Green Synthesis of Methyl Chlorides

A technology of green synthesis and methyl sulfide, which is applied in the field of green synthesis of methyl-chloride, can solve the problems of poor stability of methyl-chloride, high environmental protection pressure, and difficult filtration, so as to avoid the odor of elastic sulfur and a large amount of Saline wastewater, no waste of sulfur atoms, and low overall cost

Active Publication Date: 2022-03-08
湖北驰顺化工有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Though this method has solved the problem of disulfide dichloride, disulfide dichloride and sodium sulfide reaction process exotherm violently, and reaction system heats up faster; Because methyl-chloride stability is relatively poor, exceeds certain temperature easily Decomposes when heated, causing flushing or explosion risk
The by-product elastic sulfur has high viscosity, difficult to filter, strong odor and large quantity, so it can only be treated as waste residue
At the same time, after alkalization and hydrolysis, a large amount of sulfur- and phosphorus-containing foul-smelling wastewater is produced, and the environmental protection pressure of wastewater and waste residue treatment is huge.

Method used

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  • Green Synthesis of Methyl Chlorides
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Examples

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preparation example Construction

[0032] A kind of green synthetic method of methyl-chloride, comprises the steps:

[0033] S1. In the reaction system for preparing methyl-chloride with methyl sulfide and chlorine as raw materials, the characteristic that disulfur dichloride can be used to chlorinate methyl sulfide is used to control the amount of chlorine introduced to make the reaction The disulfur dichloride produced in the process continues to react with methyl sulfide to convert to methyl-chloride and sulfur;

[0034] S2. After the reaction is completed, add catalyst A and catalyst B to the reaction system to precipitate the sulfur in the system as loose crystals, separate sulfur and methyl-chloride crude products, and obtain high-purity methyl chloride through vacuum distillation. -chloride. In this technical solution, catalysts A and B must be added at the same time, otherwise it is difficult to realize the precipitation of sulfur or the precipitation rate is low, and the properties of sulfur precipita...

Embodiment 1

[0046] A kind of green synthetic method of methyl-chloride of the present invention, comprises the steps:

[0047] (1) Add 150g (98%) methyl sulfide (O,O-dimethyl S-hydrogen-di Thiophosphoric acid ester), 66g of chlorine gas is passed in about 3 hours at 30-40°C, the reaction tail gas (hydrogen chloride) is absorbed by water, and the chlorine flow is completed.

[0048](2) Heat up to 50°C (increase the temperature to increase the subsequent reaction speed), add 2g of sodium hydroxide, keep warm and stir for 1h, add 75g of 4% mass fraction PDS desulfurizer aqueous solution, stir at constant temperature for 1h, then cool down to 20°C (cool down can increase the crystallization speed), after 2 hours of heat preservation, filter to obtain loose crystalline sulfur, and separate the liquid to obtain the crude methyl-chloride. The crude product was transferred to a distillation flask, and rectified at -0.099 MPa high vacuum at 60°C to obtain 136.2 g of methyl-chloride (purity 99%), ...

Embodiment 2

[0050] A kind of green synthetic method of methyl-chloride of the present invention, comprises the steps:

[0051] (1) Add 300g (98%) methyl sulfide (O,O-dimethyl S-hydrogen-di Phosphorothioate), 132g of chlorine gas is passed in about 2 hours at 30-40°C, the reaction tail gas is absorbed by water, and the chlorine flow is completed.

[0052] (2) Heat up to 50°C and add 3g of sodium hydroxide, keep stirring and react for 1h, add 200g of 3% mass fraction PDS desulfurizer aqueous solution, stir at constant temperature for 0.5h, then cool down to 20°C, keep warm for 1h and filter to obtain loose crystal sulfur. The liquid was separated to obtain the crude product of methyl-chloride. The crude product was transferred to a distillation flask, and rectified at -0.099 MPa high vacuum at 60°C to obtain 268.8 g of methyl-chloride (purity 99%), yield 90.1%.

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Abstract

The invention discloses a green synthesis method of methyl-chloride, which comprises the following steps: S1. In the reaction system for preparing methyl-chloride with methyl sulfide and chlorine gas as raw materials, disulfide dichloride can be used to Make the characteristic of methyl sulfide chlorination, by controlling the intake of chlorine, the disulfur dichloride produced in the reaction process continues to react with methyl sulfide to be converted into methyl-chloride and sulfur; S2, until the reaction is completed Finally, add Catalyst A and Catalyst B to the reaction system, so that the sulfur in the system is precipitated as loose crystals, and the crude sulfur and methyl-chloride are separated, and high-purity methyl-chloride is obtained through vacuum distillation. The present invention can not only prepare high-purity methyl-chloride, increase the yield, but also obtain crystalline sulfur with excellent properties, which can be reused; effectively avoiding the production of a large amount of saline wastewater and elastic sulfur waste residue, and also avoiding the pollution caused by waste gas. Pollution, green environmental protection, social benefits and environmental benefits are remarkable.

Description

technical field [0001] The invention belongs to the technical field of preparation of pesticide intermediates, and in particular relates to a green synthesis method of methyl-chloride. Background technique [0002] O, O-dimethylphosphorothioate chloride (referred to as methyl chloride, the same below) is a special intermediate for the synthesis of phosphorothioate pesticides. Methyl-chloride can be used to prepare nearly twenty kinds of high-efficiency, medium-low toxicity organophosphorus pesticides, such as pirimiphos-methyl, chlorpyrifos-methyl, fenitrothion, tolclofos-methyl, etc. Among them, chlorpyrifos-methyl, chlorpyrifos, and pirimiphos-methyl are high-efficiency and low-toxic organophosphate varieties recommended by the Food and Agriculture Organization of the United Nations (FAO). In recent years, the demand for methyl-chloride in the pesticide market has shown an increasing trend year by year. [0003] At present, the mainstream methyl-chloride synthesis route ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07F9/14
CPCC07F9/14
Inventor 徐先金杜端陈刚竺来发王胜得曾敬刘伟吴曼曾雪云李敏陈明
Owner 湖北驰顺化工有限公司
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