改性HM沸石分子筛催化α-一异丙基萘异构化反应

摘要

The HM molecular sieve catalyst was modified by Si(OC2H5)4 chemical liquid deposition and the effects of Si(OC2Hs)4 dosage, reaction temperature and liquid-hourly space velocity on isomerization of α-isopropyl naphthalene to prepare β-isopropyl naphthalene over HM molecular sieve catalysts were investigated. The results showed that the framework structure of HM molecular sieve was almost unchanged after modification, but pore size and the acidity of inner surface decreased. The HM molecular sieve catalyst modified by 0.6 mL/g of Si(OC2H5)4 exhibited excellent catalytic performance and the conversion of a-isopropyl naphthalene and the selectivity of β-isopropyl naphthalene were 41.87% and 99.31%, respectively, under the conditions of reaction temperature 290 ℃, liquid-hourly space velocity 1.0 mL/min and reaction pressure 1.0 Mpa. The reaction standard enthalpy was 17.384 kJ/mol calculated by van't Hoff equation.%采用正硅酸乙酯化学液相沉积法对HM分子筛进行改性,并考察了正硅酸乙酯用量、反应温度和液时空速等对α-一异丙基萘异构化制备β-一异丙基萘反应的影响.结果表明,改性后的HM分子筛的骨架结构基本不变,但分子筛孔径减小,内表面酸性适当降低.以正硅酸乙酯用量为0.6 mL/g改性得到的HM分子筛为催化剂,在反应温度为290℃,液时空速1.0mL/min和压力为1.0MPa的条件下进行α-一异丙基萘异构化制β-一异丙基萘,α-一异丙基萘转化率为41.87%,β-一异丙基萘选择性为99.31%.采用van't Hoff方程计算得α-一异丙基萘异构化制备β-一异丙基萘的反应热为17.384 kJ/mol.