引用本文:ZHANG Ding-lin WEI Xi-wen WANG Xiang-zhi.[en_title][J].Journal of Chongqing University (English Edition),2007,6(3):161~165
.Application of density-functional theory to studying methylation with dimethyl carbonate and dimethyl sulfate[J].Journal of Chongqing University (English Edition),2007,6(3):161~165
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Application of density-functional theory to studying methylation with dimethyl carbonate and dimethyl sulfate
ZHANG Ding-lin WEI Xi-wen WANG Xiang-zhi
作者单位
摘要:
The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density- functional theory (DFT). B3LYP/6-31G(d, p) methods were used to optimize the structures of dirnethyl carbonate and dimethyl sulfate and calculate t
关键词:  度函数理论 二甲基碳酸盐 二甲基硫酸盐 化学分析
DOI:
分类号:O642.543
基金项目:
Application of density-functional theory to studying methylation with dimethyl carbonate and dimethyl sulfate
ZHANG Ding-lin  WEI Xi-wen  WANG Xiang-zhi
Abstract:
The activities of dimethyl carbonate and dimethyl sulfate as a methylation reagent were studied by density- functional theory (DFT). B3LYP/6-31G(d, p) methods were used to optimize the structures of dimethyl carbonate and dimethyl sulfate and calculate theirs charge densities. Dimethyl sulfate is easier than dimethyl carbonate to react with a nucleophilic reagent. In dimethyl sulfate, the alkoxy carbons are the only reactive atomic nucleus because of steric hindrance. A nucleophilic reagent is more likely to react with carbonyl carbons than alkoxy carbons of dimethyl carbonate; in the presence of a Lewis acid, the phenyl nucleophilic reagent reacts with the Lewis acid first. Lewis acid increases the negative charge density of a nucleophilic reagent in polar solvent, and also incurs an accretion of steric hindrance. Polar solvent avails to ionize dimethyl carbonate and thus enables the reaction of methylation. The frequencies of transition state calculated by Gaussion 03 confirm the inferred reaction mechanism. The harvest rates of 4-methoxyphenol in the experiments of methylation reactions of hydroquinone with respectively dimethyl carbonate and dimethyl sulfate support the foregoing theortical conclusions.
Key words:  density-functional theory  dimethyl carbonate  dimethyl sulfate
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