烷基苯催化裂化生成苯的规律

以甲苯、乙苯、正丙基苯、正丁基苯、正戊基苯和正己基苯为模型化合物，在小型固定流化床反应器装置上进行催化裂化反应，研究6种不同侧链长度烷基苯在不同反应温度及不同分子筛(USY和REY)催化剂作用下生成苯的规律。结果表明：在催化裂化条件下，烷基苯转化生成苯的产率与烷基侧链的碳数密切相关；短侧链烷基苯主要通过烷基转移反应生成苯，长侧链烷基苯主要通过脱烷基反应生成苯；侧链碳数大于等于3时，裂化产物选择性增高，苯选择性降低；低温有利于抑制烷基苯裂化生成苯；高酸密度分子筛催化剂有利于降低长侧链烷基苯脱烷基生成苯的选择性，低酸密度催化剂有利于降低烷基苯裂化生成苯的转化率。

RULES OF CATALYTIC CRACKING OF ALKYLBENZENE TO BENZENE

Using toluene, ethylbenzene, n-propylbenzene, n-butylbenzene, n-pentylbenzene and n-hexylbenzene as model compounds, the catalytic cracking reaction was carried out in a small fixed fluidized bed reactor to study the rule of benzene formation from alkylbenzenes with different side chain lengths under different reaction temperatures and using different zeolite (USY and REY) catalysts. The results showed that the yield of benzene from alkylbenzene was closely related to the carbon number of alkyl side chain under FCC conditions. The short side alkyl benzene mainly generates benzene through alkyl transfer reaction, and the long side alkyl benzene mainly generates benzene through dealkylation reaction. When the side chain carbon number is greater than or equal to 3, the selectivity of cracking products increases while benzene selectivity decreases. Low temperature is beneficial to inhibit the cracking of alkylbenzene to benzene,high acid density zeolite catalyst is conducive to reducing the dealkylation selectivity of long side chain alkylbenzene, and low acid density catalyst is conducive to reducing the conversion of alkylbenzene cracking to benzene.