JP2007070230A - Manufacturing method of azobis amidino compound hydrochloric acid salt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for simply manufacturing an azobis amidino compound hydrochloric acid salt of high grade. <P>SOLUTION: The manufacturing method of the azobis amidino compound hydrochloric acid salt comprises a step of dissolving a crude azobis-amidino compound hydrochloric acid salt in water, removing undissolved matter contained therein, and subsequently adding an inorganic salt or hydrochloric acid thereby to cause the azobis amidino compound hydrochloric acid salt to separate out. The manufacturing method permits the manufacture of the azobis amidino compound hydrochloric acid salt of high grade by readily removing impurities by-produced in reaction steps. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a method for easily and easily producing high-quality azobisamidino compound hydrochloride.

  An azo compound is a compound useful as a polymerization initiator for a high molecular polymer, a resin foaming agent, a radical generator used in a halogenation reaction of an organic hydrocarbon compound, and the shape thereof is generally a solid powder. .

  Various methods for producing such an azobisamidino compound are known. For example, as shown in the following chemical reaction formula, an azobisalkylnitrile [formula 3] is reacted with hydrogen chloride and an alcohol to produce a azoimino compound. Ether hydrochloride [Formula 4] is isolated and reacted with ammonia gas in an alcohol solvent to produce an azobisamidino compound dihydrochloride represented by [Formula 1], or isolated azoiminoether hydrochloride [Formula 4 Is reacted with an organic amine in an alcohol solvent to produce an azobisamidino compound dihydrochloride represented by [Formula 2].

  On the other hand, when producing azoguanyl compound hydrochloride by reacting azoiminoether hydrochloride with ammonia gas or organic amine, neutralization reaction is performed by adding ammonia gas or organic amine to nonpolar solvent containing azoiminoether hydrochloride. There is also a method of performing an amidinolysis reaction by adding a solvent and water necessary for the amidinolysis reaction (Patent Document 1). Examples of the organic amine used at this time include methylamine, ethylamine, and propylamine. When ammonia gas or an organic amine is added to a nonpolar solvent containing azoiminoether hydrochloride, a neutralization reaction occurs first, and by-products such as ammonium chloride and organic amine hydrochloride are generated. Next, when a certain amount or more of a solvent necessary for the amidinolysis reaction such as a lower alcohol is present in this system, the amidinolysis reaction proceeds. At this time, when a neutralization reaction is performed by adding ammonia gas or an organic amine in a nonpolar solvent, and then a predetermined amount of water is added after the reaction, the diamination reaction is promoted. The water used to accelerate the reaction is a solvent that selectively dissolves ammonium chloride and organic amine hydrochloride mixed in the target product after the reaction, so it exists in a crystalline state after the reaction is completed. It is described that a high-quality azodianil compound hydrochloride can be easily obtained simply by isolating the target product by filtration or centrifugal dehydration. The amount of water to be added may be an amount that can be used excessively during the imino etherification reaction and dissolve ammonium chloride or organic amine hydrochloride produced as a by-product due to hydrochloric acid remaining in the reaction solution, For example, ammonium chloride is about 4 to 5 times the amount of by-product. In the examples, after completion of the amidino reaction, water was added to the reaction solution and stirred sufficiently, and then the crystals were collected by filtration and dried to obtain the desired product.

  In addition, azobisnitriles are sequentially added and reacted in a preliminarily prepared acid alcohol solution at a temperature of 10 ° C. or higher and lower than 20 ° C., and then the resulting intermediate azobisiminoether salts are reacted with amines. There is also a method for producing azobisamidine salts (Patent Document 2). In the method of sequentially adding an acid to an azobisnitrile solution or the method of adding an azobisnitrile and an acid at the same time, the reaction takes a long time and the yield is not sufficient. Even in the method using a mixed solvent with a solvent having a low solubility in hydrochloric acid gas, there are problems that the reaction time is long and it is difficult to separate and recover the diluted solvent from alcohol and hydrochloric acid gas. The method described in Patent Document 2 solves this problem. When the reaction is performed by sequentially adding the alcohol solution of the acid prepared in advance at a temperature of 10 ° C. or higher and lower than 20 ° C., the alcohol solution after the reaction is reacted. Excess acid component can be removed simply by distillation under reduced pressure, and without performing isolation of the above intermediate azobisiminoether salt, without using anion exchange resin, etc., the condensation reaction with the following amines can be carried out. It can be done. In the examples, azobisisobutyronitrile was sequentially added to a hydrochloric acid methanol solution in the form of a powder to keep the reaction at 20 ° C. or lower to complete the reaction. Excess hydrochloric acid was distilled under reduced pressure together with some methanol, and then at 20 ° C. or lower. Ammonia gas was blown in and a white solid of azobisamidinopropane hydrochloride having a purity of 90% by weight was obtained with a crude yield of 70%.

