四氢萘和十氢萘的催化裂化反应途径及特征产物

Reaction Pathways and Characteristic Products of Tetralin and Decalin by Catalytic Cracking

在小型固定流化床催化裂化试验装置上,考察了十氢萘和四氢萘在酸性催化剂上的裂化反应途径及特征产物。结果表明,初始阶段质子化裂化是四氢萘裂化的主要引发反应,H^+攻击C—C键形成五配位正碳离子是十氢萘裂化的主要引发反应;随着反应深度的进行,氢转移反应成为四氢萘的主要反应,而十氢萘裂化生成的烷基环烷正碳离子的β断裂成为十氢萘的主要反应。四氢萘在酸性催化剂上的反应产物中萘、H_2和苯的摩尔分数最高,是其反应特征产物;十氢萘在酸性催化剂上的反应产物中异丁烷和汽油异构烷烃组分的摩尔分数最高,是其反应特征产物,为多环环烷烃或氢化芳烃的高效利用提供理论依据。

The reaction pathways and characteristic products of decalin and tetralin over acidic catalysts were studied on a fixed fluidized catalytic cracking test unit.Experimental results indicate that the reaction pathways of tetralin and decalin are quite different over acidic catalysts.The protolytic cracking reaction is the main initiation reaction of tetralin;with the depth of reaction,the hydrogen transfer reaction becomes the main reaction of tetralin.It has been found that the C-C bond of decalin is mainly attacked by H + to form carbonium ions,which is the most important initiation reaction.β-scission of the alkylcycloalkane carbenium ions formed by cracking of carbonium ions may have two pathways,which can better explain the product distribution.The reaction products of tetralin over acidic catalyst are mostly H 2,benzene and naphthalene,which are the characteristic products of tetralin.However,the reaction products of decalin over acidic catalyst are mainly isobutane and iso-paraffins (within gasoline boiling point range),which are the characteristic products of decalin.This work can provide fundamentals for the efficient use of polycyclic cycloalkanes or hydrogenated aromatics.