Prepn of high-purity acephate powder (1)

A technology of acephate raw powder and acephate raw powder, which is applied in the field of preparation of high-purity acephate raw powder, can solve the problem of high yield of mother liquor, low yield of acephate raw powder, organic extractant High recovery rate, high purity and low production cost can be achieved

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 that the former powder yield of acephate is small, and the mother liquor yield rate containing acephate is large
In addition, except for Chinese patent 1277201, it is necessary to treat a large amount of waste water containing organic phosphorus and other organic matter, and the amount of organic extractant is generally large

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0018] Example 1: Add 56.7 kg of dimethyl sulfate to 945 kg of O,O-dimethyl thiophosphoramide, perform isomerization reaction to obtain 75.3% O,S-dimethyl thiophosphoramide, and then add 700 kg Acetic anhydride with a mass concentration of 98% was reacted at 55°C for 3 hours to obtain 56.4% acephate crude oil. The acephate crude oil was neutralized to pH 6.5-7.0 with 25% ammonia water, and the neutralization liquid was extracted with 4500kg extractant to obtain 1600kg raffinate phase (water phase) and 5680kg extract phase (oil phase). Process and recover 420-450kg of acetic acid. After the oil phase is vacuum desolventized, it is put into a stirred crystallization kettle and cooled to -5℃-0℃ for one crystallization, washed with a solvent, separated and dried to obtain 609kg of acetyl methyl with a content of 97.6% Amidophos original powder. After the mother liquor is desolventized, it is placed in a stirred crystallization kettle and cooled to -20--10°C for secondary crystallizati...

example 2

[0020] Add 616 kg of 98% acetic anhydride and 8.8 kg of 98% sulfuric acid to 880 kg of 75% O,S-dimethyl thiophosphoramide, and react at 55°C for 3 hours to obtain 1504.8 kg of content It is 55-57% crude oil of Acephate. 500kg of solvent was added to the crude oil, and then neutralized with ammonia water to pH 6.5-7.0, the ammonium acetate crystals produced by the neutralization were filtered, and the filtrate was continuously extracted to obtain 3959.8kg of liquid with a content of 21.2%. After vacuum desolvation, put it into a stirred crystallization kettle to cool to -5°C to 0°C for one crystallization, and separate 657.5kg of crude crystals and 853.6kg of mother liquor. The mother liquor is placed in a stirred crystallization kettle to cool to -20°C Perform secondary crystallization at -10°C, and separate 281.6kg of crude crystals and 245.2kg of mother liquor of secondary crystallization with a content of 30.5%. Dissolve the crude acephate crystals obtained from the primary and...

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Abstract

The preparation method of high-purity acephate raw powder includes the folloinwg steps: making O,O-dimethyl thiophosphorylamide undergo the processes of isomerization and acetylation or making O,S-dimethyl thiophosphorylamide undergo the process of acetylation, making the acephate dcrude undergo the processes of neutralization, extraction, precipitation, crystalization, washing, solid-liquid separation and drying so as to obtain the acephate raw powder. Its yield rate and product purity are high.

Description

Technical field: [0001] The invention relates to a preparation method of high-purity acephate raw powder Background technique: [0002] Acephate, scientific name O, S-dimethyl-N-acetyl thiophosphoramide, also known as N-acetamido-O, S-dimethyl phosphate, its molecular structure is The pure product is white crystals with a melting point of 92-93°C. It is a highly effective and low-toxic pesticide. [0003] Acephate crude oil prepared from O, O-dimethyl thiophosphoramide through isomerization and acetylation, or from O, S-dimethyl thiophosphoramid crude oil through acetylation, generally contains 30- 70% (mass percentage), must be separated and purified to obtain the desired acephate original powder. Japanese patent JP-B48-34583 reports a method for separating and extracting acephate raw powder: first extract acephate crude oil with chloroform, then wash with brine, and then concentrate and crystallize. The method reported in Japanese Patent JP-A64-75494 is: first neutralize the a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
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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