RU2000295C1 - Method for manufacture of polybrominated secondary aromatic amines - Google Patents

Abstract

Use in the production of haloaromatic amines, in particular as a compound, flame retardant polymeric materials. SUMMARY OF THE INVENTION: Product-polybrominated secondary aromatic amines. Reagent 1: secondary aromatic amine. Reagent 2: bromine Reaction conditions: heating in an organic solvent using an oxidizing agent - hydrogen peroxide or sodium chlorate with acid.

Description

The invention relates to an improvement in a process for the preparation of polybromo-containing secondary aromatic amines used as flame retardants for polymeric materials.

A known method of producing hexabromodiphenylamine by bromination of diphenylamine with thionyl bromide followed by decomposition of the reaction mass with ice and recrystallization of the resulting technical product from chloroform 1. Yield 2.2; 4.4; 6.6-hexabromobiphenylamine is 98%, melting point 222-223 ° C

The disadvantage of this method is the difficulty of working with ice under production conditions and the gas contamination of the working area due to possible depressurization of the equipment.

A known method for producing 2,24.46,6-hexa bromide d and phenyl amine by bromination with molecular diphenylamine bromine or

tetrabromodiphenylamine in an organic halogen-containing solvent (bromoform. chloroform, carbon tetrachloride) in the presence of Friedel-Crafts catalyst at a temperature of 50-200 ° C and a pressure of 100-500 kPa 2. The technical product of the bromination reaction is purified by stirring at 50-100 ° C 10-30 times the amount of acetic acid loaded with bromine

The disadvantage of this method is its almost complete lack of technology due to the use of large amounts of bromine in the process and the release of / orosion-active hydrogen bromide, which requires its utilization, the complexity of the hardware design due to the reaction at elevated pressure and temperature in the presence of a catalyst, the need for additional product cleaning

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Closest to the claimed method is a method for producing 2,2,4,4-tetrabromo-dhfspcllmin 3. according to which 0.25 moles of diphenylamine in 300 cm ccfufrrma are added dropwise to the rhvum of head at a speed of 4. -.1 and a solution of 1 mol of bromine in 140 i m .- ;; of acetic acid at room 1 й th irw, -, | pt / pe until about 35 cm3 is added. The reaction mass is spontaneously heated to 60 ° C. After the initial precipitation of the precipitate, the solution becomes transparent, and then precipitates a fresh precipitate. The remainder of the solution of bromine in acetic acid was added at L0-60 ° C. Then water is added and the reaction mixture is stirred for 15 minutes. - L-NF chigo is filtered at 35 ° C. The filtrate is and / lags to 0 ° C. Dava additional number of crystals. Total 3G yield) .5%, Recrystallization of toluene sludge at О1 С дзе. 41.5% pure 2,2,4,4-tetrabromo-d1 frnilamip with a melting point of 5 1B9.

This method has serious drawbacks associated with the use of a large amount of bromine, as a result of which 5 grams of toxic and corrosive L-cm hydrogen chloride are released per 1 g O / L of tebromodiphenylamine; reaction mass, eg., knowledge of three organic solutions - I1, ei xtor1) forms, acetic acid, tolu1}

The aim of the invention is to simplify the technology and reduce the consumption of toxic bromine.

The problem is solved by the proposed method for producing polybrominated secondary aromatic amines, namely, that the initial secondary aromatic amines are subjected to oxidative bromination in an organic solvent medium or in an organic solvent-water system at a temperature of 50-95 ° C. Hydrogen peroxide or sodium chlorate are used as an oxidizing agent with acid. When the reaction mixture was cooled to room temperature, the brominated reaction product was completely isolated and separated from the mother liquor by filtration. The organic filtrate can be used in subsequent syntheses without regeneration. Water is used in the process when an organic solvent which is not miscible with water is used.

A distinctive feature of the proposed method is the use of oxidizing agents.

EXAMPLE 1. Preparation of M- (2,4,6-tribromophenyl) - (I - (bromonaphthylamine).

110 cm of chloroform are placed in a reaction flask equipped with a stirrer, thermometer, dropping funnel, reflux condenser and gas tube,

22.4 g (0.1 mol) of phenyl- / naphthylamine and are stirred until complete dissolution. 55 cm of water are added to the resulting solution, and 35.9 g (0.22 mol) of bromine in 12 cm3 of chloroform are added dropwise at a temperature of 18-20 ° C. After bromine addition, the reaction mixture is stirred for 1 min and then at 18-20 ° C, 25 cm3 (0.22 mol) of 27.5% hydrogen peroxide are carefully added. After half an hour, the mixture is heated

50 ° C and allowed to stand for 4 hours at the boiling of the reaction mixture, Cooled to 15 ° C and the precipitate formed is filtered off. The product is washed with chloroform and then with hot water until neutral.