Furthermore, a method of producing an azo cyclic amidino compound hydrochloride by reacting an azoiminoether hydrochloride with an organic diamine, wherein a nonpolar solvent solution of azoiminoether hydrochloride is added to the organic diamine or organic diamine solution, and the reaction is performed. There is also a method for producing azo cyclic amidino compound hydrochloride that efficiently removes ammonia generated by blowing an inert gas to the outside of the reaction system (Patent Document 3). In this method, hydrogen chloride remaining in the reaction system reacts with the organic diamine added in the amidation reaction or ammonia produced in the amidation reaction to produce organic diamine hydrochloride or ammonium chloride. The problem is that the purity of the mixed organic diamine hydrochloride, ammonium chloride, and azo cyclic amidino compound hydrochloride is similar due to the similar solubility in various solvents. The present invention has been made in view of the above, and it is possible to accelerate the amidation reaction by efficiently removing ammonia generated by the amidation reaction from the reaction system. In the Examples, 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride having a yield of 94.0% (vs. AIBN) and a content of 99.7% is obtained.
Japanese Patent No. 2565710 Japanese Patent No. 2593312 Japanese Patent Laid-Open No. 10-59945

  However, as described above, when excess hydrogen chloride gas is used during the synthesis of azoiminoether hydrochloride, hydrogen chloride remains in the reaction system or the extracted azoiminoether hydrochloride, and the remaining hydrogen chloride is amidified. Reaction with ammonia, organic amine or organic diamine added in the reaction produces ammonium chloride, organic amine hydrochloride or organic diamine hydrochloride. For this reason, these hydrochlorides become impurities and are mixed into the crystals of the target azobisamidino compound hydrochloride, thereby significantly reducing the purity.

  In particular, azobisnitriles used as raw materials are also azoiminoether hydrochloride, which is a production intermediate, and azobisamidino compound hydrochloride, which is a target product, is also solid, and reaction by-products such as ammonium chloride are also solid. . For example, when preparing azobisamidino compound hydrochloride, if azoiminoether hydrochloride is diluted with nonpolar solvent and added to intermediate azoiminoether hydrochloride, azoiminoether hydrochloride does not dissolve in nonpolar solvent. Then, the azobisamidino compound hydrochloride obtained by the subsequent action of ammonia or organic amine does not dissolve in the organic solvent. In this way, the target product is also solid, and by-product ammonium chloride, organic amine hydrochloride or organic diamine hydrochloride is also solid, and the manufacturing process is consistently a reaction in a solid-liquid state. It cannot be separated from the solid object. Moreover, the by-product ammonium chloride, organic amine hydrochloride or organic diamine hydrochloride is very difficult to separate from the target azobisamidino compound hydrochloride because it has similar solubility in various solvents. For this reason, there is a problem in stably obtaining a highly pure azobisamidino compound hydrochloride.

  The method described in Patent Document 1 is characterized in that water is added to promote the amidinolysis reaction, and further, by-products such as ammonium chloride are removed because ammonium chloride produced as a by-product dissolves in the added water. Suppose you can. However, when water is added to the azoiminoether compound hydrochloride, not only amidation is promoted but also hydrolysis is promoted at the same time, so that an undesired azo compound may be formed. In addition, since azobisamidino compound hydrochloride is very easily dissolved in water, the addition of water may reduce the yield of the target azobisamidino compound hydrochloride.

  In the method described in Patent Document 2, the alcohol solution after the reaction is distilled under reduced pressure to remove excess acid components out of the system, thereby suppressing the generation of by-products. The purity of amidinopropane hydrochloride is 90% by weight and requires further purification.

  In addition, the method described in Patent Document 3 suppresses the generation of ammonium salt in that ammonia generated by blowing an inert gas into the reaction is efficiently removed from the reaction system. Although 2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride is obtained, the inert gas is expensive.

