Process for producing dioctamethylene triamine

Abstract: A process for producing dioctamethylene triamine which comprises reacting octamethylene diamine with suberonitrile, characterized in that the reaction is carried out in the presence of a cobalt complex catalyst.

Description: This invention relates to a process for producing 1, 17-diamino-9-azaheptadecane (dioctamethylene triamine) (hereinunder referred to as "triamine") which is useful as an intermediate for agricultural agent. The triamine may be used as an intermediate for synthesizing guazatin, an agricultural agent which is useful as an agricultural bactericide and has antibacterial properties relative to plant pathogenic bacteria. It is known to hydrogenate dinitriles in the presence of NH₃ and a monoamine using inorganic cobalt catalysts (DE OS 20 42 760). Diethylenetriamine has been prepared by reacting ethylenediamine in the presence of e.g. Raney-Co (European publication No. 115 637 A1). U.S. Patent No. 4,277,622, European Patent Publication No. 212 287 A1 and Japanese Patent Publications (Kokai) Nos. 60-239442 and 60-239443 disclose a process for producing triamine which comprises dimerizing octamethylene diamine (hereinunder referred to as ("diamine"). U.S. Patent No. 4,277,622 discloses a process for producing triamine which comprises adding an acid catalyst, such as nitric acid, hydrochloric acid, a hydrogen chloride gas, p-toluene sulfonic acid, sulfanilic acid or the like to the diamine and heating the mixture to effect deammoniation. However, this process has the following shortcomings: (i) Strong acids, such as nitric acid must be used; (ii) The dimerization of the diamine in the presence of the acid catalyst must be carried out at about 200°C for a period of more than 5 hours; (iii) Since sodium hydroxide must be used for recovering the resulting triamine from the mixture of the triamine and the acid, large amount of waste liquor was to be discharged. European publication No. 212 287 A2 discloses a process for producing triamines, e.g. 1,17-diamino-9-azaheptadecane which comprises heating a diamine in the presence of expensive palladium, platinum, rhodium, and ruthenium catalysts. Japanese Publication No. 60-239442 (= JP-B-63-11346) discloses a process for producing triamine which comprises dimerizing the diamine in the presence of an expensive Raney catalyst and in the absence of any solvent. However, not only does the process necessitate use of the expensive Raney catalyst, but when the diamine is heated in the presence of a Raney catalyst, deammoniation is caused, such as to dimerize the diamine, and because in this process, successive reaction is normally caused, such as trimerization of the diamine, or polymerization thereof. The dimerization of the diamine needs to be carried out while maintaining the degree of conversion of the diamine at a level below 50% in order to prevent a successive reaction of this soil. This inevitably lowers the yield of triamine. The diamine employed in U.S. Patent No. 4,277,622 and Publication No. 60-239442 is obtained by hydrogenerating suberonitrile. Thus these processes require an extra step for hydrogenerating suberonitrile. Publication No. 60-239443 discloses a process for producing the triamine which comprises heating suberonitrile alone or the mixture of suberonitrile and the diamine in the presence of a Raney catalyst and a hydrogen gas. However, the process also needs expensive Raney catalyst. When the Raney catalyst contacts air, the activity of the catalyst is lost. In addition, the Raney catalyst comprises nickel-aluminum alloy. Before the Raney catalyst is used, it must be treated with potassium hydroxide to eluate the aluminum, or to reduce the catalyst. Therefore, it is difficult to handle the Raney catalyst industrially. The present inventors have made wide-ranging researches with a view to producing triamine more effective-ly and have found that if the diamine and suberonitrile are heated in the presence of a cobalt complex catalyst under the pressure of hydrogen, suberonitrile is hydrogenated to form the diamine and at the same time triamine can be obtained in a high yield. This invention relates to a process for producing dioctamethylene triamine, comprising reacting suberonitrile with octamethylene diamine and hydrogen under pressure and in the presence of a cobalt catalyst, characterized in that (a) the cobalt catalyst is a complex catalyst obtained by heating dicobalt octacarbonyl together with an aromatic nitrile in a solvent capable of dissolving dicobalt