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采用密度泛函理论和模型簇法研究了噻吩和沸石分子筛桥羟基和硅羟基的相互作用.对噻吩吸附在硅羟基H3SiOH可能的两种配位方式及吸附在沸石模型簇H3Si(OH)Al(OH)2OSiH3桥羟基B酸上可能的两种配位方式进行了比较分析.所有模型簇采用B3LYP混合方法对氢原子在6-31G基组水平上,对硅原子、铝原子、氧原子、碳原子、硫原子在6-31+G(d)基组水平上进行了全优化和频率分析.着重考察了噻吩与硅羟基及分子筛桥羟基模型簇不同配位方式所形成的配合物的结构及能量变化.计算结果表明由于在形成沸石-噻吩和硅羟基-噻吩配合物的结构和性质变化不明显,所以它们之间的相互作用为范德华作用力.从噻吩在沸石分子筛的桥羟基和硅羟基与噻吩的相互作用的吸附热可以推断,噻吩优先吸附在桥羟基上,只有桥羟基吸附饱和后方吸附在硅羟基上.由频率分析结果和实验结果的一致性可以证明所推测吸附模型的正确性.
The interaction between thiophene and zeolite bridging hydroxyls and silanols was studied by using density functional theory and model cluster method. Two possible coordination modes for the adsorption of thiophene on silanol group H3SiOH and adsorption on the zeolite model cluster H3Si (OH) Al ( OH) 2OSiH3 bridging hydroxyl B acid were compared and analyzed.All the model clusters using B3LYP hybrid method for hydrogen atoms at the 6-31G basis set level, the silicon atoms, aluminum atoms, oxygen atoms, carbon Atoms and sulfur atoms were optimized and frequency analyzed at the 6-31 + G (d) basis group level.The structures of the complexes formed by different coordination modes of thiophene with silanol groups and hydroxyl groups of molecular sieves were investigated. The results show that the interaction between them is van der Waal’s interaction due to the insignificant changes in the structure and properties of zeolite-thiophene and silanol-thiophene complexes. And thiophene interaction heat of adsorption can infer that thiophene preferentially adsorbed on the bridge hydroxyl, and only adsorbed after the bridging hydroxyl adsorption on the silanol .Frequency analysis and experimental results are consistent Sexuality can demonstrate the correctness of the putative adsorption model.