After drying, 50 tons of gray powder are obtained with a melting point of 203-204 ° C. The yield of M- (2,4,6-tribromophenyl) /) - (bromonaphthylamic) is 93% of theoretical, based on the starting amine.

PRI me R 2 Synthesis is carried out in

the conditions of example 1, with the difference that as a solvent ominp use the organic filtrate of example 1 Get 50 g of the target product with a temperature

melting point 201 ° C

EXAMPLE 3 Synthesis was carried out under the conditions of Example 1. With the difference that trichloroethylene in an amount of 220 cm1 was used as a solvent, and 110 cm3 was loaded with water. The holding temperature is 78 ° C. The final product yield was 48.2 g, which was 90% of theory. Melting point 202 ° C.

PRI me R 4 Synthesis is carried out in

conditions of example 1, with the difference that instead of hydrogen peroxide, 5.2 cm of concentrated sulfuric acid are added dropwise to the reaction mass at 20 ° C, and then 15 cm of a 38% sodium chlorate solution After

drying, 47.1 g of M- (2 / 1,6-tribromophenyl) - / 3- (bromonaphthylamine) (88% of theory, based on the starting amine) are obtained in the form of a light gray powder with a melting point 201-202 ° WITH.

PRI me R 5. The synthesis is carried out in

the conditions of example 3, with the difference that instead of hydrogen peroxide, sulfuric acid and a sodium chlorate solution are charged, as in example 4. 47 1 g of light beige are obtained.

the final product (yield 88% of theory) with a melting point of 200 to 201 ° C.

PRI me R 6. Obtaining 2.2 4.4 -tetrabromodiphenylamine

67.7 g (0.396 mol) of diphenylamine and 300 cm of carbon tetrachloride are placed in a reaction flask equipped with a stirrer, a thermometer, a reflux condenser, a dropping funnel and a vent tube. After the diphenylamine is completely dissolved, 300 cm of water are added and 133.6 g (0.832 mol) of bromine in 43 cm of carbon tetrachloride are added dropwise at 20 ° C. The mass is stirred for half an hour and then, at a temperature of 20 ° C, 93 cm3 (0.832 mol) of 27.5% hydrogen peroxide are added dropwise. It is held for one hour, heated to 50 ° C, held for two hours, heated to 65 ° C and refluxed for one hour. It is cooled to 10 ° C and the precipitate formed is filtered off. The precipitate is washed with BO cm of carbon tetrachloride and water until neutral. After drying, 185 g of 2,2,4,4-tetrabromodiphenylamine are obtained in the form of a white powder with a melting point of 188-189 ° C. The product yield was 96.4%, based on diphenylamine.

Example 7. The synthesis was carried out under the conditions of example 6, with the difference that instead of hydrogen peroxide was added 16 cm of concentrated sulfuric acid and

57.5 cm3 of a 38% sodium chlorate solution. 168.9 F (88% of theory) of 2,2,4,4-tetrabromodiphenylamine is obtained with a melting point of 186 ° C.

Example Preparation of 2,2,4,4,6,6-hexabromodiphenylamine.

17.1 g (0.1 mol) of diphenylamine and 250 cm of acetic acid are placed in a reaction flask equipped with a thermometer, stirrer, reflux condenser, dropping funnel and vent tube. After dissolving the amine at 15 ° C, dropwise

53.6g (0.33 mol) of bromine in 15 cm acetic

acids and mix popcham. Then, at the same temperature, 37 g (0.33 mol) of 27.5% hydrogen peroxide are added and stirred for one hour. Heat the reaction mass to 55 ° C and let stand for one hour. The temperature was then adjusted to 95 ° C and held for three hours. It is cooled to 15 ° C and the precipitate formed is filtered off. Washed with 50 cm1 of acetic acid and

0 water until neutral. After drying, 60 g of 2,2,4,4,6,6-hexabromobiphenylamine (93.4% of theory) are obtained with a melting point of 221-222 ° C.

PRI me R 9. The synthesis is carried out in

5 conditions of Example 8, with the difference that instead of hydrogen peroxide, 26.5 cm3 (0.105 mol) of a 33% sodium chlorate solution are added. 60 g (93.4% of theory) of hexabromobiphenylamine are obtained with a melting point of 221-222 ° C.

The technical result of the proposed method is to halve the consumption of bromine, use one solvent, the ability to return the organic filtrate to synthesis without regeneration, the ease of isolation of the finished product of high quality. In addition, oxidative bromination eliminates the release of toxic and

0 corrosive hydrogen bromide.

Claims (1)

SUMMARY OF THE INVENTION A method for producing polybrominated secondary aromatic amines by reacting a secondary aromatic amine with bromine in an organic solvent by heating, characterized in that the process is carried out in an organic or aqueous-organic medium using an oxidizing agent - hydrogen peroxide or sodium chlorate with acid.