| Summary: | 碩士 === 東海大學 === 化學工程與材料工程學系 === 100 === Because cyclohexanone/phenol mixture exhibits a binary azeotrope, a third component which is commonly referred to as mass separation agent (MSA) can be added to break the azeotrope and make separation of such a mixture possible via azeotropic distillation or extractive distillation. In this study, we focused on the selection of MSA. First, thermodynamic models were employed to help screen some twenty organic solvents as potential MSA candidates. Three best MSAs were selected, namely propanol, acetone, and butanone.
In addition to the three organic solvents, two salts (NaH2PO4 and (NH4)2HPO4), two ionic solutions ([EMIM][PF6] and [BMIM][PF6]), and five other chemicals (TBP, TPP, DPP, TTP and cyclohexanol) covered in prior patents were further assessed and compared in terms of their MSA selectivities at infinite dilution, which were obtained by means of a variable-phase ratio method using headspace gas chromatography. Changes in relative volatility of cyclohexanone to phenol in the presence of these MSAs were also measured at the azeotropic composition.
Based on MSA selectivities and changes in relative volatility, acetone and [EMIM][PF6] were screened out. Subsequent vapor-liquid equilibrium data for these two MSAs were measured and fitted with thermodynamic models. Separation systems using the two MSAs were simulated and compared against the one using sulfolane as an MSA. Results of economic analysis showed that acetone was the best MSA among the ones considered.
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