Prepn of high-purity acephate powder (2)

A technology of acephate raw powder and acephate, which is applied in the field of producing high-purity acephate raw powder, can solve the problems of high yield and large amount of organic extractant, and achieve low cost and no waste Liquid discharge, pollution reduction effect

Inactive Publication Date: 2002-08-07
XIANGTAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In above-mentioned these methods except Chinese patent 1238340 and 1277201, all there is the problem of acephate former powder yield (corresponding mother liquor yield is big)
In addition, except

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] Be 94% O at 920kg content, add 55.2kg dimethyl sulfate in the crude oil of O-dimethyl phosphorothioate and carry out isomerization, then add the acetic anhydride that 682.6kg concentration is 98% (mass), at 55 ℃ React at low temperature for 3 hours to obtain acephate crude oil with a content of 56.4%; add 3107kg of solvent to the crude oil, then neutralize with ammonia gas to a pH value of 6.5-7.0 under normal pressure, filter and neutralize the ammonium acetate crystals produced, Obtain 4330kg content and be the liquid of 21.6%; This liquid is put into the crystallization kettle with agitation after vacuum precipitating and is cooled to-5-0 ℃ and carries out primary crystallization, separates and obtains 742.6kg crude crystal and 978.4kg mother liquor; put into a crystallization kettle with stirring and cool down to -20°C--10°C for secondary crystallization, and 310.3kg of crude crystals and 282.8kg of secondary mother liquor with a content of 28.1% were separated; the ...

Embodiment 2

[0025] In 880kg of 75% O, S-dimethylphosphoramide crude oil, adding 616kg of 98% acetic anhydride and 8.8kg of 98% sulfuric acid reacted at 55°C for 3 hours to obtain 1504.8kg Acephate crude oil with a content of 55-57%; add 3107kg of solvent to the crude oil, then neutralize it with ammonia gas to a pH value of 6.5-7.0, filter and neutralize the ammonium acetate crystals, and obtain 3959.8kg with a content of 21.2% of liquid. After vacuum precipitating, put it into a stirring crystallization kettle and cool it down to -5°C-0°C for primary crystallization, and separate 657.5kg of crude crystals and 853.6kg of mother liquor. Precipitate the mother liquor and put it into a stirring crystallization kettle to cool down Carry out secondary crystallization at -20°C--10°C, and separate 281.6 kg of crude crystals and 245.2 kg of secondary crystallization mother liquor with a content of 30.5%; kg of organic solvent, gradually cool down to the end temperature of -15°C-10°C in 0.5-30 ho...

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PUM

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Abstract

The preparation method of high purity acephate raw powder includes the folloiwng steps: making O,O-dimethyl-thiophosphorylamide undergo the processes of isomerization and acetylation (or making O,S-dimethyl thiophosphorylamide undergo the process of acetylation) to obtain the acephate crude, then making the acephate crude undergo the processes of gas ammonia neutralization, solid-liquid separation, precipitation and crystallization and refining crude crystal body to obtain high-purity acephate raw powder. Its yield rate and purity are high.

Description

Technical field: [0001] The invention relates to a method for preparing high-purity acephate raw powder. Background technique: [0002] Acephate, scientific name O, S-dimethyl-N-acetylthiophosphoramide, also known as N-acetylamino-O, S-dimethyl phosphate, molecular structure is: The pure product is a white crystal with a melting point of 92-93°C. It is a pesticide with high efficiency and low toxicity. [0003] The crude oil of acephate obtained by isomerization and acetylation of O, O-dimethylphosphorothioate (or acetylation of crude oil of O, S-dimethylphosphorothioate) generally has a content of 30-70 % (mass percentage), it is necessary to obtain the desired high-purity acephate former powder through separation and purification. [0004] Japanese patent JP-B48-34583 reports a method for separating and extracting acephate raw powder: first extracting acephate crude oil with chloroform, then washing with brine, and then concentrating and crystallizing. The method repor...

Claims

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Application Information

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IPC IPC(8): C07F9/201
Inventor 罗和安王良芥刘平乐曾楚怡陈伟露熊鹰
Owner XIANGTAN UNIV
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