SU882992A1 - Method of combined production of cyclohexanol and cyclohexanone - Google Patents

Description

The invention relates to an improved process for the co-production of cyclohexanol and cyclohexanone intermediates for the production of polyamide fibers. A known method for the joint production of cyclohexanol and cyclohexanone by catalytic oxidation of cyclohexane with atmospheric oxygen under pressure. As a result, the reaction products, cyclohexanone, cyclohexanol and adipic acid, are formed. The degree of conversion of cyclohexane is 5–12%, the yield of useful products is up to 80% P. The disadvantage of this method is low conversion and low selectivity. A known method for the joint production of cyclohexanone and cyclohexanol by oxidizing cyclohexane with an acid of air at elevated pressure (up to 30 atm) and 130-1 ° C in the presence of cobalt naphthenate 21. However, with a hydrocarbon conversion of 30%, the selectivity for the target products is only jO, the total is 12 % A known method for the simultaneous preparation of cyclohexanol and cyclohexanone by oxidizing cyclohexane at a pressure of 10-3 atm in the presence of 0.3% cyclohexanol and 0.05% cobalt naphthenate. The total yield of cyclohexanone and cyclohexanol is 7090% (conversion 10-13%). The ratio of alcohol to ketone is approximately equimolecular. 3. The disadvantage of this method is low conversion. The closest to the invention is the method of conventional preparation, cyclohexanol and cyclohexanone by oxidizing cyclohexanone with air oxygen in the presence of acetylacetonate and chromium stearate. With a hydrocarbon conversion of 2, 3% at 120 ° C, the yield ratio of cyclohexanone and cyclohexanol is 3. Oxidation is carried out for 3 hours under a pressure of 30 kg / cm using 1 10 mol / l of these catalysts. The total selectivity for alcohol and ketone is 96-97 (conversion 2.8-3.3). With an increase in conversion at the hydrocarbon, the yield of the target products decreases. The use of a tert-butyl peroxide initiator in a mixture with tert-butNOL and chromium acetylacetonate changes the ketone: alcohol ratio. With a conversion of 0.325%, this ratio is 1.82: 1 C.

The disadvantages of this method are the low conversion of cyclohexane into

target products (2.8-3.3%) with a 3-m oxidation time; the limited solubility of chromium stearate and chromium acetylacetonate in a hydrocarbon; the selectivity of the cyclohexanone process is relatively low (the ratio of ketone: alcohol is 3: 1).

The purpose of the invention is to intensify the process, increase the selectivity of the process with respect to cyclohexanone and increase the conversion of cyclohexane.

The goal is achieved by the fact that the joint production of cyclohexanol and cyclohexanone is carried out by liquid-phase oxidation of cyclohexane

oxygen at elevated pressure and elevated temperature in the presence of a chromium catalyst, and a distinctive feature

is carrying out the process in the presence of cyclohexyl hydroperoxide, taken in an amount of 0.108 - 0.536 mole%, and using as a chromium catalyst

hexacarbonyl. chromium, taken in the amount of 0.0002-0.019 mol%, at 115-1 0 С and 7.5-15 atm-d.

Example 1. 100 ml of cyclohexane (0.93 mol) is oxidized by oxygen

air at 130 ° C in an autoclave at a pressure of 7.5 kg / cm in the presence of 0.05 wt.% (0.019 mol. / chromium hexacarbonyl and 0.01 mol / l (Oh, .1.08 mol.%) cyclohexyl hydroperoxide for 1 , 5 hours at an air flow rate of 5 l / min per liter of charge. Cyclohexanone and cyclohexanol are recovered by vacuum rectification. A mixture of cyclohexanone and cyclohexanol is obtained with a yield of 91% at a ratio of ketone and alcohol of 3.27: 1 (hydrocarbon conversion of 9.6%) .

Examples 2-11. The process is carried out as in Example 1. The results of the process are shown in the table.

Table continuation

Claims (3)

The proposed method has a high ketone selectivity even if the oxidation of cyclohexane is carried out in the absence of a hydrochloric acid cyclohexyl using only chromium hexacarbonyl, since the primary molecular oxidation product is cyclohexyl hydroperoxide, which is complexed with the hexacarbonyl complex and the hexacarbonyl complex is formed; and is responsible for the selective oxidation of cyclohexane to cyclohexanone. In the proposed method, along with the acceleration of the process, a mixture of cyclohexanone and cyclohexanol is obtained with a higher yield of 91-98 (conversion 3.6-13.8). At the same time, Cr (CO) b directs the oxidation process selectively to ketone. In the method using a mixture of cyclohexyl hydroperoxide and chromium hexacarbonyl, the ketone: alcohol ratio (3.277 ".60): 1. Invention 1, Method for the joint production of cyclohexanol and cyclohexanone by liquid-phase oxidation cyclohexane with atmospheric oxygen at elevated pressure and elevated temperature in the presence of a chromium-containing catalyst, characterized in that, in order to intensify the process and increase the conversion and selectivity of the process with respect to yklogeksanonu, / process is carried out in the presence of cyclohexyl hydroperoxide ,. taken in the amount of 0 108–0,536 mol.%, and hexamocarbonyl chromium, taken in the amount of 0.0002-0.019 mol, is used as the chromium-containing catalyst at 7.5–15 atm. Sources of information taken into account in the examination 1. Production of caprolactam. M., Himi, 1977, p. 35-67. 2. The patent of the Federal Republic of Germany (G, Cl. 07 C k3 / 3Q, published 1953. 3. US patent number, class. 260-586, publ. . . Pustarnakova G.F., Solnikov V.M. and Denisov, Ye.T. USSR Academy of Sciences, middle; chemical., 1975, № 3,. P. 5f7-552. (Prototype).