CS758989A3 - Process for preparing 2-bromo-4.6-dinitrochlorobenzene - Google Patents

Description

The present invention relates to organic synthesis and in particular to a process for the preparation of 2-bromo-4,6-dinitrochlorobenzene.

The present invention finds application in the manufacture of products such as dyes, for example, dispersive dyes and dyes based on metal pigments, herbicides, fungicides, antioxidants, i.e., those in the synthesis of which 2-bromo- 4,6-dinitrochlorbenzene.

Two major methods for preparing 2-bromo-4,6-dinitrochlorobenzene of formula I are currently known

in sufficiently pure form.

So he is in it. LE, G3, 2657234 describes a process based on the Sandmeyer reaction to form 2,4-dinitro-6-bromoaniline. In comparison with this procedure, it first performs the reaction of aniline with a halogenating agent to form a haloaniline which is used for further reaction with an alcohol or nitrosating agent in the presence of water and acid. The phenol ester of the corresponding alcohol with a greater or lesser amount of resin appears as a by-product. Neither the yield nor the degree of purity of the falling product are satisfactory, especially in large scale production. -2- In it. DE, B2, 2001570 describes a process for the preparation of 2-bromo-4,6-dinitrochlorobenzene based on the reaction of 2,4-dinitro-4-bromophenol with a halogenating agent, thionyl chloride or dimethylformamide. The process has not been found to be applicable on a large scale, since the reaction involves a tar resin upon completion of the reaction, from which the end product is isolated only with great difficulty, even if it is isomers, but substantially contaminated.

An improved method based on the phenol halogenation method is that described in DE, A5, 204246. According to this method, the final product is obtained by reacting dinitrohalogenophenol with chloromethylenedimethyliminotrichlorphosphate. This product is formed by the reaction of 1 mole of phosphorus oxychloride with 1 mole of dimethylformamide. The yield of the final product was about 70%. In this way, the amount of waste could be reduced to half the time before.

Nevertheless, for all these processes, the following are characteristic: - high material costs due to the need for protective measures against the harmful effects of the reagents used on the environment - when inert solvents are used, the excess halogenating agent must be separated with water and pixxedical phases from the aqueous phase or joint distillation with water tank.

The use of excess acid halocompounds, with the exclusion of solvent use, also requires the recovery of unused solvent or decomposition of the excess with water. In this case, there are a large number of unusable substances that cause corrosion and pollute the environment. SUMMARY OF THE INVENTION It is an object of the present invention to provide such a process for the preparation of 2-bromo-4,6-dinotrochlorobenzene by simultaneous dinitration and purification of chlorobenzene derivatives which exclude the use of highly toxic raw materials and the formation of kojiositic waste.

This object is solved by the fact that in the process for the production of 2-bromo-4,6-diminolobenzene from an aromatic derivative of chlorobenzene which has been previously reacted with a mixture of sulfuric acid and nitric acid, or ο-, p-, m - hydrochlorobenzene, which is reacted with bromine or with an alkali metal bromide, or with sulfuric acid, or with an olefin at the following molar ratios: aromatic halogen derivative: bromine or bromide alkali metal: nitric acid or alkali metal nitrate & sulfuric acid or oleum + 1.050.5-1.5 or 1.0: 3.0: 2.0-4.0 or 2.5-5.0: 6.0-70.0 at 20-80 ° WHAT

According to the invention, the use of highly toxic substances is avoided and the yield of corrosive wastes is 99.8%. In doing so, it allows further use of the eutectic mixture of nitro-chlorobenzene isomers in the above-mentioned process.

It is expedient to use chlorobenzene as the starting compound in order to obtain maximum yields according to the invention, which can first be reacted with a mixture of nitric acid and sulfuric acid in a molar ratio of 1.0: 1.1: 0.9 and the resulting reaction mixture cannot react. with a mixture of olea, bromine and nitric acid in a molar ratio of 1.0: 6.9: 0.552.0. When p-nitrochlorobenzene is used as the starting compound, it is expedient to react the p-nitro-benzene benzene with a mixture of sulfuric acid, bromine and nitric acid in a molar ratio of 1.0: 7.0: 1.5: 2 to achieve maximum yield. , 5 #

When o-nitrochlorobenzene is used as the starting material, its reaction is best suited to maximize the yield of sulfuric acid, bromine and nitric acid in a 1.0: 58.0: 0.5: 2.0 molar ratio. When using the eutectic mixture of β-, β-, m -nitrochlorobenzene as starting material, the reaction is carried out with a mixture of acid-sulfur, bromine and nitric acid in a molar ratio of 1.0: 59.0: 0.5: 2.0.

