Method for preparing hindered phenolic antioxidant by using composite catalyst

Abstract

The invention discloses a method for preparing a hindered phenolic antioxidant by using a composite catalyst, belonging to the field of preparation of antioxidants. The method comprises the followingsteps: evenly mixing 3-(3, 5-di-tert-butyl-4-hydroxyphenyl) methyl propionate with pentaerythritol, and then adding the lithium amide / lithium acetate composite catalyst for catalyzing, distilling, crystallizing, filtering and drying to obtain the hindered phenolic antioxidant 1010. The hindered phenolic antioxidant prepared by the method effectively avoids the influence, caused by adopting an organotin catalyst, on a human body and the environment; compared with single use of lithium amide or lithium acetate as a catalyst, the method is rapider in reaction speed, and guarantees the color of reaction liquid, thus guaranteeing the product quality.

Description

technical field [0001] The invention relates to the field of preparation of antioxidants, in particular to a method for preparing hindered phenolic antioxidants with a composite catalyst. Background technique [0002] Hydroxy-phenylpropionate undergoes transesterification reaction with aliphatic alcohols in the presence of a catalyst. After the by-product alcohol is removed during the reaction, the resulting reaction solution is purified to obtain a product that is a sterically hindered phenolic antioxidant. , which is effective in preventing oxidation and thermal degradation of various organic materials. Steric hindered phenolic antioxidants are usually used in combination with phosphite auxiliary antioxidants or ultraviolet absorbers, which have a good synergistic effect. [0003] Basic catalysts are usually used to prepare hindered phenolic antioxidants, such as β-(3,5-di-tert-butyl-4-hydroxyphenyl) methyl propionate in sodium tert-butoxide, potassium tert-butoxide, In ...

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Problems solved by technology

However, this type of catalyst is not suitable for the reaction with polyols, such as the reaction of methyl β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate with pentaerythritol to generate tetrakis[β-(3, 5-Di-tert-butyl-4-hydroxyphenyl) propionate] pentaerythritol ester (Antioxidant 1010) reacts poorly

U.S. Patent No. 4,594,444 proposes the use of tin-containing compounds, such as dibutyltin oxide catalysts, for the transesterification of sterically hindered hydroxyphenyl carboxylic acid esters and higher aliphatic alcohols. The resulting products have high yield, high purity, and good appearance and color. However, the antioxidants produced by tin-containing catalysts will cause harm to human body and the environment when used in polyolefin products. Therefore, the use of tin catalysts is limited and gradually eliminated in the production and application of antioxidants

U.S. Patent No. 4,618,700 proposes a method for preparing antioxidant 1010 by using a lithium amide catalyst. The catalyst successfully avoids the harm to the human body and the environment caused by the antioxidant produced by the tin catalyst, but the catalyst has a low reaction rate at low temperature. 1. Insufficient color difference of the reaction solution. In order to speed up the reaction rate and increase the amount of catalyst added and increase the reaction temperature, the color of the reaction solution will change more seriously, which will eventually lead to a great impact on product quality.

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