Cu(I),Ag(I)/分子筛化学吸附脱硫的π-络合机理  

The π-complexation Mechanisms of Cu(I), Ag(I)/Zeolites for Desulfurization

作　　者：周丹红[1,2] 王玉清[1] 贺宁[1] 杨刚[2] 

机构地区：[1]辽宁师范大学化学化工学院功能材料化学研究所 [2]中国科学院大连化学物理研究所,催化基础国家重点实验室,辽宁大连116023

出　　处：《物理化学学报》2006年第5期542-547,共6页Acta Physico-Chimica Sinica

摘　　要：应用DFT研究了一系列含硫的杂环化合物(噻吩、苯并噻吩、二苯并噻吩和4,6-二甲基二苯并噻吩)以及苯分子在Cu(I)-Y、Ag(I)-Y分子筛上的化学吸附.计算采用16T分子筛簇模型(H22Si15AlO22),对过渡金属采用了赝势基组,在BLYP/DNP水平上完成.相互作用能的结果表明,阳离子交换的分子筛对含硫杂环芳香族化合物吸附能力的顺序为Cu(I)-Y>Ag(I)-Y.两种吸附剂对噻吩类分子的吸附能力大于苯分子.噻吩衍生物的吸附能顺序依次为,4,6-二甲基二苯并噻吩<二苯并噻吩<噻吩<苯并噻吩,与实验结果相近.通过自然键轨道计算,研究了分子筛上担载的Cu(I)、Ag(I)金属离子与噻吩和苯分子之间的π-络合作用,分析比较了自然键电子给体-受体之间的二阶微扰稳定化能,并探索其络合机理.Density functional theory has been employed to investigate the π-complexation adsorption of aromatic sulfur compounds such as thiophene （TP）, benzothiophene （BT）, dibenzothiophene （DBT）, and 4, 6-dimethyldibenzothiophene （4, 6-DMDBT） by ion exchanging faujasite type zeolites with Cu^＋ and Ag^＋ cations. The calculations were based on the cluster models of 16T （H22Si15, AlO22）, and performed with BLYP function and DNP basis set. The effective core potential basis set was used for transition metal atoms. The calculated interaction energies indicated that the adsorption ability of the ion exchanging Y zeolites for thiophenic compounds followed the order. Cu（Ⅰ）-Y 〉 Ag（Ⅰ）-Y. Their adsorption ability for thiophenic compounds is higher than that for benzene. The calculated adsorption energy of the thiophenic compounds increased as 4, 6-DMDBT 〈 DBT 〈 TP 〈 BT, which agrees with the experiment. The natural bond orbital （NBO） analysis of the second-order perturbative energy have been performed to investigate the π-complexation adsorption mechanism of thiophene and benzene on Cu（Ⅰ）-Y and Ag（Ⅰ）-Y sorbents.

关 键 词：DFT π-络合吸附 自然键轨道 金属担载分子筛 汽油脱硫 

分 类 号：O647.31[理学—物理化学]