Further advantages of the present invention will be apparent from the following detailed description and examples of the production method of 2-bromo-4,6-dinitrochlorobenzene.

The process according to the invention results in simultaneous dinitration and purification of either chlorobenzene, which is first reacted with a mixture of nitric acid and sulfuric acid, or singly o-, p-chlorobenzene, or eutectic mixture ρ-, o-, m- nitrochlorobenzene. To carry out the aforementioned dinitration and bromination, the starting compounds are reacted with an alkali metal bromide or bromide of nitric acid or an alkali metal nitrate and sulfuric acid or olefin # The ratios of the above-mentioned constituents are: bromine or an alkali metal bromide: sulfuric acid or oleu = 1.0: 0.5-1.5 or 1.0 -5.0: 2.0: 4.0 or 2.5-5.0: 6.0-70.0. -5-

According to the present invention, the simultaneous dinitration and purification is carried out at a temperature of 20 to 80 ° C. In ratios below these values, the process does not take place or is unsatisfactory; the above-mentioned values do not allow the rate of reaction to be increased and are economically disadvantageous.

The embodiment of the process according to the invention is economically expedient at temperatures above 80 ° C; at temperatures below 20 ° C, the process proceeds slowly and results in low yields.

The embodiment according to the invention makes it possible to obtain 2-bromo-4,6-dinitro-chlorobenzene in a yield of up to 59.8, the product obtained having a high degree of purity and useful for reparative purposes. In this embodiment, the formation of waste causing corrosion and formation of highly toxic materials is avoided. In addition, the method according to the invention enhances the corresponding mixture of nitro-chlorobenzene isomers which is formed as waste.

To better illustrate the present invention, the following specific examples are set forth. EXAMPLE 1 3.8 g (0.025 mol) of p-nitrochlorobenzene are dissolved in 62 ml (1.15 mol) of sulfuric acid (a = 1.84), 2.0 g (0.0125 mol) of bromine, 2.2. ml (0.05 mol) of nitric acid (d = 1.55) and heated to 70 ° C. The mixture was stirred at this temperature for 4 hours. The reaction solution is then cooled and poured onto 150 g of ice, the precipitate is filtered off, washed with water and dried. 7.00 g of -6- (99.5 2-bromo-4,6-nitrochlorobenzene - yellow crystals from 70% aqueous acetic acid with a melting point of 61-62 ° C (Rf Q, 45) is obtained (benzene: hexane = 1: 1 »Example 2 1.4 (0.01 mol) of p-nitrochlorobenzene is dissolved in 40 ml (0.7 mol) of sulfuric acid (d = 1.83), 2.4 g (0.015 g) is added. nitric acid (d = 1.5O5) and stirred at room temperature for 65 hours. The reaction product was poured over ice, the residue was filtered, washed with water and dried. 2.67 g (94.8%) of 2-bromo-4,6-dinitrochlorobenzene are obtained. EXAMPLE 3 0.7 g (0.05 mol) of p-nitrochlorobenzene is dissolved in 40 ml (0.7 mol) of acid. of sulfuric acid (d = 1.83), 0.8 g (0.005 mol) of bromine, 0.43 ml (0.01 mol) of nitric acid (d = 1.5O5) are added and heated to 120 ° C. The reaction solution is stirred at this temperature for 3 hours, then cooled to room temperature and poured onto ice. The precipitate is filtered off and dried to give 1.40 g (99.4%) of 2-b. Example 4 47.25 g (0.3 mol) of p-nitrochlorobenzene are dissolved in 100 ml (1.8 mol) of sulfuric acid (d = 5-83), 26.4 g is added. (0.165 mol) of bromine and 26.0 ml (0.6 mol) of nitric acid (d = 1.505) dropwise, keeping the temperature between 65 and 70 ° C. at 65 ° C, cooled and poured onto ice. The precipitate is filtered off, washed with water and dried to give 83.039 g (99.7%) of 2-bromo-4,6-dinitrochlorobenzene. EXAMPLE 5 1.0 g (0.006 mol) of p-nitrochlorobenzene is dissolved in 40 ml ( 0.7 mole of sulfuric acid (d = 1.83), add 0.5 g (0.003 mole) of bromine, maintain the temperature between 65 and 70 ° C, and mix for 10 hours at 65 ° C The reaction mixture is poured onto ice, the precipitate is filtered off, washed with water and dried. 1.68 g (99.4 / 9) of 2-bromo-4, 6-dinitrochlorobenzene are obtained.

