摘要
超 (近 )临界水作为优良的有机反应溶剂适合于针对酸碱催化类型有机反应绿色工艺的开发 .本课题以具备工业生产背景的醋酸甲酯水解作为研究体系 ,在一管式反应器中 ,将原料 (5 %质量分数 )置于体系的超 (近 )临界条件下 (5 2 3～ 6 73K,2 3～ 32 MPa)进行反应操作 .实验结果表明 ,在无外加酸性催化剂情况下 ,水解反应以接近 1的选择性 ,在 1 5 0～ 30 0 s内达到热力学平衡限制 ,同时在系统临界点附近 ,溶剂化作用对反应动力学影响显著 .根据 SN2反应机理对反应动力学方程进行了回归 .
Near- and supercritical water is an excellent medium for conducting chemical reactions, and is especially propitious to the development of environmentally benign techniques for acid/base catalyzed organic reactions. The work presented in this paper focuses on experimental investigation on noncatalytic hydrolysis for methyl acetate, trying to overcome high energy consumption and other defects of conventional ones. Hydrolysis of methyl acetate(5%) in this work was carried out in a tubular reactor under near- or supercritical conditions(523-673 K, 23-32 MPa), and characteristic of hydrolysis was investigated via combining various reaction conditions. The experimental results show that under the optimized operating condition conversion of methyl acetate achieves thermodynamic equilibrium within 150 to 300 s, the selectivity of which process closes to 1, with no acid catalyst added. Due to phase transition resulted from broad experimental range and singularity of supercritical zone, the influence of temperature and pressure on the reactivity takes on a complicated trend, transition-state theory and cluster theory were adopted to interpret experimental phenomena, also reaction kinetics was established based on S N2 mechanism. Conclusion drawn from this work indicates the promising prospect of applying near- and supercritical reaction technology to the industrial practice of hydrolysis of methyl acetate.
出处
《高等学校化学学报》
SCIE
EI
CAS
CSCD
北大核心
2003年第7期1241-1245,共5页
Chemical Journal of Chinese Universities
基金
国家重点基础研究发展规划项目 (批准号 :G2 0 0 0 0 480 10 )资助
