US 2008/0167495 A1Published application

Recycling system for hydroxylamine formation and oximation

AssigneeChina Petrochemical Development Corporation

InventorsJih-Dar Hwang, Hsiu-Li Cheng, Shou-Li Luo

Life of this patent

Estimating the term…

Loading patent…

Abstract

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.

Claims11

Dependent claims

A recycling system for hydroxylamine formation and oximation, comprising:

(a) a hydroxylamine formation zone in which nitrate is reduced to hydroxylamine with a hydrogen gas in the presence of a catalyst in an inorganic process solution containing an acidic buffering agent;
(b) an oximation zone in which hydroxylamine formed in the hydroxylamine formation zone and cyclohexanone are subjected to an oximation reaction to form cyclohexanone oxime;
(c) a purification zone in which the organic impurities in the inorganic process solution are removed;
and
(d) an adjusting zone having a nitric acid absorption tower for supplementing nitrate ions to the inorganic process, the inorganic process solution fed into the adjusting zone comprises a first portion that is fed to the nitric acid absorption tower, and a second portion that is not fed to the nitric acid absorption tower, such that the volume of the first portion of the inorganic process solution does not exceed 20% (by volume) of the total volume of the inorganic process solution, and in which the first portion of the inorganic process solution, after being supplemented with nitrate ions in the nitric acid absorption tower, is mixed with the second portion of the inorganic process solution.

2 more elements

Dependencies are inferred from the claim text.