Dissolve 2.0 g (0.013 mol) of p-nitrochlorobenzene in 42 ml (0.75 mol) of sulfuric acid (d = 89), add 1.12 g (0.007 mol) of bromine and drop 2.27 ml ( 0.052 moles of nitric acid (d = 1.5O5), the temperature is maintained at 45-50 ° C, then the reaction mixture is stirred for 6 hours at 65-70 ° COPo isolation of the product yields 3.64 g (99.5%) 2-bromo-4,6-di-nitrochlorobenzene Example 7 VS 42 ml (0.75 mol) of sulfuric acid (d = 1.839) was dissolved in 2.0 g (0.013 mol) of p-nitrochlorobenzene, add 3.12 g (0.02 mol) of bromine and dropwise 1.2 ml (0.026 mol) of nitric acid, keep the temperature between 45 and 50 ° C Then stir the solution for 3 hours at 65 to 70 ° C After isolation, 3.65 g (99.8%) of 2-bromo-4,6-dinitrochlorobenzene are obtained. EXAMPLE 8 1.0 g (0.06 mol) of n-nitrochlorenzene is dissolved in 20 ml (0.55 mol). sulfuric acid (d = 1.85), followed by synthesis under the conditions of Example 5 " 69 g of product which is recrystallized from 70% aqueous acetic acid. 1.44 g (85.5%) of 2-bromo-4,6-dinitro-chlorobenzene are obtained

Dissolve 1.0 g (0.006 mol) of a mixture of o- and n-nitrochlorobenzene (1: 20.7) in 20 ml (0.55 mol) of sulfuric acid (d = 1.85).

1.0% m-nitrochlorobenzene is formed. Next, the synthesis was carried out under analogous conditions to that described in Example 5. After precipitating, 1.69 g of the product was obtained, which was recrystallized from 70% acetic acid. 1.46 g (86.4%) was obtained. 2-bromo-4,6-dinitrochlorobenzide Example 10

Dissolve 1.0 g (0.006 mol) of the o- and p-nitrochlorohenzene mixture (1.66: 1) in 200 ml (0.55 mol) of sulfuric acid (d = 1.85). Isomer0 Synthesis was carried out under similar conditions to Example 5. After isolation, 1.68 g of product were obtained, which was recrystallized from 70% acetic acid. 1.46 g (86.4%) was obtained. $$ bromo-4,6-dinitrochlorobenzene. Example 11

Dissolve 1.0 g (0.006 mol) of 9-eutectic mixture of ο-, ρ-, m-nitrochlorobenzene in 20 ml of sulfuric acid with an isomeric content of 4747%, p-59 m- 14%. under conditions analogous to Example 5o After isolation, 1.69 g of the reaction product were obtained, which was recrystallized three times from 70% acetic acid to give 1.16 g (68.9% 2-bromo-4,6-dinitrochloride). EXAMPLE 12 10.18 ml (0.1 moles) of chlorobenzene are added to 17.08 g of a nitration mixture containing 6.49 g (0.11 mol) of nitric acid (d = 1.5O5) with cooling, while cooling. 9.48 g (0.09 mol) of sulfuric acid (d = 1.83) and 0.34 g of water. The temperature is maintained between 60-65 ° C. GOPak the reaction mixture is heated to 75-80 ° C and stirred. 5 hours »

Then the reaction mixture is cooled to 60 ° C, 66.6 gol (7.6%), 8.0 g (0.05 mol) of bromine are added and 8.8 ml (0.2 mol) of nitric acid (d) are added dropwise. The mixture is heated to 70 DEG C. and stirred for 18 hours. The procedure is as in Example 5 to obtain 27.47 g of product which is recrystallized from 70% acetic acid. 83.06%) 2-bromo-4,6-dinitro-chlorobenzene »Example 13

