HM负载磷钨酸催化合成对叔丁基甲苯的研究

Synthesis of p-tert-butyltoluene with PW/HM as catalysts

以HM沸石分子筛负载磷钨酸(PW)作为催化剂,在100 mL高压釜反应器中进行甲苯与叔丁醇合成对叔丁基甲苯的烷基化反应。考察不同磷钨酸负载量对甲苯与叔丁醇烷基化反应的影响,并用XRD、TG-DSC和NH3-TPD手段对不同负载量催化剂进行了表征,并在反应中考察了他们的催化性能。结果表明,中低负载量的磷钨酸均匀分散于HM表面,当磷钨酸的负载量为25%时,磷钨酸在HM表面高度分散呈现较高活性,催化剂的焙烧温度为350℃。采用25%PW/HM作为催化剂,研究各种反应条件对催化剂性能的影响,在适宜的反应条件下,即反应温度为160℃,叔丁醇与甲苯摩尔比为3,初始压力为0.6 MPa,催化剂的质量分数为20%时,甲苯的转化率为36.3%,对叔丁基甲苯的选择性为82.1%。

The alkylation of toluene with tert-butyl alcohol（TBA） is carried out with phosphotungstic acid supported H-mordenite（PW/HM） as catalyst in a 100 mL stainless steel batch reactor equipped with a stirrer.The physicochemical properties of PW/HM with different PW loadings are characterized by X-ray diffraction（XRD）,ammonia program temperature desorption（NH3-TPD） and thermogravimetric（TG） techniques.Their catalytic performances are investigated for the tert-butylation of toluene.When the PW loading is as high as 25%,PW can be highly dispersed on the surface of HM.The calcination temperature of catalyst is 350℃.The influences of various reaction conditions on 25% PW/HM catalyst are discussed.It is found that,when using 25% PW/HM as catalyst,36.3% conversion of toluene and 82.1% selectivity of p-tert-butyltoluene（PTBT） can be obtained under following optimal conditions： 160℃ of reaction temperature,0.6 MPa of initial pressure,3 of molar ratio of tert-butyl alcohol to toluene,5 of w（reactant）/w（catalyst）.