Method for the Preparation of N-Oxyl Hindered Amine Inhibitors

摘要

The present disclosure provides a composition and method for the preparation of N-oxyl hindered amine esters by contacting a compound of Formula (I), wherein R1 and R2 are independently an alkyl, with a compound of Formula (II), wherein R3 and R4 are independently an alkyl, and n is an integer from 3 to 10, in the presence of a catalyst and a solvent, wherein the catalyst comprises at least one of tin, lithium, zirconium, and hafnium.;

主权项

1. A method of preparing a hindered amine inhibitor of Formula III: wherein n is an integer from 3 to 10, R1 and R2 are independently an alkyl, comprising: (A) contacting a compound of Formula I: wherein R1 and R2 are independently an alkyl, with a compound of Formula II wherein R3 and R4 are independently an alkyl, and n is an integer from 3 to 10, in the presence of a catalyst and a solvent to form a reaction mixture, wherein the catalyst comprises at least one of tin, lithium, zirconium, and hafnium; (B) heating the reaction mixture to a temperature from 80° C. to 135° C. and then cooling the reaction mixture to a temperature of 70° C. or cooler; (C) heating the reaction mixture a second time to a temperature to cause distillation and then cooling the reaction mixture to a temperature of 70° C. or cooler; and (D) optionally, heating the reaction mixture a third time to a temperature to cause distillation and then cooling the reaction mixture to room temperature.