摘要
采用Benson和Joback基团贡献法对吗啉与碳酸二甲酯反应体系进行了热力学分析,计算了反应体系的焓变、熵变、吉布斯自由能变及反应平衡常数,讨论了温度对吗啉与碳酸二甲酯的甲基化和甲氧羰基化反应的影响。计算结果表明,在373.15～473.15 K范围内,吗啉与碳酸二甲酯的甲基化和甲氧羰基化反应为放热反应,且反应为自发过程,反应平衡常数随温度的升高而减小;与甲氧羰基化反应相比,甲基化反应是热力学上占优势的反应,反应的平衡常数很大,反应进行得较完全;在实验温度范围内,升高温度有利于提高甲基化反应的选择性。
The enthalpy changes, entropy changes, Gibbs free energy changes and equilibrium constants in the reaction of dimethyl carbonate with morpholine to N-methyl morpholine were calculated by means of Benson and Joback group contribution methods. The effects of the reaction temperature on both methylation and methoxy-carbonylation reactions of dimethyl carbonate with morpholine were discussed. The results showed that both the methylation and the methoxy- carbonylation reactions were exothermal, and were spontaneous processes because of the negative free energy change in the temperature range of 373.15 - 453.15 K. The reaction equilibrium constant decreased with rise of the reaction temperature. Compared with the methoxy-carbonylation reaction, the methylation reaction of dimethyl carbonate with morpholine was in thermodynamic control. The reaction equilibrium constant of the methylation was larger than that of the methoxy-carbonylation. The selectivity to the methylation could be improved by raising temperature.
出处
《石油化工》
CAS
CSCD
北大核心
2012年第1期56-61,共6页
Petrochemical Technology
关键词
吗啉
碳酸二甲酯
甲基化
甲氧羰基化
N-甲基吗啉
热力学
morpholine
dimethyl carbonate
methylation
methoxy-carbonylation
N-methyl morpholine
thermodynamics
