Method for generating byproduct of low carbonate ester in fipronil intermediate precursor production process
A production process and intermediate technology, applied in chemical instruments and methods, preparation of carboxylic acid esters, preparation of organic compounds, etc., to achieve the effect of reducing salt content and CODcr
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Embodiment 1
[0015] 1) Under an ice-salt bath, slowly drop a mixed solution of 30 mL of concentrated sulfuric acid and 30 mL of formic acid into a 250 mL three-necked flask containing 0.12 mol and 8.3 g of sodium nitrite, and keep the reaction temperature at 0-5°C to obtain a thin paste shape. After continuing to stir and react for 15 minutes, add 0.1mol of 2,6-dichloro-4-trifluoromethylaniline and 50mL of 23g formic acid solution to the system dropwise. The reaction solution was cooled to obtain a light brown diazotization solution;
[0016] 2) Keep the diazotization solution below 15°C, add 0.12 mol of methyl 2,3-dicyanopropionate and 50 mL of 16 g formic acid solution dropwise, and continue stirring for 1 hour to obtain a condensate;
[0017] 3) Add 130mL of methanol to the condensation liquid, heat to 32°C, and carry out reactive distillation to obtain methyl formate as a by-product;
[0018] 4) Cool the residual liquid to normal temperature, add 50 mL of water to dilute, extract 3 t...
Embodiment 2
[0020] 1) Under the ice-salt bath, slowly drop the mixed solution of 30L concentrated sulfuric acid and 30L glacial acetic acid into a 250L reaction kettle equipped with sodium nitrite 0.12kmol, 8.3kg, and keep the reaction temperature at 0-5°C to obtain dilute paste. After continuing to stir and react for 15 minutes, add 0.1kmol of 2,6-dichloro-4-trifluoromethylaniline and 50L of 23kg of glacial acetic acid solution into the system dropwise. , the reaction solution was cooled to obtain a light brown diazotization solution;
[0021] 2) Keep the diazotization solution below 15°C, add 0.12kmol of methyl 2,3-dicyanopropionate and 50L of 16kg glacial acetic acid solution dropwise, and continue stirring for 1 hour to obtain a condensate;
[0022] 3) Add 130L of methanol to the condensation reaction liquid, heat it, carry out rectification under reduced pressure to obtain methyl acetate by-product, add a small amount of 50L of water to dilute the residual liquid, extract 3 times wi...
Embodiment 3
[0025] 1) Under the ice-salt bath, slowly drop the mixed solution of 30L concentrated sulfuric acid and 30L glacial acetic acid into a 250L reaction kettle equipped with sodium nitrite 0.12kmol, 8.3kg, and keep the reaction temperature at 0-5°C to obtain dilute paste. After continuing to stir and react for 15 minutes, add 0.1kmol of 2,6-dichloro-4-trifluoromethylaniline and 50L of 23kg formic acid solution to the system dropwise. The reaction solution was cooled to obtain a light brown diazotization solution;
[0026] 2) Keep the diazotization solution below 15°C, add 0.12kmol of ethyl 2,3-dicyanopropionate and 50L of 18kg glacial acetic acid solution dropwise, and continue stirring for 1 hour to obtain a condensate;
[0027] 3) Add a small amount of water to the condensation reaction solution for dilution, extract 3 times with 50 L of dichloromethane, wash with saturated sodium chloride solution to obtain an organic phase, condense the inorganic phase and the washing solutio...
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Abstract
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