固体超强酸S_2O_8^(2-)/Fe_2O_3-MoO_3催化合成乙酸环己酯

Synthesis of cyclohexyl acetate by the solid superacid S_2O_8^(2-)/Fe_2O_3-MoO_3 catalyst

以硝酸铁和钼酸铵为原料,柠檬酸为络合剂,采用溶胶-凝胶法,制备固体超强酸S2O82-/Fe2O3-MoO3.以乙酸和环己醇的酯化反应为探针反应,考察了(NH4)2S2O4浓度、焙烧温度、焙烧时间对催化活性的影响,实验确定的催化剂制备的较佳工艺条件为:浸泡液中c(NH4)2S2O8=0.5 mol/L,焙烧温度350℃,焙烧时间3.5 h.用在该条件下制备的催化剂催化合成乙酸环己酯,正交试验确定的最佳工艺条件为:n(环己醇)∶n(乙酸)=1.2,0.7 g S2O82-/Fe2O3-MoO3(以0.2 mol乙酸为准),带水剂V(环己烷)=12 mL,反应时间2.5 h,在此条件下,酯化率可达96.6%.

Fe（NO3）3 and （NH4）6Mo7O24 were used as the raw material and citric acid as complexant to prepare solid superacid S2O8^2-/Fe2O3-MoO3 by sol-gel method. The influence factors of catalyst activity were investigated by the esterification, i. e. probe reaction of acetic acid and cyclohexanol. The optimal condition of preparation of the catalyst were obtained as follows ： impregnation concentration was 0.5 mol/L , calcination temperature was 350℃and calcination time was 3.5 h. The cyclohexyl acetate were synthesized by the catalyst prepared under above conditions. The best conditions were obtained by the orthogonal test as follows ： while molar ratio of eyclohexyl alcohol to acetic acid was 1.2, weight of the catalyst was 0.7 g（when acetic acid was 0.2 tool） ,the amount of the water removing reagent was 12 mL,the reacting time was 2.5 h. The yield of esterification was about 96.6%.