基于COSMO-RS模型的分离油酚混合物的离子液体萃取剂筛选

Screening ionic liquids solvent for separation of oil and hydroxybenzene mixtures based on COSMO-RS model

低温煤焦油中酚类化合物的分离对其充分利用具有重要意义。基于COSMO-RS模型,以间甲酚和异丙苯作为模型化合物,研究了离子液体在分离油酚体系中的应用;利用Turbomole软件建立了包含27种离子液体阴离子和48种离子液体阳离子的σ-图谱数据库,结合COSMOtherm软件对组成的1296种离子液体进行筛选,探讨了阴阳离子对间甲酚分离效果的影响,并对筛选得到适宜的离子液体进行液液相平衡实验验证。结果表明,离子液体阴离子对间甲酚分离效果影响较大,以Cl^-和CH_3COO^-为阴离子的离子液体与间甲酚之间具有较强的氢键相互作用,因此具有较好的分离效果;阳离子对间甲酚分离效果影响较小,碳链或支链的增加能适当提高离子液体对间甲酚的分离效果。实验得到的bmim OAc、bmim Cl、emim OAc、TPAC四种离子液体-间甲酚-异丙苯的液液相平衡数据表明,四种离子液体对间甲酚均具有较大的分配系数和选择性,且萃取分离效果的顺序为:emim OAc>bmim OAc>TPAC>bmim Cl,与COSMO-RS模拟筛选得到的结果一致,表明筛选具有较高的准确性。

Phenolic compounds separation of low temperature coal tar(LTCT)is important for its effective utilization.Based on the COSMO-RS model,with m-cresol and cumene as model compounds,ionic liquids were used as extractants for the separation of the oil and phenol system.Aσ-profile database including27anions and48cations were established by Turbomole,screening the1296ionic liquids by COSMOtherm,the influences of cations and anions on the separation of the m-cresol and cumene were investigated and some of them were verified by liquid-liquid equilibrium(LLE)data of ternary system,which indicated that the selection method of ionic liquid solvents was effective.The results show that the influences of the anions on the separation were more than those of the cations,some ionic liquids were effective on separation,which contained Cl^-or CH3COO^-in anions,because of the stronger hydrogen bond interaction between these ILs and m-cresol.The increase of length of alkyl chain and the number of side chains could improve the separation effect of ionic liquid to m-cresol.The liquid-liquid equilibrium data of ternary system of bmimOAc-m-cresol-cumene,bmimCl-m-cresol-cumene,emimOAc-m-cresolcumene and TPAC-m-cresol-cumene by experiment show that the four kinds of ionic liquids had greater distribution coefficient and selectivity for m-cresol,and the order of extraction separation effect was:emimOAc>bmimOAc>TPAC>bmimCl,which is consistent with the results obtained by COSMO-RS simulation screening,indicating that the screening has high accuracy.