基于DFT和COSMO-RS理论研究多元胺型离子液体吸收SO_(2)气体  

DFT and COSMO-RS theoretical analysis of SO_(2)absorption by polyamines type ionic liquids

作　　者：米泽豪 花儿 MI Zehao;HUA Er(Chemical Science and Engineering College,North Minzu University,Yinchuan 750021,Ningxia,China;Key Laboratory of Chemical Engineering and Technology,State Ethnic Affairs Commission,Yinchuan 750021,Ningxia,China;Ningxia Key Laboratory of Solar Chemical Conversion Technology,Yinchuan 750021,Ningxia,China)

机构地区：[1]北方民族大学化学与化学工程学院,银川宁夏750021 [2]国家民委化工技术基础重点实验室,宁夏银川750021 [3]宁夏太阳能化学转化技术重点实验室,宁夏银川750021

出　　处：《化工学报》2023年第9期3681-3696,共16页CIESC Journal

基　　金：宁夏高等学校研究项目(NGY2020063)。

摘　　要：开展以质子化的正己胺([HHexam]^(+))、己基乙二胺([HHexen]^(+))及己基二亚乙基三胺([HHexdien]^(+))为阳离子,TFSA[(CF3SO_(2))2N-]为阴离子的质子化离子液体(PILs),即[HHexam][TFSA]、[HHexen][TFSA]及[HHexdien][TFSA]型PILs吸收SO_(2)的研究。首先,选择密度泛函理论,在M06-2X/6-311G(d,p)水平下,优化得到PILs-nSO_(2)(n=1,2,3,4,5,6)的若干个最优构象,PILs阳离子极性头部N—H与SO_(2)的O原子间形成N—H…O型氢键。N—H…O部位的振动频率、二阶微扰能、电子密度的结果显示,[HHexam][TFSA]、[HHexen][TFSA]及[HHexdien][TFSA]分别与3、4、5分子SO_(2)结合时,其氢键能达到最大值:57、67、85 kJ/mol,并不再与更多的SO_(2)形成氢键网络,说明PILs对SO_(2)的吸收达到饱和。可以看出,随着PILs结构中氨基数目的增多,其对SO_(2)的吸收能力随之增强。同时,采用COSMOtherm软件,计算了SO_(2)气体在1 mol PILs中的溶解度分别为5.0、5.3、6.2 mol,即随着阳离子结构中氨基数目的增多,使得其对SO_(2)的吸收能力增强,这与密度泛函理论计算得到的结论基本相一致。A computational study was conducted to investigate the absorption of sulfur dioxide(SO_(2))by protic ionic liquids(PILs)comprising the cations of N-hexylammonium([HHexam]^(+)),hexylethylenediaminium([HHexen]^(+)),hexyldiethylenetriaminium([HHexdien]^(+)),and the anion of TFSA[(CF3SO_(2))2N-].The most stable configurations of PILs-nSO_(2)(n=1,2,3,4,5,6)were determined by using density functional theory(DFT)at the M06-2X/6-311G(d,p)level.The results revealed that N—H…O type hydrogen bonding was formed between the polar N—H groups on the cations and the O atoms in SO_(2).The analysis of vibrational frequency,second-order perturbation energy,and electron density revealed that the maximum hydrogen bonding was achieved when[HHexam][TFSA],[HHexen][TFSA]and[HHexdien][TFSA]combined with 3,4,and 5 molecules of SO_(2),respectively,with maximum hydrogen bond energies of 57,67,and 85 kJ/mol.The absence of further hydrogen bonding networks with SO_(2)suggests that SO_(2)absorption has reached saturation.The data also indicate that the SO_(2)absorption capacity increases with the number of amino groups in the PILs structure.COSMOtherm software calculations corroborate the findings,revealing an increasing trend for the SO_(2)solubilities from 5.0 to 5.3 to 6.2 mol in 1 mol PILs above,respectively.That is,as the number of amino groups in the cationic structure increases,its ability to absorb SO_(2)increases,which is basically consistent with the conclusions obtained from density functional theory calculations.

关 键 词：质子化离子液体 多元胺 二氧化硫 吸收 分子间氢键作用 

分 类 号：O641.3[理学—物理化学]