Molecular modeling of ۱-ethyl-۳-methylim idazolium -based io nic liquids + H۲ S complex es

Room temperature ionic liqu ids (RTILs) are a new class of compounds comprised of an organi c cation and an anion. These com pounds are liquid over a wide temperaturerange including ambient and due to strong electrostatic attraction betw een cation and anion, ex hibit negligibly small v apor pressure [۱]. Their tunable ch emical structures make them adjustable solven ts tailored to various pr actical and industrial a pplications. Nowadays, one of the active research areas is exploring IL s as a replacement to conventional alkanolamine (MEA, DEA, MDE A, etc.) solutions in natural gas sweetening processes [۲]. A gro wing number of experimental data for solubility and diffus ion of H۲S i n various IL s have been generated in the past fe w years [۳-۱۰]. In this study we ha ve focused on the application of some imidazolium-based ILs with different a nions, i.e. [PF۶]-, [PF ۵(CF۳)]-, [PF۴ (CF۳)۲]-, [PF۳(CF۳)۳]-,in separation of H۲S from natural gas by e mploying a theoretical quantum ch emical approach. This way the int eraction of H۲S with t he cation an d anion of the IL is studied to gain a primary insight into the me chanism of dissolution of H۲S in the ILs an d the results are comp ared with pr eviously reported experimental and theoretical studies.

کلیدواژه ها:

Ionic liquid ، Interaction energy ، Ab initi o calculation ، Gas solubi lity