  Accordingly, an object of the present invention is to solve the above-mentioned problems and to produce a high-quality azobisamidino compound hydrochloride efficiently and easily industrially.

  As a result of studying a method for producing an azobisamidino compound hydrochloride to solve the above problems, the present inventors completely dissolved the crude azobisamidino compound hydrochloride in water, and removed any insoluble matter. It was found that the azobisamidino compound hydrochloride can be precipitated by adding a salt or hydrogen chloride, and by separating the azobisamidino compound hydrochloride, a high-quality azobisamidino compound hydrochloride can be produced efficiently, and the present invention has been completed.

  According to the present invention, high-quality azobisamidino compound hydrochloride can be easily produced simply by completely dissolving crude azobisamidino compound hydrochloride in water and removing insoluble matters and then adding inorganic salt or hydrogen chloride. Therefore, by incorporating the present invention, it is possible to produce a high purity azobisamidino compound hydrochloride without providing a by-product reduction step such as ammonium chloride or organic amine hydrochloride in the production process of crude azobisamidino compound hydrochloride. it can.

  Furthermore, azobisamidino compound hydrochloride is a compound used for the production of a polymer as a polymerization initiator or the like. However, since the azobisamidino compound hydrochloride according to the present invention has a very high purity, the amount of impurities in the resulting polymer is reduced. be able to.

The first of the present invention is
A method for producing an azobisamidino compound hydrochloride represented by the following [Formula 1] or [Formula 2], wherein the crude azobisamidino compound hydrochloride is dissolved in water and the insoluble matter contained therein is removed, and then an inorganic salt or hydrogen chloride Is added, and the azobisamidino compound hydrochloride is precipitated, thereby producing the azobisamidino compound hydrochloride.

(Wherein R ¹ , R ² and R ³ may be the same or different and each represents a hydrogen atom or an optionally substituted alkyl group, allyl group, cycloalkyl group or aryl group, or R ¹ and R ² may be bonded to each other to form an aliphatic ring.)

(In the formula, R ¹ and R ² have the same definitions as in the above [Formula 1], and R ⁴ represents an optionally substituted alkylene group.)
In the above [Formula 1] and [Formula 2], the “alkyl group” is a linear or branched alkyl group, for example, methyl group, ethyl group, propyl group, i-propyl group, n-butyl. A group having about 1 to 10 carbon atoms such as a group, sec-butyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group Illustrated. The cycloalkyl group is a linear or branched cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cycloheptyl group, a cyclohexyl group, a 2-methylcyclopentyl group, a cycloheptyl group, or 3-methyl. Examples include a cyclohexyl group.

In addition, when R ¹ and R ² are bonded to each other to form an aliphatic ring, R ¹ and R ² are combined together, for example, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, Hexamethylene group and the like are formed. In the present invention, R ¹ , R ² and R ³ are preferably a hydrogen atom or a methyl group.

  Furthermore, as the “aryl group”, for example, phenyl group, benzyl group, phenethyl group, o-, m- or p-tolyl group, 2,3- or 2,4-xylyl group, mesityl group, naphthyl group, anthryl Group, phenanthryl group, biphenylyl group, benzhydryl group, trityl group and pyrenyl group are exemplified.

  Examples of the substituent include a halogen atom such as a hydroxyl group, fluorine, chlorine and bromine, the aryl group described above, an alkyl group, an acetyl group, an amino group, an aryl group, and a nitro group.

In addition, examples of the alkylene group represented by R ⁴ in Formula 2 include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, and a hexamethylene group. Furthermore, as the substituent capable of substituting R ⁴ which is an alkylene group, the above-described substituents can be similarly employed. In the present invention, R ⁴ is an unsubstituted ethylene group or trimethylene group.

