and basicity of the catalysts
Lee, Hye Jin,Park, Sunyoung,Song, In Kyu,Jung, Ji Chul
, p. 531 - 537 (2011)
Ce X Zr1-X O2 catalysts with different cerium content (X) (X = 0, 0.2, 0.4, 0.5, 0.6, 0.8, and 1.0) were prepared by a sol-gel method for use in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Among these catalysts, Ce0.6Zr 0.4O2 was found to show the best catalytic performance. In order to enhance the acidity and basicity of Ce0.6Zr 0.4O2 catalyst, Ga2O3 was supported on Ce0.6Zr0.4O2 (XGa2O 3/Ce0.6Zr0.4O2 (X = 1, 5, 10, and 15)) by an incipient wetness impregnation method with a variation of Ga 2O3 content (X, wt%). Effect of acidity and basicity of Ga2O3/Ce0.6Zr0.4O2 on the catalytic performance in the direct synthesis of dimethyl carbonate was investigated using NH3-TPD and CO2-TPD experiments. Experimental results revealed that both acidity and basicity of the catalysts played a key role in determining the catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Large acidity and basicity of the catalyst facilitated the formation of dimethyl carbonate. The amount of dimethyl carbonate produced over XGa2O 3/Ce0.6Zr0.4O2 catalysts increased with increasing both acidity and basicity of the catalysts. Among the catalysts tested, 5Ga2O3/Ce0.6Zr0.4O 2, which retained the largest acidity and basicity, showed the best catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Graphical Abstract: In the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide over Ga 2O3/Ce0.6Zr0.4O2 catalysts, the amount of DMC showed a volcano-shaped curve with respect to Ga2O3 content. The amount of DMC increased with increasing both acidity and basicity of the catalysts [Figure not available: see fulltext.]
Triorganotin(iv) cation-promoted dimethyl carbonate synthesis from CO2 and methanol: Solution and solid-state characterization of an unexpected diorganotin(iv)-oxo cluster
?vec, Petr,Cattey, Hélène,R??i?ková, Zdeňka,Holub, Josef,R??i?ka, Ale?,Plasseraud, Laurent
, p. 8253 - 8260 (2018)
Two novel C,N-chelated organotin(iv) complexes bearing weakly coordinating carborane moieties were prepared by the reaction of the corresponding C,N-chelated organotin(iv) chloride (i.e. LCNR2SnCl, R = n-Bu (1) and Ph (2); LCN = 2-(N,N-dimethylaminomethyl)phenyl)) with monocarba-closo-dodecaborate silver salt (AgCB11H12; Ag·3). Both products of the metathesis, [LCN(n-Bu)2Sn]+[CB11H12]- (4) and [LCNPh2Sn]+ [CB11H12]- (5), respectively, were characterized by both multinuclear NMR spectroscopy and elemental analysis. The instability of 4 and 5 towards water is discussed. The solid-state structure of LCN(n-Bu)2SnOH·B(C6F5)3 (4a) as a model compound with a Sn-O(H)?B linkage is also reported. The evaluation of the catalytic activity of 4 and 5 was carried out within the direct synthesis of dimethyl carbonate (DMC) from methanol and CO2. While 5 was shown to be definitively inactive, presumably due to cleavage of the Sn-Ph bond, compound 4 exhibits a beneficial action, since it leads to an amount of DMC higher than the stoichiometry (nDMC/nSn(cat) = 1.5). In addition, the solid state structures of [BnNMe3]+[CB11H12]- (6) and [(n-Bu)20Sn10O2(OMe)6(CO3)2]2+·2[CB11H12]- (7), isolated as single-crystals and resulting from the recombination of 4 under the reaction conditions (methanol/CO2), were established by sc-XRD analyses within the term of this work as well. 6 and 7 were also fully characterized by IR spectroscopy, multinuclear NMR in solution and elemental analysis.
Graphene oxide supported molybdenum cluster: First heterogenized homogeneous catalyst for the synthesis of dimethylcarbonate from CO2and methanol
Kumar, Subodh,Khatri, Om P.,Cordier, St??phane,Boukherroub, Rabah,Jain, Suman L.
