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Method for separating and purifying by-product trimethyl thiophosphate

A technology of trimethyl phosphorothioate and by-products, which is applied in the field of separation and purification of trimethyl phosphorothioate by-products, and can solve the difficulty of comprehensive utilization of trimethyl esters due to lack of attention to separation and purification of trimethyl esters, which affects product yield , by-products increase the cost of wastewater treatment, etc., to meet the effect of clean production

Inactive Publication Date: 2013-07-03
浙江嘉化集团股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the above-mentioned production process can separate high-purity amides, it does not pay enough attention to the separation and purification of trimethyl esters. The separated trimethyl esters still contain more amides, which affects the product yield and the difficulty of comprehensive utilization of trimethyl esters. , the discharge of a large number of by-products also increases the cost of wastewater treatment

Method used

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  • Method for separating and purifying by-product trimethyl thiophosphate

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] a. The fully washed methyl chloride amination reaction product (in which spermine content is 91.6%, trimethyl ester content is 8.2%, and unknown impurities are 0.2%) is flowed at a flow rate of 2.5m 3 / h, with 0.55m 3 After the water per hour is fully mixed by the static mixer, the condensed water recovered by the preheater and the methanol tower is heat-exchanged to 70-75°C;

[0018] b. Enter the middle part of the stripping and rectifying tower, the vapor-liquid ratio of the stripping tower is 2:1, the vacuum degree is controlled at -0.085~-0.088MPa, the temperature is 60~65°C, and the reflux ratio is 1:5 to carry out vacuum stripping and distillation. distillation;

[0019] c. The gas phase is discharged from the top of the rectifying section, enters the top condenser to condense, and the condensate enters the stratified tank;

[0020] d. Part of the water phase obtained from the separation of the upper part enters the water storage tank for mechanical use, and the...

Embodiment 2

[0024] a. The low-concentration O,O-dimethylphosphorothioate solution recovered after evaporation by the lifting film and thin film evaporator, in which spermine (83.7% content, 15.7% trimethyl ester content, 0.6% unknown impurity) was used as a flow rate 2.0m 3 / h, with 1.2m 3 After the water per hour is fully mixed by the static mixer, the condensed water recovered by the preheater and the methanol tower is heat-exchanged to 75-80°C;

[0025] b. Enter the middle part of the stripping and rectifying tower. The stripping tower is controlled at a vapor-liquid ratio of 1.3 to 1.4:1, a vacuum of -0.07 to -0.075MPa, a temperature of 65 to 70°C, and a reflux ratio of 1:2 for decompression. Stripping and distillation;

[0026] c. The gas phase is discharged from the top of the rectifying section, enters the top condenser to condense, and the condensate enters the stratified tank;

[0027] d. Part of the water phase obtained from the separation of the upper part enters the water s...

Embodiment 3

[0031] a. The low-concentration O,O-dimethylphosphorophosphoramide solution recovered after evaporation by the lifting film and thin film evaporator, in which spermine (content 77.5%, trimethyl ester content 22.8%, unknown impurity 0.7%) in the flow rate 2.0m 3 / h, with 2.0m 3 After the water per hour is fully mixed by the static mixer, the condensed water recovered by the preheater and the methanol tower is heat-exchanged to 85-90°C;

[0032] b. Enter the middle part of the stripping and rectifying tower. The stripping tower is controlled at a vapor-liquid ratio of 1.6 to 1.8:1, a vacuum of -0.06 to -0.065MPa, a temperature of 70 to 75°C, and a reflux ratio of 1:1.25 for decompression. Stripping and distillation;

[0033] c. The gas phase is discharged from the top of the rectifying section, enters the top condenser to condense, and the condensate enters the stratified tank;

[0034] d. Part of the water phase obtained from the separation of the upper part enters the water...

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Abstract

The invention relates to a method for separating and purifying by-product trimethyl thiophosphate, comprising the following steps of: a, mixing a low-concentration O,O-dimethyl thiophosphoryl amide solution with water, and then heating to 50-90 DEG C; b, carrying out decompression steam stripping and rectification; c, carrying out gas-phase condensation; d, delaminating condensed fluids to obtainoil-phase trimethyl thiophosphate; e, evaporating tower bottoms for dehydration through a film so as to obtain O,O-dimethyl thiophosphoryl amide with content higher than 95 percent; and f, indiscriminately applying the condensed fluids obtained through gas-phase recovery by a film evaporator by entering a water storage tank. According to the invention, the content of the by-product trimethyl thiophosphate can reach more than 97 percent, fine chemical products, i.e. methyl chloride, the O,O-dimethyl thiophosphoryl amide, phosphoester, and the like can be further synthesized, and the content ofthe obtained O,O-dimethyl thiophosphoryl amide can reach more than 95 percent, therefore, the problem that a large quantity of by-products are generated in the refining process of orthene because the O,O-dimethyl thiophosphoryl amide contains the by-product trimethyl thiophosphate in the prior art is solved.

Description

technical field [0001] The invention relates to a method for isolating high-purity trimethyl phosphorothioate from methyl chloride amination reaction products or low-concentration O, O-dimethylphosphorothioate solutions recovered through other refining processes. A method for separating and purifying by-product trimethyl phosphorothioate. Background technique [0002] Acephate is an organophosphorus insecticide widely used at home and abroad, and it is also one of the pesticide varieties with the largest production tonnage in my country. At present, the production process of domestic acephate technical raw material is to use phosphorus trichloride as raw material, through secondary alcoholysis, ammonolysis, catalytic isomerization, and then acylation. In the process of trichlorphos alcoholysis, part of the by-product O, O, O-trimethyl phosphorothioate (hereinafter referred to as trimethyl) is formed in the final stage of the series reaction (usually 5-10%), And exist as an...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F9/17C07F9/24
Inventor 钱柯伟徐芸邵生富徐文梅应春辉陈其良
Owner 浙江嘉化集团股份有限公司