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Method for preparing caprolactam by nitrosation reaction

A caprolactam and nitrosation technology, applied in the preparation of lactam, chemical instruments and methods, organic chemistry, etc., to achieve high conversion rate and selectivity, improve selectivity, and avoid the effect of vapor-liquid entrainment

Active Publication Date: 2009-07-08
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0013] The purpose of the present invention is to provide a simple and feasible method to reduce the consumption of cyclohexyl formic acid or its derivatives, improve the selectivity of primary and reverse reactions, and simultaneously solve the problem of gas-liquid entrainment in view of the shortcomings of the nitrosation reaction process in the existing toluene-based caprolactam industrial technology. Etc caprolactam preparation method

Method used

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  • Method for preparing caprolactam by nitrosation reaction
  • Method for preparing caprolactam by nitrosation reaction
  • Method for preparing caprolactam by nitrosation reaction

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Experimental program
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Effect test

Embodiment 1

[0061] Embodiment 1: get 10.0g mass percent concentration and be the cyclohexyl formic acid of 99.19%, add 6.8g free SO 3 The concentration is 41.21% of fuming sulfuric acid to react to obtain mixed anhydrides. Under normal pressure, 6.2g of nitrosyl sulfuric acid with a mass percentage concentration of 73.54% was added dropwise to the mixed acid anhydride to carry out the nitrosation reaction. After quenching in a water bath, n-hexane was added, and 9.6 g of water was added to carry out the hydrolysis reaction, and the hydrolysis temperature was controlled not to exceed 30°C. After standing still, 26.0 g of the heavy phase product and 118.9 g of the light phase product were separated. The concentration of caprolactam in the heavy phase was 13.23% by liquid chromatography analysis, and 4.81% of cyclohexyl formic acid in the light phase was obtained by titration analysis. As shown in Table 2, the conversion rate of nitrosation reaction is 42.34%, the yield of caprolactam is 39...

Embodiment 2

[0062] Embodiment 2: Raw material proportioning, feeding method is the same as that of Embodiment 1, the difference lies in the dropping time and reaction time, and the conversion rate, yield and selectivity of nitrosation reaction are shown in Table 2.

Embodiment 3～4

[0063] Embodiments 3 to 4: The feeding method is the same as that of Embodiment 2, except that the concentration of oleum is 39.47%, the time for dropping and the temperature rise of the reaction, and the conversion rate, yield and selectivity of the nitrosation reaction are shown in Table 2.

[0064] Table 2 Results of nitrosation reaction under solvent-free conditions

[0065]

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Abstract

The invention discloses a method for preparing caprolactam, which comprises: making fuming sulfuric acid react with hexahydrobenzoid acid or derivatives of the hexahydrobenzoid acid to generate mixed acid anhydride substances, performing nitrosation reaction with a nitrosation agent in a plurality of tandem reactors without the presence of a solvent, and controlling adiabatic temperature rise through external circulation heat exchange; and adding a solvent and water into reaction products for hydrolysis, and generating a light phase and a heavy phase which are continuously recycled, wherein the heavy phase is a caprolactam-sulfuric acid solution, and the light phase contains unreacted hexahydrobenzoid acid or derivatives of the hexahydrobenzoid acid. The method can inhibit loss of raw materials of the nitrosation reaction, and realizes improvement of the main nitrosation reaction selectivity on the premise of not increasing the total acid consumption and the number of byproducts.

Description

technical field [0001] The invention relates to a method for preparing caprolactam, in particular to a method for preparing caprolactam through nitrosation of cyclohexyl formic acid or its derivatives. Background technique [0002] Caprolactam is an important petrochemical product, most of which are used to produce nylon 6 fiber and nylon 6 resin. There are many preparation methods of caprolactam, all of which use aromatic hydrocarbons or their derivatives as raw materials, namely benzene, phenol and toluene. Currently representative caprolactam production processes mainly include cyclohexanone-hydroxylamine method, Toray cyclohexane photonitrosation method and the toluene method developed by SNIA Company. There are low yields in the reaction process in various processes, and a large amount of oleum is consumed, resulting in environmental pollution and by-products in varying degrees. [0003] The toluene method is a method for the production of caprolactam developed by the...

Claims

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Application Information

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IPC IPC(8): C07D223/10C07D201/10
Inventor 罗和安吴剑夏珺
Owner CHINA PETROLEUM & CHEM CORP
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