Cs_(2.5)H_(0.5)PW_(12)O_(40)/SiO_2固体酸催化剂上乙酸与烯烃的酯化和叔戊烯与甲醇的醚化

Esterification of Acetic Acid with Olefin and Etherification of Tertiary Amylene with Methanol over Cs_(2.5)H_(0.5)PW_(12)O_(40)/SiO_2 Solid Acid Catalysts

以硅胶为载体,制备了负载型的Cs2.5H0.5PW12O40催化剂,将该催化剂用于乙酸与1 丁烯的酯化反应和叔戊烯与甲醇的醚化反应,考察了其活性组分负载量、载体硅胶性质和焙烧温度对催化剂性能的影响.研究了催化剂用量、反应温度、反应压力、n(1 丁烯)/n(乙酸)、反应时间等反应条件对酯化反应中乙酸转化率的影响.与其他类型催化剂的醚化活性进行了对比,并进行了Cs2.5H0.5PW12O40/SiO2催化剂的醚化稳定性实验.结果表明,以低钠硅胶为载体,在活性组分负载量为40%,焙烧温度为300～400℃时制备的Cs2.5H0.5PW12O40/SiO2催化剂具有较高的催化活性.随着负载量增大,催化剂孔径、孔容和比表面积减小,而催化活性先增加后减小.在反应温度120℃、压力1.5MPa、n(1 丁烯)/n(乙酸)比3.0、催化剂用量4%、反应时间7h的条件下进行酯化反应,乙酸的转化率为87.36%.在反应温度80℃、压力1.0MPa、n(甲醇)/n(叔戊烯)比1.1、LHSV为1h-1的条件下进行醚化反应,叔戊烯的转化率为68.57%.制备的新型Cs2.5H0.5PW12O40/SiO2催化剂对于乙酸与1 丁烯的直接酯化反应和叔戊烯与甲醇的醚化反应具有良好的活性与选择性,催化剂寿命长.因此,Cs2.5H0.5PW12O40/SiO2是一种理想的乙酸与烯烃直接酯化和叔戊烯与甲醇醚化反应的催化剂.

Several supported cesium salts of 12tungstophoric acid (Cs2.5H0.5PW12O40) with silica gel support were prepared as catalysts. The catalysts prepared were used to catalyze the esterification of acetic acid with 1butene and etherification of tertiary amylene with methanol. The effects of loading of Cs2.5H0.5PW12O40,properties of silica gel support and calcinating temperature on the performance of silica supported Cs2.5H0.5PW12O40 catalysts were studied. The catalysts prepared were characterized. The effect of amount of the used catalyst,reaction temperature,reaction pressure,reaction time and n(1betene)/n(acetic acid) on the conversion of acetic acid in esterification were investigated. The contrast of etherification activaties of different kind of catalysts and a stablities experiment of Cs2.5H0.5PW12O40/SiO2  as etherification catalyst was done. The results showed that the 40% Cs2.5H0.5PW12O40/SiO2 catalysts calcinated at 300-400 ℃ have excellent acidities,with the increasing of loading of active constituent,the pore size and pore volume decrease,and the catalytic activity first increases then decreases. Under the ammount of catalysts 4%,reaction temperature 120 ℃,reaction pressure 1.5 MPa,reaction time 7 h and n(1betene)/n(acetic acid) 3,the conversion of acetic acid is up to 87.36%. Under reaction temperature 120 ℃,reaction pressure 1.0 MPa,n(methanol)/n(tertiary amylene) 1.1 and LHSV 1 h-1,the conversion of tertiary amylene is 68.57%. The Cs2.5H0.5PW12O40/SiO2 catalyst have good activity,selectivity and stablity for the esterification and etherification,which could replace liquid acids and become a environmentally friendly solid acid catalyst for the esterification and etherification.