High-temperature oxidant for ester oil and preparation method of oxidant

The invention belongs to the technical field of lubricating oil additives, and particularly relates to a high-temperature oxidant for ester oil and a preparation method of the oxidant. The general formula of the oxidant is (img file=' 317369dest_path_image001.TIF' wi='212' he='63'/), in the formula, R is C1-8 alkoxy or C2-8 oligo-ether; the general formula of the C2-8 oligo-ether is (img file='2013107468234100004dest_path_image002.TIF' wi='136' he='23'/); R position is one or more of ortho-position, para-position or meta-position. The preparation method comprises the following steps: with 2-chlorine phenothiazine and substituted aniline as raw materials, using an aprotic solvent under protection of an inert gas; and carrying out one-step synthesis, separation and purification in the presence of a catalyst, so as to obtain a target product. According to the oxidant and the preparation method thereof disclosed by the invention, phenothiazine with outstanding high-temperature antioxidant ability is taken as a parent; an aniline structure is introduced, so as to form a bifunctional antioxidant. Meanwhile, the solubleness in the ester oil is enhanced by the introduced alkoxy or oligo-ether, and the excellent high-temperature oxidant for the ester oil is obtained by two antioxidant groups in the same antioxidant molecules. The high-temperature oxidant is simple in synthetic method, rapid in reaction speed and high in product purity.