Back to results
US 9,518,024 B2Granted
Method and system for preparing caprolactam
AssigneeChina Petrochemical Development Corporation
InventorsYung-Shun Kung, Jih-Dar Hwang, Yao-Ching Tsai
Life of this patent
Estimating the term…
Abstract
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.
Claims15
A method for preparing caprolactam, comprising steps of:
- (a) subjecting cyclohexanone oxime and sulfuric acid to a Beckmann rearrangement reaction to obtain a rearrangement mixture;
- (b) neutralizing the rearrangement mixture with a base to obtain a first crude caprolactam solution rich in caprolactam and a second crude caprolactam solution rich in sulfate;
- (c) extracting at least the first crude caprolactam solution with an organic solvent to obtain a caprolactam organic solution;
- (d) mixing the caprolactam organic solution with hydrogen to perform a hydrogenation reaction in a hydrogenation reactor having a hydrogenation catalyst, wherein a weight hourly space velocity of the caprolactam organic solution is 1 to 20 per hour, a feeding hydrogen flow rate is NM3 0.01 to 0.15 NM3 per hour per cubic meter of the caprolactam organic solution, and a hydrogen gauge pressure of an outlet of the hydrogenation reactor is 3 kg/cm2 to 20 kg/cm2;
- and
- (e) purifying the hydrogenated caprolactam organic solution, wherein the purification includes steps of evaporation and distillation to separate the caprolactam.
3 more elements
Dependencies are inferred from the claim text.