Method for synthesizing multifunctional antioxidant in one step

The invention relates to a method for synthesizing a multifunctional antioxidant in one step, which comprises the following steps of: synthesizing the antioxidant by taking bromooctadecane and hydroxylamine hydrochloride as main raw materials, tertiary amine as a catalyst and fat alkane as a reaction solvent under the conditions of normal pressure and reflux reaction, and controlling the temperature to 50-80 DEG C; the molar ratio of the bromooctadecane to the hydroxylamine hydrochloride is 2: (1.3-1.7); the catalyst is a tertiary amine; the mass ratio of the tertiary amines to the bromooctadecane is 1: (0.12-0.16), preferably 13%; sodium carbonate is added in the manufacturing step, and hydrogen chloride and hydrogen bromide gas generated by the reaction are absorbed by the sodium carbonate; the method is a substitution reaction, and is low in equipment investment, simple to operate and short in reaction time; a method of adding sodium carbonate is adopted, so that hydrogen chloride and hydrogen bromide gene