| Acetyl hydroxamic acid is a intermediate in organic synthesis which has antibacterialactivity and can be used as good organic ligands. It has wide applications in medicine,metallurgical industry and so on. O-benzylhydroxylamine hydrochloride belongs toO-substituted hydroxylamines compound, which is an expensive intermediate in organicsynthesis and has wide applications. The acetyl hydroxamic acid was synthesized byamidation from PVA alcoholysis liquor and hydroxylamine hydrochloride in the alkalinealcohol solution. On this basis, the acetyl hydroxamic acid-sodium salt and benzyl chloridecould synthesize the O-benzylhydroxylamine hydrochloride by etherification, hydrolysis.In the synthesis process of acetohydroxamic acid, hydroxylamine hydrochloride andsodium hydroxide aqueous solution reacted at low temperature, producing freehydroxylamine. The free hydroxylamine reacted with PVA alcoholysis liquor to form acetylhydroxamic acid-sodium salt. Then maked the pH of the reaction solution to be5by instilling20%HCl and then vacuum distilled. So the acetohydroxamic acid was formation. The bettertechnology obtained by orthogonal experiment was that the ratio of hydroxylaminehydrochloride, PVA alcoholysis liquor (According to the methyl acetate) and sodiumhydroxide was1:2.30:2, the reaction temperature was40℃, the reaction time was3h. Underthese conditions, the best yield of acetohydroxamic acid could reach95.3%, purity was98.1%. Meanwhile, recyclabled the methanol through fractionating the solution which hasbeen vacuum distilled.Using N,N-dimethyl formamide(DMF) as solvent, synthesized the benzyloxyacetylhydroxylamine from the acetyl hydroxamic acid-sodium salt and benzyl chloride byetherification. Finally, to add hydrochloric acid into the reaction system, then acquired the O-benzylhydroxylamine hydrochloride. The better technology obtained by orthogonalexperiment was that in the etherification reaction, the ratio of acetyl hydroxamic acid-sodiumsalt and benzyl chloride was1:1.05, the reaction temperature was90℃, the reaction time was5h, the DMF consumption was30ml(acetyl hydroxamic acid-sodium salt was0.07mol). Inthe hydrolysis reaction, the reaction temperature was70℃, the reaction time was3h, thehydrochloric acid consumption was70ml (benzyloxyacetyl hydroxylamine was0.07mol).Under these conditions, the best yield of O-benzylhydroxylamine hydrochloridecould reach90.3%, purity was99.3%.Compared with the traditional process, the yield of this process is obviously improved.For the first time, the PVA alcoholysis Liquor was used as raw material to synthesize theacetohydroxamic acid and O-benzylhydroxylamine hydrochloride. Meanwhile, recyclabledthe methanol. Not only solve the issue of treatment of the PVA alcoholysis liquor, saving theenergy consumption and capital, but finding the cheap raw materials to produceO-benzylhydroxylamine hydrochloride. Transform waste into assets, serve multiplepurposes. |
