Synthetic method and system of 4-chloro-3-cresol

Abstract

The invention belongs to the field of organic compounds, and provides a synthesis method of 4-chloro-3-cresol. The method is characterized in that m-cresol is used as a raw material, sulfuryl chloride is used as a catalyst, the molar ratio of sulfuryl chloride to m-cresol is (0.5-1.0):1, and the reaction temperature is 0-50 DEG C. According to the synthesis method provided by the invention, without catalysts and solvents, chlorination reaction is performed at 30-40 DEG C in a molten state, and a main substance generated by the reaction is 4-chloro-3-cresol; the conversion rate of the reaction is controlled at 75-90%, and the generated target product is not chloridized again into a byproduct; by reusing the fraction and transition component before rectification, the final yield of the reaction is greatly improved; the distilled product can reach the standard directly; after recrystallization during which the solution temperature is 80-100 DEG C, the product is cooled to below 20 DEG C for discharge and filtration; the filtered water can be used for 5-10 times to obtain a finished product, and other treatment processes are saved.

Description

technical field [0001] The invention belongs to the field of organic compounds, in particular to a method for synthesizing halogenated carbocyclic compounds. Background technique [0002] 4-Chloro-3-cresol is a colorless crystal with a melting point of 66°C and a boiling point of 235°C. At 20°C, 1g can dissolve in 250ml of water, and it can dissolve more in hot water. It is easily soluble in benzene, ether, ethanol, acetone, Chloroform and petroleum ether. It is widely used in organic synthesis, such as the synthesis of dyes and film preservatives. Also used as a pharmaceutical preservative. [0003] At present, there are two traditional production methods of 4-chloro-3-cresol, one is the reaction between m-cresol and dichlorosulfuryl. Under stirring, m-cresol was slowly added to dichlorosulfuryl, and the reaction temperature was controlled at 30-50°C. After adding, keep warm for 16 hours, wash with water, wash with sodium carbonate solution until alkaline, and then wash...

AI Technical Summary

Problems solved by technology

The other is to slowly add sulfuryl dichloride to m-cresol in an organic solvent under stirring, the amount added dropwise is a molar ratio of 1:1-1.2 (sulfuryl dichloride: m-cresol), after the reaction The yield of 4-chloro-3-cresol is between 75-78%, the yield is low, and the main impurities are 6-chloro-3-cresol and 4,6-dichlorocresol

The boiling point of 6-chloro-3-cresol is 196°C, the boiling point of 4,6-dichlorocresol is 225°C, and the boiling point of the product 4-chloro-3-cresol is 235°C, so the removal of 4,6-dichlorocresol Cresol (the difference in boiling point is only 10°C), requires a high number of theoretical plates and requires a large investment in rectification equipment

At the same time, the organic solvents used in the process also pollute the environment

[0004] In the synthetic methods of the prior art, the yield is generally relatively low, and the desiccant and organic solvent used in the process increase the production cost and pollute the environment

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