Patent ID: 8653300
Filing Date: 2014-02-18
Classification: C07C

Abstract:
1. A method for making a hindered phenolic antioxidant, comprising the steps of: a) preparing a mixture of methyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate and 1-octadecanol having less than 100 ppm of water as a reactant mixture; b) preparing a methanol solution containing alkali metal methoxide as a catalyst solution, wherein a concentration of the alkali metal methoxide dissolved in the catalyst solution is 1-25 wt % and filtering out insoluble matters unperceivable to human eyes from the catalyst solution with a filter device with a filter pore diameter of less than 50 μm, c) reacting the reactant mixture of Step a), in the presence of the filtered catalyst solution of 30-150 ppm based on a total amount of the reactant mixture, in a reactor at a reaction temperature of 120° C.-240° C. and at a reaction pressure of 10 millibars-1013 millibars for transesterification; d) removing methanol by-products continuously during transesterification by vaporization to obtain a crude product of octadecanol 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate; and e) treating the crude product of Step d) with a purification process including crystallization, filtering and drying to obtain a final product of hindered phenolic antioxidant which is octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate having a purity of 99.0 wt % and an APHA color value less than or equal to 60.