KR840000418B1 - Process for the preparation of 2,3-dihalopropionitrile - Google Patents

Abstract

Alkali and alkali earth carbonates, bicarbonates, and hydrogen phosphates catalyzed the reaction of acrylonitrile with halogens to yield 2,3-dihalopropionitriles. Thus, Cl gas was introduced in a mixt. of 53.1g acrylonitrile, 40 ppm hydroquinone, and 12.7g anhyd. Na2CO3 at 5˜10≰C to give 119.2g 2,3-dichloropropionitrile (b.p=62˜63oC; 150mmHg).

Description

Method for preparing 2,3-dihalo genopropionitrile

The present invention relates to a method for producing 2, 3-dihalogenopropionitrile, which is a compound useful as a substance for bioactive substances, pesticides and pharmaceuticals such as polymers or amino acids.

Various conventional methods have been used to produce 2, 3-dihalo genopropionitrile by halogenating acrylonitrile, such as using photo-radical reactions in the presence or absence of a catalyst.

Several methods of directly halogenating acrylonitrile in the absence of a catalyst have been proposed. For example, a process for the preparation of 2,3-dichloropropionitrile by introducing chlorine gas into acrylonitrile in the presence of water is described in US Patent Publication No. 2,231,360 and German Patent Publication No. 842,193. However, this method cannot be industrially performed because the production yield is as low as 26 to 29%. In addition, a method for producing 2,3-dihalogenopropionitrile by directly halogenating acrylonitrile in a chloroform or a carbon tetrachloride solvent with a halogenoase is disclosed in US Patent Publication No. 2,298,739; C. Mourey and R. L. Brown, Bull. Soc. Chim, Fr., Vol. 27, p. 901 (1920) and L. Petit and P. Touratier, Bull. Soc. Chim. Fr., Vol. 3, page 1136 (1968), but this method is inadequate for industrial practice because the solvent must be recovered. In addition, a method of producing 2,3-dibromopropionitrile by directly acting bromine on acrylonitrile is described in M.A. Naylor and A.W. Anderson, J. Am. Chem. Soc., Vol. 75, page 590 (1954) and U.S. Patent Publication No. 2,710,304, according to this method have a low yield of about 70 to 89%. In addition to the aforementioned methods, a method of dibrominating acrylonitrile using dioxane dibromide as a halogenating agent is described in A. V. Dombrovskii, Zhur. obshch. Although described in Khim, Vol. 24, p. 610 (1954), this method requires a special halogenating agent, which leads to higher manufacturing costs and lower product yields of 50 to 55%. I can't.

Methods using catalysts have also been proposed, such as the method of halogenating acrylonitrile in the presence of a pyridine catalyst is described by H. Brintzinger, K. Pfannstiel and H. Koddebusch, Angew. Chem., Vol. A (60), page 311 (1948); W. H. Jura and R. J. Gaul, J. Am. Chem. Soc., Vol. 80, 5402 (1958); S.S Ivanov and M. M. Koton, Zhur, Obshch. Khim., Vol. 28, p. 139 (1959) and N.O. Pastushak, A.V. Dombrovskii and L. I. Pogovik, Zhur. Obshch, Khim., Vol. 34 (7), page 2243 (1964). According to this method, part of the resulting 2,3-dihalogenopropionitrile is dissolved in water together with unreacted acrylonitrile because it must be washed with water to remove the pyridine catalyst in the reaction product obtained by the reaction. In addition to the drawback of reducing the yield of the target, there are also problems in wastewater treatment. In addition, the method of halogenating acrylonitrile in the presence of N, N-dimethylformamide catalyst is described in I. P. Losev, O. V. Smirnova and L. M. Lutsenko, Trudy Moskov. Khim, Tekhnel, Inst. im. D.I. Mendeleeva, Vol. 29, pp. 17 (1959) and M.A. Askarov, K.A. Avlyanov and A.B. Alovildinov, Uzbeksk, Khim, Zh., Vol. 7 (5), 50 pages (1963). In this method, it is stated that 2, 3-dichloropropionitrile is obtained in a yield of 92.3% by adding and chlorinating 3% by weight of N, N-dimethylformamide to acrylonitrile. As a result of examination, it was found that the conversion rate of acrylonitrile was as low as 40 to 45% when the amount of N and N-dimethylformamide was 3% by weight. Therefore, this method is also impossible industrially.

