SU852851A1 - Method of preparing 1,3-dibromoadamantane - Google Patents

Description

one

The invention relates to basic organic synthesis, in particular, to a method for producing polycyclic halogen-substituted hydrocarbons, which are the initial products for the production of polymeric materials, pharmaceutical preparations, as well as in organic synthesis.

There is a known method of direct bromination of adamantane to 1,3-dibromadamantane using aluminum and boron halides as catalyst. In this way, adamantane is introduced into an eightfold excess of bromine with a catalyst with vigorous stirring and cooling.

However, the process is complicated by the use of highly toxic, moisture-sensitive aluminum and boron bromides, high consumption of bromine, difficulty in removing heat from the reaction medium, which leads to process instability and contamination of the target product by side compounds. The method requires a special sealing boot to introduce adamantane into the reaction mixture, which complicates the process technology.

The closest to the proposed method is the method of producing 1,3-dibromadomantane by synthesizing eight-fold excess of bromine adamantane in the presence of metallic iron 2. However, the introduction of bromine into adamantane B in the presence of metallic iron (and 6 other catalysts mentioned above) does not lead to selectively producing 1,3-dibromadomamantane, and gives an unstable mixture of brominated products of ada 10 mantana, in which the content of 1,3-dibromadamantane does not exceed.

The aim of the invention is to reduce the consumption of bromine, increase the yield of the target product and increase the selectivity and stability of the process.

 To achieve the goal, adamantane is first brominated, first without catalyst, for 1.0-1.5 hours at a molar ratio of adamantane: bromine 1: 2.5 to 4.0, and then in

20, the reaction mixture is added with a metallic iron catalyst at such a rate that the process temperature is maintained at 15-25 ° C.

25 In addition, during bromination, predominantly bromine is introduced into adamantane.

The temperature conditions in the first stage are not limited. In the second stage, the temperature does not exceed 25 ° C,

30 since polyhaloadamantanes and tar products are formed with increasing temperature.

When the molar ratio of adamantane: bromine is 1: 2.5, the process is conducted in chloroform to homogenize the reaction mixture, with an even greater decrease in the amount of bromine, products of incomplete bromination appear.

Example 1. In a reaction flask, add, add 10 g of adamantane and gradually add 15 ml of bromine (adamantane: bromine ratio 1: 4). The mixture is stirred for 1 h.

Thereafter, while cooling, 0.81 g of metallic iron is introduced into the reaction mass at such a rate that the temperature in the flask does not rise above 25 ° C (the reaction is exothermic), and the reaction mixture is stirred for 2-3 hours under these conditions. Product the reactions are neutralized with sodium metabisulfite, washed with water until neutral, filtered and dried to constant weight. The purity of the product is confirmed by gas-liquid chromatography and the physicochemical constants of 1,3-dibromo mamantane. The yield of 1,3-dibromodamantane is 92.6%.

Example 2. The procedure is the same as in Example 1, but the process is carried out with an adamantane: bromine ratio of 1: 2.5. The reaction is carried out in chloroform medium, which is added in the first stage after the addition of bromine. The yield of 1,3-dibromadicanta is 91.6%.

PRI me R 3. (comparative). The molar ratio of adamantane: bromine 1: 1. The composition of the final product,%: monobromomamantane 97, adamantane 3.

Example 4 (comparative). The experiment was carried out without cooling the reaction mixture, the temperature during catalyst introduction was maintained above 25 ° C. The composition of the final product,%: dibromadamanta 8.1, tribromadamantane 82, tetrabromomamantane 5.8.

Example 5. (comparative). A sample of adamantane 10 g and 0.81 g of metallic iron is loaded into the reaction flask, then 15 ml of bromine are added dropwise (the molar ratio is adamantane;

bromine 1: 4). The mixture is stirred for 2-3 hours, the temperature of the experience support not higher than 25 ° C. The composition of the final product,%: dibromadicanthane 2, monobromodamantan 8, tribromomadmantan 80, tetrabromomamantan 10.

Claims (2)

1. A method for producing 1,3-dibromadamantane, including the bromination of adamantane with liquid bromine in the presence of a catalyst — metallic iron, which is mainly due to the fact that in order to reduce bromine consumption, increase the yield of the target product, increase the selectivity and stability of the process, Adamantane is first brominated for 1–1.5 hours with a molar ratio of adamantane and bromine 1: 2.5–4.0, and then the catalyst is introduced into the reaction mixture at such a rate that the process temperature is maintained at 15–25 ° C. 2. The process according to claim 1, is distinguished by the fact that bromine is introduced into adamantane. Sources of information taken into account in the examination 1.E. Tolaty, A. Concienne, A. Dupiiy., “Selective dibromtion of adamantane J Cnem. Sos. (C) 1968. No. 15, 1902. 2.Lihotvorin I.P., Dovgan N.J., Danilenko G.I., Synthesis of dibromadamantap. Journal of Organic Chemistry, 13, 897, 1977 (prototype).