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Method for preparing low sulfonated caprolactam

A technology of caprolactam and sulfonation, applied in the field of preparation of caprolactam, can solve the problems of no solution, intensified side reaction of sulfonation, uneconomical and the like, achieve high conversion rate and yield, ensure product quality, and reduce the effect of residual concentration

Active Publication Date: 2010-05-26
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] (1) The excess cyclohexylcarboxylic acid in the amidation reaction solution is easily absorbed by SO in the subsequent rearrangement reaction. 3 Further sulfonation, which will lead to the loss of cyclohexyl formic acid, it is obviously uneconomical to increase raw material consumption in order to reduce by-products
[0008] (2) In order to ensure the quality of the reaction product, it is necessary to improve the conversion rate of cyclohexanone oxime as much as possible and reduce the concentration of residual cyclohexanone oxime. It is necessary to prolong the residence time of rearrangement or increase the temperature, which will lead to the aggravation of sulfonation side reactions
[0009] (3) The Beckmann rearrangement of cyclohexanone oxime is an extremely fast and strong exothermic reaction, the viscosity of the material increases with the increase of caprolactam, microscopic uneven mixing and local overheating are still inevitable
[0010] And these problems above are also the difficulties that plague the existing technicians. At present, there is no relevant solution that can solve the above problems well.

Method used

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  • Method for preparing low sulfonated caprolactam
  • Method for preparing low sulfonated caprolactam
  • Method for preparing low sulfonated caprolactam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037]Embodiment 1: Get the nitrosation liquid of the toluene method industrial device, leave standstill and go out light phase, analyze and obtain its weight composition: 20.63% of cyclohexyl formic acid, 21.93% of caprolactam, 11.71% of sulfur trioxide. Take a certain amount of heavy phase and place it in a 250ml three-port glass reactor, add n-hexane with an equal volume to the heavy phase, stir vigorously at 60°C, and use a constant temperature water bath to control the temperature with an accuracy of ±1°C. After the material reaches the set temperature, it is allowed to stand still to balance, and samples of light and heavy phases are taken respectively, which are recorded as 1#. Separate the light and heavy phases, then add n-hexane of equal volume to the heavy ones, repeat the above steps, and record the samples as 2#, 3# and 4# in turn to achieve the effect of multi-stage extraction. The contents of cyclohexyl formic acid in the extract phase and the raffinate phase we...

Embodiment 2

[0043] Example 2: Take 115.2 g of cyclohexyl formic acid and dissolve it in the mixed hydrocarbon of cyclohexane and n-hexane, wherein 20 g of cyclohexane and 50 g of n-hexane. Add 51.5g free SO 3 Fuming sulfuric acid with a concentration of 63.5% was reacted to obtain mixed anhydrides. Add 60.1 g of nitrosyl sulfuric acid with a concentration of 81% to the mixed acid anhydride under normal pressure to carry out nitrosation reaction at a temperature of 73° C. for 15 minutes. After the reaction was completed, it was quenched and left to stand, and 200.2 g of the heavy phase product was separated. Get 100g heavy phase to analyze, obtain its composition as cyclohexyl formic acid 17.40%, caprolactam 21.30%, SO 3 11.07%, sulfuric acid 47.53%. Add 29.84g of cyclohexanone oxime into 122.56g of n-hexane to form an oxime solution. Add the oxime solution dropwise to the remaining 100.2 g of the nitrosation heavy phase product, and stir rapidly to ensure uniform heat transfer. Added...

Embodiment 3

[0045] Example 3: At 35°C, cyclohexyl formic acid and n-hexane were sent to the circulation pump at a flow rate of 207.5kg / h and 144.1kg / h for mixing, and separated by flash evaporation and decanting to obtain 65% cyclohexyl formic acid Solution, add free SO at a flow rate of 76.4kg / h 3 Fuming sulfuric acid with a concentration of 63.5% is mixed, and the temperature is controlled not to be higher than 40° C. through external circulation heat exchange. The mixed acid anhydride enters the first stage of the 9-stage fully mixed flow series reactor with a flow rate of 284.8kg / h, and the concentration is 72% nitrosyl sulfuric acid solution and n-hexane with a flow rate of 124.1kg / h and 5693.7kg / h respectively Graded addition, nitrosation reaction. The pressure is 113 kPa, the corresponding temperature is 73° C., and the residence time is 20 minutes. The reaction product is 374.9kg / h, and the analysis composition is 23.11% cyclohexyl formic acid, 16.01% caprolactam, SO 3 11.12%, ...

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Abstract

The invention discloses a low sulfonated hexanolactam preparation method. In the hexahydrobenzoic acid or the nitrosation reaction product of the derivant, the cyclohexanone oxime-inertia organic solvent solution is added to produce the Beckmann rearrangement reaction, which is performed with extraction, maturation and hydrolization through inertia organic solvent, so as to produce light and heavyphases and segregation, the obtained heavy phase is hexanolactam-sulphuric acid solution, the light phase is solution of hexahydrobenzoic acid or the derivant which is incompletely reacted, and the reaction is circulated to the nitrosation reaction part. The invention effectively utilizes the Beckmann rearrangement of the catalyzing cyclohexanone oxime in the hexahydrobenzoic acid nitrosation reaction product, and through the steps of composite reaction, extraction, maturation and hydrolization, the loss of the raw material and the by-product quantity of the unit finished product hexanolactamare reduced.

Description

technical field [0001] The invention relates to a preparation method of caprolactam, and further illustrates that it is based on the toluene method nitrosation and the benzene method Beckmann rearrangement, and realizes the caprolactam preparation method with low sulfonation and low by-products through reaction combination, extraction and aging. Background technique [0002] Caprolactam, scientific name ε-caprolactam, molecular formula C 6 h 11 NO, molecular weight 113.16, structural formula [0003] [0004] It is a white crystal at room temperature with a melting point of 69.3°C. As a monomer of polyamide 6, it is an important petrochemical product widely used in the manufacture of nylon and engineering plastics. [0005] There are many preparation methods of caprolactam, but there are only a few industrial methods that can meet the requirements of polymerization and are economical and reasonable. Volume 3 of the second edition of "Encyclopedia of Organic Chemical R...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D201/04C07D223/10
Inventor 罗和安吴剑
Owner CHINA PETROLEUM & CHEM CORP
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