, p. 3488 - 3494 (2015)
The octahedral molybdenum cluster-based compound, Cs2Mo6Bri8Bra6 was immobilized on graphene oxide (GO) by using a facile approach. High resolution transmission electron microscopy results revealed that molybdenum clusters were uniformly distributed on the GO nanosheets. Cs2Mo6Bri8Bra6 was attached to the GO support via chemical interaction between apical ligands of Mo6Bri8Bra6 cluster units and oxygen functionalities of GO, as revealed by XPS studies. The developed material was used for the synthesis of dimethyl carbonate by reduction of carbon dioxide. The synthesized catalyst, that is, GO-Cs2Mo6Bri8Brax, exhibited higher catalytic efficiency than its homogeneous analogue without using dehydrating agent. The catalyst was found to be efficiently recyclable without significant loss of catalytic activity.
Synthesis of dimethyl carbonate from methyl carbamate and methanol catalyzed by mixed oxides from hydrotalcite-like compounds
Wang, Dengfeng,Zhang, Xuelan,Zhao, Wenbo,Peng, Weicai,Zhao, Ning,Xiao, Fukui,Wei, Wei,Sun, Yuhan
, p. 427 - 430 (2010)
A series of mixed oxides calcined from hydrotalcite-like compounds with different cations were prepared and their catalytic activities were studied by the synthesis of dimethyl carbonate (DMC) from methyl carbamate and methanol. Among them, ZnFe mixed oxide possessed the best catalytic ability. Furthermore, the zinc-based mixed oxides as well as the corresponding hydrotalcite-like compounds were characterized by using ICP, TGA, CO2-TPD and N2 adsorption/desorption techniques.
Effects of Mo promoters on the Cu-Fe bimetal catalysts for the DMC formation from CO2 and methanol
Zhou, Ying-Jie,Xiao, Min,Wang, Shuan-Jin,Han, Dong-Mei,Lu, Yi-Xin,Meng, Yue-Zhong
, p. 307 - 310 (2013)
The Mo-promoted Cu-Fe bimetal catalysts were prepared and used for the formation of dimethyl carbonate (DMC) from CO2 and methanol. The catalysts were characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), laser Raman spectra (LRS), energy dispersive spectroscopy (EDS) and temperature programmed desorption (TPD) techniques. The experimental results demonstrated that the Mo promoters can decrease the reducibility and increase the dispersion of Cu-Fe clusters. The concentration balance of base-acid sites can be readily adjusted by changing the Mo content. The moderate concentration balance of acid and base sites was in favor of the DMC formation. Under optimal experimental conditions, the highest methanol conversion of 6.99% with a DMC selectivity of 87.7% can be obtained when 2.5 wt% of Mo was loaded.
Synthesis of dimethyl carbonate from ethylene carbonate and methanol over nano-catalysts supported on CeO2-MgO
Jun, Jin Oh,Lee, Joongwon,Kang, Ki Hyuk,Song, In Kyu
, p. 8330 - 8335 (2015)
A series of CeO2(X)-MgO(1-X) (X = 0, 0.25, 0.5, 0.75, and 1.0) nano-catalysts were prepared by a co-precipitation method for use in the synthesis of dimethyl carbonate from ethylene carbonate and methanol. Among the CeO2(X)-MgO(1-X) catalysts, CeO2(0.25)-MgO(0.75) nano-catalyst showed the best catalytic performance. Alkali and alkaline earth metal oxides (MO = Li2O, K2O, Cs2O, SrO, and BaO) were then supported on CeO2(0.25)-MgO(0.75) by an incipient wetness impregnation method with an aim of improving the catalytic performance of CeO2(0.25)-MgO(0.75). Basicity of the catalysts was determined by CO2-TPD experiments in order to elucidate the effect of basicity on the catalytic performance. The correlation between catalytic performance and basicity showed that basicity played an important role in the reaction. Yield for dimethyl carbonate increased with increasing basicity of the catalysts. Among the catalysts tested, Li2O/CeO2(0.25)-MgO(0.75) nano-catalyst with the largest basicity showed the best catalytic performance in the synthesis of dimethyl carbonate.