octacarbonyl and aromatic nitriles and having a boiling point of more than 100°C, while the reactants are pressurized in an oxygen-free atmosphere, (b) the reaction is carried out in a solvent within a temperature range of 120°C to 180°C. When the diamine and suberonitrile are maintained in the presence of the catalyst under the pressure of hydrogen, it is assumed that the following reactions are caused to proceed: NC(CH₂)₆CN + 4H₂ → H₂N(CH₂)₈NH₂ (1) NC(CH₂)₆CN + H₂N(CH₂)₈NH₂ → H₂N(CH₂)₈NH(CH₂)₈NH₂ + NH₃ (2) According to the present invention, triamine is produced through the reaction between the diamine and suberonitrile. As the reaction proceeds, the diamine is consumed, but at the same time diamine is newly formed through the hydrogenation of suberonitrile. It is, therefore, unnecessary to replenish the diamine in the present invention while the reaction is proceeding. The catalyst employed in the present invention is the one employed for hydrogenating an aromatic nitrile. The present catalyst can be obtained by heating a solution of dicobalt octacarbonyl and an aromatic nitrile in a solvent in the substantial absence of oxygen at 100° - 200°C. The present catalysts can be prepared by adapting the following method: Aromatic nitriles that may be employed for preparing the catalysts include, for example, benzonitrile, phthalonitrile, isophthalonitrile, terephthalonitrile and the like. Solvents capable of dissolving dicobalt octacarbonyl and aromatic nitriles and having a boiling point of more than 100°C can be used as a solvent for preparing the catalysts. Examples of such solvents include hydrocarbons, such as toluene, xylene and mesitylene; amides such as dimethyl formamide and dimethyl acetamide; alcohols, such as benzyl alcohol and methylbenzyl alcohol; ketones, such as dipropyl ketone, dibutyl ketone and cyclohexanone; and esters, such as methyl benzoate, propyl benzoate and isobutyl butylate. It is preferable for the solution of dicobalt octacarbonyl and an aromatic nitrile in a solvent to be heated at 100° - 200°C. The heating time should be more than 0.5 hours, and preferably 1 - 3 hours. When the solution is heated in the presence of oxygen, an active catalyst cannot be obtained. For this reason, the air in the atmosphere in which the heating of the solution is to be conducted should be replaced by nitrogen, argon, helium, methane, hydrogen or carbon monoxide. The cobalt complex obtained by heating the solution of dicobalt octacarbonyl and an aromatic nitrile in a solvent can be used as it is to serve as a catalyst in the present invention. If necessary, the cobalt complex obtained by separating it from the solvent and then drying it can be used as the catalyst. The cobalt complex once dried is stable in air, so it can be handled in the atmosphere. However, the heat-drying of the wet cobalt complex must be carried out in the absence of oxygen. The dried cobalt complex can be used alone as the catalyst, or it can be blended with diatomaceous earth, followed by molding of the mixture. It is unnecessary to reduce the cobalt complex with hydrogen. The triamine can be prepared by mixing the diamine with suberonitrile and the catalyst and then heating the mixture under the pressure of hydrogen with stirring. The mixture may be pressurized by hydrogen to 30 - 300 kg/cm² and preferably 50 - 200 kg/cm². If the mixture is pressurized by hydrogen to a pressure of less than 30 kg/cm², the reactivity is low, due to insufficient hydrogeneration of suberonitrile. Though a pressure of more than 300 kg/cm² is usable, it adds unnecessarily to the cost. The hydrogen gas employed for pressurizing the mixture may contain nitrogen, methane and another inert gas. In this case, the partial pressure of hydrogen must be within the above range. The reaction temperature is carried out in the range of 120° - 180°C and preferably 130° - 170°C. High boiling point condensates such as polyamine are likely to be formed at temperatures above 180°C, and the reactivity of the diamine and the yield of triamine are lowered at temperatures below 120°C. The reaction time may be in the range of 0.5 - 5 hours, and preferably 1 - 3 hours. If the reaction time is too short, the reaction and yield are lowered. If it is too long, an excessive amount of polyamine is formed. According to the present invention, since a specific cobalt complex is used, triamine can be effectively produced from suberonitrile. The advantages of this invention are as follows: (1) The triamine can be produced through the reaction between the diamine