Abstract: 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.

Key words: alkylbenzene, catalytic cracking, benzene, cracking catalyst