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Method for lowering caprolactam inclusion content in ammonium sulfate crystals

A technology of caprolactam content and caprolactam, which is applied in the field of reducing the amount of caprolactam entrained in ammonium sulfate crystals, can solve the problems of cumbersome treatment, pollution of ammonium sulfate finished products, high cost, etc., and achieve the effect of less dosage, low price and low cost of addition

Active Publication Date: 2013-02-27
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] During the above ammonium sulfate reaction crystallization and sedimentation separation process, a small amount of caprolactam oil will inevitably be entrained on the crystal grain surface, which will cause waste of caprolactam and pollution of ammonium sulfate finished product to a certain extent. It is urgent to study to reduce the adsorption and entrainment of ammonium sulfate crystal grain surface A New Method to Reduce Amide Oil Loss
At present, existing literature mainly focuses on reducing the generation of ammonium sulfate (CN02139829, CN02112331, CN01106915, CN95117244), but the cost is higher, and the method for reducing the by-product of ammonium sulfate has reached a bottleneck stage
In addition, Dutch DSM (Disman) Co., Ltd. adopts the method of extraction to recover caprolactam (CN98804541), but the post-processing is more cumbersome
For how to reduce the adsorption of ammonium sulfate crystals to caprolactam, there is no patented technology at home and abroad

Method used

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  • Method for lowering caprolactam inclusion content in ammonium sulfate crystals

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0020] Add 100g ammonium sulfate, 2g caprolactam, and 250mL saturated ammonium sulfate aqueous solution of 20-40 meshes into a 500mL conical flask with stopper, add 0.08g of anionic surfactant sodium lauryl sulfate into the solid-liquid solution of caprolactam-water-ammonium sulfate In the mixed system, place in a constant temperature water bath shaker and shake at 150r / min for 24 hours, and the temperature of the shaker is controlled at 25°C. After shaking the adsorption equilibrium, separate by suction filtration, analyze the content of caprolactam entrained on the surface of ammonium sulfate by liquid chromatography, the amount of caprolactam entrained on the surface of per 100g of ammonium sulfate is 84.1% higher than when no surfactant is added, indicating that sodium lauryl sulfate It has the effect of increasing the adsorption of ammonium sulfate crystal grains to caprolactam, and cannot be used as an effective alternative additive.

Embodiment 2

[0022] The anionic surfactant sodium dodecylbenzene sulfonate of 2.0g is added in the solid-liquid mixed system of caprolactam-water-ammonium sulfate identical with embodiment 1, adsorption, separation and analysis method are the same as embodiment 1, oscillation adsorption equilibrium After that, the content of caprolactam entrained on the surface of every 100g of ammonium sulfate increased by 25.0% than when no surfactant was added. Sodium dodecylbenzenesulfonate has the effect of increasing the adsorption of ammonium sulfate crystal grains to caprolactam, and cannot be used as an effective alternative additive.

Embodiment 3

[0024] The cationic surfactant lauryltrimethylammonium bromide of 0.06g is added in the solid-liquid mixed system of caprolactam-water-ammonium sulfate identical with embodiment 1, adsorption, separation and analysis method are the same as embodiment 1, shake After adsorption equilibrium, the content of caprolactam entrained on the surface of every 100g of ammonium sulfate is 90% lower than when no surfactant is added. Dodecyltrimethylammonium bromide has the effect of reducing the adsorption of ammonium sulfate crystal grains to caprolactam, which can be used as an effective way to reduce Entrained additives.

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Abstract

The invention relates to a method for lowering the amide oil inclusion content in ammonium sulfate crystal grains by adding a surfactant into ammonium sulfate mother liquor to carry out surface modification on the ammonium sulfate crystals. The method provided by the invention is easy to implement and has low cost and high efficiency. The added surfactant can be separated from caprolactam during later rectification and other subsequent separation processes, so that the quality of final products ammonium sulfate and amide oil can not be affected.

Description

technical field [0001] The invention relates to a method for reducing the amount of caprolactam entrained by ammonium sulfate crystals by adding a surfactant, which is suitable for the recovery of caprolactam in the caprolactam process, and can also be applied to mineral flotation, petroleum exploitation, leather making and other chemical, chemical, resource and environmental fields. adsorption and separation problems. Background technique [0002] Caprolactam (CPL) is an important petrochemical product. Ammonium sulfate is an important by-product of the caprolactam process. For example, the Italy SNIA toluene process produces about 4.2 tons of ammonium sulfate per ton of caprolactam by-product. Obtain cyclohexane carboxylic acid, then carry out amidation reaction between cyclohexane carboxylic acid and nitrosyl sulfuric acid in oleum at 70°C, the reaction product is hydrolyzed to separate caprolactam and sulfuric acid, the reaction formula is as follows: [0003] [00...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07D223/10C07D201/16
Inventor 雍玉梅何晓辉杨超毛在砂张广积禹耕之
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI