SO4^2-/TiO_2固体超强酸催化合成二苄基甲苯的研究

Research on Catalytic Synthesis for Dibenzyl Toluene by SO_4^(2-)/TiO_2 Solid Super Acid

二苄基甲苯是一种性能优良的合成高温导热油,其典型的合成方法是Friedel-Crafts烷基化反应。Friedel-Crafts烷基化反应需要使用酸性催化剂,但传统的液体催化剂存在腐蚀性强,分离困难等缺陷。用沉淀法制备的SO_4^(2-)/TiO_2固体超强酸催化剂解决了腐蚀性和分离困难的问题,并具有良好的催化活性。对单苄基甲苯和氯化苄合成二苄基甲苯的反应条件进行了研究。考察了SO_4^(2-)/TiO_2固体超强酸催化剂用量,反应温度,反应时间和单苄基甲苯/氯化苄摩尔比对氯化苄转化率和二苄基甲苯选择性的影响。适宜的反应条件为SO_4^(2-)/TiO_2固体超强酸催化剂用量1.6%质量分数,反应温度为100℃,反应时间为3 h,单苄基甲苯/氯化苄的摩尔比为5。在该合成条件下,氯化苄的转化率达到99%,二苄基甲苯的选择性达到88%。合成的二苄基甲苯可用作高温导热油。

Dibenzyl toluene was an excellent synthetic high-temperature heat transfer oil, and its typical synthetic method was Friedel-Crafts alkylation reaction.The use of an acidic catalyst was required in Friedel-Crafts alkylation reaction.However,the traditional liquid catalysts were corrosive and difficult to be separated.SO-2/4-/TiO_2 solid super acid catalyst prepared by precipitation method solved the problems of corrosion and separation difficulties and had good catalytic activity.The reaction conditions for the synthesis of dibenzyl toluene with monobenzyl toluene and benzyl chloride were studied.The effects of the dosage of SO-2/4-/TiO_2 solid super acid catalyst, reaction temperature and reaction time, the molar ratio of monobenzyl toluene/benzyl chloride on the conversion of benzyl chloride and the selectivity of dibenzyl toluene were investigated.The optimum reaction conditions were as follows：the mass fraction of SO-2/4-/TiO_2 solid super acid catalyst was 1.6%, the reaction temperature was 100 ℃, the reaction time was 3 h,the molar ratio of monobenzyl toluene/benzyl chloride was 5.Under these synthetic conditions,the conversion rate of benzyl chloride reached 99% and the selectivity of dibenzyl toluene reached 88%.Synthesized dibenzyl toluene would be used as a high-temperature heat transfer oil.