553-90-2Relevant articles and documents
Cyclization of Dimethyl Oxalate upon Electron Impact
Liehr, J. G.,Larka, E. A.,Beynon, J. H.
, p. 34 - 36 (1981)
Isotope labelling experiments and also consecutive fragmentation investigations of metastable ions, a novel technique in mechanistic studies, have been carried out to elucidate structure and genesis of the m/z 45 ions from dimethyl oxalate as well as dimethyl carbonate.It is shown that the formation of the m/z 45 ions, CH3O(1+)=CH2, in the mass spectra of these compounds arises via single step processes.Mechanisms involving hydrogen transfer and subsequent formation of cyclic intermediates which then collapse to give CH3O(1+)=CH2 directly from molecular ions are suggested.No evidence was found for a two-step fragmentation route to m/z 45 from the molecular ions of either dimethyl oxalate or dimethyl carbonate.
Mechanistic study of the oxidative carbonylation of methanol catalyzed by palladium diphosphane complexes with nitrobenzene as oxidant
Mooibroek, Tiddo J.,Bouwman, Elisabeth,Drent, Eite
, p. 1403 - 1412 (2012)
The reactivity of Pd complexes having bidentate diarylphosphane ligands was studied in the oxidative carbonylation of CH3OH to dimethyl carbonate/oxalate (DMC/O) with PhNO2 as the oxidant. Different ligands were employed with variation in backbone length and aryl ring substituent, and the acidity, CO pressure, or the partial pressure of H 2 was varied. At two different stages in the catalytic cycle, one equivalent of DMC/O may evolve for every equivalent of PhNO2 reduced, which means that the efficiency with which nitrobenzene can function as the oxidant for the oxidative carbonylation of methanol (EOC) can potentially be 200a% relative to nitrobenzene conversion. The selectivity for DMC relative to DMO is thought to be determined by a species of the type [P 2PdC(O)OCH3(R)]; the DMO/DMC ratio can be increased by increasing the CO pressure, by addition of an acid, or by using a ligand with a relatively large bite angle. On the basis of the collected results, we conclude that an ideal catalyst for oxidative carbonylation would have a relatively acidic palladium center and be sterically undemanding in the axial positions but sterically demanding in the equatorial positions of palladium. The Pd complex of bis(diphenylphosphanyl)ferrocene meets these criteria and was found to function most efficiently with PhNO2 as oxidant for the oxidative carbonylation of methanol among the series of compounds studied, that is, with about 50a% of the theoretical maximum efficiency EOC. The catalytic reactivity of palladium complexes having bidentate diarylphosphane ligands was studied in the oxidativecarbonylation of methanol to dimethylcarbonate (DMC) and dimethyl oxalate (DMO) with nitrobenzene as terminal oxidant. Nitrobenzene can be reduced to aniline by the hydrogen atoms liberated, and thus a catalytic coupling between methanol oxidation and nitrobenzene hydrogenation is established.
Catalytic Synthesis of Oxalate Esters
Current, Steven P.
, p. 1779 - 1780 (1983)
A new catalyst system, palladium(II) acetate, cobalt(II) acetate, triphenylphosphine, and 1,4-benzoquinone, produces oxalate esters in high selectivity from carbon monoxide, oxygen, and alcohol.Up to 140 mol of dimethyl oxalate is obtained per mole of palladium while only traces of dimethyl carbonate or methyl formate are formed.
Lewis acid sites in MOFs supports promoting the catalytic activity and selectivity for CO esterification to dimethyl carbonate
Guo, Guo-Cong,Jing, Kai-Qiang,Tan, Hong-Zi,Wang, Zhi-Qiao,Xu, Yu-Ping,Xu, Zhong-Ning
, p. 1699 - 1707 (2020)
CO esterification to dimethyl carbonate (DMC) is an attractive route, although the catalyst is the main problem restricting the industrialization of this route. Supported palladium catalysts have been often used for this route. However, the effect of the support is not always clear. In this work, we firstly introduced three metal-organic frameworks (MOFs) materials as catalyst supports, namely UiO-66, MIL-101 and MOF-5, and studied the effect of Lewis acid sites in the MOFs supports on the catalytic activity and selectivity for CO esterification to DMC. Interestingly, the Pd(ii)/UiO-66 catalyst exhibits superior catalytic performance to the other catalysts, with 87.9% CO conversion and 98.5% DMC selectivity due to the abundant Lewis acid sites in UiO-66. It was proven that UiO-66 with more defects would have a large number of Lewis acid sites, and the catalytic performance was positively correlated with the number of Lewis acid sites in MOFs supports, which can be demonstrated by characterization by NH3-TPD, pyridine-IR, XPS and in situ DRIRS. The current work not only revealed the relationship between the Lewis acidity of the support and catalytic performance, but also promotes the development of practical catalysts for CO esterification to DMC.
