原位傅里叶变换红外光谱研究Y型分子筛表面酸性对吸附有机分子的影响  

Influence of Surface Acidity of Y Zeolites on the Adsorption of Organic Molecules by In situ Fourier Transform Infrared Spectroscopy

作　　者：张晓彤[1] 于文广[1] 秦玉才[2] 董世伟[1] 裴婷婷[1] 王琳[1] 宋丽娟[1,2] 

机构地区：[1]辽宁石油化工大学辽宁省石油化工催化科学与技术重点实验室,辽宁抚顺113001 [2]中国石油大学华东化学化工学院,山东青岛266426

出　　处：《物理化学学报》2013年第6期1273-1280,共8页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(20976077,21076100);中国石油天然气股份有限公司炼油催化剂重大专项(10-01A-01-01-01);辽宁省高校创新团队项目(200T110);辽宁省高端人才队伍建设项目资助~~

摘　　要：采用吡啶原位吸附傅里叶变换红外(Py-FTIR)光谱对液相离子交换(LPIE)和固相离子交换(SSIE)法制备的CeY分子筛以及HY和NaY的酸性进行了测定.在原位条件下采用单探针分子噻吩、环己烯和苯对其在分子筛上的吸附过程进行了研究;以噻吩和环己烯、噻吩和苯组成的双探针分子对吸附过程中存在的竞争吸附、催化反应以及吸附机理进行了系统研究.结果表明,HY和L-CeY分子筛表面强Brnsted(B)酸性位可导致吸附在其表面的噻吩发生低聚反应以及吸附的环己烯产生二聚环己烯碳正离子.低聚的噻吩和吸附的环己烯在分子筛上发生强的化学吸附,进一步抑制和阻碍噻吩硫化物与分子筛吸附活性中心发生作用,从而降低了吸附剂的选择性以及吸附硫化物的能力.吸附剂表面Lewis(L)酸中心是吸附的主要活性中心,大量弱的L酸,有利于噻吩吸附.并且,S-CeY分子筛表面弱的L酸对吸附噻吩具有一定的选择性,它受到环己烯的影响较小,NaY吸附剂对噻吩、环己烯和苯选择性较差,它只与吸附质作用的先后有关.The surface acidity of Y-type zeolites （HY and NaY） modified by solid state ion exchange （SSIE） and liquid phase ion exchange were characterized by in situ Fourier transform infrared （FTIR） spectroscopy using pyridine as the probe molecule （Py-FTIR）. The adsorption of single probe molecules （thiophene, cyclohexene and benzene） and double probe molecules （thiophene and cyclohexene, thiophene and benzene） compared with sorbents were studied using in situ FTIR spectroscopy. The results indicated that the Bronsted acid （B acid） of HY （L-CeY） is the catalytic center of cyclohexene dimerized alkenyl carbenium ions and thiophene oligomerization, while the Lewis acid （L acid） is the major center of adsorption of thiophene, cyclohexene, and benzene. In addition, there is strong chemisorption and competitive adsorption of cyclohexene and thiophene, which provides evidence for the poor performanceof removing sulfur. The S-CeY zeolite has abundant of weak Lewis acid sites. The sorbent is good at absorbing thiophene, while the influence of the competition adsorption of cyclohexene was not predominately. As to NaY zeolite, there is no preference for adsorption of thiophene, cyclohexene and benzene.

关 键 词：原位傅里叶变换红外光谱 改性Y分子筛 表面酸性 竞争吸附 催化反应 

分 类 号：O643.32[理学—物理化学]