Background and overview[1-2]
The composition of high-boiling chlorophenols is very complex, mainly containing o-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, 4-bromo-2,5-dichlorophenol, 4 , 4-dichlorodiphenylsulfone and dichlorophenoxychlorophenol, etc. Among them, chemical products with relatively high added value are o-chlorophenol, 2,4-dichlorophenol and 2,4,6-trichlorophenol. The content of 2,4,6-trichlorophenol is the largest among high-boiling chlorophenols, at about 55 wt%, while the content of 2,4-dichlorophenol is second, at about 15 wt%. 2,4,6-Trichlorophenol is an important intermediate for the high-efficiency, broad-spectrum, and low-toxicity imidazole fungicide imidazole. Imidazole has multiple functions such as prevention, protection and treatment. It is an imidazole broad-spectrum fungicide containing prochlorazine group. It works by inhibiting the biosynthesis of sterols and has no systemic effect. It has excellent control effect on various diseases caused by Ascomycetes and Deuteromycetes. Gene induction technology is used to activate the expression of plant disease resistance genes. It has good quick effect, long lasting effect and no systemic effect. 2,4,6-Trichlorophenol also acts as a blocking agentfor polymethylene polyphenyl polyisocyanate (PAPI). Sodium 2,4,6-trichlorophenol is the sodium salt of 2,4,6-trichlorophenol.
Preparation[1]
The preparation method of sodium 2,4,6-trichlorophenolate is: (1) Place phenol in a three-necked flask with a reflux condenser, heat to 50~55°C and start to pass 1/3 of the stoichiometric amount of chlorine, and then Add 2/3 of the stoichiometric amount of chlorine at 70 to 75°C. After the reaction is complete, cool to obtain a crude product. (2) Refining: Dissolve the above crude product in hot anhydrous ethanol and recrystallize to obtain white needle crystals. (3) Add 2,4,6-trichlorophenol and react with sodium hydroxide to prepare sodium 2,4,6-trichlorophenol.
Main reference materials
[1] CN201410460142.6 A synthesis method of 2,4,6-trichlorophenol
[2] CN201810751759.1 A method for resource utilization of high-boiling chlorophenols