The influence of halogen anions and N-ligands in CuXn/N-ligands on the catalytic performance in oxidative carbonylation of methanol
Mo, Wanling,Xiong, Hui,Hu, Jianglin,Ni, Youming,Li, Guangxing
, p. 576 - 580 (2010)
The catalytic properties of CuXn/N-ligands (X=Cl, Br and I; n = 1 or 2) in oxidative carbonylation ofmethanolwere investigated. It was found that the interaction of halogen anions, N-ligands and Cu (I) affected the catalytic performance of copper complex catalyst in the reaction, especially iodide anion and 1,10-phenanthroline (Phen). When CuI/Phen was used as a catalyst, the conversion of methanol was 42.6%, the selectivity to dimethyl carbonate was 99.2% and the TOF was 13.1 h-1 at an optimized conditions: CuI/Phen 0.2 mol l-1, 120 °C, 2 h, 2.4 MPa, PCO/PO2 = 2:1. Compared with the plain CuI catalyst, the catalytic activity of CuI/Phen increased about 36 times.When CuI/Phen catalystwas immobilized on polystyrene (PS), the heterogenized catalyst,CuI/Phen-NH-PS, also exhibited veryhigh catalytic activity in oxidative carbonylation. The CuI/Phen - NH - PS catalyst remained its high catalytic activity even after seven recycles. The average weight loss of CuI/Phen - NH - PS after reaction was less than 1.0%, and the leaching of copper was only about 0.15% in each recycling test. Copyright
Efficient ceria-zirconium oxide catalyst for carbon dioxide conversions: Characterization, catalytic activity and thermodynamic study
Kumar, Praveen,With, Patrick,Srivastava, Vimal Chandra,Gl?ser, Roger,Mishra, Indra Mani
, p. 718 - 726 (2017)
In this study, ceria-zirconia based catalysts (CeO2, ZrO2and Ce0.5Zr0.5O2) were synthesized by hydrothermal method and characterized by N2-sorption, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Acidity and basicity of synthesized catalysts were investigated by NH3[sbnd] and CO2[sbnd] temperature-programmed desorption (TPD). Brunauer-Emmett-Teller (BET) surface area of CeO2, Ce0.5Zr0.5O2and ZrO2were found to be 88, 117 and 70?m2?g?1and average crystallite sizes was 9.48, 7.09 and 9.45?nm, respectively. These catalysts were further used for direct conversion of CO2with methanol for the synthesis of dimethyl carbonate (DMC). DMC yield was found to be highly dependent upon the both basicity and acidity of catalysts. Ce0.5Zr0.5O2catalysts showed better activity as compared to CeO2and ZrO2catalysts. Effect of reaction conditions (such as catalyst dose, reaction temperature and reaction time) and catalyst reusability was studied with Ce0.5Zr0.5O2catalyst. The optimum operating condition for direct conversion of CO2into DMC at constant pressure of 150 bar were found to be reaction time?=?24?h, catalyst dose?=?1.25?g and temperature?=?120?°C. Moreover, chemical equilibrium modeling was performed using Peng–Robinson–Stryjek–Vera equation of state (PRSV-EoS) along with the van der Waals one-fluid (1PVDW) mixing rule to calculate the heat of reaction and Gibbs free energy change.
Carbon dioxide conversion to dimethyl carbonate: The effect of silica as support for SnO2 and ZrO2 catalysts
Ballivet-Tkatchenko, Danielle,Dos Santos, Jo?o H.Z.,Philippot, Karine,Vasireddy, Sivakumar
, p. 780 - 785 (2011)
Abundant in nature, CO2 poses few health hazards and consequently is a promising alternative to phosgene feedstock according with the principles of Green Chemistry and Engineering. The synthesis organic carbonates from CO2 instead of phosgene is highly challenging as CO2 is much less reactive. As part of our ongoing research on the investigation of catalysts for dimethyl carbonate (DMC) synthesis from methanol and CO 2, we herein report results aimed at comparing the catalytic behavior of new SnO2-based catalysts with that of ZrO2. Silica-supported SnO2 and ZrO2 exhibit turnover numbers which are an order of magnitude higher than those of the unsupported oxides. Tin-based catalysts also promote methanol dehydration which makes them less selective than the zirconium analogues. Last but not least, comparison with soluble Bu2Sn(OCH3)2 highlights the superiority of the organometallic precursor for achieving 100% selectivity to DMC but it deactivates by intermolecular rearrangement into polynuclear tin species.
