超临界条件下甲基萘与甲醇烷基化反应

引　言2 ,6 二甲基萘 (2 ,6 DMN)是生产新型高性能聚酯材料聚萘二甲酸乙二醇酯 (PEN)的重要原料 .目前已工业化的邻二甲苯与丁二烯烷基化生产2 ,6 DMN路线生产步骤多 ,工艺过程复杂 ,生产成本高 ,制约了PEN的发展1,2 ] .HZSM 5沸石是一种具有强酸性、高硅铝比和独特孔道结构的分子筛 ,对许多正碳离子反应有良好的择形催化性能3] .HZSM 5催化甲基萘 (DMN)与甲醇烷基化合成 2 ,6 DMN路线工艺过程简单 ,产品选择性高 ,是一条具有发展前景的技术路线4 ] .然而 ,在常压下进行烷基化反应时 ,反应活性低 ,催化剂容易因结焦而失去原有的活性5～ 7] .超临界流体具有良好的溶解和扩散性能 .在超临界条件下进行的化学反应不仅可以提高催化剂的反应活性 ,而且还可以原位维持非均相催化剂的活性 ,延长催化剂的寿命8,9] .本文正是基于超临界流体独特的性质 ,探索在超临界条件下甲基萘与甲醇烷基化反应中提高反应活性和延长催化剂寿命的可能性 .1　实验部分1 1　催化剂的制备NaZSM 5沸石 (硅铝比为 38)由南开大学催化剂厂提供 .在 80℃下用 1mol...

ALKYLATION OF METHYLNAPHTHALENE AND METHANOL UNDER SUPERCRITICAL CONDITION

Alkylation of methylnaphthalene with methanol is one promising technology for producing 2,6-dimethylnaphthalene. When the alkylation is carried out under ambient pressure by using HZMS-5 catalysis, the reaction activity is very low and obvious deactivation of catalyst is observed in a short run.This paper aims at slowing down catalyst deactivation and improving reaction activity of alkylation of methylnaphthalene with methanol by taking advantage of some special properties of supercritical fluids, such as higher solubility than gases and higher diffusivity than liquids. The results indicate that the reaction under supercritical condition will achieve high reaction activity and long catalyst life. When the reaction was carried out at 460℃ and 7.0MPa which is above the critical temperature and pressure of the inert reaction solvent,1,3,5-trimethylbenzene, the reaction activity increased by 3 times and catalyst life was extended by 25 to 30 times than those under ambient pressure and at the same temperature.