CS271716B1 - Method of cyclohexane oxidation - Google Patents

Abstract

It solves the improvement of the removal of the action and into the oxidation process is introduced water using an inert component in the oxidation mixture that forms an azeotropic mixture with the water. As the inert component benzene is used containing high molecular substances - by-products of the oxidation of cyclohexane. The cyclohexane oxidation method increases the production capacity of cyclohexanone, increasing at the same time the oxidation selectivity and decreasing the feed material consumption norms.<IMAGE>

Description

The invention relates to a process for the oxidation of cyclohexane to cyclohexanol and cyclohaxanone by addition of a catalyst and an inert water-forming component of azeotropic grains;

Oxidation of cyclohexane to cyclohaxanone and cyclohexanol with oxygen from the air at the same temperature of the catalyst at a temperature of 100 to 200 ° C and a pressure of 0.5 to 1.5 MPa takes place in a cylindrical, horizontal and three-chamber reactor, the individual chambers of the reactor being · Oxidation of cyclohexane It is an exothermic reaction with a considerable thermal effect, while excess of the heat of reaction evaporates part of the reaction solution · Vapors together and used air pass through a series of cooling · A non-condensable residue is discharged into the atmosphere · With the degassing of the reactor, a substantial part of the reaction water, which affects the oxidation of cyclohexane to cyclohexanol and cyclohexanone, is also drained off.

The disadvantage of the described cyclohexane oxidation process is the lack of separation of water from the reaction mixture. · Water causes increased formation of high molecular weight compounds forming a minor part of the oxidation reactor deposits. · The ingredients have a negative effect on cyclohexane production capacity. where the liquid meets the countercurrent with the gas · The reactor is divided into four zones: oxidation, concentration, digester and stripping-cooling · The air at the oxidizer ea delivers 1 · to 10 · reins, 11 · to 14 · the tray serves as the heating zone of the reactor · Stages 15 · 18 · determine reactor etr etr cooling zone · Below 18 · reactor deck ea feeds inert gas · Advantage of the described solution is a continuous directing of the oxidation gas fed to higher floors using the air from lower levels · Disadvantage is the way of cooling the reaction mixture in the reactor itself ·

U. S. Patent 2,557,281 recommends the continuous separation of water resulting from oxidation so as to allow aeparation of the isolated oxidation products and subsequent acid extraction with water. However, even with this technology, and as much as 20% of the cyclohexane reacted, it springs to undesired by-products. German Patent No. 1 047 77Θ, the formation of high molecular weight compounds during oxidation that deposit on the reactor walls and slow down the reaction can be prevented by washing cyclohexane again before oxidation with acidic water, but even this way ea does not achieve a significant increase in cyclohexanone and cyclohexanol yield.

The method of oxidizing cyclohexane to cyclohexanol and cyclohoxanone according to the present invention aa is carried out in the presence of a catalyst at a temperature of 130 to 200 ° C and a pressure of 0.5 MPa to 1.5 MPa. Benzene is used as the inert component in concentrations of 1 to 12% by weight, preferably 2 to 5% by weight, forming an azeotropic mixture with water.

The advantage of the cyclohexane oxidation process of the present invention is the ability to continuously degrade the reaction and feed water. · Benzene forms a lower-boiling azeotropic mixture over a water-cyclohaxane mixture. In addition, benzene increases the solubility of cyclohexane oxidation by-products to cyclohaxanone and cyclohexanol. In the cyclohexane oxidation process according to the present invention, the likelihood of reactor fouling will be reduced, which will have a positive effect on increased cyclohexanone production capacity and lowering of feedstock consumption standards.

The operation of the oxidation reactor according to the invention is described in the following examples.

Example 1

Combined state oxidation of cyclohexane to cyclohaxanone and cyclohexanol · Oxidation takes place in a six chamber horizontal valeovon reactor · ^ 8 ^ 8 ^ (. ^ 488 .-. 88888888888888888808888888 ^ 8888888888888888888888888 ^ 88 ^

CS 271 716 -1 —1

600 a * h cyclohexane e containing 0.3 to 0.99% by weight of benzene · Cyclohexane is oxidized by oxygen from the air in the presence of a Co ² * catalyst at a temperature of 155 to 165 ° C and pressure

0.9 MPa · Oxidation reactor fouling lasts only 2 to 3 msec for cyclohaxane oxidation, which negatively affects cyclohexanone production capacity and feedstock consumption standards. It is assumed that water in the oxidation reactor causes increased formation of high molecular weight compounds and hence deposit · r

Example 2

The cyclohexane oxidation process described in Example 1 proceeds with the reaction clutter having an operating cycle count of 1 to 3% by weight of benzene · Oxidation reactor cycle / time between court readings of the reactor / takes 6 months ·

Example 3

The process described in Example 1 is that the reaction mixture contains 3.5 to 8% by weight of benzene, with the addition of banzene to the return cyclohexane. The operating cycle of the cyclohexane oxidation node takes five months and the planned outage of the oxidation node has taken place.

Example 4

The process described in Example 1, wherein 1 to 3.5% by weight of benzene is present in the reaction mixture, wherein benzene is fed to the reaction mixture via an oxidation catalyst mixture. · The operation cycle of the oxidation reactor is four months.

Claims (4)

PREOMET OF THE INVENTION A process for the oxidation of cyclohexane to cyclohexanol and cyclohexanone using a catalyst at a temperature of 130 to 200 ° C and a pressure of 0.5 to 1.5 MPa, characterized in that the inert component benzene is added to the cyclohexane and / or reaction equipment at a concentration of 1 to 12%. %, preferably 2 to 5% by weight, of water forming an azeotropic mixture.