The Study On Phenol Ethylation And Synthesizing Glyoxylic Acid

The p-hydroxy phenylethyl alcohol/acid is a depressant of activating oxide which inhibits DNA from peroxide's damage, and reduces oxidization of marrow cell, so that it would protect the generation of erythrocyte. The p-hydroxy phenylethyl alcohol/acid is also an important intermediate in pharmaceutical industry. At present, the series products are so increasingly needed all over the world that the price is high. Because of the high cost of the products as well as the material and catalyst, the long route of synthesis, the difficulty of industrialization, the purpose of this paper is to find a method to synthesize p-hydroxy phenylethyl alcohol/acid which is of low-cost and easy-industrialized.The methods of preparing p-hydroxy phenylethyl alcohol/acid are generalized and three-step process is proposed. Firstly, oxygen atom is protected with esterification in the phenol hydroxyl. Secondly, phenyl acetate is made to acetic acid-(4-β- halogen eshyl) with alkylation reaction or alkyl halide reaction. Finally, p-hydroxy phenylethyl alcohol/acid is obtained by means of run-of–blocking group with hydrolyzes reaction.The reaction of producing phenyl acetate by means of directly esterification with the phenol and acetic anhydride as materials is investigated. The outgrowth is phenyl acetate proved by physical measurement and IR. Kinetics of phenol esterification is also discussed and the optimum techniques are confirmed. Phenol and acetic anhydride (1: 1.2) reacted in the temperature of 140℃, and the reaction time is 120min. At last, transforming rate is 91.8%, and the yield of phenyl acetate is 90.2%.The substitution ethide reaction is also considered with phenyl acetate in this paper. Other factors are discussed in the influences of the substitution ethide reaction.The factors included catalyst, catalyst consumption, solvents, reaction temperature, reaction time and alkylating agent etc. In this condition of anhydrous aluminum chloride as catalys, -bromofume as alkylating agent, reaction temperature at 120～130℃, reacting 8hours, the reaction of phenyl acetate is better. Prospective outgrowth is not discovered by the analysis of GC-MS. Absolutely,it offers the proof of the substitution ethide reaction of phenol.Synthetic reaction of glyoxal with glyoxylic acid is studied, and oxidation process is monitored in time. The best process is determined .When glyoxal: H2O2 equal to 1:0.9, pH at 9, at 40℃, reacting 4.5 hours, glyoxylic acid productivity can reach 79.84%. Gyoxylic acid is declutched as calcium glyoxylate by precipitation. It is clear that separation process is simple and etchnic would have a perspetive application for more preparation as raw material.