  The crude azobisamidino compound hydrochloride used in the present invention is an azobisamidino compound hydrochloride produced by a conventionally known method. For example, an azobisamidino compound hydrochloride containing by-products generated in the reaction process or impurities contained in the raw material compound is used. Can be widely used. For example, a neutralization reaction is performed by adding ammonia gas or an organic amine to a nonpolar solvent containing azoiminoether hydrochloride described in Japanese Patent No. 2565710, and then a solvent and water necessary for an amidinolysis reaction are added. Was added to the reaction solution, or a neutralization reaction and amidinolysis reaction were carried out by adding a lower alcohol and ammonia gas or an organic amine, and then water was added to the reaction solution to obtain an azoguanyl compound hydrochloride. There is something. Further, an intermediate azo obtained by sequentially adding azobisnitriles described in Japanese Patent No. 2593312 to an acid alcohol solution prepared in advance in a temperature range of 10 ° C. or more and less than 20 ° C. and reacting them. An azobisamidine salt obtained by reacting an amine with a biiminoether salt, or a nonpolar solvent of an organic diamine described in JP-A-10-59945, is added to the azoiminoether hydrochloride to efficiently produce ammonia. There are azo cyclic amidino compound hydrochlorides manufactured by removing them outside the reaction system. Specifically, as such azobisamidino compound hydrochloride, 2,2′-azobis-2-amidinopropane dihydrochloride, 2,2′-azobis [2- (imidazolin-2-yl) propane] dihydrochloride, 2,2′-azobis (N, N′-dimethyleneisobutylamidine) dihydrochloride, 2,2′-azobis (N-phenylisobutylamidine) dihydrochloride, 2,2′-azobis (2-amidinobutane) 2 Hydrochloride, 2,2′-azobis-4,4′-methyl-2,2′-azodinopentane dihydrochloride, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane Dihydrochloride, 2,2′-azobis [2- (3,4,5,6-tetrahydropyridin-2-yl) propane] dihydrochloride, 2,2′-azobis [2- (5-hydroxy-) 3, 4, 5, - tetrahydropyridin-2-yl) propane], and the like dihydrochloride.

  Further, impurities contained in such azobisamidino compound hydrochloride include hydrogen chloride added to the reaction system, ammonia, and a reaction product with organic amine, and specifically, ammonium chloride, organic amine hydrochloride, organic There are by-products generated in the reaction process such as diamine hydrochloride. Furthermore, the water-insoluble solid content etc. which are contained in a raw material compound are also object. Moreover, there is no restriction | limiting in particular in the purity of crude azobisamidino compound hydrochloride, What is necessary is just the purity of what was obtained without refine | purifying in the conventional manufacturing method mentioned above.

  In the method for producing an azobisamidino compound hydrochloride of the present invention, first, crude azobisamidino compound hydrochloride is dissolved in water. Although the temperature of water is not particularly limited, it is generally preferable to set the temperature to about 0 to 45 ° C. If the temperature of the water is too low, the solubility is lowered and the production efficiency is lowered. On the other hand, if the temperature of the water is too high, the azobisamidino compound hydrochloride is difficult to precipitate even after the inorganic salt is added thereafter, and the productivity is lowered.

  The concentration of the crude azobisamidino compound hydrochloride is preferably 5 to 30% by mass, more preferably 10 to 30% by mass, and particularly preferably 15 to 23% by mass. If it is less than 5% by mass, it is difficult to precipitate the target product even if an inorganic salt is added thereafter, which is disadvantageous. On the other hand, when it exceeds 30 mass%, the solubility of impurities to be removed, such as ammonium chloride, may decrease, or the solubility of inorganic salts added thereafter may decrease. The water in which the azobisamidino compound hydrochloride is dissolved may contain other solvents such as acetone, ethanol, and methanol as long as the object of the present invention is not impaired.

  In order to sufficiently dissolve the azobisamidino compound hydrochloride, this aqueous solution may be allowed to stand for an appropriate time as necessary.

  Next, if there is an insoluble matter such as a precipitate in the aqueous solution in which the azobisamidino compound hydrochloride is dissolved, it is collected. Such insoluble matter can be removed by, for example, filtration or centrifugation, but filtration with a filter is simple.

  In the present invention, an inorganic salt or hydrogen chloride is then added to the azobisamidino compound hydrochloride solution. Thereby, the solubility of the azobisamidino compound hydrochloride in the solution is lowered, and azobisamidino compound hydrochloride is precipitated. According to the present invention, precipitation of ammonium chloride contained as an impurity can be suppressed to a minimum at this time.

  The inorganic salt used in the present invention is not particularly limited and can be appropriately used as long as it is an inorganic salt that can achieve the above-described object. Usually, it has a solubility higher than that of the target azobisamidino compound hydrochloride. However, even if the inorganic salt has the same or lower solubility than the hydrochloride, it can be preferentially solvated with water molecules as long as it has a stronger interaction with water molecules. It can be used in the invention.

