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Preparation method of dialkyl hypophosphite

A technology of dialkylphosphinate and dialkylphosphinic acid, applied in the field of preparation of dialkylphosphinate

Inactive Publication Date: 2011-05-11
GUANGZHOU KINGSKY MATERIAL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The above method has the following defects: the addition of olefins to hypophosphorous acid will generate monoalkylphosphinate by-products while obtaining dialkylphosphinate; Free radicals are easily quenched and inactivated in water, so the reaction yield is extremely low, resulting in a large input of raw materials and a small amount of products, resulting in a large amount of waste polluting the environment

Method used

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  • Preparation method of dialkyl hypophosphite

Examples

Experimental program
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Effect test

Embodiment 1

[0039] (1) Preparation of diethylphosphine oxide

[0040] Under the protection of argon, add 22g (0.9mol) magnesium powder and 250ml dry THF into a 2000ml three-necked flask, first add 5ml bromoethane, after the reaction is triggered, start stirring, dropwise add 71ml bromoethane and 400ml dry The mixture of THF (1.0 mol of ethyl bromide in total) was kept in a slightly boiling state. After about 2.5-3 hours of dripping, the stirring reaction was continued at room temperature for 30 minutes.

[0041] Under cooling in an ice-water bath, add dropwise a mixture of 40ml (0.3mol) diethyl phosphite and 150ml dry THF to the above-prepared ethylmagnesium bromide. React in a water bath for about 4 hours. Under cooling in an ice-water bath, ice-cold potassium carbonate solution (126.5g (0.9mol) potassium carbonate dissolved in 150ml water) was added dropwise for hydrolysis. Filtrate, remove the solvent from the filtrate on a rotary evaporator (50°C, vacuum degree of the circulating wa...

Embodiment 2

[0048] Prepare diethylphosphorus oxide as in Example 1, add the obtained diethylphosphorus oxide into a 500ml three-necked flask, add 120ml of water, stir and add NaOH solution (40gNaOH dissolved in 80ml of water), heat to 50°C, drop it in 1 hour 50ml of 30% hydrogen peroxide, keep warm at 50~70℃ for 2 hours. After cooling, dilute hydrochloric acid (60ml of concentrated hydrochloric acid dissolved in 60ml of water) was added dropwise to neutralize to pH=2 to obtain an aqueous solution of diethylphosphinic acid. The HPLC result shows that the purity is 99.2%, and its content is 7.5% according to titration analysis, and the yield is 87%. 95 g of aluminum diethylphosphinate was obtained in the same manner as in Example 1, and the cumulative total yield was 81.5%. Infrared and TG are the same as Example 1.

Embodiment 3

[0050] Under the protection of argon, add 22g (0.9mol) magnesium powder and 250ml dry THF into a 2000ml three-necked flask, first add 10ml of ether solution filled with methyl chloride through the steel cylinder, after the reaction is triggered, start stirring, and add dropwise under cooling in a water bath 350ml ether solution of methyl chloride (total 1.0 mol of methyl chloride), keep in a slightly boiling state, after about 2.5-3 hours, continue to stir and react at room temperature for 30 minutes.

[0051] Under ice-water bath cooling, in the above-mentioned prepared methylmagnesium chloride, add dropwise the mixed solution of 40ml (0.3mol) diethyl phosphite and 160ml dry ether, operation method obtains dimethyl phosphorus oxide 18.7g with embodiment 2 afterwards, Yield 80%; Obtain dimethylphosphinic acid 22g, accumulative yield 78%, 31 The P-NMR spectral shift value δ was -48 ppm.

[0052] Heat the aqueous solution of dimethylphosphinic acid to about 85°C, drop the aqueo...

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Abstract

The invention discloses a preparation method of dialkyl hypophosphite. The structure of the dialkyl hypophosphite is disclosed as a Formula (I). The preparation method of the dialkyl hypophosphite comprises the following steps: preparing a Grignard reagent from alkylogen, magnesium powder and organic solvent, preparing dialkyl phosphorus oxide from the Grignard reagent and diethylester phosphite,carrying out reaction on the dialkyl phosphorus oxide and an oxidant, acidifying to obtain a dialkyl phosphinic acid solution, and carrying out reaction on the dialkyl phosphinic acid solution and a metal salt to obtain the corresponding dialkyl hypophosphite. The preparation method of dialkyl hypophosphite has the advantages of high yield and simple synthesis technique, is convenient to operate,greatly lowers the production cost, simplifies the production equipment and enhances the safety of the production process.(I).

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of dialkyl phosphinate. technical background [0002] Polymer materials (plastic, rubber, chemical fiber, etc.) are widely used in construction industry, automobile industry, medical and health care, household appliances and other fields. Polymer materials are usually flammable or combustible, and the requirements for their flame retardancy are getting higher and higher in practical applications. In order to ensure the safety of synthetic materials, the most effective way is to add flame retardants. [0003] Dialkyl phosphinate is a commonly used flame retardant, the higher the content of phosphorus in dialkyl phosphinate, the better the flame retardant effect. In the prior art, for the synthesis of small molecular alkyl hypophosphite technology, free radicals are used to initiate the reaction with ethylene, such as: [0004] Hoechst AG of Germany applied ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F9/30
Inventor 柴生勇李积德徐观成韩俊峰
Owner GUANGZHOU KINGSKY MATERIAL
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