低碳化学与化工2025，Vol.50Issue(6)：52-62,11.DOI:10.12434/j.issn.2097-2547.20240391
不同酸强度HY分子筛对正己烷裂解机理影响的理论研究
Theoretical study on effects of HY zeolites with different acid strengths on cracking mechanism of n-hexane
摘要
Abstract
Growth of energy demand and depletion of fossil fuels have made efficient conversion of heavy crude oil a research focus.Alkane cracking technology can convert long-chain alkanes into short-chain hydrocarbon products,thereby increasing the economic value of long-chain alkanes.HY zeolites are one of the commonly used catalysts for alkane catalytic cracking due to their advantages of high specific surface area and suitable acid strength.However,there are relatively few theoretical studies on the effect of HY zeolites acid strengths on alkane cracking mechanism.Using periodic density functional theory calculation method,with propane and n-hexane as model substrates,the effects of HY zeolites with different acid strengths(Al substitution structures are 1Al substitution,3Al substitution and 6Al substitution,and the corresponding n(Si)/n(Al)are 47,15 and 7,respectively)on the alkane cracking mechanism were systematically studied,and the difficulty of breaking different C—C bonds in n-hexane was analyzed.The results show that with the increase of the Brønsted acid strength of HY zeolites,the apparent Gibbs free energy barrier of the protonation reaction of propane and n-hexane decreases,and the catalytic activity of HY zeolites in alkane cracking reaction is enhanced.The difficulty of breaking the three C—C bonds in n-hexane from easy to difficult are C3—C4 bond,C2—C3 bond and C1—C2 bond.关键词
HY分子筛/Brønsted酸强度/正己烷/裂解机理/周期密度泛函理论Key words
HY zeolites/Brønsted acid strengths/n-hexane/cracking mechanism/periodic density functional theory分类
化学工程引用本文复制引用
卫丽莎,王慧,董奇,李永旺,相宏伟..不同酸强度HY分子筛对正己烷裂解机理影响的理论研究[J].低碳化学与化工,2025,50(6):52-62,11.基金项目
国家重点研发计划(2022YFB4101201) （2022YFB4101201）
中国科学院先导专项(XDA29030700). （XDA29030700）