Dimethyl carbonate production via the oxidative carbonylation of methanol over Cu/SiO2 catalysts prepared via molecular precursor grafting and chemical vapor deposition approaches
Drake, Ian J.,Fujdala, Kyle L.,Bell, Alexis T.,Tilley, T. Don
, p. 14 - 27 (2005)
The influence of catalyst synthesis method and Cu source on the activity and selectivity of Cu/SiO2 catalysts for the gas-phase oxidative carbonylation of methanol to dimethyl carbonate (DMC) is reported. [CuOSi(O tBu)3]4, [CuO tBu]4, and CuCl were used as precursors to produce highly dispersed silica-supported copper. XANES and EXAFS characterization prior to reaction (but after thermal treatment under He) showed that Cu in the catalysts prepared with CuCl and [CuOSi(O tBu)3]4 was present primarily as isolated Cu(I) species, whereas [CuO tBu]4 produced 1-nm Cu particles. During the catalytic reaction, the Cu in catalysts prepared from CuCl and [CuOSi(O tBu)3]4 formed highly dispersed CuO moieties, whereas the Cu in catalysts prepared from [CuO tBu]4 formed a cuprous oxide layer over a Cu(0) core. For comparison, poorly dispersed Cu on silica was prepared via traditional incipient wetness impregnation with Cu(NO3)2. It was found that activity for DMC formation increased with increasing Cu dispersion. The selectivity for DMC formation (relative to CO) decreased with decreasing Cu dispersion when the original state of the Cu was Cu(0) directly preceding reaction conditions.
Synthesis of dimethyl carbonate from propylene carbonate and methanol over Y2O3/CeO2-La2O3 catalysts
Song, Ji Hwan,Jun, Jin Oh,Kang, Ki Hyuk,Han, Seung Ju,Yoo, Jaekyeong,Park, Seungwon,Kim, Do Heui,Song, In Kyu
, p. 10810 - 10815 (2016)
A series of CeO2(1 - X)-La2O3(X) (X = 0, 0.05, 0.1, 0.15, and 0.2) mixed metal oxide catalysts with different La2O3 molar ratio (X) were prepared by a citric acid-assisted sol-gel method. The catalysts were applied to the synthesis of dimethyl carbonate (DMC) via transesterification of propylene carbonate with methanol. Among these catalysts, it was found that CeO2(0.85)-La2O3(0.15) catalyst showed the highest DMC yield. To improve the catalytic performance of CeO2(0.85)-La2O3(0.15), different amount of Y2O3 was introduced onto CeO2(0.85)-La2O3(0.15) by an incipient wetness impregnation method. The prepared XY2O3/CeO2(0.85)-La2O3(0.15) (X = 0, 3, 6, 9, 12, and 15 wt%) catalysts were then applied to the synthesis of DMC from propylene carbonate and methanol. Basicity of the catalysts was measured by CO2-TPD (temperature-programmed desorption) experiments to investigate the effect of basicity on the catalytic performance. A correlation between basicity and catalytic performance demonstrated that basicity of the catalyst played an important role in the transesterification of propylene carbonate with methanol. Yield for DMC increased with increasing basicity of the catalyst. Among the catalysts tested, 9Y2O3/CeO2(0.85)-La2O3(0.15) catalyst with the largest basicity showed the highest DMC yield.
