Performance of amide compound extractant to promote the separation of chain/cycloalkanes
N,N-dimethylformamide(DMF)and N,N-dimethylacetamide(DMAC)were used as the main solvents,and cyclodextrin(CD)was used as the additives to obtain the extractant DMF+CD(DMFM)and DMAC+CD(DMCM).At the same time,n-hexane and cyclohexane were used to represent the chain/cycloalkane mixture.The liquid-liquid equilibrium(LLE)data of n-hexane+cyclohexane+DMFM and+DMCM were measured within the temperature from 283.15 K to 303.15 K under atmospheric pressure.With the help of distribution coefficient and selectivity,the separation performance of two mixed extractants on the mixture of chain/cycloalkane was evaluated,and the viscosity of the mixed solvent was further measured to investigate its fluidity.The results showed that the selectivity of the mixed extractant for cyclohexane increased with the increase of CD content in the extractant,and the selectivity DMFM<DMCM and the distribution coefficient DMFM<DMFM.The viscosity of the compound extractant also increases with the increase of CD content,and DMCM>DMFM.The experimental LLE and viscosity data were satisfactorily correlated by NRTL and VTF models,respectively,and new model parameters were obtained.The results can provide basic data and theoretical support for the separation process design of chain/cycloalkane in naphtha.