EFFECTS OF MASS-TRANSFER AND EXTRACTION OF QUATERNARY-SALTS ON A SUBSTITUTION-REACTION BY PHASE-TRANSFER CATALYSIS

The substitution reaction of hexachlorocyclotriphosphazene with 2,2,2-trifluoroethanol using quaternary ammonium salts as the phase-transfer catalysts in an organic solvent/alkaline solution has been investigated. The pseudo-first-order reaction rate constant of the two-phase reaction and the rate constant ratios of the sequential substitution reaction in the organic phase were obtained. The hydration number of the catalyst, QOCH2CF3, is determined from the experimental data. The reaction reactivity is influenced by the content of the acids, which include water and alcohol in the aqueous phase. For an extraction mechanism, the reactivities of all kinds of catalysts in the organic phase with the same kind of solvent are the same. The effects of mass transfer and the extraction of quaternary ammonium salts on the conversion are used to explain the experimental data. The obtained results can be used as a reference for selecting the appropriate solvent and catalyst as well as for determining the appropriate content in the aqueous phase. Meanwhile, the desired distributed products, including the intermediate and final products, can be obtained by the appropriate choice of reaction conditions. © 1990, American Chemical Society. All rights reserved.