RU1801963C - Method of monochloroacetic acid synthesis - Google Patents

Abstract

Usage: as an intermediate of organic synthesis. SUMMARY OF THE INVENTION: Monochloracetic Acid Product BF C2H3CSO2. Yield 82.9-83.3%. Selectivity 88.5-88.9%. Acetic acid is chlorinated in the liquid phase at 85-1 ° C in the presence of acetic anhydride in a cascade of reactors. Chlorine is supplied countercurrent to the movement of chloromass in reactors. The supply of liquid products in the reactor is from above, and gaseous - through the barter from below. 1 s.p. f-ly. 1 tab.

Description

 The invention relates to a technology for the production of monochloroacetic acid, which is an intermediate product of organic synthesis in the production of herbicides of the phenoxyacetic acid group and pharmaceutical preparations.

The purpose of the invention is to increase yield and selectivity and simplify the process.

Acetic acid is chlorinated in the presence of acetic anhydride in a cascade of reactors in the liquid phase at 85 - 110 ° C. Chlorine is supplied countercurrent to the movement of chloromass in the reactors; preferably, liquid products are fed into the reactor from above, gaseous from below through a bubbler.

Example 1 (comparative according to the prototype, chlorine and chlorine masses are fed through).

The chlorination of acetic acid (AC) is carried out in a continuous laboratory setup in two reactors connected in series at a temperature of 97.5 ° C. The supply of chlorine is carried out through a bubbler in the flow direction of the mass. The initial mixture of UK and acetic anhydride (UA) in a mass ratio of 93% and 7% is fed to the top of the packed adsorber with a feed rate of 1 g / h. The supply of chlorine is carried out according to the minimum slip of it from the system and is 18 ± 0.2 g / h. Eight hours after the unit is in stationary mode, after the 11th reactor, 24.3 g / h of chlorine mass are obtained, in May. %: monochloracetic acid (MCC) 91.7; dichloroacetic acid (DCAA) 4.1. Conversion of starting products 93.7%. The yield of MCCA is 81.5%. The content of DHAK in chlormes was 4.1 May. %

Calculation of the conversion and yield of the MCC:

ABOUT

Yu

Filed by CC:

14.68 1.12 120 60102 -60

 0.248 + 0.022 0.27 mol / h.

Received, g:

MHUK 22.28 (0.235 mol)

DHUK1.00

U K 1.02 (0.017 mol)

Converse

0.27-0.017 0.27

 93.7%

The selectivity of the process is 0.235 / 0.270 87.0%. - The output of the Moscow Art Theater K 0.87 0.937 81.5%.

EXAMPLE 2 (by average values of the proposed method).

The chlorination of acetic acid was carried out under the conditions of Example 1 at a temperature of 97.5 ° C. The supply of chlorine is carried out according to the minimum slip through countercurrent through a bubbler located in the lower part of the II reactor. Liquid products: UK and UA or chloromass enter the first and second reactors from above. Chlorine feed rate 17.8 ± 0.2 g / h. Product sampling is carried out from the bottom of the reactor through a water trap. Eight hours after the unit is in stationary mode, after the second reactor, 24.3 g / h of chlorine mass are obtained, May. %: MHUK 93.4; DHUK 2.5; UK 4.1.

Converse

0.27-0.0165 0.27

93.7%

P 94

Selectivity 88.9%

Yield 0.889 -0.937 83.3%.

Example 3 (according to the boundary values of the proposed method).

Chlorination of CCs is carried out using the countercurrent chlorine feed circuit of Example 2. The mixture of CCs and HCs in a mass ratio of 93% and 7% is supplied at a rate of 16 g / h. Temperature

0

5

0

chlorination 110 ° C. Chlorine supply 17.8 ± 0.2 g / h. After 8 hours of chlorination, 24.3 g / h of chloroform composition, after May II, are obtained. %: MHUK93.4; DHUK2.6; UK4.0. Conversion 94.0%. Selectivity 88.9%. The yield of MHC K is 83.5%.

Example 4 (according to the boundary values of the proposed method).

The chlorination of CC is carried out according to Example 2 at a temperature of 85.0 ° C. After 9.5 hours of chlorination, 24.3 g / h of chloroform composition, after May II, are obtained. %: MHUK 93 (2; DKHUK 2.6; UK 4.2. Conversion 93.7%. Selectivity 88.5%. The yield of MHUK 82.9%.

Example 5 (comparative, supply of liquid and gaseous products from below).

Chlorination of CC is carried out according to Example 2 with countercurrent movement of chlorine and chlorine mass. The supply of liquid and gaseous products was carried out from below the reactor. # Chlorine supply 17.9 ± 0.2 g / h. After 8 hours receive 24.3 g / h of chloromass composition, in May. %: MHUK 92.6; DHUK 3.0; UK 4.4. Conversion of starting products 93.4%. Selectivity 5 88.15%. Yield 82.19%. .

The results of the examples are summarized in table ..

Claims (2)

1. The method of producing monochloroacetic acid by chlorination of acetic acid in the liquid phase at a temperature of 85-110 ° C in the presence of acetic anhydride in the cascade of reactors using the absorption of gases by the starting reagents, and so on, and that In order to increase the yield, selectivity and simplify the process, chlorine is supplied countercurrent to the movement of chloromass in the reactors. 2. The method according to claim J, with the exception that the supply of liquid products to the reactors is carried out from above, and gaseous - through a bubbler from below. 0 5 0 Conditions and results of chlorination of acetic acid. Table continuation