Processes for the preparation of 2,3-dihalogenopropionitrile by photoradical reactions are described, for example, in W.W. Moyer Jr., T. Anyos and J. L. Dennis Jr., J. Org. Chem., Vol. 31 (4), page 1014 (1966), and in German Patent Application Publication No. 6,612,041. According to this method, photoradical reaction of acrylonitrile is carried out using hydrogen phosphate alkali metal as an ionic reaction inhibitor to obtain 2,3-dihalogenopropionitrile. In addition, a process characterized by acrylonitrile perchlorination core in the absence of additives is disclosed in U.S. Patent Nos. 2,390,470 and N.B. Lorette, I. Org. Chme., Vol. 26, page 2324 (1961). However, in these methods employing a photoradical reaction, the yield of 2,3-halogenopropionitrile is low and the reaction apparatus to perform the photoreaction is complicated. I have it.

It is an object of the present invention to provide a process for industrially advantageously producing 2,3-dihalogenopropionitrile.

The inventors have conducted extensive research and have shown that a 2, 3-dihalogenov is characterized by halogenating acrylonitrile with a halogenating agent in the presence of carbonate, hydrogencarbonate or phosphate of alkali or alkaline earth metal substantially in the absence of light. It has come to provide a method for preparing lopionitrile.

Since the halogenation reaction in this invention is not a photochemical reaction, a special reaction apparatus is not needed. In addition, since little by-product is produced and 2, 3-dihalogenopropionitrile is obtained in a quantitative yield, the method of the present invention is an industrially superior method.

In the method of the present invention, since the catalyst used is an inorganic salt insoluble in the reaction mixture, the catalyst can be easily separated from the reaction product by simple filtration or the like. Therefore, the method of the present invention is industrially superior to the known methods.

Illustrative halogenating agents used in the process of the present invention may include bromine, chlorine, iodine and fluoride.

Examples of the carbonate or hydrogen carbonate of an alkali or alkaline earth metal include carbonates or hydrogen phosphates of sodium, potassium, lithium, magnesium and calcium. Usually, sodium carbonate, potassium carbonate, sodium hydrogen carbonate and potassium hydrogen carbonate are used.

Examples of alkali or alkaline earth metal phosphate salts include dipotassium hydrogen phosphate, sodium hydrogen phosphate, and calcium hydrogen phosphate.

The inorganic salts mentioned above may be used alone or in combination of two or more.

The catalyst remaining in the reaction solution can be recovered by extracting it with water in an inorganic salt which is insoluble in the reaction solution, but can be easily recovered by simple filtration or decantation. When alkali or alkaline earth metal phosphate salt is used as a catalyst, the recovered catalyst can be easily regenerated by treating with strong alkali.

Alkali or alkaline earth metal carbonate, hydrogen carbonate or hydrogen phosphate as a catalyst is used in an amount of 0.05 to 2 moles per 1 mole of acrylonitrile. In practice, an amount of 0.05 to 1.0 mole is sufficient.

Halogenation of acrylonitrile in the process of the present invention is carried out in the absence of a common solvent, but if necessary, it can also be carried out in an organic solvent commonly used for halogenation, such as chloroform or carbon tetrachloride.

The process of the invention is usually carried out under substantially anhydrous conditions. However, even in the case of using a catalyst containing crystal water or an acrylonitrile industrial product containing some water, practical problems are not caused.

The halogenation operation of acrylonitrile and the optional distillation operation of the reaction product in the method of the present invention are preferably carried out in the presence of a polymerization inhibitor. Examples of polymerization inhibitors include hydroquinone, phenyl-p-naphthylamine, diphenyl-p-phenylenediamine, tert-butylcatechol, picric acid, phenothiazine, sulfur, compounds, copper and copper compounds, and the like. The amount of the polymerization inhibitor is 5 to 100 ppm with respect to acrylonitrile, but 20 to 60 ppm is sufficient in practical use.

The halogenation operation is usually carried out under atmospheric pressure, and if necessary, no effect is obtained even under pressure or reduced pressure. The reaction temperature is -70 to 100 ° C, and the reaction time is 2 to 20 hours. In industrial implementation, it is preferable to carry out at -20-40 degreeC for 4 to 10 hours.

Since the method of the present invention does not require positive light irradiation for the halogenation operation, the reaction proceeds even in the absence of substantial light. However, if necessary, the halogenation operation may be performed even in the presence of scattered light passing through the glass.

