- Production method of 2-methyl-3(5 or 6)-methylthio pyrazine
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The invention discloses a production method of 2-methyl-3(5 or 6)-methylthio pyrazine. The method comprises the following steps: adding solvents dichloroethane and triethylamine into a reaction kettle, sealing the reaction kettle, introducing chlorine to control the pressure in the kettle at 0.02-0.03 MPa, pumping a methylpyrazine solution into the reaction kettle by using a metering pump, controlling the temperature at 45-60 DEG C, reacting, and transferring reaction liquid(containing the chlorine)in the kettle into a dichloroethane turnover tank through filter pressing for recycling after the reaction is finished; dissolving the residual 2-methyl-3(5 or 6)-chloropyrazine hydrochloride solid in the reaction kettle with water, adjusting the neutrality, and layering to obtain a 2-methyl-3(5or 6)-chloropyrazine crude product; and dropwise adding thechloropyrazine crude product is into sodium methyl mercaptide, performing reflux reaction , and after reaction liquid is extracted, adding an aid into an organic phase to generate a hydrochloride for separating the non-pyrazine product from the product to greatly improve the aroma quality of the obtained product. The product grade is improved, and the whole production process is safe and environmentally friendly.
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Paragraph 0027-0028; 0031-0032
(2020/04/17)
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- Reactions of Halogenomethanes in the Vapor Phase. Part 4. The Reactions of Imidazoles with Chloroform at 550 deg C, and a Comparison with their Liquid-phase Reactions with Trichloroacetate Ion or Hexachloroacetone and Base
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1-Unsubstituted imidazoles and chloroform at 550 deg C in a flow system give mainly 5-chloropyrimidines, together with 4-chloropyrimidines and chloropyrazines.The effects of methyl substituents on the ratio of products is considered.The liquid-phase reactions of 2-methyl- and 2,4,5-trimethyl-imidazole under conditions in which dichlorocarbene is said to be formed in basic or neutral conditions were studied, and compared with the gas-phase reactions with chloroform.
- Busby, Reginald E.,Khan, Mohammad A.,Khan, Mohammad R.,Parrick, John,Shaw, C. J. Granville,Iqbal, Mohammad
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p. 1427 - 1430
(2007/10/02)
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