Catalyst design criteria and fundamental limitations in the electrochemical synthesis of dimethyl carbonate
?ari?, Manuel,Davies, Bethan Jane Venceslau,Schj?dt, Niels Christian,Dahl, S?ren,Moses, Poul Georg,Escudero-Escribano, María,Arenz, Matthias,Rossmeisl, Jan
, p. 6200 - 6209 (2019)
Dimethyl carbonate is an environmentally friendly precursor in various chemical reactions and is currently synthesized by hazardous processes. An electrocatalytic approach could result in a process abiding to the principles of Green Chemistry. Herein we demonstrate how density functional theory (DFT) calculations and experiment advance our understanding of electrocatalytic production of chemicals. Using density functional theory, we form design criteria for dimethyl carbonate electrosynthesis on metallic surfaces. The criteria are based on adsorption free energies of reactants and reaction energies of possible products. The design criteria allow us to identify copper as an interesting candidate for the electrode material as it is classified as being selective to dimethyl carbonate and requires ≈1 V lower potential than a gold electrode. By further addressing electrode stability copper was found to dissolve and produce copper-carbonyl species which lead to dimethyl carbonate as a consequence of a reaction in the solution, therefore not occurring by surface electrocatalysis. This shows that the design criteria presented herein are necessary but not sufficient requirements that the ideal electrode should satisfy.
A kinetic study of the solvolyses of methyl and ethyl chloroglyoxalates
Kevill, Dennis N.,Park, Byoung-Chun,Kyong, Jin Burm
, p. 9032 - 9035 (2005)
Solvolyses of methyl and ethyl chloroglyoxylates proceed about 10 6 times faster than the identical solvolyses of the corresponding chloroformates. The correlation parameters obtained from application of the extended Grunwald-Winstein equation are consistent with an addition-elimination (association-dissociation) mechanism over the full range of solvents, with the addition step being rate determining.
Remarkable Decrease in Overpotential of Oxalate Formation in Electrochemical CO2 Reduction by a Metal-Sulfide Cluster
Kushi, Yoshinori,Nagao, Hirotaka,Nishioka, Takanori,Isobe, Kiyoshi,Tanaka, Koji
, p. 1223 - 1224 (1995)
Triangular metal-sulfide cluster, 3(μ3-S)2>2+ and 3(μ3-S)2>2+, catalyse the electrochemical CO2 reduction to selectively produce oxalate at -1.30 and -0.70 V (vs.Ag/AgCl), respectively, in MeCN.
New aspects of the synthesis of dimethyl carbonate via carbonylation of methyl alcohol promoted by methoxycarbonyl complexes of palladium(II)
Cavinato, G.,Toniolo, L.
, p. C65 - C66 (1993)
suspended in MeOH reacts with carbon monoxide (40-80 atm, 50 deg C), in the presence of a base such as NEt3 to give the methoxycarbonyl complex trans-.When the carbonylation reaction is carried out at 90-100 deg C reduction to Pd0 carbonyl-phosphine complexes occurs, with formation of dimethyl carbonate, selectively and in an almost quantitative yield.The above complexes are less reactive than the acetato-analogues, which give dimethyl oxalate as the main organic carbonylation product even at 50 deg C.
Active Pd(II) complexes: Enhancing catalytic activity by ligand effect for carbonylation of methyl nitrite to dimethyl carbonate
Tan, Hong-Zi,Wang, Zhi-Qiao,Xu, Zhong-Ning,Sun, Jing,Chen, Zhe-Ning,Chen, Qing-Song,Chen, Yumin,Guo, Guo-Cong
, p. 3785 - 3790 (2017)
Palladium (Pd)-based catalysts have been widely used for carbonylation of methyl nitrite to dimethyl carbonate (DMC), but a high-performance chloride free catalyst combining both excellent carbon monoxide (CO) conversion and DMC selectivity has not been developed yet. In this work, a chloride free, Pd-based catalyst with good activity and selectivity (conversion of CO: 60.1%, selectivity to DMC: 99.9%) has been successfully fabricated. By thorough characterization and analysis, it is found that the good catalytic activity is positively correlated with the high oxidation states of the Pd species, which could be tuned by their ability to accept the backdonation electron of the ligands. The strong electron backdonation from Pd to π? antibonding orbitals of the ligand in the palladium acetylacetonate [Pd(acac)2] complex accelerates the step where Pdδ+ reoxidizes to Pd(ii), resulting in the higher catalytic activity. In addition, a catalytic mechanism was proposed based on the results of X-ray photoelectron spectroscopy and in situ diffuse reflectance infrared spectroscopy. This work not only explains the positive relationship between the catalytic activity and the oxidation state of the Pd species, but also provides a new way to enhance catalytic performance by utilizing the abilities of accepting the backdonation electron of the ligands.
MgO: An excellent catalyst support for CO oxidative coupling to dimethyl oxalate
Peng, Si-Yan,Xu, Zhong-Ning,Chen, Qing-Song,Wang, Zhi-Qiao,Chen, Yumin,Lv, Dong-Mei,Lu, Gang,Guo, Guo-Cong
, p. 1925 - 1930 (2014)
Pd/MgO catalysts are found, for the first time, to be extraordinarily active and stable for CO oxidative coupling to dimethyl oxalate. A series of Pd/MgO catalysts with Pd loadings of 0.1, 0.3, 0.5, 1 and 2 wt% were prepared by a wet impregnation method and systematically characterized by XRD, TEM, ICP, UV-DRS, H2-TPR and CO2-TPD. It has been demonstrated that the amount of Pd loading has a pronounced effect on the catalytic activity for CO oxidative coupling to dimethyl oxalate. CO conversion increases with the increase of the Pd loading due to high dispersion and similar sizes of Pd nanoparticles, as well as, the increase in number of surface active sites. The Royal Society of Chemistry 2014.
