A process for the high yield preparation of hydroxamic acids
By introducing an acyl halide reagent and controlling the pH value in the hydroxylation reaction, the problems of low conversion rate and purity in the preparation of hydroxamic acid were solved, realizing efficient and low-cost production of hydroxamic acid, which is suitable for industrial applications.
CN122325355APending Publication Date: 2026-07-03河南德峰新材料有限公司
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Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 河南德峰新材料有限公司
- Filing Date
- 2026-04-28
- Publication Date
- 2026-07-03
AI Technical Summary
Technical Problem
Existing hydroxamic acid preparation processes suffer from low conversion rates, insufficient purity, and high ammonia nitrogen content in wastewater, resulting in high production costs and difficulties in environmental treatment.
Method used
Introducing a highly reactive acyl halide reagent into the hydroxylation reaction, adding it dropwise in stages and controlling the pH value, ensures complete conversion of the carboxylic acid ester, consumes residual hydroxylamine, and inhibits side reactions.
Benefits of technology
It improves the conversion rate of hydroxamic acid to over 98%, achieves a product purity of ≥98%, significantly reduces ammonia nitrogen content in wastewater, lowers production costs, and is suitable for industrial production.
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Abstract
This invention discloses a high-yield method for preparing hydroxamic acid, relating to the field of organic synthesis technology. The specific steps are as follows: Hydroxylamine hydrochloride is dissolved in water and cooled; liquid alkali is added dropwise to generate free hydroxylamine; a carboxylic acid ester is added, and the pH is adjusted to 8–10, reacting until the ester residue is ≤2%; a small amount of the corresponding acyl halide is added, and the pH is maintained to continue the reaction until complete; acidification and crystallization yield high-purity hydroxamic acid. This invention uses carboxylic acid ester as the main raw material and a small amount of acyl halide as a synergist, employing a staged reaction to overcome the later-stage kinetic bottleneck, significantly reducing ammonia nitrogen in wastewater. The process is mild, low-cost, and easily industrialized, suitable for the preparation of high-purity products such as benzoyl hydroxamic acid, salicylic acid, and octanoyl hydroxamic acid.
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