PHASE-TRANSFER CATALYSIS OF THE REACTION OF ALPHA-BROMO-P-XYLENE WITHIRON CARBONYLS

The carbonylation of alpha-Bromo-p-xylene (BrCH2C6H4CH3, BX) with iron pentacarbonyl (Fe(CO)(5)) by phase-transfer catalysis was studied in an organic solvent/alkaline solution. The reaction mechanism was corre cted and clarified. The concentrations of base, reactant and catalyst, volume ratio, the kind of catalysts, organometals and solvents were e valuated to find the optimum condition in this reaction. The technique of phase-transfer catalysis has a dramatic accelerating effect on the reaction. In examining eight kinds of phase-transfer catalysts, tetra -n-butylammonium cation and tetra-n-butylphosphonium cation were found to be the best for increasing the yield of bis(p-methylbenzyl) ketone ((p-CH3C6H4CH2)(2)CO, BMBK). The amount of phase-transfer catalyst, t he concentration of NaOH, the molar ratio of EX to Fe(CO)(5) and the v olume ratio of aqueous to organic phase affected the product selectivi ty.