The end point of the reaction can be easily confirmed by analyzing the reaction mixture quantitatively by gas chromatography, by measuring the weight increase of the reaction mixture, or by measuring the specific gravity of the reaction mixture.

Analysis of the gas chromatography of the reaction mixture is carried out while filling the filler (Porapak Q, 80 to 100 mesh) into a tower having an inner diameter of 2 mm and a height of 1 m, using nitrogen as a carrier gas chamber and maintaining the tower temperature at 190 ° C.

In the process of the present invention, the halogenation reaction and any distillation under reduced pressure for 2,3-dihalogenopropionitrile are preferably carried out in an atmosphere containing no oxygen. In actual operation, the reaction and distillation operation are carried out in an atmosphere of an inert gas such as nitrogen gas or dioxide gas.

The material of the reaction apparatus used in the method of the present invention may be any material as long as it is a material that is not subjected to corrosion attack of halogen, hydrogen halide and products. Generally, glass or glass-coated materials are used.

After completion of the reaction, the reaction mixture is filtered, decanted or extracted with water to remove the catalyst. Distillation under reduced pressure yields 2,3-dihalogenopropionitrile quantitatively. Of course, purification may be performed after the distillation operation to obtain 2,3-dihalogenopropionitrile having higher purity.

In the process of the present invention, almost no by-products are generated, so that the reaction mixture can be used as a starting material for various reactions using 2,3-dihalogenonitrile as a starting material when the catalyst is removed by filtration or water extraction.

The present invention will be described in more detail with reference to the following examples.

Example 1

Introduced 53.1 g (0.1 mol) of acrylonitrile containing 40 ppm of hydroquinone and 12.7 g (0.12 mol) of anhydrous sodium carbonate in a 300 ml brown flask equipped with a thermometer, agitator, a gas blower with a glass ball filter, and a reflux condenser. I was. The reaction mixture was cooled to 5 ° C. by ice water while nitrogen gas was purged inside the reactor. When the internal temperature of the flask reached 5 ° C., chlorine gas was introduced into the reaction solution through a glass ball filter at a rate of 0.23 to 0.24 g / min, and the reaction was continued at 5 to 10 ° C. for about 5 hours. The reaction mixture was analyzed by gas chromatography, and the time when the starting material acrylonitrile in the reaction mixture remained only in a small amount was regarded as the end point of the reaction.

After the completion of the reaction, the introduction of chlorine gas was stopped and nitrogen gas was blown into the reaction solution to remove chlorine gas dissolved in the reaction solution. The reaction solution was filtered at room temperature to separate sodium carbonate. In a nitrogen stream, 122.7 g of a filtrate (colorless transparent liquid) were distilled under reduced pressure to obtain 1.6 g of a first oil having a boiling point of 43 to 45 ° C. (150 mmHg) (yield 2.2% for acrylonitrile) and a boiling point of 62 to 63 ° C. 119.2 g of 2, 3-dichloropropionitrile (yield 96.5% with respect to acrylonitrile) as a second fraction of 150 mmHg) were obtained.

Example 2

Acrylonitrile (53.1 g) was chlorinated in the same manner as in Example 1 at -10 to -5 ° C in the presence of 12.6 g (0.15 mol) of anhydrous sodium carbonate. After the reaction, the reaction mixture was dechlorinated, filtered and vacuum distilled in the same manner as in Example 1 to give 120.5 g of 2,3-dichloropropionitrile (yield of acrylonitrile: 97.2%). No production of 2-chloroacrylonitrile was observed.

Example 3

In the same manner as in Example 1, 53.1 g of acrylonitrile and 13.8 g (1.0 mol) of anhydrous potassium carbonate were introduced into the flask, and 159.8 g (1.0 d 2 mol) of bromine were added dropwise at 0? 5 占 폚 for 3 hours. The reaction was carried out at this temperature for 2 hours, and after the reaction, the reaction solution was washed three times with 100 ml of water, dehydrated on anhydrous magnesium sulfate, and then distilled under reduced pressure. As a result, 209.3% of 2,3-dibromopropionitrile (98.3% of yield for acrylonitrile) having a boiling point of 70 to 80 ° C (14 mmHg) was obtained.