1.0 g (0.006 mol) of p-nitrochlorobenzene is dissolved in 20 ml (0.35 mol) of sulfuric acid (d = 1.83). Further, the reaction is carried out under conditions analogous to Example 5, except that 0, 37 ml (0.009 mol) of nitric acid and the reaction mixture was allowed to stand for 20 hours. 3 *, 37 g of a mixture of 2,4-dinitrochlorbenzene and 2-bromo-4,6-dione triphenzene was obtained. a solution of 1.56 g (0.01 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1.83 is added 2.4 g (0.015 mol) of bromine and 5.24 (0.033 mol) at 40-50 ° C) The reaction mixture is poured onto ice, the precipitate is filtered off, washed with water, 5%: solution of water, washed again with water and dried to give 2.12 g (75%). 1% 2-bromo-4,6-dinitrochlorobenzene Example 15 To a solution of 0.78 g (0.005 mol) of p-nitro-chlorobenzene in 40 ml of sulfuric acid (d = 1.83) is added 0, 8 g (0.005 mol) of bromine and 2.02 g (2.02 m) The mixture was left to stand for 20 minutes, then cooled and poured out on ice. The precipitate was filtered off, washed with water, 5% soda solution, and water. again with water · Then dry · 1.38 g (99.0%) of 2-bromo-4, β-di-chloro-benzene is obtained Example 16 To a solution of 47.25 g (0.3 mol) of p-nitrochlorobenzene in 100 ml of sulfuric acid (d = 1, 83) are added 26.4 g (0.15 mol) of bromine and 64.2 g (0.75 mol) of sodium nitrate at 40 to 50 ° C, let stand for 20 minutes, warm up at 70 ° C and allowed to stand for 30 hours at this temperature. Isolation of the product was carried out as in Example 11, yielding 80.73 g (95.6%) of 2-bromo-4,6- dinitroclorobenzene. EXAMPLE 17 To a solution of 2.05 g (0.015 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1.83) at 4 DEG to 50 DEG C. was added 1.12 g (0.15 mol) of bromine and 6.59 g ( 0.065 mol) of potassium nitrate. The mixture was allowed to stand for 20 minutes, then heated to 70 ° C. Allowed to stand for a further 6 hours. The product was isolated analogously to Example 15 # 5.62 g (98.9%) of 2-bromo was obtained. -4,6-dinitroorborbenzene. Example 18 Add 0.8 g (0.005 mol) of bromine and 1.00 g to a solution of 0.78 g (0.005 mol) of p-nitrochlorobenzene in 20 ml of sulfuric acid (d = 1.83) at 40-50%. The mixture was allowed to stand for 20 minutes, then heated to 80 ° C and allowed to stand for an additional 25 hours. Under the same conditions as in Example 15, 1.03 g of a mixture of 2,4-dinitrocinobenzene and 2-bromo-4,6-dinitrochlorobenzene are precipitated. Example 19 3.58 g (0.03 mole) of potassium bromide are added to a solution of 1.56 g (0.01 mole) of p-nitrochlorohenzene in 40 ml of sulfuric acid (d = 1.83) at 4 to 50 ° C. 100 ml (0.025 mol) of acid (d = 1.5O5) and allowed to stand at 20 ° C for 70 hours. The product was isolated under conditions analogous to Example 15. 2.14 G (70.0%) of 2-bromo-4,6-dinitrochlorobenzene was obtained. Example 20 1.20 g (0.01 mol) of bromide was added to a solution of 0.78 g (0.005 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1.85) in 40 ml of sulfuric acid (d = 1.85). potassium and 0.65 ml (0.015 mol) of nitric acid (d = 1.5O5), allowed to stand for 20 minutes and heated to 120 ° C. The mixture is left at this temperature for 2 hours, then the resulting product is isolated analogously to Example 15 «1.59 g (99.7%) of 2-bromo-4,6-dinitro-hortoenzene is obtained. of a solution of 47.25 g (0.5 mol) of p-nitrochlorobenzene in 100 ml of sulfuric acid (d = 1.85) is added 54.0 g (0.5 mol) of sodium bromide at 4 ° to 50 ° C; 26.02 ml (0.6 mol) of nitric acid (d = 1.5O5) and allow to stand for 20 minutes * Then the mixture was heated to 70 ° C and allowed to stand for 25 hours at this temperature * Under conditions analogous to Example 15 to give the final product in 85.42 g (98.8%) of 2-bromo-4,6-dinitrochlorobenzene. EXAMPLE 22 To a solution of 2.05 g (0.015 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1) 1.85 g (0.015 mol) of potassium bromide and 2.27 ml (0.052 mol) of nitric acid (d = 1.5O5) were added at 40-50 ° C and left to stand for 20 minutes. The reaction mixture was heated to 70 ° C and allowed to stand for a further 6 hours. The product was isolated as in Example 15 to give 5.64 g (99.5%) of 2-bromo-4,6-dinitrochlorobenzene. EXAMPLE 25 To a solution of 0.78 g (0.005 mol) of p-nitrochlorobenzene in 20 ml of sulfuric acid (d = 1.5, 0.59 g, 0.005 mol) of potassium bromide and 0.50 g (0.005 mol) was added. 5 ml (0.0075 mol) of nitric acid (d = 1.5O5) and allowed to stand for 20 minutes. The solution was then heated to 80 ° C and left at this temperature for an additional 55 hours. The product was isolated under analogous conditions to Example 15 to give 1.07 g of a mixture of 2-4-dinitrochlorobenzene and 2-bromo-4. EXAMPLE 24 To a solution of 1.56 g (0.01 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1.85) at a temperature of 40 to 50 DEG C. is added 5.58 g ( 0.05 mole of potassium bromide and 5.24 g (0.055 mole) of potassium bisulfate and leave to stand at 20 ° C for 75 hours. The product is then isolated analogously to Example 15 to give 2.05 g (75%) of 2-bromo-4,6-dinitrochlorobenzene. Example 25 To a solution of 0.78 g (0.005 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid ( 1.20 g (0.01 mole) of potassium bromide and 2.02 g (0.02 mole) of potassium nitrate are added at 40-50 ° C and left for 20 minutes. 120 ° C and allowed to stand for a further 2.5 hours. Under the conditions of Example 15, the final product is isolated. 1.55 g (96.8%) of 2-bromo-4,6-dinitrochlorobenzene are obtained Example 26 X of a solution of 47.25 g (0.5 mol) of .beta.-nitrochlorobenzene in 100 ml of sulfuric acid. (d = 1.85), 54 µg (0.5 mol) of sodium bromide and 64.2 g (0.75 mol) of sodium nitrate are added at 40 to 50 ° C, allowed to stand for 20 minutes and then heated to 70 ° C. The solution remains at that temperature for another 50 hours. Under the conditions analogous to Example 15, 75.8 g (85.7%) of 2-bromo-4,6-dinitrochlorobenzene are obtained. EXAMPLE 27 To a solution of 2.05 g (0.015 mol) of p-nitrochlorobenzene in 40 ml of sulfuric acid (d = 1, S5) was added 1.55 g (0j < 3 > mol) of potassium bromide and 6; 5 g (0.065 mol) of nitrous potassium. The solution was allowed to stand for 20 minutes and warmed to 70 ° C. The product was isolated analogously to Example 15. 5.58 g (97.8%) of 2-bromo-4,6-dinitrochlorobenzene were obtained. EXAMPLE 28 0.59 g (0.005 mol) of potassium bromide is added to a solution of 0.78 g (0.005 mol) of p-nitrochlorobenzene in 20 ml of sulfuric acid (d = 1.85) at 40-50 ° C. 1.00 g (0.01 mole) of nitric potassium. The solution was allowed to stand for 20 minutes and heated to 80 ° C.

