Separation Of Aromatic And Aliphatic Hydrocarborn By Ionic Liquids

Firstly,the basic law of the separation of the aromatic and aliphatic hydrocarborn system is acquired which calculated by COSMO-RS model,while some proper ionic liquids are preselected.The cation for extraction separation with short alkyl chain and aromatic substituent have advantages,that with alkyl sidechain hydroxyl substituent have disadvantage,that with cyano substituent,side-chain substituent,alkoxy substituent,double chain substituent have no obvious effects.In general,the anion with type of [ABx]– have a good separation performance.Preliminary screening out of ionic liquid with the cation of [BMim]+ and [BenBMim]+,and anion of [FeCl₄]–、[AlCl₄]–。Secondly,liquid liquid experiments（LLE）are carried out to test the law by calculate,and [BMim][FeCl₄] is supposed to be the best solvent for its excellent solubility properties.With a low concentration of benzene（7.11¹6.64 wt%）for benzene/cyclohexane system,the extraction performance index of [BMim][FeCl₄] is 15.19¹0.90,which is 3.46².56 times higer than sulfolane’s.[BMim][FeCl₄] is a kind of hydrophobic ionic liquids with viscosity is 31.4 mPa·s and density is 1.36 g/cm3 both tested at 25 ℃.Finally,the binary interaction parameters of the no-random two liquid equations（NRTL）are fitted well with RMSD 0.94% by using LLE data for the benzene/cyclohexane system,and the extaction process is simulated by Aspen Plus with the main parameters optimized.Deal with low concentration of benzene（15 wt%）of benzene/cyclohexane system,after reaching a extraction requirements with cyclohexane purity of 99.5 wt% and benzene recovery of 98 wt%,the dosage and energy consumption for [BMim][FeCl₄] is 1580.4 kg/t and 151 kW/t,While is 3.4 times and 5.1 times higer than for sulfolane which is 5451.7 kg/t、775.4 kW/t respectively.The results show that compared to conventional solvent sulfolane in the separation process of aromatic and aliphatic hydrocarbon,the ionic liquid [BMim][FeCl₄] prosses simpler process,smaller ratio of solvent and feed,less energy consumption and so on.