Synthesis method of oxaphosphine phenanthrine fire retardant intermediate-2-(2'hydroxy phenyl) phosphenylic acid

Abstract

A process for synthesizing 2-(2'-hydroxyphenyl) phenyl phosphonic acid used as the intermediate of the flame retardant oxaphosphophenanthrene includes such steps as sequential esterifying reaction, acylating reaction and hydrolyzing reaction between o-phenylphenol, phosphorus trichloride and catalyst, and simple post-treating.

Description

technical field [0001] The invention relates to a method for synthesizing the key intermediate 2-(2'-hydroxyphenyl)phenylphosphonic acid (hereinafter referred to as HBP) ​​for preparing oxaphosphine phenanthrene flame retardants from o-phenylphenol and phosphorus trichloride . Background technique [0002] In recent years, aromatic cyclic phosphate-oxaphosphine series compounds have been widely used in lubricating oils, antioxidants, flame retardants, adhesives, fungicides, insecticides, etc., especially as both New flame retardants with anti-oxidation and heat-resistant functions show good development prospects under the requirements of the global development trend of flame retardants without halogenation, and are also a research hotspot in the field of phosphorus-based flame retardants. The oxaphosphine phenanthrene compound flame retardant is used, which can be copolymerized or blended with the polymer. No ether bond is formed during the copolymerization, and the compati...

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Problems solved by technology

[0007] The HBP synthesis method reported in the literature is carried out step by step according to the reaction. It not only needs to separate and purify the reaction intermediate product, but also the operation process is complicated and difficult to implement. Some operations are even harmful to human health and the environment. The reaction time is generally as long as 20h to 30h, while HBP The yield is only 70% to 80%

[0008] U.S. Patent US 3,702,878 and Japanese Patent JP 74,45,397 use the catalyst zinc chloride to be added after the esterification reaction is completed. Although zinc chloride is used as the acylation catalyst, the addition of zinc chloride to the system in the acylation stage conforms to the reaction process, but because the system continuously emits Hydrogen chloride, at this time, the solid feeding operation is not easy, and it is easy to cause environmental pollution

However, in German Patent DE 2,730,371 and European Patent EP 582,957, all phosphorus trichloride is added dropwise, although the reaction yield is improved, the reaction time is greatly extended

The hydrolysis technology disclosed in German Patent DE 2,034,887 and Japanese Patent JP 75,17,979 is to treat with lye first, then use activated carbon to adsorb, decolorize and filter, and finally acidify and crystallize. The process is quite complicated, the total yield is not high, and a large amount of inorganic salts and Waste liquid, not conducive to environmental protection, not suitable for large-scale production

U.S. Patent No. 5,650,530 proposes a method of directly obtaining DOPO without HBP generation and separation during the hydrolysis process. It seems to simplify the process, but after the acylation reaction, high-vacuum rectification must be added to purify the intermediate product. The product yield of this process is On the low side, the response time is prolonged, especially the investment in equipment is increased, and the operation is difficult. After repeated verification tests, we found that the product quality is difficult to stabilize

In addition, there are some studies at home and abroad, proposing the method of hydrolysis in aromatic hydrocarbon solvents such as chlorobenzene. Although the process is more environmentally friendly, decolorization, washing, and phase separation in the process require heat preservation operations, and a separation device with heating must be equipped, which increases the equipment. Investment and Operational Difficulty

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