JPH0142259B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to diaminomaleonitrile (hereinafter referred to as
It is called "DAMN". ), and more specifically, relates to a method for producing DAMN in which hydrogen cyanide (hereinafter referred to as "HCN") is tetramerized using a basic substance and an organic mercaptan or an organic disulfide as a catalyst.

In recent years, various derivatives of DAMN have been developed,
It is occupying an important position as a raw material for manufacturing pharmaceutical and agrochemical intermediates, and its stable supply is required.
DAMN is usually synthesized by tetramerizing HCN using a basic substance as a catalyst;
Since low polymers such as trimers and high polymers such as pentamers and more are simultaneously produced, the reaction yield is generally extremely low, and the purity of the crude DAMN obtained by the reaction is also low. HCN is tetramerized in an aprotic polar solvent such as DMF or SMSO using an inorganic basic substance such as sodium cyanide, potassium cyanide, or sodium hydroxide as a catalyst, with a reaction yield of approximately 70%.
A method for manufacturing DAMN (see Japanese Patent Publication No. 1976-7618) was proposed, paving the way for industrialization, but
This method has the disadvantage that it is extremely difficult to separate the produced DAMN from the reaction solvent. A method for producing DAMN by tetramerizing HCN in a non-polar solvent such as benzene, toluene, or xylene in the presence of activated carbon using organic amines such as trimethylamine, triethylamine, and triethanolamine as a basic catalyst (Unexamined Japanese Patent Publication No. (Refer to Publication No. 1517/1983), and a method for producing DAMN by tetramerizing HCN in a mononitrile solvent such as aliphatic mononitrile or aromatic mononitrile using the same type of organic amine as a basic catalyst ( (Refer to Japanese Patent Publication No. 57-16094) have also been proposed, but these methods
Although HCN has the advantage of being easy to separate from the reaction solvent, the polymerization rate of HCN is extremely low at around 30%.
The yield of DAMN based on the reacted HCN is approximately 60%, but the yield relative to the charged HCN is extremely low at less than 20%, and it also has the disadvantage that a large amount of unreacted highly toxic HCN remains in the solvent. There is.

As an improvement over the prior art, the present applicant tetramerized HCN in an aprotic polar solvent using an inorganic basic substance and an organic mercaptan as a catalyst, and selectively tetramerized HCN with a reaction yield of about 90%. A method for producing DAMN (see JP-A-49-80020), and using an organic basic substance such as organic amines and an organic mercaptan or an organic disulfide as a catalyst,
DAMN-insoluble organic solvents such as aromatic hydrocarbons such as benzene and toluene, saturated aliphatic hydrocarbons such as n-heptane, carbon tetrachloride, chloroform,
HCN is dropped into halogenated hydrocarbons such as dichloroethylene or halogenated aromatic hydrocarbons such as monochlorobenzene to obtain 70% crude DAMN with a purity of 70-80%.
We proposed a method for selective production with a reaction yield of ~80% (see Japanese Patent Application Laid-open No. 11057/1983). However, in the former case, although the reaction yield is good, the drawback that it is difficult to separate the produced DAMN from the reaction solvent is not improved, and in the latter case, the product purity and reaction yield are not satisfactory.

The present invention allows easy separation of DAMN and solvent,
The object of the present invention is to provide a method for producing highly pure crude DAMN in high yield.

As a result of intensive research to achieve the above object, the present inventors achieved a purity of 80% by tetramerizing HCN in an organic acid ester solvent using an organic basic substance and an organic mercaptan or an organic disulfide as a catalyst. The inventors have completed the present invention by discovering that the above crude DAMN can be obtained with a reaction yield of 80% or more and that it is extremely easy to separate the crude DAMN from the solvent.

The present invention is a method for producing diaminomaleonitrile in which hydrogen cyanide is tetramerized using a basic substance and an organic mercaptan or an organic disulfide as a catalyst, characterized in that an organic acid ester having a boiling point of 150°C or less is used as a reaction solvent. This is a method for producing diaminomaleonitrile.

In the present invention, organic acid esters having a boiling point of 150°C or less, such as n-butyl formate, methyl acetate, ethyl acetate, methyl propionate, and ethyl propionate, are used as reaction solvents. do. Organic acid esters with a boiling point of 150°C or higher have the same effect as the lower esters in terms of reaction yield, but the resulting crude DAMN
This is not preferable since it becomes difficult to separate it from the solvent.
In particular, ethyl acetate is preferably used because it has a low boiling point.

