- On the origin of nitrogen-containing promoters in the cobalt-catalyzed methoxycarbonylation of epoxides
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The detailed promotion mechanism of nitrogenous compounds in the cobalt-catalyzed methoxycarbonylation of epoxides has not been studied to date. Herein, we present the intrinsic correlation between nitrogenous promoters and activity and selectivity in the alkoxycarbonylation of epoxides by a comprehensive in situ IR spectroscopy and DFT studies. In situ IR spectroscopy confirmed the acid-base neutralization of the nitrogenous promoters and HCo(CO)4, resulting in reduction of the acidity of the catalyst. With the reduced acid-derived activity for formation of ethers as by-products, the selectivity of desired esters was increased. DFT calculations showed that a nitrogenous base could facilitate the methanolysis of cobalt-acyl species with lowered activation energy, which is considered to be the rate-determining step in the catalytic cycle. As a result, the reaction activity towards carbonylation was also improved by nitrogenous promoters. The present studies will provide new insights to the long-term confusing problems in epoxides carbonylation.
- He, Jianghua,He, Lin,Li, Zhen,Liu, Jianhua,Liu, Mengli,Wang, Fang,Xia, Chungu,Yun, Dong,Zeng, Bo
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- CO2-MEDIATED ETHERIFICATION OF BIO-BASED DIOLS
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A method of etherifying glycols or other diols by employing renewable reagents is disclosed. In particular, the method involves contacting a diol with an alkylating agent in an alcoholic solvent, catalyzed with a catalyst (carbonic acid) generated in situ (from CO2). The mono- and di-ether products can serve as valued precursors to an array of renewable surfactants, dispersants, and lubricants, among others.
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Paragraph 0057; 0058; 0059; 0060
(2016/07/05)
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- Anodic Oxidation. Part 17. The Formation of Alkyl Methyl Carbonates in the Hofer-Moest Reaction in Methanol
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The liquid products from the electrolysis of sodium butanoate in methanol containing methyl sodium carbonate at a graphite anode include propyl and 1-methylethyl methyl carbonates. 1,1-Dimethylethyl methyl carbonate is amongst the liquid products from the electrolysis of sodium 2,2-dimethylpropanoate in methanol at a platinum anode in the presence or absence of methyl sodium carbonate.Typical secondary products derived from propene or 2-methylpropene are also present in the liquid products from each of these electrolyses.
- Brettle, Roger,Khan, M. Akhram,Rowbottom, John D.
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p. 2927 - 2929
(2007/10/02)
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