  Specific examples of inorganic salts that can be suitably used in the present invention include, for example, sodium chloride, potassium chloride, ammonium chloride, sodium bromide, potassium bromide, sodium sulfate, calcium chloride and the like. The technical scope of the present invention should be determined based on the description of the scope of claims, and of course, other inorganic salts may be used in some cases. Since the amount of the inorganic salt used varies depending on the concentration of the azobisamidino compound hydrochloride in the solution and the temperature of the solution, it is difficult to define it in general. However, from the viewpoint of sufficiently precipitating the target product, the amount of the inorganic salt added is preferably as the amount of the inorganic salt dissolved in the solution increases, and as a particularly preferable form, a form in which a saturated amount of the inorganic salt is added. Is mentioned. However, from the viewpoint of avoiding the mixture with the azobisamidino compound hydrochloride due to the precipitation of the inorganic salt, the addition amount of the inorganic salt may be controlled so that the added inorganic salt does not precipitate.

  In the present invention, even if hydrogen chloride is added to the azobisamidino compound hydrochloride solution, the same effect as that of the inorganic salt as described above can be obtained. At this time, the form of adding hydrogen chloride is not particularly limited, and hydrogen chloride gas may be blown in, or an aqueous hydrogen chloride solution (hydrochloric acid) may be added. Preferably, however, hydrogen chloride is blown in gaseous form. Also, the amount of hydrogen chloride added is not particularly limited, but if the amount is too small, a sufficient effect may not be obtained. Therefore, in general, the amount of hydrogen chloride added is preferably as large as possible. Although it is conceivable to add a hydrogen halide other than hydrogen chloride (for example, hydrogen bromide), the addition of a hydrogen halide other than hydrogen chloride is not preferable because a salt exchange reaction proceeds in part. .

  In the present invention, after the inorganic salt is added, the solution is maintained at an appropriate temperature (usually room temperature), and the solution is allowed to stand for an appropriate time (several minutes to several hours). The temperature conditions and the standing time at this time are preferably set as appropriate so that the azobisamidino compound hydrochloride is sufficiently precipitated.

  In the present invention, the precipitate can be collected to obtain a high-quality azobisamidino compound hydrochloride. In addition, although fractionation can be performed by, for example, filtration, centrifugation, etc., filtration with a filter is simple.

  EXAMPLES Next, although an Example is given and this invention is demonstrated concretely, these Examples do not restrict | limit this invention at all.

(Comparative Example 1)
AIBN (2,2′-azobisisobutyronitrile) 66.5 g and methanol 33.7 g were charged with 350 ml of toluene, stirred, cooled to 20 ° C., and 35.4 g of hydrogen chloride gas were blown at the same temperature. Aged overnight.

  In another container, 62.5 g of ethylenediamine and 220 ml of methanol were charged, cooled to 25 ° C., and the reaction solution was slowly added dropwise to this solution. After completion of the dropwise addition, pressure reduction was started, the pressure was adjusted to 100 to 200 torr (133 to 266 hPa), and an amidation reaction was performed at 25 ° C. for 8 hours. After completion of the reaction, the reaction mixture was filtered and dried to obtain 114.5 g of crude 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride. The pure content of 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride was 91.6%, and the pure yield was 79.9%.

Example 1
AIBN (2,2′-azobisisobutyronitrile) 66.5 g and methanol 33.7 g were charged with 350 ml of toluene, stirred, cooled to 20 ° C., and 35.4 g of hydrogen chloride gas were blown at the same temperature. Aged overnight.

  In another container, 62.5 g of ethylenediamine and 220 ml of methanol were charged, cooled to 25 ° C., and the reaction solution was slowly added dropwise to this solution. After completion of the dropwise addition, pressure reduction was started, the pressure was adjusted to 100 to 200 torr (133 to 266 hPa), and an amidation reaction was performed at 25 ° C. for 8 hours. After completion of the reaction, the reaction mixture was filtered to obtain crude 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride.

  The total amount of the crude 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride obtained above was dissolved in 406.0 g of water, and 102.5 g of sodium chloride was further added. 97.4 g of 2,2′-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride was obtained by stirring at 0 ° C. for 5 hours, filtering and drying. The pure content of 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride was 99.5%, and the pure yield was 74.0%.

