Ce/USY改性分子筛催化苯酚甲醇烷基化的实验研究

摘要

以USY分子筛为载体,通过浸渍法制备了不同Ce负载量的Ce/USY分子筛,采用X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线衍射能谱(EDS)、氨气程序升温脱附(NH3-TPD)等手段对样品进行表征,并考察了不同Ce负载量催化剂对苯酚甲醇烷基化性能的影响.结果表明,Ce的引入并未破坏载体的结构,却提高了催化剂表面酸中心的强度和数量,从而显著提高苯酚的转化率和邻甲酚选择性.当Ce负载量(质量分数)为10%时,在苯酚/甲醇摩尔比1/4、反应温度460℃、质量空速3.0 h-1、常压的条件下,Ce/USY分子筛催化苯酚甲醇烷基化性能最好,苯酚转化率为58.4%,邻甲酚选择性为49.2%.%USY zeolite was modified with different contents of Ce by the impregnation method.The samples were characterized by XRD, SEM, EDS and NH3-TPD.The introduction of Ce did not destroy the structure of USY but increased both the strength and the number of the surface acids.As a result, the conversion of phenol and selectivity to o-cresol both increased significantly.When the mass fraction of Ce was 10%, n(Phenol)(Methanol) was 1/4, reaction temperature was 460℃, MHSV was 3.0 h-1, Ce/USY zeolite achieved its best performance of alkylation.In this condition, the conversion of phenol was 58.4% and the selectivity to o-cresol was 49.2%.