In the present invention, in the organic acid ester solvent,
Dissolve the basic substance and organic mercaptan or organic disulfide, and further add 0.2 to 0.4
Charge HCN in a weight ratio, preferably 0.3 to 0.4 weight ratio, and heat at a temperature of 40 to 80°C, preferably 50 to 70°C.
By stirring and reacting for hours, crude DAMN with a purity of 80% or more can be obtained at a high yield of 80% or more based on the charged HCN. As the basic substance, lower trialkylamines such as trimethylamine, triethylamine, tripropylamine, and tri-n-butylamine can be preferably used, and the amount used is 0.05 or more in weight ratio to solvent, preferably in the range of 0.15 to 0.25. . Organic mercaptans include methyl mercaptan, ethyl mercaptan, butyl mercaptan,
Alkyl mercaptans having 1 to 8 carbon atoms such as octyl mercaptan, aromatic, alicyclic and heterocyclic mercaptans such as thiophenol, thiocatechol, cyclohexyl mercaptan, and 2-mercaptobenzothiazole are organic disulfides such as dimethyl disulfide. Diphenyl disulfide, diethyl disulfide, diphenyl disulfide, etc. can be used. The amount of organic mercaptan or organic disulfide used is such that the weight ratio to the solvent is 0.02 or more, preferably 0.05 to 0.2.
is within the range of Although the amount of HCN to be charged may be less than 0.2 by weight to solvent, it is not preferable considering the volumetric efficiency of the reactor, the thermal energy required for drying up the solvent, etc.
This is not preferable because DAMN will precipitate. The reaction temperature varies depending on the type of catalyst used, the amount used, etc., but below 40°C the reaction rate is slow and the reaction takes a long time, and above 80°C promotes the formation of higher order polymers, so it is preferable. do not have. The reaction time varies depending on the type of catalyst used, the amount used, the reaction temperature, etc., but if it is too long, higher order polymers will form, so 1 to 3 hours is appropriate.

In the present invention, separation of the produced crude DAMN from the reaction solvent can be carried out extremely easily by dry-up the solvent. By drying up the reaction solvent, the catalyst used at the same time is also separated from the crude DAMN, so crude DAMN with a purity of 80% or more is obtained, which suppresses the high polymerization of DAMN.
It can be used as a raw material for producing derivatives without being purified.

The present invention achieves a crude product with a purity of 80% or more due to the synergistic effect of using an organic mercaptan or an organic disulfide as a cocatalyst in addition to a basic substance, and using an organic acid ester with a boiling point of 150°C or less as a reaction solvent. DAMN is 80 against HCN
% or more, and the obtained crude
DAMN can be isolated simply by dry-up the solvent. Furthermore, by using organic acid esters as the reaction solvent, the ratio of conventionally charged HCN to reaction solvent was reduced to 0.1.
Since it is possible to reduce the value of ~0.2 to 0.3~0.4, the reaction apparatus can be made smaller, and the additional effect of reducing the thermal energy required for recovery operations such as drying up the reaction solvent can be achieved.

The present invention enables easy separation of DAMN and solvent, and obtains highly pure DAMN in high yield.
This provides an industrial method for manufacturing DAMN that can be mass-produced, and its industrial significance is extremely large.

Hereinafter, the present invention will be explained in more detail by giving Examples and Comparative Examples. However, the scope of the present invention is not limited in any way by the following examples.

Example 1 Ethyl acetate was added to a 500 ml four-necked flask equipped with a stirrer, a thermometer, and a condenser through which 0°C brine was passed.
200 g of diphenyl disulfide, 20 g of triethylamine, and 70 g of HCN were charged, and the temperature was gradually raised to 60° C. while stirring, and the reaction was completed by maintaining the temperature for 2 hours. After the reaction was completed, 500 g of ethyl acetate was added to dissolve the DAMN attached to the wall. The resulting reaction solution was filtered through a Teflon filter to separately remove higher-order polymers, which were reaction by-products, and then transferred to a rotary evaporator, where ethyl acetate and triethylamine were distilled out under reduced pressure and recovered.
The obtained crude DAMN was washed twice with 200 g of chloroform to remove diphenyl disulfide, and then vacuum-dried to obtain 69.5 g of ocher-colored crude DAMN. The obtained crude DAMN was analyzed using high performance liquid chromatography (hereinafter referred to as "HPLC") to determine the absorption wavelength.
As a result of analysis using 294 nm, the purity was 85.3%. The yield based on the charged HCN was 84.7%.

