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Preparation method of dialkyl phosphinate

A technology of dialkyl phosphinate and alkyl phosphinate, which is applied in the field of preparation of dialkyl phosphinate, can solve the problems of needing acidification and the like, and achieves a low recovery cost, simple process and high purity. Effect

Inactive Publication Date: 2014-07-02
NANJING NORMAL UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Moreover, by-products are easily produced when oxidizing dialkyl phosphorus oxides are used, and acidification is required after oxidation, resulting in a large amount of waste water

Method used

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  • Preparation method of dialkyl phosphinate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] 1) Preparation of ethyl methyl ethyl phosphinate

[0037] In a dry 500ml four-neck flask equipped with a condenser tube (with a drying tube at the end), a thermometer, a constant pressure dropping funnel, and a nitrogen inlet, after nitrogen replacement, add 100mL of dry tetrahydrofuran and 12g (0.5mol) of freshly treated magnesium Crumbs, stirring, adding a grain of iodine, first slowly drop 10mL (1mol / L) of a dry tetrahydrofuran solution of methyl iodide, and raise the temperature to 40°C, after the reaction is initiated, add the remaining 190mL of a dry tetrahydrofuran solution of methyl bromide. During the dropwise addition, keep a slight boiling reflux, react for 20 minutes after the dropwise addition, and cool to 0°C with ice water.

[0038] Put the above-mentioned Grignard reagent in an ice-water bath at 0-10°C, add 100mL (2mol / L) of a dry THF solution of diethyl ethyl phosphate dropwise under a nitrogen atmosphere, and keep the temperature at 10-15°C during the ...

Embodiment 2

[0044]As in Example 1, magnesium nitrate was used as the metal salt, and 250 g of a 30% magnesium nitrate aqueous solution was added at 85° C. A white solid was formed, cooled, filtered, washed with hot water and dried in vacuo. 113.7 g of magnesium (II) methyl ethyl phosphinate was obtained, the yield was 95.3%, and the total yield of the product was 89.5%.

Embodiment 3

[0046] As in Example 1, calcium nitrate was used as the metal salt, and 280 g of 30% calcium nitrate aqueous solution was added at 85° C. A white solid was formed, cooled, filtered, washed with hot water and dried in vacuo. 120.8 g of calcium methyl ethyl phosphinate (II) was obtained, the yield was 93.0%, and the total yield of the product was 87.3%.

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Abstract

The invention discloses a preparation method of dialkyl phosphinate with a structure shown in a formula (I). The preparation method of the dialkyl phosphinate comprises the following steps: 1) carrying out reaction on Grignard reagent R1MgX and alkyl phosphonic acid diester in amount-of-substance ratio of 1:1, and hydrolyzing reaction products under acidic condition for preparing dialkyl phosphinic acid ester; 2) hydrolyzing the dialkyl phosphinic acid ester in water, and distilling out alcohol-water mixture, so that dialkyl phosphinic acid is obtained; 3) regulating the pH value of the dialkyl phosphinic acid with inorganic base, then mixing the dialkyl phosphinic acid with a metal salt solution, and heating, so that the dialkyl phosphinate is obtained. The preparation method of the dialkyl phosphinate has the advantages that less Grignard reagent is used, hydrolysis conditions are simple, the operation is simple, the product purity is high, the yield is high and industrialization is easily realized. The formula (I) is described in the specification.

Description

technical field [0001] The invention relates to a preparation method of a green and environment-friendly halogen-free flame retardant, in particular to a preparation method of a dialkylphosphinate. Background technique [0002] As a flame retardant with superior performance, dialkyl phosphinate can be widely used in the halogen-free flame retardant of polyamide, polyester, printed circuit board, etc. [0003] Dialkylphosphinates as flame retardants can be prepared by various methods. There have been many studies on the synthesis methods of dialkylphosphinates at home and abroad. The earliest application of the Grignard reagent method, the yield is relatively low, the operation of washing and separation is relatively complicated, and the process flow and raw material allocation are complicated. The metal complex catalytic addition method is generally only applied to the synthesis of monoalkylphosphinic acid or its salt, the reaction time is long and the process is complicat...

Claims

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Application Information

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IPC IPC(8): C07F9/30
Inventor 杨锦飞王岩黄小冬杨凯职慧珍顾毅泓李丽
Owner NANJING NORMAL UNIVERSITY