RELATION BETWEEN 3RD-PHASE PROPERTIES AND RATE OF DEHYDROHALOGENATIONOF 2-BROMOOCTANE IN PHASE-TRANSFER CATALYTIC-SYSTEM

The purpose of this paper is to investigate the relationship between t he properties and catalytic activity of the third phase in a phase tra nsfer catalytic system, The conditions of formation of the third phase are investigated by changing the kind of phase transfer catalyst (PTC ), organic solvents, and concentration of potassium hydroxide in the a queous phase. When tetrabutylammonium bromide, (Bu)(4)NBr. is used as the phase transfer catalyst, the third phase is formed with both dodec ane and toluene as organic solvents. On the other hand, when tetrahexy lammonium bromide, (Hex)(4)NBr, is used as the phase transfer catalyst , the third phase forms with dodecane but not with toluene. The volume of the third phase, the base strength, the concentration of catalyst, water, and organic solvent in the third phase were measured, Solidifi cation phenomena are observed for some cases of higher KOH concentrati ons in the aqueous phase, Dehydrohalogenation of 2-bromooctane in the organic phase was carried out in a batch reactor with the potassium hy droxide solution in the aqueous phase. The observed reaction rate cons tant (k(obs)), which is determined from the first order kinetics, incr eases remarkably with the increase in concentration of KOH in the aque ous phase (xi(KOH)) for the condition of third phase Formation. Howeve r, for the solidification condition, the reaction rate drops sharply b ecause only the external surface of the solid is effective for the rea ction. The distribution coefficient of reactant between the organic ph ase and the third phase, (KA) and the reaction rate constant in the th ird phase (k(third)) can be related to the concentration of water in t he third phase(C-H2O) independent of the catalysts and organic solvent s. Since PTC exists in the third phase, it can be reused without any l oss of catalytic activity.