摘要
以ZSM-5为硅源,采用水热法制备ZSM-5-MCM-41介微孔复合分子筛,并分别采用浸渍法和离子交换法对它进行磷酸(P)改性;根据XRD、NH3-TPD和Py-IR等分析技术,对改性ZSM-5-MCM-41进行表征和催化乙醇脱水性能评价.结果表明:磷酸(P)改性未影响ZSM-5-MCM-41的晶相性质,但使其L酸量显著增加、B酸量减少;与未改性的ZSM-5-MCM-41相比,磷酸(P)离子交换法改性ZSM-5-MCM-41的催化乙醇脱水活性和稳定性得到明显改善;在常压、温度为295℃、液时空速(LHSV)为2h-1的条件下,在P改性ZSM-5-MCM-41催化剂上乙醇的转化率和乙烯选择性大于98%,连续反应100h催化剂的活性未下降.P改性ZSM-5-MCM-41可作为工业规模乙醇脱水过程的催化剂.
The ZSM-5-MCM-41 composite zeolite with mesoporous-microporous structure was prepared by hydrothermal method,using ZSM-5as silica source,and was modified by phosphorus impregnation and phosphorus ion exchange.The characterization results obtained by XRD,NH3-TPD,Py-IR and evaluated results of the catalysts showed that the addition of phosphorus had no effect on the crystalline phase of the catalyst,but greatly increased the amount of L acid sites,and slightly reduced the amount of B acid sites.Compared with unmodified composite ZSM-5-MCM-41 catalyst,the catalytic activity and the stability of the ZSM-5-MCM-41 catalyst modified with phosphorus ion exchange were considerably improved.Under the conditions of standard atmosphere,295 ℃,LHSV 2h-1,the ethanol conversion and ethylene selectivity were both above 98%,and the catalytic activity of the catalyst was not declining after 100 hrunning.The ZSM-5-MCM-41 modified with P may be used as the catalyst for a commercial process of ethanol dehydration.
出处
《东北石油大学学报》
CAS
北大核心
2015年第5期106-111,11-12,共6页
Journal of Northeast Petroleum University
