Process development aspects of production of dibenzyl ether

To develop an economically viable process for the synthesis of dibenzyl eth er, the reaction of benzyl chloride with aqueous sodium hydroxide in the pr esence of phase-transfer catalysts has been investigated. The effects of ag itation speed, catalyst type and concentration, reaction temperature, mole ratio of reactants, concentration of aqueous sodium hydroxide on the conver sion of benzyl chloride, and yield of dibenzyl ether have been evaluated, T ributylamine is found to be a suitable catalyst. The reaction is favored by high molar ratio of sodium hydroxide to benzyl chloride, Conversion of ben zyl chloride to benzyl alcohol is found to be the rate-controlling step at high sodium hydroxide concentration. Deprotonation of benzyl alcohol at the interphase by aqueous sodium hydroxide is a key step in the formation of d ibenzyl ether. The yield of dibenzyl ether is dependent on the concentratio n of sodium hydroxide in the aqueous phase, the yield being almost 100% at high concentrations of sodium hydroxide, The successful recycle of excess N aOH in the aqueous phase in subsequent batches, without affecting the progr ess of the reaction, has been demonstrated,