A kind of improved synthetic method of cymoxanil
A synthetic method, the technology of cymoxanil, which is applied in the field of improved synthesis of cymoxanil, can solve the problems of difficult separation, difficult treatment of three wastes, poor atom economy, etc., and achieve the effect of single three wastes and reduce the pressure on environmental protection
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Embodiment 1
[0028] see figure 1 , the present invention provides a technical solution: an improved synthesis method of cymoxanil, in which 500 grams of sodium 2-cyano-2-oximylacetamide obtained in the previous step are added to a 1000 ml four-necked bottle with good airtightness The mixed solution of methanol and water of salt, (wherein the percentage content of 2-cyano-2-oximylacetamide sodium salt is 103 grams, 0.5 mole), then add 1.0 gram of tetrabutylammonium bromide, heat to 20 27 gram of chloromethane after 1.5 hours, stop ventilating, keep the temperature of 20-25 ℃ and stir for 2 hours, at this time, the pH value of the reaction solution is about 6, slowly cool down to 0- Between 5 degrees, a large amount of crystals gradually precipitated, filtered, and the filtrate was collected once to apply mechanically. The filter cake was washed with water and dried by suction, and dried under reduced pressure at 70 degrees to constant weight to obtain 83 grams of cymoxanil as a white powder...
Embodiment 2
[0032] According to Example 1, without changing other conditions, the catalyst is replaced by PEG400, and the reaction temperature is increased to about 35 degrees for reaction. As a result, the average yield of 8 times is reduced to about 95.6%, and the product content is reduced to about 96.8%. .
[0033] Example, 3:
[0034] According to Example 1, under the condition of not changing other process conditions, the filtered mother liquor is not applied mechanically, and the single yield can only reach about 82%, and the content is more than 97.6%.
Embodiment 4
[0036] According to Example 1, without changing other process conditions, the reaction solution does not add any phase transfer catalyst, the average reaction time will be extended by about 2-3 times, and the average yield will drop to about 95%, but the quality of cymoxanil is not obvious change.
[0037] In the mixed solution of methanol and water of 2-cyano-2-oximinoacetamide sodium salt, add an appropriate amount of phase transfer catalyst, and then evenly pass in metered methyl chloride, and measure the pH value of the reaction solution after it is between 6-7 Stop feeding the methyl chloride, cool the reaction solution to 0-5 degrees, filter, wash the filter cake with water, and dry to obtain a high content of cymoxanil, and apply the filtrate to 2-cyano-2-oximyloacetamide sodium salt In this step, wait until the sodium chloride is saturated to filter out the sodium chloride, and let the filtrate go directly to the methylation reaction. This process does not use highly ...
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