METHOD OF PREPARING AMINE ANTIOXIDANT FOR STABILIZING RUBBER Russian patent published in 2017 - IPC C07C209/16 C07C213/02 C07C211/55 C07C215/68 C08K5/18 

FIELD: chemistry.

SUBSTANCE: method consists in the alkylating 4-aminodiphenylamine with high-boiling alcohol in the presence of potassium hydroxide at a temperature of 190-220°C with distillation of an alcohol azeotrope with reaction water. Then, the organic layer is separated by aqueous extraction, and the desired product is isolated therefrom. Alcohol used for alkylation is 1,2-propanediol at a ratio of 1,2-propanediol, 4-aminodiphenylamine and potassium hydroxide ranging from 3:1:0.07 to 2:1:0.15. The resulting alkylate is washed from the alkaline solution with water, followed by a triple extraction of the desired product from the aqueous-glycol mixture with butyl acetate. The solution of the desired product in butyl acetate is peeled off from the water-alcohol layer, after which the butyl acetate extracts are combined, butyl acetate is distilled off under vacuum, and then the desired product is converted to a solid form by fusion with stearic acid at a weight ratio of 0.5:1 to 1:1, respectively. The amine antioxidant is essentially a racemic mixture of mono-and disubstituted 4-aminodiphenylamine in the hydroxy group of 1,2-propanediol molecules.

EFFECT: method makes it possible to prepare an antioxidant using a simpler technology, does not require additional steps to isolate and convert the resulting product into a commercial product, the antioxidant has a high elasticity and a lower tendency to embrittlement compared to the previously known amine antioxidants with the same increased resistance to oxidation.

2 cl, 1 dwg, 1 tbl, 3 ex