Synthesis of Oxidized Corn Starch by Composite Oxidation with Microwave

Using corn starch as raw material,hydrogen peroxide and potassium sulfate as composite oxidant,Fe2+ as catalyst,the oxidized corn starch was prepared by composite oxidation with microwave under acid conditions. With reaction temperature, microwave catalytic synthesis/extraction apparatus power, catalyst mass fraction, composite oxidant mass fraction, starch milk concentration, system pH value and reaction time as variable,with oxidation degree as index,the optimum synthetic conditions of oxidized corn starch were determined by single factor experiment and orthogonal experiment as follows: the reaction temperature was 55 ℃, the microwave catalytic synthesis/extraction apparatus power was 400 W, the catalyst mass fraction was 0.3%, the composite oxidant mass fraction was 8%,the starch milk concentration was 45%, the system pH value was 4.00, the reaction time was 21 min.Under above conditions,oxidized corn starch could be obtained with oxidation degree(-COOH) of 0.140%.