Oxidative carbonylation of methanol to dimethyl carbonate (DMC): a new catalytic system
Delledonne, Daniele,Rivetti, Franco,Romano, Ugo
, p. C15 - C19 (1995)
Oxidative carbonylation of methanol to dimethylcarbonate catalysed by cobalt complexes is reported.Cobalt complexes with oxygen and or nitrogen donor ligands such as carboxylate, acetylacetonate, picolinate and Schiff bases are suitable catalysts.The oxidative carbonylation of methanol catalysed by cobalt complexes which has never been reported, affords dimethylcarbonate with remarkably high selectivities.Of the cobalt complexes, those with Schiff bases show the highest reactivity.The influence of co-solvents was also examined.Keywords: Cobalt; Carbonylation; Methanol; Catalysis; Dimethyl carbonate
Graphene supported Cu nanoparticles as catalysts for the synthesis of dimethyl carbonate: Effect of carbon black intercalation
Shi, Ruina,Ren, Meijiao,Li, Haixia,Zhao, Jinxian,Liu, Shusen,Li, Zhong,Ren, Jun
, p. 257 - 268 (2018)
Reduced graphene oxide (rGO) intercalated with a carbon black (CB) supported copper catalyst (Cu/rGO-CB) was employed in the synthesis of dimethyl carbonate (DMC) via liquid-phase oxidative carbonylation of methanol. The conversion of methanol and the space-time yield of DMC (STYDMC) over Cu/rGO-CB reached 5.6% and 2757 mg/(g h), higher than over a Cu/rGO catalyst, 4.7% and 2334 mg/(g h), respectively. The characterization indicates that CB particles, acting as spacers, ensured the high utilization of graphene layers and enhanced the interaction between Cu and the support, and the oxygen containing groups on the surface of CB play an important role in stabilizing Cu clusters. In comparison with Cu/rGO, the loss of copper concentration in Cu/rGO-CB is significantly decreased, from 15.37% to 1.96%. Catalyst reusability tests show that Cu/rGO-CB could be reused five times without almost any catalytic activity loss, implying distinct enhanced catalytic stability compared to the Cu/rGO catalyst.
Phosphinite-Ni(0) Mediated Formation of a Phosphide-Ni(II)-OCOOMe Species via Uncommon Metal-Ligand Cooperation
Kim, Yeong-Eun,Oh, Seohee,Kim, Seji,Kim, Onnuri,Kim, Jin,Han, Sang Woo,Lee, Yunho
, p. 4280 - 4283 (2015)
Reversible transformations are observed between a phosphide-nickel(II) alkoxide and a phosphinite-nickel(0) species via a P-O bond formation coupled with a 2-e- redox change at the nickel center. In the forward reaction, the nickel(0) dinitrogen species (PPOMeP)Ni(N2) (2) and {(PPOMeP)Ni}2(μ-N2) (3) were formed from the reaction of (PPP)NiCl (1) with a methoxy anion. In the backward reaction, a (PPP)Ni(II) moiety was regenerated from the CO2 reaction of 3 with the concomitant formation of a methyl carbonate ligand in (PPP)Ni(OCOOMe) (7). Thus, unanticipated metal-ligand cooperation involving a phosphide based ligand is reported.
Synthesis of dimethyl carbonate from ethylene carbonate and methanol using TS-1 as solid base catalyst
Tatsumi,Watanabe,Koyano
, p. 2281 - 2282 (1996)
The titanium silicate molecular sieve, TS-1, exchanged with an aqueous solution of K2CO3 is an excellent heterogeneous catalyst for the synthesis of dimethyl carbonate by an ester exchange reaction between ethylene carbonate and methanol.
PREPARATION OF DIMETHYL CARBONATE FROM METHANOL AND CARBON DIOXIDE IN THE PRESENCE OF Sn(IV) and Ti(IV) ALKOXIDES AND METAL ACETATES
Kizlink, Juraj,Pastucha, Ivan
, p. 687 - 692 (1995)
The synthesis of dimethyl carbonate by the reaction of methanol with carbon dioxide in the presence of metal alkoxides and metal carboxylates was studied.The best results have been achieved with Ti(IV) and Sn(IV) alkoxides which at 130 to 180 deg C and low CO2 pressures yield dimethyl carbonate in 30 to 100 mole percent or 40 to 130 mole percent yields with respect to the metal alkoxides, depending on the carbon dioxide (gaseous and solid one, respectively).The yields can be further increased up to 70-190 mole percent and 90-270 mole percent, respectively, by the use of chemical scavengers of the reaction water.
Spectro-Electrochemical Examination of the Formation of Dimethyl Carbonate from CO and Methanol at Different Electrode Materials
Figueiredo, Marta C.,Trieu, Vinh,Eiden, Stefanie,Koper, Marc T.M.
