Preparation background and overview of 2-mercaptopyridine-N-oxide
2-Pyrithione-N-oxyfluoroborate can be used to prepare zinc pyrithione. Add an appropriate amount of zinc oxide to the 2-pyrithione-N-oxide solution, react at 40-90°C for 3-6 hours, filter and wash with water , after drying, zinc pyrithione is obtained. Zinc pyrithione is used in shampoos to remove dandruff and can inhibit the growth of Gram-positive and Gram-negative bacteria and mold. It can effectively care for hair, delay hair aging, and control the occurrence of gray hair and hair loss. In addition, it is also used as a cosmetic preservative, oil agent, and paint biocide. It can also be used as a preservative, antifouling agent, etc., and is widely used in agriculture, industry, medicine, health, cosmetics and other fields.
Preparation of 2-mercaptopyridine-N-oxide
Preparation report of 2-mercaptopyridine-N-oxide 1.
Add 20g 2-chloropyridine and 0.6g catalyst TiO2 into a 500ml reaction bottle, raise the temperature to 50°C, and add 20g 30% hydrogen peroxide dropwise. The amount of hydrogen peroxide and 2-chlorine The material ratio of pyridine is 1:1, react for 10 hours, cool to room temperature, filter, drain the filter cake, and wash with 10g of deionized water. The filtrate is 2-chloropyridine nitrogen oxide aqueous solution; the system is heated to 70°C. Add dropwise to the mixed solution of 30g 25% NaOH solution and 21g 43% NaHS solution, and keep warm for 6 hours. Then cool to room temperature, adjust the pH value to 4.5, add 1g of activated carbon for decolorization for 0.5h, and obtain a 2-mercaptopyridine-N-oxide solution;
Preparation report 2 of 2-mercaptopyridine-N-oxide,
Step 1: Oxidation reaction: Add 2-chloropyridine, catalyst and deionized water to the reactor, raise the temperature to 60°C, stir for 2.5h, slowly add hydrogen peroxide dropwise, raise the temperature to 80°C, keep warm for 5h, and then Add sodium hydroxide dropwise to adjust the pH to 8 to generate a 2-chloro-N-oxypyridine solution;
Second benzylpyridine step: thiolation reaction: Add sodium hydrogen sulfide solution and sodium hydroxide solution dropwise into the reaction kettle of the 2-chloro-N-oxypyridine solution in the first step to adjust the pH to 10, and adjust the pH to 90 Stir for 3 hours at a temperature of ℃ to generate a 2-mercapto-N-oxypyridine solution.
References
[1]CN107628995-A synthesis method of zinc pyrithione
[2]CN105906560-A method for producing uniform plate crystal zinc pyrithione
