改性HM催化剂上2-甲基萘的择形异丙基化反应

SHAPE-SELECTIVE ISOPROPYLATION OF 2-METHYLNAPHTHALENE OVER MODIFIED HM CATALYSTS

采用等体积浸渍法制备了不同含量CeO2和MgO复合改性的HM催化剂,以2-甲基萘与异丙醇的异丙基化反应为探针,在固定床反应器上考察其催化性能。结果表明,2-甲基萘择形异丙基化反应的最佳条件是反应压力2 MPa、反应温度200℃、n(2-MN)∶n(i-PrOH)∶n(Cyclohexane)=1∶3∶70。在质量分数20%的CeO2改性后的HM催化剂上,在上述最佳反应条件下反应8 h后,2-甲基萘的转化率为37.7%,目的产物2-甲基-6-异丙基萘(2,6-MIPN)的选择性和产率分别为83.0%和28.7%;在加入少量MgO复合改性后的HM催化剂上,2,6-MIPN的选择性达到89.5%。CeO2和MgO的复合改性使分子筛内、外表面的强酸酸量减少,抑制了非择形催化反应的发生,提高了2-甲基-6-异丙基萘的选择性。

A series of HM catalysts modified with CeO2 and MgO were prepared by impregnation method.Isopropylation reaction of 2-methylnaphthalene（2-MN） with isopropanol to 2-methyl-6-isopropylnaphthalene（2,6-MIPN） catalyzed by modified HM catalyst was carried out in fixed-bed down-flow reactor.The results showed that the optimal reaction conditions of 2-MN isopropylation were the reaction pressure of 2 MPa,reaction temperature of 200℃,n（2-MN）∶n（i-PrOH）∶n（Cyclohexane）=1∶3∶70.Under the optimal conditions and over 20%CeO2/HM catalyst,2-MN conversion reached 37.7%,2,6-MIPN selectivity and yield were 83.0% and 28.7%,respectively,after 8 h reaction on stream,and over the HM catalyst modified by CeO2 and MgO,the selectivity of 2,6-MIPN could reach 89.5%.The reason is that CeO2 and MgO can decrease the internal and external acid sites of HM catalysts,reduce the non-shape-selective reaction and improve the selectivity to 2,6-MIPN.