466775 Esterification and Extraction with Supported Liquid Membrane Permeation
The results confirm applicability of the membrane process for the combination of separation by membrane permeation with rigid membranes and esterification of acetic acid with octanol. Via combination of membrane permeation and esterification, the reaction equilibrium related to the aqueous phase may be overcome because of limited solubility of water in the membrane phase. Acetic acid is transferred from the aqueous bulk phase to the rigid interface of the membrane where it converts to the nearly water insoluble ester by releasing water to the aqueous phase while the ester diffuses into the membrane bulk phase. Esterification in the aqueous phase would need the catalyst sulfuric acid which cannot be recycled. In phase transfer catalysis diethylhexylphosphoric acid (DEHPA) or sulfonates (e.g. Dodecylbenzenesulfonic acid) may be used as catalyst in the solvent phase. DEHPA is not catalyzing this reaction sufficiently while dodecylbenzenesulphonic acid (DBSA) is catalyzing the esterification reaction to a sufficient extent. Emulsion formation of DBSA in the solvent phase is avoided by separation from the aqueous phase with the rigid membrane.
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