环氧乙烷氢甲酯化制3-羟基丙酸甲酯工艺条件和动力学研究

以环氧乙烷、甲醇和CO为原料,Co2(CO)8为催化剂,3-羟基吡啶为配位体,合成3-羟基丙酸甲酯。考察了反应温度、压力、环氧乙烷浓度、催化剂和配位体添加量等对环氧乙烷转化率和目的产物选择性的影响,得到的较适宜反应条件为:温度70℃,压力7.0MPa,n(环氧乙烷)/n(主催化剂)=100/1;n(配体)/n(主催化剂)=6/1;n(甲醇)/n(环氧乙烷)=6/1。在该条件下环氧乙烷转化率接近100%,对3-羟基丙酸甲酯的选择性达到93%。反应中环氧乙烷浓度对时间的微分与其浓度成正比,呈一级关系。用阿仑尼乌斯方程求得的反应速率常数为(0.2～0.61)×10-3min-1,表观活化能为72.75kJ·mol-1,指前因子为ko=4.97×107min-1。

Study on reaction conditions and kinetics of methoxycarbonylation of ethylene oxide into methyl 3-hydroxpropanate

Preparation of methyl 3-hydroxpropanate from ethylene oxide, methanol and CO using Co2(CO)8 as catalyst and 3-hydroxylpyridin as ligand was studied. The influences of temperature, pressure, concentration of ethylene oxide, cata-lyst and ligand dosages on the conversion of ethylene oxide and the selectivity to target product were investigated. Optimal conditions were determined to be as follows: temperature 70℃, pressure 7.0MPa, ethylene oxide/catalyst molar ratio 100:1, ligand/catalyst molar ratio 6:1, and methanol/ethylene oxide molar ratio 6:1. Under above conditions, the conversion of ethylene oxide and the selectivity to 3-hydroxpropanate were 100% and 93%, respectively. Kinetics study showed that the differential of ethylene oxide concerntration to reaction time was proportional to ethylene oxide concerntration, thus this is a first order reaction with respect to ethylene oxide. The re-action rate constant, apparent activated energy and pre-exponential factor were calculated by Arrhenius equation to be (0.2～0.61)×10- 3min-1, 72.75kJ.mol-1, and 4.97×107 min-1, respectively.