It is allowed to stand at this temperature for a further 55 hours. Under conditions analogous to Example I, 0.96 g of a mixture of 2,4-dinitro-chlorobenzene and 2-bromo-4,6-dinitrochlorobenene is isolated.

J .5 1 i Λ b Ϊ; 7

Claims (2)

I -1 5- tTE νττΐΐ A process for the preparation of 2-bromo-4,6-dinitrochlorobenzene with a halogenated compound, characterized in that chlorobenzene is used as the aromatic halide derivative and which is not previously reacted with a mixture of sulfuric acid and nitric acid or individually. or p-nitrochlorobenzene or a eutectic mixture of ο-, p-, m -nitrochlorobenzene, which is reacted with bromine or an alkali metal bromide, with nitric acid and with an acid or sulfur molar ratio, an aromatic halogen derivative: bromine or alkali bromide metal $ nitric acid or alkali metal nitrate: sulfuric acid or oleum = 1.0: 0.5 - 1.5 or 1.0 - 5, o: 2.0 - 4.0 or 2.5 - 5.0 :: 6.0 - 70.0 at 20 to 120 ° C with subsequent product isolation » 2. The process of claim 1 wherein the starting compound is chlorobenzene which is reacted with a mixture of nitric acid and sulfuric acid in a molar ratio of 1.0: 1.1: 0.9 and the resulting reaction mixture is worked up. with mixtures of oleate, bromine and nitric acid in a molar ratio of 1.0: 6.9:: 0.5: 2.0. 5. The process of claim 1 wherein the p-nitrochlorobenzene is reacted with a mixture of sulfuric acid, bromine and nitric acid in a molar ratio of 1.0: 70.0: 1.5: 2.5. 4. The process of claim 1 wherein the o-nitrochlorobenzene is reacted with a mixture of sulfuric acid, bromine and nitric acid in a molar ratio of 1.0: 58.0: 0.5: 2.0: nnmmm. 5. A process according to claim 1, wherein the eutectic mixture of ο-, p-, m-nitrochlorobenzene is reacted with a mixture of sulfuric acid, bromine and nitric acid in a ratio of 1.0 to 59. , 0; 2.0, 2.0. -^ PA1EhiISER 40 HA HA J iven 40 40 40 40 40 40 40 40