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A method for synthesizing caprolactam in one step by cyclohexanone and ionic liquid type hydroxylamine salt

A technology of ionic liquid and caprolactam is applied in the preparation of lactam, chemical instruments and methods, and the production of bulk chemicals. It can solve problems such as equipment corrosion, unfriendly environment, and complicated routes, and achieve no corrosion of equipment and reduce production costs. , The effect of simple process

Active Publication Date: 2016-03-30
HEBEI UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is: in view of the complex route in the current production process of caprolactam, and the equipment corrosion caused by the use of inorganic acid hydroxylamine salt, the environment is not friendly, etc., and at the same time realize the one-step clean synthesis of caprolactam, we use self-made ionic liquid Type hydroxylamine salt (expressed as (NH 2 Oh) 2 ·ILs) (Chinese patent, application number 201310481404.2) replaces inorganic acid hydroxylamine salt, uses zinc salt as a catalyst, and realizes one-step clean synthesis of caprolactam under solvent-free conditions. The reaction process is as follows:

Method used

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  • A method for synthesizing caprolactam in one step by cyclohexanone and ionic liquid type hydroxylamine salt
  • A method for synthesizing caprolactam in one step by cyclohexanone and ionic liquid type hydroxylamine salt

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Embodiment 1

[0025] 1-sulfobutyl-3-methylimidazole hydrogensulfate ionic liquid hydroxylamine salt was synthesized according to the method of Chinese patent, application number 201310481404.2:

[0026] The first step is the preparation of free hydroxylamine aqueous solution (US5266290, 1993): Weigh 41.0g of hydroxylamine sulfate (0.5mol based on hydroxylamine) and dissolve in 100ml of distilled water (5.56mol), and place the above hydroxylamine sulfate aqueous solution at a low temperature of -5°C In the constant temperature reactor, add dropwise 40g of 50% NaOH solution (wherein, the alkali is 0.5mol in terms of hydroxide, and the water is 1.11mol) under stirring; continue to stir for 0.1h after the addition is complete, and filter to separate the reaction 100ml of filtrate was obtained. The filter cake was washed with 40ml of distilled water. The combined filtrate and lotion totaled 140ml; in the combined filtrate and lotion, 0.105g of ascorbic acid as a stabilizer (0.08% by weight) was adde...

Embodiment 2

[0030] Add cyclohexanone (1 mmol), the ionic liquid hydroxylamine salt (2 mmol) obtained in Example 1 and the ground zinc chloride catalyst (2 mmol) into a 10 ml single-necked flask, seal the reaction system, and stir uniformly at room temperature. Then, it was reacted for 1.5h at a temperature of 150°C. The reaction product was extracted twice with dichloromethane, the extracts were combined, and the extracts were directly subjected to qualitative and quantitative analysis on gas chromatography. The reaction result was that the conversion of cyclohexanone was 98.6% and the selectivity of caprolactam was 76.1%.

Embodiment 3

[0032] The steps are the same as in Example 2, except that the added catalyst is zinc oxide (2 mmol), the reaction result is that the conversion of cyclohexanone is 98.0%, and the selectivity of caprolactam is 4.7%.

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Abstract

The invention relates to a method of directly synthesizing hexanolactam by cyclohexanone and ionic liquid type hydroxylamine salt. The method comprises the following steps: adding cyclohexanone, ionic liquid type hydroxylamine salt and a zinc salt catalyst into a reactor and uniformly stirring at room temperature; and then, carrying out a reaction at 140-160 DEG C for 0.5-2.5 hours in a closed system to obtain the product hexanolactam, wherein the material molar ratio of cyclohexanone to ionic liquid type hydroxylamine salt to zinc salt catalyst is 1 to (1-2) to (1.5-3), and the ionic liquid type hydroxylamine salt is 1-sulfobutyl-3-methylimidazole hydrosulfate ionic liquid type hydroxylamine salt. The method provided by the invention integrates oximation of cyclohexanone and rearrangement of cyclohexanone-oxime in a same reactor, so that the reaction flow is shortened and the production cost of hexanolactam is remarkably saved. The method has the advantages of no corrosion to equipment, environment-friendliness and the like and meets the requirements on green chemistry. The conversion ratio of cyclohexanone and the selectivity of hexanolactam are high, and the maximum can be up to 100% and 91.0% respectively.

Description

Technical field [0001] The invention relates to the synthesis of organic chemical products, in particular to a method for one-step synthesis of caprolactam from cyclohexanone and ionic liquid hydroxylamine salt. Background technique [0002] Caprolactam is an important organic chemical intermediate, mainly used in the production of nylon 6 fiber, engineering plastics, food packaging film and pharmaceutical raw materials (Fine Chemical Raw Materials and Intermediates, 2011(1): 38-43). Industrially, caprolactam is mainly prepared by the cyclohexanone-hydroxylamine method, that is, cyclohexanone and hydroxylamine salt react to form cyclohexanone oxime, and cyclohexanone oxime is rearranged by Beckman under the catalysis of concentrated sulfuric acid or fuming sulfuric acid to obtain caprolactam. However, this process has disadvantages such as complicated process route, corrosion of equipment, unfriendly environment, and a large amount of low-value ammonium sulfate by-product (Jiangx...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D201/06C07D223/10
CPCY02P20/52
Inventor 王延吉李志会张东升齐旭东徐元媛杨秋生赵新强
Owner HEBEI UNIV OF TECH