, p. 14693 - 14698 (2017)
In this work, we report a fundamental mechanistic study of the electrochemical oxidative carbonylation of methanol with CO for the synthesis of dimethyl carbonate on metallic electrodes at low overpotentials. For the first time, the reaction was shown to take place on the metallic catalysts without need of oxidized metals or additives. Moreover, in-situ spectroelectrochemical techniques were applied to this electrosynthesis reaction in order to reveal the reaction intermediates and to shed light into the reaction mechanism. Fourier transformed infrared spectroscopy was used with different electrode materials (Au, Pd, Pt, and Ag) to assess the effect of the electrode material on the reaction and the dependence of products and intermediates on the applied potentials. It was observed that the dimethyl carbonate is only formed when the electrode is able to decompose/oxidize MeOH to form (adsorbed) methoxy groups that can further react with CO to dimethyl carbonate. Furthermore, the electrode needs to adsorb CO not too strongly; otherwise, further reaction will be inhibited because of surface poisoning by CO.
La-modified mesoporous Mg-Al mixed oxides: Effective and stable base catalysts for the synthesis of dimethyl carbonate from methyl carbamate and methanol
Wang, Dengfeng,Zhang, Xuelan,Ma, Jie,Yu, Haiwen,Shen, Jingzhu,Wei, Wei
, p. 1530 - 1545 (2016)
A series of La-containing Mg-Al hydrotalcite-like (HTl) precursors with different La contents (Mg2+:Al3+:La3+ = 3:1:x, where x varies from 0 to 1.0) were synthesized using a co-precipitation method followed by hydrothermal treatment. X-ray diffraction and thermogravimetric measurements demonstrated that the yield of the HTl phase decreased with increasing La content. The La-modified Mg-Al mixed oxides (HTC-La) were then obtained by thermal decomposition of the corresponding HTl precursors, and the mesoporous structure was formed during calcination. It was demonstrated that the structure and surface basic properties of the HTC-La samples strongly depended on the amount of La additive. Simultaneously, the resulting HTC-La materials were used as solid base catalysts for the synthesis of dimethyl carbonate (DMC) from methyl carbamate (MC) and methanol. Then, the correlation between their basic properties and catalytic performance was studied in detail. The incorporation of a suitable amount of La into HTC-La catalysts was beneficial for the production of DMC, and a DMC yield of 54.3% with a high DMC selectivity of 80.9% could be achieved when x was tuned to 0.5 under the optimized reaction conditions. In addition, the HTC-La catalyst could be readily recycled while maintaining high catalytic activity and selectivity for DMC. Furthermore, in situ FTIR experiments were carried out to elucidate the adsorption behaviours of the reactants. On the basis of the experimental results, a plausible basic catalytic mechanism wherein MC and methanol were activated simultaneously on the basic sites of the catalyst was proposed for this catalytic reaction.
The promotion and stabilization effects of surface nitrogen containing groups of CNT on cu-based nanoparticles in the oxidative carbonylation reaction
Zhang, Guoqiang,Zhao, Dan,Yan, Junfen,Jia, Dongsen,Zheng, Huayan,Mi, Jie,Li, Zhong
, p. 18 - 29 (2019)
N-doped carbon nanotubes (NCNTs)with different contents of N were prepared by pre-oxidation and subsequent N-doping strategy and employed as the supports to fabricate Cu-based catalysts for oxidative carbonylation of methanol. The supports and their corresponding catalysts were characterized thoroughly by BET, XPS, XRD, H2-TPR, TEM, N2O chemisorption, CO-TPD, CH3OH-TPD and ICP-OES measurements. It is found that the increase of oxygen containing groups generated by pre-oxidation can effectively improve the content of the nitrogen containing groups during the subsequent N-doping process. The nitrogen containing groups, especially the pyridine N groups, serving as the preferred anchoring site, significantly promotes the dispersion of Cu species. With the increased content of N from 0 to 5.2%, the dispersion of Cu species increases from 11.0 to 21.6% and the space time yield of DMC increases from 150.5 to 1789.6 mg g?1h?1. Moreover, the incorporation of nitrogen containing groups enhances the interaction between Cu species and CNT support, which suppresses the auto-reduction of Cu2+ to Cu+ and Cu0, while improves the anti-agglomeration, anti-oxidation and anti-leaching properties of Cu species. From the perspective of stability, the space time yield of DMC for Cu/CNT decreases from 150.5 to 86.9 mg g?1 h?1 after four consecutive runs, while that of Cu/NCNT200 slightly decreases from 1789.6 to 1557.9 mg g?1 h?1, and the declined degrees are 42.3% and 12.9%, respectively. The superior dispersion, anti-agglomeration, anti-oxidation and anti-leaching properties of Cu species as well as the promotion effect of pyridine N groups are contributed to the increased activity and stability of the Cu/NCNT200 catalyst.
