Pyrithione Zinc Powder CAS 13463-41-7

Technique 1: The prep work concept is that ZnSO4 · 7H2O responds with SPT to generate ZPT and sodium sulfate. Consider a proper amount of zinc sulfate heptahydrate to prepare 0.25 mol/L and also 0.50 mol/L zinc sulfate services respectively. Step an appropriate quantity of salt pyrithione remedy, as well as prepare 0.5 mol/L and 1.0 mol/L salt pyrithione services respectively. The process conditions of the reaction process are regulated, and also both are rapidly added into a three-necked flask at a certain volume ratio for response to acquire pyrithione zinc crystals, which are after that suction filtered, cleaned, and vacuum-dried to get Pyrithione Zinc Powder.

Approach 2: Making use of pyridine as raw material, after 30% H2O2 oxidation, synthesize N-oxide-2-hydroxypyridine in a system of dimethyl sulfoxide, toluene, and sulfur powder, and ultimately form a salt with Zn2 +, although this method Simple, easy to get and also economical basic materials, but the total return is very reduced, only about 17%.

Method 3: 2-carboxypyridine is used as the raw product, the response problems are fairly extreme, and also catalysts such as NaH as well as LiCl are used in the reaction procedure, which is pricey and also has a high threat factor, and also large industrialization is hard.

Approach 4: Using 2-chloropyridine as raw material, utilizing a catalytic oxidation system made up of maleic anhydride and acetic acid, and also better managing the mercaptolation response with the Na2S-NaSH buffer system, Pyrithione Zinc Powder was gotten with a yield of concerning 75%.

1) Synthesis of 2-chloro-N-oxypyridine (1 ): Include 20.0 g (0.18 mol) 2-chloro Pyridine, 1.3 g (0.013 mol) maleic anhydride, 5.0 mL 50% H2O2 as well as 50 mL ethyl acetate were stirred to liquify them all. After the temperature was elevated to 80 ° C, 9.5 mL H2O2 was added dropwise, and also the dropwise addition was finished within 15 minutes. Reaction 4 h, tender loving care to establish the reaction endpoint. The product was washed with water as well as distilled under lowered stress to get a light yellow fluid.

2) Synthesis of 2-mercapto-N-oxypyridine (2 ): add NaOH solution to compound 1, adjust to pH 9.0 ~ 11.0, raise the temperature to 50 ° C, safeguard with N2 and also decrease 100 The barrier service including 17.6 g (0.31 mol) NaSH and 9.4 g (0.12 mol) Na2S in mL was added dropwise in about thirty minutes. Take note of regulate the adjustment of pH throughout the process, raise the temperature to 90 ℃, as well as react for 2 hours. After the reaction was completed, it was decreased to space temperature, and 1 mol/L HCl service was contributed to change the pH to 2. There was a large amount of white precipitate, which was filteringed system by suction and also dried out to acquire the product.

3) Synthesis of 2-mercapto-N-oxypyridine sodium salt (3 ): add NaOH solution to substance 2, adjust to pH 6 ( ± 0.5), and also a little heat to dissolve it completely, creating a clear yellow option.

4) Synthesis of zinc pyrithione (4 ): Weigh 14.0 g (0.05 mol) of ZnSO4 · 7H2O solid, dissolve it in 150 mL of pure water, as well as slowly add it dropwise to intensify 3 at 50 ° C via a constant stress dropping funnel. A huge quantity of white precipitate developed, and also stirring was continued for 2 h. Suction filtering, cleaning two times with water, cleaning with cyclohexane, as well as drying out to obtain 22.9 g of white solid with a complete return of 68%.