(Comparative Example 2)
AIBN (2,2′-azobisisobutyronitrile) 66.5 g and methanol 33.7 g were charged with 350 ml of toluene, stirred, cooled to 20 ° C., and 35.4 g of hydrogen chloride gas were blown at the same temperature. Aged overnight.

  A solution in which 17.4 g of ammonia gas was absorbed in 240 ml of methanol in another container was cooled to 25 ° C., and the reaction solution was slowly added dropwise to this solution. After completion of the dropping, an amidation reaction was performed at 25 ° C. for 8 hours.

  After completion of the reaction, filtration and drying yielded 102.1 g of crude 2,2'-azobis (2-amidinopropane) dihydrochloride. The pure content of 2,2'-azobis (2-amidinopropane) dihydrochloride was 91.6%, and the pure yield was 85.9%.

(Example 2)
AIBN (2,2′-azobisisobutyronitrile) 66.5 g and methanol 33.7 g were charged with 350 ml of toluene, stirred, cooled to 20 ° C., and 35.4 g of hydrogen chloride gas were blown at the same temperature. Aged overnight.

  A solution in which 17.4 g of ammonia gas was absorbed in 240 ml of methanol in another container was cooled to 25 ° C., and the reaction solution was slowly added dropwise to this solution. After completion of the dropping, an amidation reaction was performed at 25 ° C. for 8 hours. After completion of the reaction, the mixture was filtered to obtain crude 2,2'-azobis (2-amidinopropane) dihydrochloride.

  The total amount of the crude 2,2′-azobis (2-amidinopropane) dihydrochloride obtained above was dissolved in 480.0 g of water, 120.0 g of sodium chloride was added, and the mixture was stirred at 20 ° C. for 5 hours, filtered. Then, 84.3 g of 2,2′-azobis (2-amidinopropane) dihydrochloride was obtained by drying. The pure content of 2,2'-azobis (2-amidinopropane) dihydrochloride was 99.7%, and the pure yield was 76.5%.

(Example 3)
AIBN (2,2′-azobisisobutyronitrile) 66.5 g and methanol 33.7 g were charged with 350 ml of toluene, stirred, cooled to 20 ° C., and 35.4 g of hydrogen chloride gas were blown at the same temperature. Aged overnight.

  A solution in which 17.4 g of ammonia gas was absorbed in 240 ml of methanol in another container was cooled to 25 ° C., and the reaction solution was slowly added dropwise to this solution. After completion of the dropping, an amidation reaction was performed at 25 ° C. for 8 hours. After completion of the reaction, the mixture was filtered to obtain crude 2,2'-azobis (2-amidinopropane) dihydrochloride.

  The total amount of the crude 2,2'-azobis (2-amidinopropane) dihydrochloride obtained above was dissolved in 464.1 g of water, and 83.1 g of hydrogen chloride gas was blown at 5 to 10 ° C. Thereafter, the mixture was stirred at 5 ° C. for 1 hour, filtered and dried to obtain 85.2 g of 2,2′-azobis (2-amidinopropane) dihydrochloride. The pure content of 2,2'-azobis (2-amidinopropane) dihydrochloride was 99.4%, and the pure yield was 77.1%.

  From the comparison between the above Examples and Comparative Examples, according to the production method of the present invention, impurities produced as a by-product in the reaction step can be easily removed, and a high-quality azobisamidino compound hydrochloride can be produced. .

Claims (2)

A method for producing an azobisamidino compound hydrochloride represented by the following [Formula 1] or [Formula 2], wherein the crude azobisamidino compound hydrochloride is dissolved in water and the insoluble matter contained therein is removed, and then an inorganic salt or hydrogen chloride A method for producing an azobisamidino compound hydrochloride, comprising a step of adding azobisamidino compound hydrochloride to precipitate the azobisamidino compound hydrochloride.

(Wherein R ¹ , R ² and R ³ may be the same or different and each represents a hydrogen atom or an optionally substituted alkyl group, allyl group, cycloalkyl group or aryl group, or R ¹ and R ² may be bonded to each other to form an aliphatic ring.)

(In the formula, R ¹ and R ² have the same definitions as in the above [Formula 1], and R ⁴ represents an optionally substituted alkylene group.)   The azobisamidino compound hydrochloride is 2,2'-azobis-2-amidinopropane dihydrochloride or 2,2'-azobis [2- (imidazolin-2-yl) propane] dihydrochloride according to claim 1. Production method.