Template-derived carbon: An unexpected promoter for the creation of strong basicity on mesoporous silica
Sun, Lin-Bing,Liu, Xiao-Yan,Li, Ai-Guo,Liu, Xiao-Dan,Liu, Xiao-Qin
, p. 11192 - 11195 (2014)
Template-derived carbon is demonstrated to effectively promote the creation of strong basicity on mesoporous silica, for the first time. New materials owning ordered mesoporous structure, strong basicity, and excellent catalytic activity are thus successfully constructed at low temperatures, which are impossible to achieve using conventional methods.
Kinetics of dimethyl carbonate synthesis from methanol and carbon dioxide over ZrO2-MgO catalyst in the presence of butylene oxide as additive
Eta, Valerie,M?ki-Arvela, P?ivi,W?rn, Johan,Salmi, Tapio,Mikkola, Jyri-Pekka,Murzin, Dmitry Yu.
, p. 39 - 46 (2011)
A kinetic investigation of dimethyl carbonate (DMC) synthesis from methanol and CO2 over ZrO2-MgO was performed by using butylene oxide as a chemical trap for the water formed during the reaction. The effect of the catalyst amount, the stirring speed, the temperature, as well as the amount of butylene oxide on the reaction rate and the selectivity to DMC was studied. The analysis of the reaction pathway suggests that DMC and butylene glycol are formed via the reaction of adsorbed mono-methoxycarbonate intermediate and methoxybutanol or methanol. A kinetic model was developed based on the reaction mechanism and it was in agreement with the experimental data. The apparent activation energy for the formation of DMC was 62 kJ/mol.
Selective carbonylation of methanol to dimethyl carbonate by gas-liquid-solid-phase boundary electrolysis
Yamanaka, Ichiro,Funakawa, Akiyasu,Otsuka, Kiyoshi
, p. 448 - 449 (2002)
Selective and efficient electrochemical carbonylation of MeOH to DMC was performed over PdCl2/VGCF (vapor grown carbon fiber) anode by utilizing the three-phase boundary electrolysis at 1 atm (CO) and 298 K.
Synthesis of Dimethyl Carbonate by Electrolytic Carbonylation of Methanol in the Gas Phase
Otsuka, Kiyoshi,Yagi, Toshikazu,Yamanaka, Ichiro
, p. 495 - 498 (1994)
Electrolytic carbonylation of methanol has been attempted in the gas phase under atmospheric pressure at 343 K. The graphites added with PdCl2 and CuCl2 are favorable anodes for the synthesis of dimethyl carbonate (DMC). The formation of DMC occurs at a lower applied voltage than that for dimethoxy methane and methyl formate. However, a considerable CO2 formation accompanies the DMC formation.
NiO/CeO2-ZnO nano-catalysts for direct synthesis of dimethyl carbonate from methanol and carbon dioxide
Kang, Ki Hyuk,Lee, Chang Hoon,Kim, Dong Baek,Jang, Boknam,Song, In Kyu
, p. 8693 - 8698 (2014)
XNiO/CeO2(0.7)-ZnO(0.3) (X =0, 1, 5, 10, and 15) nano-catalysts were prepared by a wet impregnation method with a variation of NiO content (X, wt%). The prepared catalysts were then applied to the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. Successful formation of XNiO/CeO2(0.7)-ZnO(0.3) nano-catalysts was confirmed by XRD and ICP-AES analyses. Acidity and basicity of XNiO/CeO2-ZnO were measured by NH3-TPD (temperature-programmed desorption) and CO2-TPD experiments, respectively, with an aim of elucidating the effect of acidity and basicity of the catalysts on the catalytic performance in the reaction. It was revealed that the catalytic activity of XNiO/CeO2(0.7)-ZnO(0.3) was closely related to both acidity and basicity of the catalysts. The amount of dimethyl carbonate produced over XNiO/CeO2(0.7)-ZnO(0.3) increased with increasing acidity and basicity of the catalysts. Thus, both acidity and basicity of the catalysts played important roles in determining the catalytic performance in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide.
