JPS61280464A - Production of disubstituted cyanamide - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an epoxy resin hardener, etc., in high yield and purity, without separating hazardous cyanogen chloride, by reacting a disubstituted amine with sodium cyanide, etc., in the presence of chlorine in an aqueous solvent. CONSTITUTION:The objective disubstituted cyanamide can be produced by reacting a disubstituted amine (e.g. diethylamine, methylethylamine, etc.) with sodium cyanide (or potassium cyanide) in the presence of chlorine in an aqueous medium. The disubstituted amine is the compound of formula (R1 and R2 are 1-6C alkyl provided that at least one of R1 and R2 is 2-6C alkyl, etc.). The amine is preferably introduced together with sodium cyanide (or potassium cyanide) into the reactor in the form of a solution or suspension in the aqueous solvent. The aqueous solvent is an aqueous solution of an organic solvent having a boiling point of about <=100 deg.C (e.g. methyl alcohol).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a di-substituted cyanamide, and more specifically, a curing agent for epoxy resin, an etching agent, a raw material for polyurethane resin, a raw material for amine resin, and a pharmaceutical use. This article relates to a method for producing di-substituted cyanamide, which is expected to find many uses in recent years as an intermediate raw material. More specifically, a disubstituted amine and sodium cyanide (or potassium cyanide) are reacted in an aqueous solvent in the presence of chlorine f! :Relating to a method for producing characteristically di-substituted cyanamides.

[Conventional technology]

Conventionally, several methods for producing tetra-substituted guanidine are known which essentially involve di-substituted guanidine.

First, Japanese Patent Publication No. 49-48932 discloses that at least 2 equivalents of dimethylamine are mixed with cyanogen chloride in a water-immiscible solvent, and the resulting mixture is heated under pressure until the reaction is completed. 1.1.3 Heat to a temperature of 130-180°C as needed.
．． 1.3, characterized in that 3-tetramethylguanidine is separated from its hydrochloride by reaction with a base;
．． A method for producing 3-tetramethylguanidine or its hydrochloride is disclosed, and the publication describes that cydimethyl cyanamide is produced by the reaction of dimethylamine and cyanogen chloride.

However, the reaction of dimethylamine and cyanogen chloride in the above proposal requires the recovery of water-immiscible solvents such as benzene, toluene, chlorobenzene, cyclo-\xane or organic solvents with a boiling point range of 60-120°C. Moreover, since the reaction is carried out under pressure because it requires a relatively high temperature to complete the reaction, it has many problems such as large restrictions on the reactor, and for this reason it has not been widely adopted industrially. It didn't work out. Note that the above proposal does not include any description or suggestion regarding di-substituted cyanamides other than dimethyl cyanamide.

The applicant of the present invention has conducted research on an industrially suitable method for producing 1.1.3.3-tetramethylguanidine that improves the above-mentioned problems, and has previously filed a patent application (Japanese Patent Laid-Open No. 55
-133352).

The above patent application describes a method for producing 1,3,3-tetramethylguanidine salt by reacting cyanogen halide and dimethylamine in the presence of a solvent, which is characterized in that an aqueous solvent is used as the reaction solvent. 1, 1.3.3.

-Production method of tetramethylguanidine salt It is related to.

However, even in the second proposal, since the highly dangerous cyanogen halide is used as a raw material, there are problems in terms of work@environmental hygiene and equipment costs such as exhaust and wastewater treatment are high.
Further, like the first proposal, the second proposal does not mention any di-substituted cyanamides other than dimethyl cyanamide.

The present inventors continued to improve the problems of the second proposal, and as a result of conducting intensive research on methods for producing disubstituted cyanamides other than dimethyl cyanamide, the present inventors discovered that disubstituted amines and sodium cyanide (or potassium cyanide) could be used together. The present invention was completed based on the unexpected discovery that a high-yield, high-purity di-substituted cyanamide can be obtained by reacting in an aqueous solvent in the presence of chlorine.

[Purpose of the invention]

That is, an object of the present invention is to provide a method for industrially producing high-purity disubstituted cyanamide useful as raw materials for various plastics, pharmaceutical intermediates, etc. in a safe manner in terms of operational and environmental health.

