- Preparation Method of Dialkylcarbonate using selenite catalyst and Composition Comprising Dialkylcarbonate Prepared Therefrom
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The present invention relates to a composition which contains: an alkali metal selenite catalyst of chemical formula 2, an alkali metal alkyl selenite catalyst of chemical formula 3, or dialkyl carbonate (DAC) of chemical formula 1, obtained by an oxidation carbonylation process which conducts a reaction of alcohol of chemical formula 4: ROH with a mixed gas of carbon monoxide (CO) and oxygen (O_2); and a selenium-containing by-product, wherein the content of the selenium-containing by-product is 7,000 ppm or less. In addition, the present invention provides a method for manufacturing DAC of the chemical formula 1. The composition according to the present invention can produce DAC of the chemical formula 1 in an economically feasible yield compared to a conventional carbonylation process.COPYRIGHT KIPO 2020
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Paragraph 0095-0102; 0116-0120
(2020/05/13)
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- Vanadocene and niobocene dihalides containing electron-withdrawing substituents in the cyclopentadienyl rings: Synthesis, characterization and cytotoxicity
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The first example of the group V metallocene dihalides substituted in the cyclopentadienyl rings with electron-withdrawing substituents is reported. This study includes synthesis and spectroscopic characterization of the series of vanadocene and niobocene
- Klepalová, Iva,Honzí?ek, Jan,Vinklárek, Jaromír,Padělková, Zdeňka,?ebestová, Lucie,?ezá?ová, Martina
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p. 109 - 115
(2013/07/27)
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- Processes for the preparation of ethers
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A process for preparing ethers which comprises contacting a carboxylated ether with a metal oxide catalyst under conditions effective to produce the ether.
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- Decarboxylation processes using mixed metal oxide catalysts
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A decarboxylation process which comprises contacting a carboxylated compound with a metal oxide catalyst under conditions effective to decarboxylate the carboxylated compound.
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- Nucleophilic Substitutions at Carbonic Acid Derivatives. XIX. Alcoholysis and Hydrolysis of Bis(trichloromethyl)carbonate
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The rate constants of hydrolysis and alcoholysis of bis(trichlormethyl)carbonate in dioxane have been determinated conductometrically.The effects of the water and alcohol concentrations, the temperature and deuterium have been studied.By the hydrolysis and alcoholysis of bis(trichlormethyl)carbonate the nucleophilic attack of water and alcohol is the rate-determining step, followed by a fast elimination of unstable trichloromethanol.
- Cotarca, Livius,Bacaloglu, Radu,Marcu, Nicolae,Tarnaveanu, Alexandru
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p. 881 - 886
(2007/10/02)
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- Uncatalyzed and General Acid Catalyzed Decomposition of Alkyl Xanthates and Monothiocarbonates in Aqueous Solutions
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The decomposition of potassium alkyl xanthates and alkyl monothiocarbonates follows the rate law kobbsd = kH3O++> + kHA + kH2O in aqueos buffer solutions.The Broested coefficient βlg for the kH2O terms is -1.1 for the monothiocarbonates and -1.3 for the xanthates.These results complement the value of -1.1 observed for the alkyl monocarbonates and have been interpreted as late transition states in the decomposition direction.The reactions are also subject to general acid catalysis with α values of 0.9 +/- 0.2 and 0.8 +/- 0.1 for ethyl and methoxyethyl xanthates; α values for the monothiocarbonates are 0.58 +/- 0.05 and 0.57 +/- 0.01 for the methyl and methoxyethyl compounds, respectively.Solvent kinetic isotope effects (kD3O+/kH3O+) for ethyl and methoxyethyl xanthates are 2.53 and 2.12, respectevely; for ethyl, methyl, and methoxyethyl monothiocarbonate they are 1.95, 1.94, and 1.91, respectevely.The high Broensted value for ethyl xanthate and the resultant uncertainly in its numerical value coupled with the high inverse solvent isotope effect place this reaction on the borderline between a specific acid catalyzed mechanism and a concerted mechanism.The latter is favored because the value for kH3O+ is larger than that predicted for the protonation of the alcohol oxygen of the xanthates and monothiocarbonates; further, the formation of such protonated species is estimated to be sufficiently unfavorable as to require a breakdown step faster than a molecular vibration to account for the observed rates.Acetic acid does not catalyze the kH3O+ term for ethyl xanthate at very low pH; the small amount of catalysis at higher pH must therefore be true general acid catalysis and not a solvent effect.Broensted βlg values for the acid-catalyzed decompositions of the xanthates and monothiocarbonates are small.These results have been interpreted in terms of concerted general acid catalysis where little change in charge occurs on the leaving group oxygen in going from the starting material to the transition state.
- Millican, Robert J.,Angelopoulos, Maria,Bose, Anita,Riegel, Bram,Robinson, Darlyne,et al.
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p. 3622 - 3630
(2007/10/02)
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