Nafion结构催化剂及响应面辅助优化催化精馏制取丙酸甲酯的过程研究

Catalytic Distillation for the Synthesis of Methyl Propionate:Nafion Structured Catalyst and Experimental Optimization Via Response Surface M

工业中酸/醇酯化法传统工艺中存在无机强酸催化剂腐蚀设备、废液污染环境、产品分离提纯工艺复杂和传质传热限制等问题。为避免此类问题的影响,实验借助微结构催化剂和反应器设计理念,选择不锈钢金属纤维作为结构载体,制备具有良好催化活性和稳定性的固体酸Nafion结构催化剂。利用催化精馏技术在结构催化剂作用下通过丙酸和甲醇制备丙酸甲酯,响应面Box-Behnken设计对催化精馏过程进行优化分析,考查不同工艺条件对丙酸甲酯产率的影响。软件分析得出最佳工艺参数是再沸器加热温度216℃,重时空速0.47 h^(-1),回流比1.53,进料酸醇摩尔比为2.24:1,该条件下测量得到的实际丙酸甲酯产率95.41%,与预测值95.68%一致。

Industrially,carboxylic ester is commonly produced via direct esterification of acid with alcohol.However,this traditional process would generate homogeneous catalyst such as inorganic mineral acids with highly corrosive media,polluting the environment in the presence of waste streams,making both product separation and purification difficult and high heating effect and mass transfer limitation.In order to avoid the influence of such problems,we used the stainless steel microfiber as supports to prepare the microfiber Nafion solid acid structured catalysts with good catalytic activity and stability under the design concept of structured catalyst and reactor.The propionic acid and methanol were used in the catalytic distillation with the structured catalyst.The response surface Box-Behnken design was used to optimize the catalytic distillation to examine the influence of different conditions on the yield of methyl propionate.A high methyl propionate actual yield of 95.41%was achievable under the optimal conditions which including the reboiler temperature of 216℃,molar feed ratio of propionic acid to methanol of 2.24:1,WHSV of 0.47 h^(-1)and reflux ratio of 1.53 obtained by response surface analysis,while the actual yield of methyl propanoate was consistent with the predicted yield of 95.68%.