According to the method of the present invention, the isolation of cyanogen chloride, which is highly dangerous, can be omitted, so there is an advantage that a cyanogen chloride generating group and accompanying exhaust and wastewater treatment equipment are not required.

[Structure of the invention]

The present invention is a method for producing a di-substituted cyanamide, which is characterized by reacting a di-substituted amine and sodium cyanide (or potassium cyanide) in an aqueous solvent in the presence of chlorine.

The above di-substituted amine has the following general formula: It is a compound represented by

The above-mentioned di-substituted amines include alkyl groups in which both R1 and R have 1 to 6 carbon atoms (however, at least one of them has 2 to 6 alkyl groups), a human tetraxyalkyl group, and/or a cycloalkyl group. Compounds consisting of an alkyl group, such as methylethylamine, diethylamine, di-n-propylamine, di-1so-propylamine, di-n-butylamine, ethylmybutylamine, jetanolamine,
Dicyclohexylamine, etc.; Compounds in which one of R1 and R is an alkyl group having 1 to 6 carbon atoms and the other is a group containing an aryl group ζ For example, N-methylaniline,
N-methylbenzylamine, etc.; compounds in which R8 and R1 together with N form a saturated heterocycle, such as aziridine, azetidine, pyrrolidine, piperidine, morpholine, pyrazoline, imidacilline, piperazine, etc.; and R1 and R1
Compounds in which, together with N, form an unsaturated heterocycle, for example,
pyrroline, pyrazole, imidazole, imidacillin,
Triazole, tetrazole, etc. can be mentioned.

The above di-substituted amines can be used alone or in combination of two or more.

Among the above disubstituted amines, from the viewpoint of purity and yield of the obtained disubstituted cyanamide, both R1 and R1 have 1 to 1 carbon atoms.
A compound consisting of 6 alkyl groups (at least one of which is an alkyl group having 2 to 6 carbon atoms), a hydroxyalkyl group, and/or a cycloalkyl group; and R1 and R2 together with N form a saturated heterocycle Compounds are preferred, and diethylamine is particularly preferred.

The amount of the disubstituted amine used is preferably about 1.5 to about 3 equivalents, particularly preferably about 2 to about 2.5 equivalents, per mole of sodium cyanide (or potassium cyanide). However, it is possible to replace about half (the number of equivalents) of the amount of the di-substituted amine used with a strong alkali such as caustic soda. In particular, when using disubstituted amines such as jubutylamine whose hydrochloride has poor water solubility, from the viewpoint of ease of isolation of the resulting disubstituted cyanamide, approximately It is preferable to replace the hand t (equivalent number) with a strong alkali such as caustic soda. Conversely, when using a disubstituted amine such as diethylamine whose hydrochloride has relatively high water solubility, the yield of the disubstituted cyanamide is From this point of view, it is preferable that the amount of the disubstituted amine used is not less than about 2 equivalents per mole of sodium cyanide (or potassium cyanide).

The method of introducing the above-mentioned disubstituted amine is not particularly limited, but for example, it is prepared as a solution or suspension in an aqueous solvent together with sodium cyanide (or potassium cyanide), and the solution or suspension is introduced into a reaction tank. It's good. In order to suppress the generation of hydrocyanic acid gas, the pH of the above solution or suspension is preferably adjusted to not be less than about 7.

The aqueous solvent is an aqueous solution of water and a water-soluble organic solvent, and such organic solvents include methyl alcohol, ethyl alcohol, flobyl alcohol (n-1iso
), tert, butyl alcohol, etc. with 1 carbon atom
~4 aliphatic-hydric alcohols; other monohydric alcohols such as furfuryl alcohol; ethylene glycol,
C1-4 aliphatic polyhydric alcohols such as propylene glycol (1,2-11,3-) and glycerin;
Polyethylene glycol that is liquid at room temperature; monoetherified products of ethylene glycol and aliphatic alcohols having 1 to 4 carbon atoms, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monomethyl ether; diethylene glycol monomethyl Ether, diethylene glycol monoethyl ether, diethylene glycol monobutyl ether, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, etc.
',! : Mono- or dietherized product of aliphatic alcohol having 1 to 4 carbon atoms; glycerin such as 1-glycerin monomethyl ether and aliphatic alcohol having 1 to 4 carbon atoms
Monoetherified product Nidioxane (1,
3-11,4-), cyclic ether compounds such as tetrahydrofuran, and the like. The above organic solvents can be used alone or in a mixture of two or more. Note: When separating the di-substituted cyanamide produced from the reaction solution, the organic solvent should preferably have a boiling point of about 100°C or less, as it is preferable to remove it by means such as vacuum distillation prior to separation. Preference is given to using organic solvents, particularly methyl alcohol, ethyl alcohol and hisopropyl alcohol.

