HPW/Ti_3(PO_4)_4的制备及其催化酯化性能

制备了系列磷酸钛原位负载不同含量x(wt%)磷钨酸H3PW12O40(HPW)的酯化催化剂HPW-x/Ti3(PO4)4,通过催化丙酸与正戊醇的酯化反应考察了其催化酯化性能,并采用IR分析对催化剂进行了表征。结果表明,300℃焙烧2h条件下,磷钨酸含量15%的催化剂HPW-15/Ti3(PO4)4具有最佳的催化活性,催化合成低碳链羧酸酯丙酸戊酯的适宜条件为:0.2mol丙酸,催化剂用量0.4g,n(正戊醇)∶n(丙酸)=1.6∶1,反应时间4h,酯化率达97.7%。该催化剂循环利用6次酯化率减小幅度不足7.5%。该催化剂对长碳链羧酸酯庚酸戊酯的合成循环利用6次酯化率为93.2%～83.5%。

Preparation of HPW/Ti3(PO4)4 and Its Catalytic Behavior for Esterification Reaction

A series of esterification catalysts with different contents of H3PW12O40(HPW)supported on titanium phosphate,HPW-x/Ti3(PO4)4,was prepared and calcined at 300℃ for 2.0 h.All of them were characterized by IR techniques.The catalyst containing 15%HPW,HPW-15/Ti3(PO4)4,had the optimal catalytic activity.The optimized conditions for synthesis of amyl propionate by HPW-15/Ti3(PO4)4 were as follows: propionic acid 0.2 mol,mole ratio of alcohol to acid 1.6∶1,catalyst dosage 0.4 g and reaction time 4.0 h.The esterification rate could reach 97.7%.After recycling for six times,the esterification rate of amyl propionate reduced less than 7.5%.Moreover,by using the catalyst HPW-15/Ti3(PO4)4 for six times pentyl heptanoate was also synthesized and the esterification rates were 93.2%~83.5%.