Preparation method of hydroxamic acid

A technology of hydroxamic acid and acid anhydride, which is applied in the field of preparation of hydroxamic acid, can solve the problems of limiting the popularization and application of hydroxamic acid, low product conversion rate, hazardous waste of chemical by-products, etc., and achieves reduction in consumption of alkali and reduction in consumption. Reduced, highly reactive effects

Active Publication Date: 2020-06-12
BEIJING MINING & METALLURGICAL TECH GRP CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this production process needs to consume a large amount of acid and alkali, and some also use a large amount of methanol, and the product conversion rate is not high in the reaction process, the product purity is low (only 30-50%), and a large amount of waste water and waste residue are discharged.
The production of 1 ton of hydroxamic acid discharges about 4 to 5 tons of production wastewater, and the wastewater is difficult to reuse. A large amount of waste residue NaCl is produced in the process of wastewater treatment, which is a chemical by-product hazardous waste, and the treatment cost is high, which seriously limits the promotion and application of hydroxamic acid.

Method used

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Embodiment 1

[0029] The present embodiment provides a kind of preparation method of 2-carboxynaphthalene hydroxamic acid, comprises the following steps:

[0030] Put the reaction bottle into the ice-water mixture for cooling, add hydroxylamine hydrochloride and naphthalic anhydride with a molar ratio of 1.3:1.0 therein, and add water to dissolve it; under stirring, add 40 wt% NaOH aqueous solution dropwise to control the rate of addition Keep the reaction temperature below 30°C, the molar ratio of naphthalic anhydride to NaOH is 1:1.6, continue to stir for 5 hours after the NaOH aqueous solution is added dropwise, to ensure sufficient reaction; then add 30wt% dilute sulfuric acid dropwise for acidification, Acidify to pH 6, and finally filter and separate the reaction solution to obtain 2-carboxynaphthalene hydroxamic acid as a light yellow solid with a product yield of 91.5% and a purity of 70.5%.

Embodiment 2

[0032] The present embodiment provides a kind of preparation method of 2-carboxybenzohydroxamic acid, comprises the following steps:

[0033] Put the reaction bottle into the ice-water mixture to cool, add hydroxylamine hydrochloride and phthalic anhydride with a molar ratio of 1.25:1.0, and add water to dissolve it; under stirring, add 40 wt% NaOH aqueous solution dropwise to control the drop Acceleration keeps the reaction temperature below 30°C, the molar ratio of phthalic anhydride to NaOH is 1:1.5, and the NaOH aqueous solution is added dropwise and then stirred for 2 hours to ensure sufficient reaction; then 30wt% dilute sulfuric acid is added dropwise Acidification until the pH is 5, and finally the reaction solution is separated by filtration to obtain 2-carboxyphenylhydroxamic acid as a white solid with a product yield of 92.8% and a purity of 70.2%.

Embodiment 3

[0035] The present embodiment provides a kind of preparation method of 3-carboxy-octenyl hydroxamic acid (CMCA), comprises the following steps:

[0036] The reaction bottle is put into the ice-water mixture for cooling, and the hydroxylamine hydrochloride and pentylmaleic anhydride that the molar ratio is 1.35:1.0 are added thereto, and water is added to make it dissolve; Acceleration keeps the reaction temperature below 30°C, and the molar ratio of acid anhydride to NaOH is 1:1.65. After the NaOH aqueous solution is added dropwise, continue to stir for 3 hours to ensure sufficient reaction; then add 30wt% dilute sulfuric acid dropwise to The pH is 5, and finally the reaction solution is separated by filtration to obtain CMCA as a pasty product with a yield of 95.8% and a purity of 75.2%.

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Abstract

The invention provides a preparation method of hydroxamic acid. The preparation method comprises the following steps: reacting acid anhydride with hydroxylamine under the catalysis of alkali, and acidifying after the reaction is completed, wherein the acid anhydride is C4-C12 cycloalkane fatty acid anhydride or aromatic acid anhydride. According to the preparation method, hydroximation reaction can be realized without heating, the reaction conditions are mild, side reactions are few, the purity of the obtained product is high, and the concentrate product obtained by flotation is high in recovery rate and grade. Secondly, the synthesis conversion rate of the product is high, the raw material consumption ratio is reduced, the synthesis cost is greatly reduced, the alkali consumption in the preparation process of the method is greatly reduced, the acid required in the subsequent acidification process is also reduced, the generated waste residue sodium chloride is reduced and the wastewater discharge amount is reduced by about 50% or above.

Description

technical field [0001] The invention relates to the preparation of hydroxamic acid and the field of mineral flotation, in particular to a preparation method of hydroxamic acid. Background technique [0002] Hydroxamic acid was first discovered by Lossen in 1869. It has two forms, hydroxamic acid and hydroxamic acid, and hydroxamic acid is the main form. Since hydroxamic acid molecules contain N and O atoms, they all have lone pairs of electrons, and are easy to coordinate with metal cations to form stable cyclic chelates. Therefore, hydroxamic acid is widely used in the mineral processing industry, such as in oxidation It is widely used as a collector in the flotation of oxide ores such as lead-zinc ore, copper oxide ore and rare earth ore, and hydroxamic acid is used for cassiterite, tungsten ore, ilmenite, rutile, bastnaesite, niobium-tantalum ore The flotation of iron ore is the most effective and commonly used collector. [0003] Commonly used hydroxamic acids include ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C259/10C07C259/06B03D1/01
CPCC07C259/10C07C259/06B03D1/01B03D2201/02
Inventor 吴桂叶朱阳戈李成必刘崇峻刘慧南纪爱亮
Owner BEIJING MINING & METALLURGICAL TECH GRP CO LTD
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