Green synthesis of new process for food antioxidant n-octyl gallate

n- octyl gallate was synthesized by n- octanol and gallic acid with sodium bisulfate as catalyst under microwave irradiation.The reaction products were structurally identified by means of melting point measurement and infrared ( IR) spectral analysis.Factors affecting the yield of esterification, such as microwave irradiation power and time, molar ratio of gallic acid to n - octanol, dosage of catalyst and catalyst reuse were studied. Through orthogonal experiments, the optimum reaction conditions were as follows: 0.025mol gallic acid, microwave power 360W, the molar ratio of gallic acid and n-octanol 1∶18, dosage of catalyst 1.25g, for 15min, with no water-carrying reagent.Under the above conditions, the yield of n-octyl gallate could reach up to 91.2%.The results indicated that sodium bisulfate had good catalytic activity and could be used repeatedly, over the traditional heating methods, the optimized method showed the advantages of shorter reacting time and lower energy consumption.