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Purification method of dialkyl methylphosphite

A technology of dialkyl methylphosphonite and dialkyl chlorophosphinate is applied in the field of purification of dialkyl methylphosphonite, and can solve the problems of low yield and purity of the purification process, and the like, To achieve the effect of less residue in distillation still, mild reaction conditions, and avoidance of hydrolysis

Pending Publication Date: 2020-12-04
HEBEI VEYONG BIO CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] Aiming at the problem of low yield and purity in the existing purification process of dialkyl methylphosphonite, the invention provides a method for purifying dialkyl methylphosphonite

Method used

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  • Purification method of dialkyl methylphosphite
  • Purification method of dialkyl methylphosphite
  • Purification method of dialkyl methylphosphite

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042]Preparation of diethyl methyl phosphonite reaction solution:

[0043]Under the protection of nitrogen, add 40mL of tetrahydrofuran and 15.6g (0.1mol) of diethyl phosphonite chloride into a four-neck flask, cool to -10°C, dropwise add 41.1g (0.11) of a tetrahydrofuran solution containing 20wt% methylmagnesium chloride mol), keep the temperature at -10 to 0 DEG C for 2 hours, the content of diethyl chlorophosphinate is less than 0.3% detected by gas chromatography, the reaction is over, and the reaction solution of diethyl methyl phosphonite is obtained.

Embodiment 2

[0045]Preparation of dibutyl methyl phosphonite reaction solution:

[0046] Under the protection of nitrogen, add 40 mL of tetrahydrofuran and 21.3 g (0.1 mol) of dibutyl chlorophosphinate into a four-necked flask, cool to -10°C, and add dropwise 41.1 g (0.11 mol), keep the temperature at -10 to 0° C. and react for 2 hours, the content of dibutyl chlorophosphinate detected by gas chromatography is less than 0.3%, the reaction is over, and the reaction solution of dibutyl methyl phosphonite is obtained.

Embodiment 3

[0048]Purification of diethyl methyl phosphonite:

[0049]Add 9.2g of toluene to the reaction solution of diethyl methylphosphonite obtained in Example 1, add 0.5g of triethylamine, keep the temperature at -10°C, stir slowly for 15h, filter, and dry to obtain a content of over 97% Of anhydrous magnesium chloride. The filtrate was rectified under reduced pressure, and 60-70°C / 50mmHg fractions were collected to obtain 12.2 g of diethyl methylphosphonite, with a gas content of 98.1% and a yield of 87.9%. According to Kjeldahl nitrogen determination method, the nitrogen content in anhydrous magnesium chloride is 0.06%.

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Abstract

The invention relates to the technical field of compound purification, and particularly provides a purification method of dialkyl methylphosphite. The purification method comprises the following steps: adding a weak polar solvent into a reaction solution containing dialkyl methylphosphite, magnesium chloride and an ether solvent, conducting cooling to -10 DEG C to 40 DEG C, adding a nitrogen-containing organic alkali compound, carrying out a heat preservation reaction, and conducting filtering to obtain magnesium chloride and a filtrate; and rectifying the filtrate to obtain a dialkyl methylphosphite product. According to the purification method provided by the invention, the purity and the yield of the dialkyl methylphosphite are improved, the obtained magnesium chloride does not containcrystal water, the nitrogen content in the magnesium chloride is 0.01-0.5%, and the purity of the anhydrous magnesium chloride can reach 97% or above; and the purity of the obtained dialkyl methylphosphite product can reach 97% or above, and the yield can reach 85% or above. The method has the advantages of simple process, no need of special equipment, mild reaction conditions and no need of high-temperature distillation or low-temperature brine treatment process, and is suitable for large-scale industrial production.

Description

Technical field[0001]The present invention relates to the technical field of compound purification, in particular to a method for purifying dialkyl methyl phosphonite.Background technique[0002]Dialkyl methyl phosphonite is a key intermediate for the synthesis of many phosphine flame retardants and agricultural herbicide glufosinate-ammonium. The synthesis of glufosinate-ammonium is mainly based on phosphine trichloride, triethyl phosphonite, and methyl chloride as starting materials, through Grignard, disproportionation, and coupling reactions to obtain diethyl methyl phosphonite. At present, most domestic glufosinate-ammonium production enterprises adopt this synthetic route. The process route is shown in formula 1:[0003][0004]At present, the purification method of diethyl methyl phosphonite obtained by the above preparation process is mainly: distilling the reaction solution through high vacuum (0.01 atm) to distill out solvents such as diethyl methyl phosphonite and tetrahydrofur...

Claims

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Application Information

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IPC IPC(8): C07F9/48
CPCC07F9/4816C07F9/4866
Inventor 史秀肖高永民范立攀李志锋李立华范朝辉贾成国
Owner HEBEI VEYONG BIO CHEM
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