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Preparation method of dimethyl n-cyanodithioiminocarbonate with super-low mercury content

A technology of dimethyl cyanimide dicarboxylate and ultra-low mercury, which is applied in organic chemistry and other fields, can solve problems such as difficulty in meeting strict requirements and obstacles to product export and sales, and achieve stable product quality, meet strict requirements, and high purity. Effect

Inactive Publication Date: 2019-03-22
阜新达得利化工股份有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because lime nitrogen and other raw materials are used, the product usually contains a certain amount of mercury (about 200ppb), and it is difficult for the product to meet the strict requirements of high-end users in Europe and the United States for heavy metals (generally ≤50ppb), which creates obstacles for the export sales of this product

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] The preparation method of dimethyl cyanoimide dicarboxylate with ultra-low mercury content specifically comprises the following steps: 200 g of conventional crude dimethyl cyanoimide dicarboxylate (content about 90%) is dissolved in ethanol aqueous solution (the mixture of ethanol and water The weight ratio is 2:1), add 5g of activated carbon powder and 1g of mercury removal agent sodium sulfide, heat up to 60°C, stir and keep warm for 1h and then filter, the filtrate is slowly cooled to 15°C, and dimethyl cyanimide dicarboxylate is precipitated, filtered After washing with ethanol for 3 times and drying at 45° C. for 1.5 h, ultra-low mercury content dimethyl cyanimide dicarboxylate was obtained; the mercury content was determined to be 12 ppb by atomic absorption.

Embodiment 2

[0015] The preparation method of ultra-low mercury content dimethyl cyanoimide dicarboxylate specifically comprises the following steps: 200 g (content of about 90%) of conventional dimethyl cyanoimide dicarboxylate is dissolved in ethanol aqueous solution (the mixture of ethanol and water The weight ratio is 2.5:1), add 5g of activated carbon powder and 1g of mercury removal agent sodium sulfide, heat up to 45°C, stir and keep warm for 1h and then filter, the filtrate is slowly cooled to 10°C, and dimethyl cyanoimide dicarboxylate is precipitated, filtered After washing twice with ethanol and drying at 405°C for 2 hours, 150 g of dimethyl cyanimide dicarboxylate with ultra-low mercury content was obtained; the mercury content was determined to be 15 ppb by atomic absorption.

Embodiment 3

[0017] The preparation method of ultra-low mercury content dimethyl cyanoimide dicarboxylate specifically comprises the following steps: 100 g of conventional dimethyl cyanoimide dicarboxylate (content about 90%) is dissolved in ethanol aqueous solution (the mixture of ethanol and water The weight ratio is 2:1), add 2.5g of activated carbon powder and 0.5g of mercury removal agent sodium sulfide, heat up to 60°C, stir and keep warm for 1h and then filter, the filtrate is slowly cooled to 15°C, and dimethyl cyanoimide dicarboxylate is precipitated , washed with ethanol three times after filtration, and dried at 40°C for 1 hour to obtain 85 g of ultra-low mercury content dimethyl cyanimide dicarboxylate; the mercury content was determined by atomic absorption to be 10 ppb.

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PUM

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Abstract

The invention belongs to the field of compound preparation, and particularly relates to a preparation method of dimethyl n-cyanodithioiminocarbonate with super-low mercury content. The preparation method specifically comprises the following steps: dissolving a conventional dimethyl n-cyanodithioiminocarbonate crude product (the content is about 90 percent) in ethanol water; adding active carbon powder and sodium sulfide serving as a mercury remover; performing cooling crystallization at a temperature of -60 to -50 DEG C; separating out dimethyl n-cyanodithioiminocarbonate; filtering the dimethyl n-cyanodithioiminocarbonate, and washing the filtered dimethyl n-cyanodithioiminocarbonate with ethanol for 2 to 3 times; drying at a temperature of 40 to 45 DEG C for 1 to 2 h to obtain the dimethyl n-cyanodithioiminocarbonate with super-low mercury content. By adopting the method, the aim of removing heavy metal mercury in the crystallization purification process of the dimethyl n-cyanodithioiminocarbonate is fulfilled, the mercury content is reduced from 300 ppb to about 30 ppb, and the mercury removing rate is up to 90 percent.

Description

technical field [0001] The invention belongs to the field of compound preparation, and in particular relates to a method for preparing dimethyl dicarboxylate with ultra-low mercury content. Background technique [0002] Dimethyl cyanoimide dicarboxylate is an important intermediate for the manufacture of cimetidine, a new type of high-efficiency and low-toxicity pesticide thiacloprid, and a variety of pesticide products. At present, the global production capacity of this product is mainly concentrated in China. The domestic annual production and sales volume is about 6000 tons / year, and the main products are crude products with a content of 90%, which are low in content, high in impurities, high in moisture, and high in heavy metal content. [0003] The current mainstream production process of dimethyl cyanimide dicarboxylate is: using lime nitrogen and carbon disulfide as raw materials, the crude product of dimethyl cyanimide dicarboxylate is prepared through two-step react...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C333/20
CPCC07C333/20
Inventor 聂强刘欢张振良
Owner 阜新达得利化工股份有限公司
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