甲烷与含氮有机杂环化合物吸附作用的DFT研究

根据煤中氮的存在形式,提炼出11种具有不同杂化方式及含氮量的有机环状化合物.应用密度泛函理论(DFT)模拟方法对甲烷在这11种含氮化合物上的吸附模型进行结构优化,并结合吸附能、电荷分布及静电势能面的分析,从微观角度考察了甲烷与这些化合物之间的相互作用.计算结果表明:甲烷与含氮化合物的相互作用能在3.81-6.82kJ·mol-1范围内,且通过氢键和静电力相互作用;当化合物中氮的杂化方式为sp2时,其与甲烷的作用能大于sp3杂化方式的;当化合物中的氮含量增加时,可以提供更多的甲烷吸附位点.

A DFT Study of Methane Adsorption on Nitrogen-Containing Organic Heterocycles

In coal,nitrogen exists in a variety of forms.We presented 11 compounds of different hybridization forms and nitrogen contents.Density functional theory(DFT)simulation method was employed to study the adsorption behaviors of methane on these nitrogen-containing organic compounds.The interactions were studied and characterized by their adsorption energies,Mulliken charges and electrostatic potential surfaces.The adsorption energies varied from 3.81 to 6.82 kJ·mol-1,attributable to the weak hydrogen-bonding and electrostatic interactions.The results revealed that the adsorption energy of sp 2-N with methane was higher than that of sp 3-N and that higher nitrogen contents provided more positive sites for methane adsorption.