China Petrochemical Development Corporation

Jih-Dar Hwang

Yung-Shun Kung

Yao-Ching Tsai

Shou-Li Luo

Hsiu-Li Cheng

Shu-Hui Chen

Kai-Hung Haung

Kuang-Ruei Chen

The present disclosure provides a method for preparing a caprolactam and the method includes steps of subjecting cyclohexanone oxime and sulfuric acid to a Beckmann rearrangement reaction to obtain a rearrangement mixture; neutralizing the rearrangement mixture and extracting the neutralized rearrangement mixture using an organic solvent sequentially; and subjecting the extracted organic solution to a hydrogenation reaction so as to simplify the process to produce a high quality caprolactam.

Method and system for preparing caprolactam

A method for continuously preparing a carboxylic acid ester is disclosed. In the method of the present invention, a vertical reactor is filled with a solid catalyst, a carboxylic acid and an alcohol are introduced into a lower part of the vertical reactor, esterification is performed to form an esterized mixture, the esterized mixture is output from an upper part of the vertical reactor, and distillation is performed to isolate the carboxylic acid ester. The method of the present invention is simple, easily controlled and environmental friendly, and has significantly high conversion rate and selectivity.

Method for continuously preparing carboxylic acid ester

A recycling system for hydroxylamine formation and oximation is proposed. The recycling system includes a hydroxylamine formation zone, an oximation zone, a purification zone, and an adjusting zone having a nitrate absorption tower. An inorganic process solution, used by the recycling system, partially enters the nitrate absorption tower supplementing nitrate, followed by mixing with the residual inorganic process solution, thereby reducing the loss rate of hydroxylamine in the inorganic process solution due to degradation. In addition, the organic impurities with high boiling point in the inorganic process solution can be effectively removed in the purification zone. As a result, the reduced activity or selectivity of the catalyst for hydroxylamine formation, caused by the toxic effects of these organic impurities on the catalyst, can be avoided, and hence, a high concentration of hydroxylamine can be obtained.

Recycling system for hydroxylamine formation and oximation

Provided is a process of producing cyclohexanone oxime comprising the steps of: pre-mixing an inorganic process solution containing a high concentration of hydroxylamine phosphate with a first stream of cyclohexanone such that the concentration of hydroxylamine phosphate is reduced to 80% or less of its initial concentration; and subjecting hydroxylamine phosphate in the premixed inorganic process solution to an oximation reaction with a second stream of cyclohexanone. According to the process, oximation is performed after the inorganic process solution containing a high concentration of hydroxylamine phosphate has been pre-mixed with the first stream of cyclohexanone to reduce the concentration of hydroxylamine phosphate. As a result, not only that the efficiency of oximation and the yield of cyclohexanone oxime are increased, but also the organic content of the inorganic process solution discharged from the oximation tower is reduced.

Process for production of cyclohexanone oxime

A method of recovering adipic acid and 6-hydroxycaproic acid from the waste solution of alkali metal salts of organic acids coming from the process of cyclohexane oxidation, which comprises:

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Taipei, Taiwan

Jih-Dar Hwang