The amount of the organic solvent in the aqueous solvent is preferably about 80 volume i% or less, since the aqueous solvent needs to completely dissolve sodium cyanide (or potassium cyanide).

Further, when the disubstituted amine is a diethylamine-hydrovalent amine, it is preferable to use only water as the aqueous solvent.

As a method of making chlorine exist, for example, a method of directly introducing chlorine gas into the reaction tank can be mentioned. In this case, the chlorine gas can be directly blown into the reaction solution alone, or the chlorine gas can be appropriately diluted with air, nitrogen, etc. and then introduced. The amount of chlorine used is
It is preferable to use 58 to 2.0 moles of O per 1 mole of sodium cyanide (or cyanide power +7), and 1.0 to 1.
Particular preference is given to using 5 mol.

The reaction of the present invention can be represented by the following reaction formula.

NaCN + NH+ (/4 + Ba5eR3 When using a di-substituted amine as Ba5e, NaCN
CN+2NH+CL.

R.

becomes.

The pH of the reaction solution during the above reaction is preferably about 7 to about 11. If the pH is less than about 7, hydrocyanic acid may be generated, and if the pH exceeds about 11, the reaction solution tends to be colored due to side reactions, and in either case, the yield of the di-substituted cyanamide obtained tends to decrease. be. The above pH condition is more preferably about 7 to about 10, particularly preferably about 7.
~9.

It is preferable that the introduction of chlorine be carried out while controlling the introduction so as not to deviate from the above PH conditions.

The reaction temperature of the present invention described above is preferably about 0 to about 50°C. If the above reaction temperature is about 0°C or less, the reaction rate tends to decrease, and if the reaction temperature exceeds about 50°C, the reaction solution tends to be colored due to side reactions, and in either case, the obtained The yield of disubstituted cyanamide tends to decrease. The reaction temperature is more preferably about 10 to
About 35°C, particularly preferably about 30°C to about 1O.

As a method for isolating the disubstituted cyanamide, a known method can be selected and adopted as appropriate depending on the type of substituent. For example, the water-soluble organic solvent is removed from the solution after the reaction is completed by vacuum distillation, etc. After that, a method of extraction using a water-insoluble organic solvent can be adopted.

Examples of the water-insoluble organic solvents include aromatic hydrocarbons such as benzene, toluene, and xylene; halogenated hydrocarbons and halogenated carbons such as dichloromethane, chloroform, trichloroethylene, and carbon tetrachloride; petroleum ether, petroleum benzine, etc. Petroleum solvents; ethers such as diethyl ether and diimpropyl ether; esters such as ethyl acetate; ketones such as methyl ethyl ketone and methyl isobutyl ketone; , each can be used alone or in combination with two inserts.

The aqueous solution after the extraction of the di-substituted cyanamide can be brought into contact with chlorine gas while maintaining the pH at about 10 or higher using, for example, caustic soda, to easily and completely remove any trace amounts of cyanide ions that may remain. It can be decomposed and made non-toxic.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1: Approximately 30 m of deionized water was placed in a reaction tank equipped with a stirrer, a thermometer, a PH electrode, an aqueous liquid inlet pipe, and a gas inlet pipe.Meanwhile, about 1 ml of diethylamine was added to about 300 m of deionized water.
After adding 612 (approximately 262 equivalents), an aqueous solution for addition is prepared by stirring and dissolving approximately 51f (approximately 1 mol) of sodium cyanide by weight, and the aqueous solution for addition is made into an aqueous solution while stirring the contents in the reaction tank. The liquid was added sequentially into the reaction tank from the liquid introduction tube over a period of about 2 hours. At the same time, chlorine gas was introduced from the gas introduction pipe while taking care that the P)I of the reaction solution in one reaction tank was on average 8.5 and that the pH did not deviate from the range of about 8 to about 9. . The total amount of chlorine gas introduced is approximately 24.6 Nt (
approximately 1.1 mol). The temperature of the reaction tank was adjusted so that the temperature of the reaction solution was maintained at about 30°C.

