丁硫醚在HZSM-5分子筛上的催化转化反应研究

STUDY ON THE CATALYTIC CONVERSION OF Di-n-BUTYL SULFIDE OVER HZSM-5 ZEOLITE

在固定床微型反应器中,探讨了丁硫醚在HZSM-5分子筛作用下的催化转化反应规律。丁硫醚比较容易发生转化,在350℃可大部分发生裂解,主要生成硫化氢(含量达90%以上)气体,在裂解时也可环化生成四氢噻吩。通过浸渍法引入稀土Ce离子使HZSM-5分子筛对丁硫醚的裂解活性得到提高,裂解产物四氢噻吩的量也有增大趋势,CeO2负载量达到1.5%时,丁硫醚的转化率为较高值96.9%,硫化氢的产率也为较高值72.4%。甲醇与溶剂的体积比为0.33时,丁硫醚的转化率达到100%,而H2S的产率也达到最大值91.2%。探讨了丁硫醚的反应历程,认为烷基硫醚类化合物裂解过程中的裂解关键步骤为碳硫键的断裂生成类硫醇物种。

The catalytic conversion of di-n-butyl sulphide over HZSM-5 zeolite was studied by a fixed bed micro-reactor. It was found that di-n-butyl sulphide was easy to crack and was mainly converted to H2S（more than 90 %）over HZSM-5 zeolite at a reaction temperature of 350 ℃. Tetrahydrothiophene （THT）was also detected in the cracked product. HZSM-5 zeolite modified with cerium by impregnation method showed improved cracking activity,e, g. at a CeO2 content of 1.5 %, the conversion of di-n-butyl sulphide reached 96.9 % and the hydrogen sulfide yield was 72.4%. The effect of adding methanol to the reaction system was investigated as well. The test results showed that at a volume ratio of methanol to benzene（as solvent）of 0.33, the conversion of di-n-butyl sulfide reached 100% with a maximum hydrogen sulfide yield of 91.2%. The reaction mechanism was studied briefly,and the rupture of C S bond was proposed as the key reaction step to form thiol-like intermediate.