SU1203082A1 - Method of producing bromine- or iodine-aromatic hydrocarbons - Google Patents

Description

The invention relates to organic chemistry, namely, to an improved method for producing -bromo- or iodo-aromatic hydrocarbons, which are used as intermediates in organic synthesis, in the preparation of drugs, for the synthesis of heat-resistant plastics.

The aim of the invention is to simplify the process (through the use of an available, easily regenerable and non-toxic oxidant), an increase in the yield of the target product.

Example 1. 20 ml of a solution containing 5 ml of water, 15 ml of trifluoroacetic acid, 4.6 g (0.05 mol of toluene and 5.6 g (0.05 mol) of potassium bromide) are treated with 80 ml of trifluoroacetic acid containing 23.6 g (0.1 mol) of cobalt acetate (III). The molar ratio of toluene:: potassium bromide: cobalt acetate (III) is 1: 1: 2. The concentration of trifluoroacetic acid is 95% by volume. After 15 min, the reaction The reaction mixture is diluted with water and extracted with chloroform or petroleum ether. The solvent is distilled off from the extract, the residue is distilled. 6.85 g of benzyl bromide are obtained (Bp. 198-201 C). Yield 80%.

Example 2. The experiment was carried out as in Example 1, starting from 4.6 g (0.05 molG of toluene, 4.9 g (0.05 mol) of ammonium bromide, 23.6 g (0.1 mol) of cobalt acetate (B) in 100 ml of 85% trifluoroacetic acid. The expected product is isolated as in Example K. 7.1 g of benzyl bromide are obtained. The yield is 84%.

Example 3 To a solution of 7.8 g (0.1 mol) of benzene and 30 g (0.2 mol of sodium iodide) in 45 ml of trifluoroacetic acid and 5 ml of water are added 50 ml of trifluoroacetic acid containing 70.8 g (0.4 mole) of cobalt acetate (III). The concentration of trifluoroacetic acid is 95% by volume. After 10 min, the reaction is completed, the precipitated diiodobenzene is washed with water and dried, the yield is 29.7 g (88%), mp. 130 C.

Example 4. The experiment was carried out as in Example 1, based on

five

0

five

0

five

0

five

0

five

7.8 g (0.1 mol) of benzene, 30 g (0.2 mol) of sodium iodide and 70.8 g (0.4 mol) of cobalt acetate per 100 ml of 70% trifluoroacetic acid. The product is isolated as in Example 1. 28.5 g, 1 (87.5%) are obtained. M.p. 129-130 ° C.

EXAMPLE 5 The experiment was carried out as in Example 1, starting from 0.78 g (0.01 mol) of benzene, 3.0 g (0.02 mol) of sodium iodide and 7.08 g (0 , 04 mol) of cobalt acetate (III) in 40 ml of 60% (by volume) aqueous trifluoroacetic acid. The desired product is isolated as in Example 1. 1.5 g of diiodobenzene is obtained. Yield 45%.

Example 6. General procedure for the reaction of toluene bromination. To a solution of 4.6 g (0.05 mol) of toluene in 20 ml of trifluoroacetic acid containing 0.1-0.2 mol of alkali metal bromide, add the required amount (15-220 ml) of trifluoroacetic acid containing 0.1 mol cobalt acetate (III) —23.6 g or manganese (III) —23.2 g. After 0.5–10 min, the reaction is complete. The reaction mixture is diluted with water and extracted with chloroform. The composition of the extract is analyzed by GLC. Then the solvent is distilled off from the extract, a mixture of ortho-and para-bromotoluenols (m.p. 181-184 ° C, p: o 80:20) is distilled from the residue.

The data on the oxidative b-formation of toluene in the Co (OAc) –NaBr and Mn (OAc) К –Crg system are given in Table. I and 2 respectively.

Thus, the proposed comparison with the known one makes it possible to exclude the use of toxic and aggressive .molecular chlorine and sajNieHHTb as an oxidant, its available and easily regenerated cobalt (III) or manganese acetate (III), to exclude the use of initiators ( or irradiation) and reduce the time and temperature for obtaining the desired products from several hours when heated to and irradiation to several minutes at room temperature.

Table 1

Claims (1)

METHOD FOR PRODUCING BROMINE OR IODAROMATIC HYDROCARBONS by oxidizing halogenation of aromatic hydrocarbons with a halogenating agent - an alkali metal salt using an oxidizing agent in an aqueous organic solvent, characterized in that, in order to simplify the process and increase the yield of the target product, acetate is used as an oxidizing agent or manganese, and as an aqueous-organic solvent, 60-95% aqueous trifluoroacetic acid.