The extract was combined with the separated upper layer and distilled under reduced pressure to obtain the desired diethyl cyanamide. The boiling point of the diethyl cyanamide is 95°C under reduced pressure of 36mHf.
The yield based on sodium cyanide was 95.8%, and the purity as determined by gas chromatography (hereinafter abbreviated as GC method) was 99.6% by weight.

Example 2 Using the same reaction vessel as in Example 1, and using deionized water in place of the aqueous addition solution in Example 1, about 80 f (about 1.1 molar mass) of diethylamine, about 93 Diethyl cyanamide was synthesized in the same manner as in Example 1, except that an aqueous addition solution containing about 432 (about 1 equivalent) of caustic soda by weight and about 511 (about 1 mol) of about 96% by weight sodium cyanide was used. The yield of the obtained diethyl cyanamide based on sodium cyanide was 75.3%, and the purity by GC method was 99.7% by weight.

Example 3 Using a reaction vessel similar to Example 1, approximately 111 t (approximately 131 equivalents) of di-1so-propylamine and approximately 9
Addition liquid (two-layer separation) fc mixed with about 25.52 (about 0.5 mol) of 6th grade sodium cyanide is used, and during addition, the addition liquid is forcedly dispersed by strong stirring. The total amount of chlorine gas introduced was approximately 12 hours.
Di-1ao-propyl 7-anamide was synthesized in the same manner as in Example 1 except that 3Nt (approximately 0.55 mol) was used. The yield of di-fiso-propyl cyanamide obtained,
Purity and physical properties are shown in Table 1.

Example 4 Using a reaction vessel similar to that of Example 1, in place of the aqueous addition solution of Example 1, about 111 mm of di-n-butylamine was added in about 200 mm of deionized water. (approximately 0.6 equivalent t), approximately 93 parts by weight caustic soda approximately 21.5P (approximately 0.5 M amount) and approximately 96 parts by weight sodium cyanide approximately 25.59 (approximately 0.5 mol) tl- for addition. Addition time is about 1 hour), and the total amount of introduced chlorine gas is about L2.3.
Dibutyl cyanamide was synthesized in the same manner as in Example 1 except that Nt (approximately 0.55 mol) was used. The yield, purity, and physical properties of the obtained dibutyl cyanamide were the first
Shown in the table.

Example 5 Using the same reaction bath as in Example 1, 100 m of deionized water and 20 m of methanol were added instead of the aqueous solution for addition of Example 1.
About 581 (about 581) hexahydrate of piperazine (
Approximately 0.6 equivalent), approximately 96 weight of sodium cyanide approximately 25.5y
(about 0.5 mol) and about 93% caustic soda by weight of about 21%.
59 (approximately 0.5 equivalent) was used (sequential addition time approximately 1 hour), and the total amount of introduced chlorine gas was approximately 12.3 Nt (approximately 0.55 mol). The reaction was carried out in the same manner as in Example 1. After the reaction is complete, methanol is distilled off from the reaction solution under reduced pressure.Next, approximately 50% of deionized water is added and the resulting white crystals are thoroughly stirred and mixed. Di7anobiverazine was obtained.

The yield, purity and physical properties of the above N,N-zineanopiperazine are shown in Table 1.

Claims (1)

[Claims] 1. A method for producing a di-substituted cyanamide, which comprises reacting a di-substituted amine and sodium cyanide (or potassium cyanide) in an aqueous solvent in the presence of chlorine. 2. The production method according to claim 1, wherein the temperature in the reaction is about 0 to about 50°C, and the pH of the aqueous solvent during the reaction is about 7 to about 11. . 3. The production method according to claim 1 or 2, wherein the disubstituted amine is diethylamine. 4. The manufacturing method according to claim 3, wherein the aqueous solvent is water.