Example 2 Into the same apparatus as in Example 1, 100 g of methyl acetate, 20 g of diphenyl disulfide, and 30 g of trimethylamine were added.
g and 70 g of HCN were charged, and the mixture was reacted for 2 hours at a reaction temperature of 55°C. Thereafter, the same treatment as in Example 1 was carried out to obtain 69.4 g of crude DAMN. The resulting crude
DAMN HPLC (absorption wavelength 294nm and 304nm)
The analysis result was 84.7% purity, and the purity was 84.7%.
The yield based on HCN was 84.0%.

Example 3 Methyl propionate was added to the same apparatus as in Example 1.
200g of 2,2'-dithiodianiline, 30g of triethylamine, and 70g of HCN were charged, and the mixture was reacted at a reaction temperature of 60°C for 2 hours. The resulting reaction solution was filtered through a Teflon filter to remove higher-order polymers, and then treated in the same manner as in Example 1 to obtain a crude product.
69.6g of DAMN was obtained.

The purity of the crude DAMN obtained was 85.2%, and the yield based on the charged HCN was 84.7%.

Example 4 In the same apparatus as in Example 1, 100 g of n-butyl formate was added.
15 g of dibenzyl disulfide, 30 g of tri-n-butylamine, and 70 g of HCN were charged and reacted at a reaction temperature of 60° C. for 2 hours.

Thereafter, the treatment was carried out in the same manner as in Example 3, and the rough
68.8g of DAMN was obtained.

The purity of the obtained crude DAMN was 73.4%, and the yield based on the charged HCN was 72.1%.

Comparative Example 1 Methyl propionate was added to the same equipment as in Example 1.
100g, triethylamine 30g, and HCN 70g
was charged and allowed to react at a reaction temperature of 60°C for 2 hours.
Thereafter, it was treated in the same manner as in Example 3 to obtain 34.2 g of crude DAMN. The purity of the obtained crude DAMN was 65.2%,
The yield based on the charged HCN was 31.9%.

Comparative Example 2 100 g of xylene, 50 g of triethylamine, and 40 g of diphenyl disulfide were charged into the same apparatus as in Example 1 and heated to 60°C. under stirring
When 69.8 g of HCN was dropped onto the liquid surface at a rate of 0.70 g/min, DAMN began to precipitate after 35 minutes. 100
The dropwise addition of HCN was completed within a few minutes, and after the completion of the dropwise addition, the reaction was aged at a temperature of 60°C for 30 minutes, and then the product was separated by cooling to 20°C. The obtained product was washed with xylene and dried to obtain 65.2 g of crude DAMN. The purity of the crude DAMN obtained was 75.2%, and
The yield based on HCN was 70.2%.

Claims (1)

[Claims] 1. A method for producing diaminomaleonitrile in which hydrogen cyanide is tetramerized using a basic substance and an organic mercaptan or an organic disulfide as a catalyst, in which an organic acid ester with a boiling point of 150°C or less is used as a reaction solvent. A method for producing diaminomaleonitrile, which is characterized by: 2. The method according to claim 1, wherein the reaction catalyst is an organic acid ester having 3 to 5 carbon atoms and a boiling point of 150°C or lower. 3. The method according to claims 1 and 2, wherein the reaction solvent is ethyl acetate. 4. The method according to claim 1, wherein the basic substance is a lower trialkylamine. 5. The method according to claim 1, wherein the organic mercaptan is an alkyl mercaptan having 1 to 8 carbon atoms, an aromatic mercaptan, an alicyclic mercaptan, or a heterocyclic mercaptan. 6 The organic disulfide is dimethyl disulfide,
The method according to claim 1, which is diethyl disulfide or diphenyl disulfide. 7 The amount of hydrogen cyanide charged is the weight ratio to the solvent.
2. The method according to claim 1, wherein the particle size is between 0.3 and 0.4. 8. The method according to claim 1, wherein the reaction temperature is 50 to 70°C and the reaction time is 1 to 3 hours.