Example 4

In the same manner as in Example 1, 53.1 g of acrylonitrile was chlorinated at 20 to 25 ° C. in the presence of 20.0 g (0.2 mol) of anhydrous calcium carbonate. The reaction was stopped when the weight of the reaction solution reached 124 g of 2,3-dichloropropionitrile as the estimated amount. Chlorine dissolved in the reaction solution was removed with nitrogen. At this time, the weight of the reaction product was 116.6 g. Filtration was carried out to remove the catalyst, the reaction solution was distilled under reduced pressure, and 0.7 g of acrylonitrile having a boiling point of 23 ° C. (100 mmHg) and a second oily 2-chloroacryl having a boiling point of 43 to 44 ° C. (150 mmHg) were used. 3.1 g nitrile (yield 4.2% for acrylonitrile) and a third fraction 2, 3-diclopropionitrile (yield 90.5% for acrylonitrile) having a boiling point of 62 to 63 ° C. (13 mmHg) were obtained.

Example 5

Into the same flask as used in Example 1, 53.1 g of acrylonitrile containing 17% by weight of hydroquinone and 17.4 g of sodium hydrogen phosphate were introduced, the inside of the reactor was purged with nitrogen gas, and chlorine gas was released at 10 to 15 ° C. It was introduced into the flask through a filter. Chlorine was fed at 5 to 6 o'clock at this temperature, and it was confirmed that the specific gravity (d ₂₀ ) of the solution reached 1.37. The reaction solution was stirred for 1 hour to replace nitrogen with chlorine dissolved in the solution. Analysis of the reaction product by gas chromatography found that 98.0% 2, 3-dichloropropionitrile, 1.6% 2-chloroacrylonitrile and 0.3% unreacted acrylonitrile were contained. The reaction solution was filtered to remove the catalyst, and the residue of 62 to 63 DEG C under reduced pressure of 13 mmHg was distilled in a brown glass distillation apparatus to obtain 120.0 g of 2,3-dichloropropionitrile having a specific gravity (d ₂₀ ) of 1.35 (acrylo) Yield 96.8% for nitrile).

Example 6

In the same manner as in Example 1, 53.1 g of acrylonitrile was chlorinated in the presence of dipotassium hydrogen phosphate. Chlorine gas was fed to the reaction system for 6 to 7 hours while the reaction temperature was maintained at 0 to 5 ° C. Reaching the end point of the reaction was confirmed by gas chromatography, and the catalyst was separated from the reaction mixture by filtration to obtain 2,3-dichloropropionite in a yield of 99.7%. As a byproduct, 0.3% of 2-chloroacrylonitrile was produced.

Example 7

In the same manner as in Example 1, 53.1 g of acrylonitrile and disodium hydrogen phosphate hexahydrate (Na ₂ HPO ₄ .12H ₂ O) were introduced into the flask. 160 g of bromine was added dropwise over 5 hours while maintaining the reaction temperature at 20 to 25 ° C.

At this temperature the mixture was stirred for 1-2 h and 100 g of water were added to dissolve Na ₂ HPO ₄ .12H ₂ O. The reaction mixture was separated from the aqueous layer, dehydrated on anhydrous magnesium sulfate and distilled under reduced pressure of 15 mmHg at 90-91 ° C. to 206.5 g of 2,3-dibromopropionitrile (yield 97.0% for acrylonitrile, specific gravity d ₂₀ 2.11)

The aqueous layer was heated with 50 g of 45% aqueous sodium oxide solution and concentrated under reduced pressure. The precipitate was filtered off and dried and the dried product could be used again as catalyst for the next reaction.

Example 8

In the same manner as in Example 1, 53.1 g of acrylonitrile, 8.5 g of sodium hydrogen phosphate, and 10.5 g of sodium hydrogen phosphate were introduced into the flask. 160 g bromine was added dropwise to the flask over 5 hours in the dark at a temperature between 30 and 40 ° C. After the addition was complete the reaction mixture was stirred at this temperature for 1 hour and then the catalyst was filtered off. Analysis by gas chromatography showed that this product contained 99.2% of 2, 3-dibromopropionitrile, 0.7% of 2-bromoacrylonitrile and traces of unreacted acrylonitrile.

Claims (1)

2,3-dihalogenopropionitrile characterized by halogenation as a halogenating agent at -10 ° C to 110 ° C in the presence of a carbonate, hydrogencarbonate or hydrogen chloride catalyst of an alkali or alkaline earth metal per mole of acrylonitrile. Manufacturing method.