and suberonitrile. As the reaction proceeds, the diamine is consumed and it is newly formed through the hydrogenation of suberonitrile. It is, therefore, unnecessary to replenish the diamine in the reaction system. In addition, it is also unnecessary to hydrogenate suberonitrile in a separate step. (2) Use of an expensive Raney catalyst is unnecessary. Since no strong acid is used, treatment of waste liquor becomes unnecessary. Therefore, the cost of production is low. The industrial significance of this invention is very high. The present invention is further illustrated by the following non-limiting Examples and Comparative runs. All percentages and parts in these Examples and Comparative runs are by weight, unless otherwise specified. The yield of the triamine in these examples is calculated in the following way: Example 1 Into a 500 mℓ flask equipped with a reflux condenser and an inlet for gas were charged 11.4 g of dicobalt octacarbonyl, 12.5 g of isophthalonitrile and 300 mℓ of meta-xylene diamine (solvent). The flask was purged with nitrogen by introducing nitrogen into the flask through the inlet for nitrogen. The flask was heated in an oil bath being maintained at 160°C. The flask was kept at the temperature for 90 minutes under the refluxing conditions while passing nitrogen through the flask. The flask was cooled to room temperature to obtain the cobalt complex catalyst. Into a 500 mℓ stainless steel autoclave were charged suberonitrile (14 g, 0.103 mol) , diamine (21 g, 0.146 mol), mesitylene (100 mℓ: solvent) and the cobalt complex catalyst (15 g) obtained by carrying out thermal treatment of dicobalt octacarbonyl together with isophthalonitrile. The autoclave was sealed and pressurized by hydrogen to 100 atms. The autoclave was set in a shaking apparatus. The reaction was carried out at 150°C for 2 hours with shaking. After the reaction had been completed, the autoclave was cooled to room temperature and the excess hydrogen was discharged. The catalyst was filtered. The solvent, mesitylene was discharged by an evaporator at a reduced pressure. The residue was distilled at a reduced pressure under an nitrogen atmosphere to obtain triamine (9.5 g). The yield of triamine was 68.0%. The diamine (23 g) was recovered by reducing-distillation as mentioned above. Example 2 The procedure of Example 1 was repeated except that the reaction was 1 hour instead of 2 hours. A yield of 5.5 g of triamine was obtained. The yield of triamine was 39.3%. The diamine was recovered in an amount of 28 g. Example 3 The procedure of Example 1 was repeated except that the amount of suberonitrile charged was 17.5 g (0.128 mol) and the amount of diamine charged was 17.5 g (0.121 mol). A yield of 9.5 g of triamine was obtained. The yield of triamine was 54.4% and 22 g of the diamine was recovered.

Claims: A process for producing dioctamethylene triamine, comprising reacting suberonitrile with octamethylene diamine and hydrogen under pressure and in the presence of a cobalt catalyst, characterized in that (a) the cobalt catalyst is a complex catalyst obtained by heating dicobalt octacarbonyl together with an aromatic nitrile in a solvent capable of dissolving dicobalt octacarbonyl and aromatic nitriles and having a boiling point of more than 100°C, while the reactants are pressurized in an oxygen-free atmosphere, (b) the reaction is carried out in a solvent within a temperature range of 120°C to 180°C. The process of claim 1, characterized in that the solvent for obtaining the cobalt catalyst is selected from hydrocarbons, aromatic hydrocarbons substituted by amino groups, amides, alcoholes, ketones, and esters. The process of claim 1 or 2, characterized in that heating of the dicobalt octacarbonyl with the aromatic nitrile is carried out in the presence of hydrogen gas. The process of any of claims 1 to 3, characterized in that the reaction pressure produced by hydrogen is in the range of 30 to 300 kg/cm². The process of any of claims 1 to 4, characterized in that the reaction time is in the range of 0,5 to 5 h. The process of any of claims 1 to 5, characterized in that the solvent and the octamethylene diamine which is produced by the reaction of suberonitrile with hydrogen gas are recovered by reducing-distillation.

Inventors: MARUYAMA KEIJI, SAITO MASAO, TSUKAHARA KENGO, MARUYAMA, KEIJI, SAITO, MASAO, TSUKAHARA, KENGO
Applicants: MITSUBISHI GAS CHEMICAL CO, MITSUBISHI GAS CHEMICAL COMPANY, INC.
Application year: 1988
Main classification: C07C211
IPC codes: C07C211, C07C209, C07C67, C07B61, B01J31