Synthesis of Benzyl p-Hydroxybenzoate by Ultrasonic Phase Transfer Catalysis

By using ultrasonic phase transfer catalysis technique, with tetrabutyl ammonium bromide (TBAB) as phase transfercatalyst, p-hydroxybenzoic acid reacted with potassium carbonate to form potassium p-hydroxybenzoate, then potassium p-hydroxybenzoate reacted with benzyl chloride in two-phase system of water and dimethyl benzene to synthesize benzyl p-hydroxybenzoate.The optimum reaction conditions obtained by orthogonal experiment design were shown as follows: the power of ultrasonic radiationwas 160W, reaction temperature was 85~90℃, reaction time was 1h, the mole ratio of benzyl chloride and p-hydroxybenzoic acid was2:1, the mole ratio of TBAB and p-hydroxybenzoic acid was 0.02:1, and the volume ratio of xylene and water was 1:4. The optimumproduction yield could reach 90.3%.