CuCl catalyst heterogenized on diamide immobilized SBA-15 for efficient oxidative carbonylation of methanol to dimethylcarbonate
Cao, Yong,Hu, Jun-Cheng,Yang, Ping,Dai, Wei-Lin,Fan
, p. 908 - 909 (2003)
CuCl has been successfully immobilized on a novel diamide modified SBA-15, and proven to be an efficient heterogenized catalyst for the oxidative carbonylation of methanol to dimethylcarbonate.
The Influence of Iron Group Promoters on the Synthesis of Dimethyl Carbonate over CuY Catalysts Prepared via Modified Vapor Impregnation Method
Yuchun Wang,Liu, Zhaorong,Tan, Chao,Sun, Hong,Li, Zhong
, p. 705 - 712 (2021/04/22)
Abstract: CuY and CuMY (M = Fe, Co, Ni) catalysts were prepared by modified vapor impregnation using cupric acetylacetonate as copper source and M acetylacetonate as promoter. The catalysts were evaluated in heterogeneous catalytic vapor phase oxidative carbonylation of methanol to dimethyl carbonate (DMC). The catalyst samples were analyzed by XRD, H2-TPR, XPS, CO-TPD, and NH3?TPD, and their catalytic performance was assessed in a fixed-bed reactor. The experimental results indicate that all introduced species were well dispersed on zeolite Y, and the addition of iron group promoters have effect on the Cu+ contents, acidity and CO adsorption-desorption performance. Finally the influence of various promoters was examined with the aim of increasing space-time yield of DMC from methanol. Space-time yield of DMC was increased with the addition of iron group promoters in the order Fe? Co Ni, but the selectivity follows the order of Fe Ni Co, respectively.
Urea-Functionalized Swelling Poly(ionic liquid)s as Efficient Catalysts for the Transesterification and Hydrolysis of Ethylene Carbonate
Hu, Hao,Wang, Xin,Chen, Bihua,Gao, Guohua
, p. 3945 - 3952 (2021/07/31)
Urea-functionalized poly(ionic liquid)s (PILs) were synthesized through polymerization of urea tethered imidazolium ionic liquid monomers (urea-IL) with sodium acrylate, and N,N′-methylenebisacrylamide (MBA) as a crosslinker. Close-packed and interconnected pores (1–4 (Formula presented.)) under swollen state could be observed from the cryogenic scanning electron microscopy (cryo-SEM) images. The promising catalytic activity of the PILs was illustrated for the transesterification reaction of ethylene carbonate with methanol. High activity and selectivity could be achieved by using poly(urea-IL)-n catalysts, which was similar to that of corresponding homogeneous ionic liquid catalysts. The urea tethered imidazolium in PILs acted as hydrogen-bonding donor to activate ethylene carbonate and intermediate 2-hydroxyethyl methyl carbonate (HEMC) for enhancing catalytic activity. The swelling ability of urea-functionalized PILs in methanol enabled active urea sites accessible for substrates. However, the complete conversion of ethylene carbonate was limited by reversible reaction between ethylene carbonate and HEMC. A possible synergistic activation mechanism for the transesterification reaction was proposed and supported by NMR titrations. The catalyst can be reused and recycled five times with stable activity. Furthermore, urea-functionalized swelling PILs also exhibited high catalytic activity for the hydrolysis of ethylene carbonate.
Preparation method of dialkyl carbonate
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Paragraph 0051-0079, (2021/05/01)
The invention relates to a preparation method of dialkyl carbonate. The method comprises the following steps: by using cyclic carbonate and monohydric alcohol as raw materials, carrying out transesterification under the catalysis of triazole onium ionic liquid to obtain the dialkyl carbonate. According to the brand-new method for preparing the dialkyl carbonate, the cyclic carbonate and the monohydric alcohol are catalyzed by using the triazolium ionic liquid to be subjected to transesterification to obtain the dialkyl carbonate, and the dialkyl carbonate prepared by using the method has relatively high selectivity and conversion rate; and the selectivity of the obtained dialkyl carbonate can reach 99.5%. Compared with a method for preparing dialkyl carbonate in the prior art, the triazolium ionic liquid catalyst used in the invention has the advantages of high catalytic efficiency, high stability, no need of other solvents or cocatalysts, mild reaction conditions and the like, and has high industrial application value.