Piroctone olamine synthesis

Yield:68890-66-4 73.72 %

Reaction Conditions:

with hydroxylamine hydrochloride in ethanol;water at 85;

Steps:

1-4 Synthesis steps:

General procedure: add 4-methyl-6-(2,4,4-trimethylpentyl)-2-pyrone (CAS No.: 50650-75-4, molecular weight: 222.32300, 3.80 to the 30L reaction kettle) kg, 17.0922mol), ethanol (2.0kg) with a water content of 5wt%, first add hydroxylamine hydrochloride (CAS No.: 5470-11-1, molecular weight: 69.49090, 2.14kg, 30.7954mol) under stirring conditions, then slowly add Ethanolamine (CAS No.: 141-43-5, Molecular Weight: 61.08310, 2.61kg, 42.7287mol), heat up to 85°C to carry out transesterification and complexation reaction for 8h to obtain a reaction containing piroctone ethanolamine salt and ethanolamine hydrochloride liquid.The conversion rate of 4-methyl-6-(2,4,4-trimethylpentyl)-2-pyrone in the reaction solution was monitored by HPLC and was 100%.Post-processing steps: first remove the ethanol in the reaction solution by rectification under reduced pressure; then add water (40° C., 1.0kg) and ethyl acetate (10.0kg) to the reaction solution for extraction, and after the extraction is completed, stand for fractionation. layer for 0.5h, and then separate liquids to obtain an aqueous phase and an organic phase; the organic phase is washed once with water (normal temperature, 0.5kg), left to stand for 1 h, and the layers are separated and the aqueous phases are combined.Put the organic phase in a 30L reaction kettle, first add piroctone ethanolamine salt seed crystals (20g) under the conditions of stirring and temperature at 20-30°C for initial crystallization for 30min, and then stir and temperature at 0-10°C Secondary crystallization was carried out at for 180 min; centrifuged and dried to obtain piroctone olamine salt (CAS number: 68890-66-4, molecular weight: 298.42100, 3.65 kg, 12.1 mol, yield : 71.56%, purity: 99.62%).The water phase was placed in a 30L reactor equipped with a reflux receiving device, and sodium hydroxide (CAS: 1310-73-2, molecular weight: 39.99710, 1.5kg, 37.50272mol) was slowly added; the reactor was in a high vacuum of 100300Pa Under the temperature condition of 70°C, rectify water first, and then rectify ethanolamine (CAS No.: 141-43-5, molecular weight: 61.08310, 1.77kg, 28.9769mol) under the temperature condition of 90100°C, recover Rate:

References:

CN114874137,2022,A Location in patent:Paragraph 0029-00