C25沸石分子筛催化合成2-乙酰噻吩连续反应

摘要

With C25 zeolite molecular sieve as catalyst,thiophene and acetic anhydride as raw materials,continuous synthesis of 2-acetyl thiophene was conducted in a trickle bed reactor. The effects of reaction temperature,molar ratio of raw materials,feed flow rate on the Friedel-Crafts acylation reaction were investigated via orthogonal experiment. The optimum reaction condition was:reaction temperature 70℃,molar ratio of thiophene and acetic anhydride 1∶2,feed flow rate 0.05mL/min. Considering the influence of acetic acid on the reaction,the best molar ratio of thiophene,acetic anhydride and acetic acid was 1∶2∶1. Under those conditions,output of 2-acetyl thiophene was 15.10g per unit mass of catalyst,catalyst service life was 4215 min and initial conversion of thiophene could reach 99.98%. The catalyst was characterized with 13C NMR MAS,27Al NMR MAS,and TGA analysis. Bronsted acid sites played an important role in catalysis and the main deactivation type was coking deactivation by compounds with high boiling point.%在滴流床反应器中，以C25沸石分子筛为催化剂，噻吩和乙酸酐为原料对噻吩酰化合成2-乙酰噻吩进行了连续反应实验研究。通过正交试验研究了反应温度、原料配比、进料流量对噻吩 Friedel-Crafts 酰基化反应的影响，确定了最佳反应条件：反应温度70℃，噻吩与乙酸酐摩尔配比1∶2，进料流量0.05mL/min。考察了副产物乙酸对反应的影响，确定了噻吩、乙酸酐和乙酸的最佳摩尔比为1∶2∶1，在最佳反应条件下，单位质量催化剂的2-乙酰噻吩产量为15.10g，催化剂寿命是4215min，噻吩初始转化率高达99.98%。采用固体13C、27Al 核磁共振技术、热重分析对催化剂进行表征，结果表明，催化剂主要催化活性在 B 酸位，失活类型为高沸点物质的积炭失活。