SU1641804A1 - Method for obtaining cyclohexanone and cyclohexanol - Google Patents

Abstract

The invention relates to cyclic alcohols and ketones, in particular the production of cyclohexanone and cyclohex. The invention relates to an improved method for producing cyclohexanone and cyclohexanol, which are intermediates in the synthesis of caprolactam and adipic acid, and can be used in the chemical industry. The purpose of the invention is to increase the yield of the final products and the productivity of the installation. Sanola - industrial intermediates for the synthesis of caprolactam and adipic acid. The purpose of the invention is to increase the yield of target substances and increase plant productivity. To do this, cyclohexane is oxidized with an O-containing gas in the presence of a catalyst of cobalt naphthenate at a pressure of 7-25 kg / cm and a temperature of 140-200 ° C in a multisection reactor with an additional feed (stepwise) cyclohexane with a temperature of 100-120 ° ; C in the amount of 70-100% of the amount of feed to the first section. The residence time of the reaction mass gradually decreases from section to section according to the equation jO, / (n + 2)}:: (Јg / n) (n-Ol (n-2YJ:: ... Ј „/ 2 С ± 0.1 C, where Ј is the residence time of the reaction mass E of each section, n is the number of sections, C is a constant value, calculated by the mode parameters. In this case, the yield of the target substances increases by 1.5–3%, and the productivity is 1 , 5 - 1.7 times. Table 2 Example 1. The cyclohexane is oxidized in a continuous process in a four-section reactor having a useful volume of 71 m3 (24 + 17 + 16 +

Description

the sections are 11, 38 and 59 cyclohexane and 1300, 1600 and 2200 nm e / h of air, respectively, while the supply of cyclohexane in sections 2-4 is 100% of the supply to the first.

We set the load on the organic layer at the exit from the fourth section of the Zykhf 16 ° m3 / 4 (with

The residence time of the oxide is calculated by the formula

"

3ebl n-f ° / #

(60

de V.n - the volume of the corresponding sec- 1

tion, m9; 0.93 - coefficient taking into account

organic gas content. who would be;

Г и20

I 160

f - density of cyclohexane at

20 ° С (0.778 kg / dme) and 160 ° С (0.630 kg / dm3); OWH amount of organic

layer at the exit of the n-th section, which is calculated by the formula

pvtyhp (3vkho) 1 + 3kho912. + + JBX (), (Hee, + 3yhoci + ... + Ji),); thirty

where j tsipe. - cyclohexane ablation, m / h

CBS

Part (determined by air temperature, pressure and load; at 160 ° C and 8.5 atm per 1000 air, 8 m e / h of cyclohexane is carried away).

Then

14 o

 M h-7 777 7 7 7 -z ° -0659 h

 3.95 min.

In accordance with the above formula

(mf JU / n e / (, - 0 -...- - {- with

where C

i 2 2

-Ґ-5- - .. "in,

. 98 (p-1) 5.94 min; g 1,98 1 p 7,92 min;

1 1.98 (n + 2) 11.88 min.

The value of the load on the organic layer leaving each section is determined by the following formula:

H

Jewxn to.

In accordance with the above formula, JsbJX%. 121 m3 / h; J 0x2. 98: D Vmh, 97 m3 / h.

The supply of cyclohexane to the first section and the additional supply in 2 to 4 sections are calculated by the formulas:

0

0

0

five

50

five

 -J prom

+ koci;

+ i + KOC4

Jeifo - bbDie

-1., V

VHOCH J Bbl) (+ CCOS +

. .

+ Tskos z J buo J wuo

, BDIX f- + + J HOC2 + + J KQC5 + JUKOC, :).

- entrance, W U9 s

The corresponding values of cyclohexane carried away with the exhaust gases (Excess) are determined by calculation using the vapor pressure of cyclohexane at a given temperature, pressure values and air supply rate.

Given these values (J

 , 20 m3 / h) we obtain the values of J eyoft.-t

AND; 3 UkOC2.

 108; 3ххрг 53.

11 J braid

Pz.

- 15., p38 O

;

Values 3

its

respectively 97; 98; 121 and 160 me / h. When carrying out the oxidation under the conditions described, the oxidate at the outlet of the fourth section contains 0.090 mol / l of cyclohexanone; 0.155 mol / l cyclohexanol; 0.035 mol / l cyclohexyl hydroperoxide; 0.025 mol / l acid; 0.015 mol / l ethers, degree of conversion of cyclohexane 4.0%. The yield of useful products is 89.5%. The productivity of the reactor in terms of the amount of useful products in terms of cyclohex anon is 5.1 tons / h.

The conditions of the experiment in examples 1-9 are presented in table 1.

The results of the experiments in examples 1-9 are shown in table 2.

An increase in the supply of an additional amount of cyclohexane in 2-4 steps above 100% of the supply to the first section leads to an increase in the oxygen content in the exhaust gases above the normalized rules of safe process limits due to the short residence time in these sections of the reactor.

Reducing the supply of cyclohexane in stages 2–4 to 60% of the supply to the first stage (as can be seen from a comparison of examples 1,2 and 6) leads to a decrease in the yield of useful products by 2–2.5%.

Example 7. Comparative, carried out under the conditions of a known method.

Try on The oxidation of cyclohexane is carried out in a continuous manner in a five-section reactor with a net volume of 83 Me (24 + 17 + 16 + + 14 + 12), at a pressure of 8.5 atm and a temperature of 155-160 ° C.

PRI me R 9. The oxidation of cyclohexane is carried out in a continuous way in a six-section reactor having a useful volume of 95 m3 (25 + 18 + 16 + 14 + + 12 + 10), at a pressure of 8.5 atm and a temperature of 155-160 ° WITH.

Thus, the proposed method for producing cyclohexanol and cyclohexanone allows to increase the yield of target products by 1.5-3% compared with the known method and to increase the productivity of the process by 1.5-1.7 times, which leads to savings of special steel in the manufacture reactor.

five

Claims (1)

Invention Formula The method of producing cyclohexanone and cyclohexanol by liquid-phase oxidation of cyclohexane with oxygen-containing gas in continuous mode in the presence of a catalyst of cobalt naphthenate at a pressure of 7-25 kg / cm and a temperature of 140-200 ° C in a multi-compartment reactor with an additional loop-fed cyclohexane having a temperature below the temperature in the reactor section, starting from the second one, characterized in that, in order to increase the yield of the final products and the capacity of the installation, the additional supply of cyclohexane to the sections is with a temperature of 100-120 ° C in the amount of 70-100% of the supply of cyclohexane to the first section and with the residence time of the reaction mass gradually decreasing from section to section according to the equation 25 where Ј is the residence time of the reaction mass in each of the sections; n is the number of sections; С - constant value, calculated by parameters mode. (Table The ratio of the amount of additionally supplied cyclohexane to the feed in the first section,%. Temperature additionally supplied cyclohexane, 0C. 6lit2