Thiodicarb synthesis

Yield:59669-26-0 90.63%

Reaction Conditions:

with pyridine;sulfur dichloride in 5,5-dimethyl-1,3-cyclohexadiene at -4 - 30; for 4.16667 h;Large scale;Temperature;

Steps:

1-5; 1 Example 1
1. Material preparation 295Kg of xylene was sucked into the synthesis kettle by vacuum, and the stirring was turned on;Metering SCl₂141Kg of liquid, pumped into the upper tank with vacuum;Measure 104Kg of pyridine and pump it into the synthesis kettle;Measure methomyl 400Kg (content 97.3%), ready for use;Measured the catalyst trialkyl tertiary amine 1.6Kg;2. Ligand synthesisPass the freezing liquid into the jacket of the synthesis kettle for later use, the temperature in the kettle is lowered to -4°C, and start to add SCl₂, Control the dropping speed, keep the reaction temperature at 3, and control the dropping time at 90 minutes.SCl₂After the addition is complete, continue to stir for 20 minutes;3. Thiodicarb synthesisDrain the freezing liquid in the jacket of the synthesis kettle, add 400Kg methomyl and 1.6Kg catalyst from the manhole, then stir for 20 minutes, pour nitrogen into the synthesis kettle, maintain the nitrogen pressure in the kettle at 0.15MPa, and control in three stages Control the reaction temperature at 10°C for 70 minutes, control the reaction temperature at 20°C for 90 minutes, and control the reaction temperature at 30°C for 90 minutes.Drain the nitrogen until the pressure in the synthesis kettle drops to 0, sample and analyze when the methomyl content is less than 1.5%, add 600Kg of tap water to the synthesis kettle, continue stirring for 15 minutes, and pour the materials from the synthesis kettle into a washing kettle;4. One washMeasure 520Kg of tap water into the primary washing kettle, pass water vapor into the jacket, adjust the temperature in the kettle to 32°C, stir for 150 minutes, and filter by pressure;5. One-time filter pressUse a pump to pump the materials in the primary water-washed kettle into a plate and frame filter press, and then send the filtrate to the separation kettle to stand for stratification. Separate the organic phase (mainly xylene and a small amount of pyridine) from water, and reuse the organic phase. The water is alkalized with sodium hydroxide to obtain pyridine, and the water will be reused after the post-treatment reaches the standard.6. Second washingMeasure tap water into the secondary water washing kettle, add the filter cake obtained by pressure filtration to the secondary water washing kettle, pass steam into the jacket, adjust the temperature in the kettle to 22°C, stir for 150 minutes, press filter; send the filtrate to the separation kettle Stand for stratification;7. Methanol washingMeasure 950Kg of methanol into the methanol washing kettle, add the filter cake obtained from the second pressure filtration to the methanol washing kettle, pass steam into the jacket, adjust the temperature in the kettle to 35°C, stir for 130 minutes, pass cooling water into the jacket 8. Centrifugation and dryingWhen the temperature of the kettle drops to 20°C, use a pump to pump the materials from the methanol washing kettle into the centrifuge for centrifugation.The filtrate is put into the methanol filtrate storage tank and used for the second time. The filter cake is sent to a double cone dryer, and vacuum-dried under the conditions of a temperature lower than 45° C. and a vacuum degree of not lower than 0.07 MPa to obtain a finished product.

References:

CN112479957, 2021, A Location in patent:Paragraph 0020-0062

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