Preparation method of 4, 4'-biphenol

Abstract

The invention discloses a preparation method of 4, 4'-biphenol. The preparation method comprises the following steps: adding 4-iodophenol, zinc powder, alkali and a solvent into a reaction bottle, replacing air in the reaction bottle with nitrogen for three times, adding triethylamine formate into the reaction bottle under the protection of nitrogen, stirring for 30-60 minutes, heating to reflux,reacting for 1-16 hours, cooling the reaction liquid to room temperature, filtering, and concentrating filtrate to dryness to obtain 4, 4'-biphenol.

Description

technical field [0001] The invention belongs to the field of chemical synthesis, and in particular relates to a preparation method of 4,4'-biphenyldiol. Background technique [0002] Biphenol is an important class of organic intermediates. Common biphenols include 4,4'-biphenol and 2,2'-biphenol, which can be used as rubber antioxidants and plastic antioxidants. It can be used for colorless vulcanized rubber products, rubber products for food packaging and medical latex products, and also used for sulfur chloride cold vulcanized products (such as medical gloves, condoms), etc. In terms of synthetic polymers, due to its excellent heat resistance, it can be used as a modified monomer for polyester, polyurethane, polycarbonate, polysulfone and epoxy resin to manufacture excellent engineering plastics and composite materials, etc. . [0003] 4,4'-biphenyldiphenol is no longer dominant in the rubber antioxidant industry in the domestic and foreign markets, and is mainly used fo...

AI Technical Summary

Problems solved by technology

[0004] The current typical preparation methods of 4,4'-biphenyldiphenol are as follows: 1) Using biphenyl as the starting material, it is prepared by sulfonation, alkali fusion and hydrolysis, represented by patent US6410238, etc. Although this method can obtain high Yield product, but need to consume a large amount of concentrated acid, strong alkali in the reaction process, the production cost is expensive, easily causes pollution to the environment; Represented by CN101817713B, etc., the reaction process uses peroxide as an oxidant, and the oxidation reaction in a low-boiling solvent at high temperature is prone to explosion, and there are many by-products in the actual production process, which need to be purified by a special process. It is only suitable for small laboratories. Batch production; 3) Carry out oxidative coupling and disproportionation reactions through phenolic compounds, and then carry out de-tert-butyl reaction in aromatic hydrocarbon solvents, represented by patent JPH04338347A, the method produces tert-butyl-substituted biphenol A large amount of yellowish-brown benzoquinone by-products are generated in these compounds, and the use of aromatic hydrocarbon solvents to do the de-tert-butyl reaction solvent is highly toxic, the product purity is not high, and expensive noble metal catalysts are used, and the cost is relatively high; 4) by containing tert-butyl The tert-butyl group-substituted biphenol compounds are prepared by melting at high temperature under an inert atmosphere, represented by the patent US4205187. This method is solvent-free at high temperature for removing tert-butyl groups. The system has a high viscosity and is difficult to stir, and the resulting product is easy to coke.

[0005] At present, the contradiction between the supply and demand of 4,4'-biphenyldiphenol in China is still prominent. The main reason for this phenomenon is that the synthesis technology is backward, there are problems such as low product yield and purity, harsh reaction conditions, and serious environmental pollution.