JP5681985B2 - Production method of urea compounds by carbon dioxide fixation - Google Patents

Description

  The present invention relates to a method for producing a urea compound by carbon dioxide immobilization. More specifically, carbon dioxide-containing water is used as a medium to react the carbon dioxide with a starting amine compound, thereby producing carbon dioxide. This method relates to a method for producing a urea compound, in which a urea compound is synthesized chemically and a urea compound for the raw material is synthesized. The present invention provides a new technology relating to synthesis of a urea compound by carbon dioxide immobilization, which makes it possible to synthesize a urea compound corresponding to the raw material amine compound by immobilization of carbon dioxide from the raw material amine compound and carbon dioxide. Is.

  Urea compounds, like urea, have a wide variety of uses, such as plant protection agents for pest control, medicines and agricultural chemicals and pigments, plastic plasticizers and stabilizers for plastics, and fuels such as gasoline. There are oxidizing agents. In particular, there are examples such as brain cancer and the effect of HIV protease enzyme, which may be used in various fields.

Conventionally, as an example of urea synthesis, an ammonia synthesis method is known. For example, in a reaction between a raw material gas (H ₂ , N ₂ , CH ₄ , Ar) and carbon dioxide, a temperature condition of 100 to 600 ° C. is used. The yield is 80-90% under a pressure condition of 101.3 MPa using the gas phase as a medium.

  In the reaction of ammonia and carbon dioxide, the temperature is 160 to 250 ° C. and the pressure is 40 MPa, the yield is 50 to 60%, the temperature is 150 to 215 ° C. and the pressure is 13.2 MPa, the yield is 50%, The temperature is 150-200 ° C., the pressure is 8.2-12.4 MPa, and the yield is 20-34%.

  Methods for synthesizing urea compounds from amine compounds and carbon dioxide include reacting amine compounds with isocyanate, formamide, carbamate, etc., oxidative reaction between amine and carbon monoxide, and direct reaction from amine and carbon dioxide. Synthetic methods are known. Thus, urea itself has already been driven by a method for synthesizing urea from excess ammonia and carbon dioxide, and the direct synthesis method has advantages in terms of economy.

  On the other hand, in the method of reacting an amine compound with carbon dioxide, the direct synthesis method often requires reaction conditions of 200 MPa or higher and 10 MPa or higher (Non-Patent Document 1), triethylamine (Non-Patent Document 2), An equivalent amount of amine such as diazabicycloundecene (Non-Patent Document 3) is required, and dicyclohexylcarbodiimide (Non-Patent Document 2) and diphenylphosphoric acid (Non-Patent Document 4) are required as a dehydrating agent.

  Moreover, although there is an example using a ruthenium compound etc. as a catalyst (nonpatent literature 5), it is mentioned that a yield is low. In addition, these methods use organic solvents such as N-methylpyrrolidone, acetonitrile, dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, etc. In view of recent environmental problems and oil depletion problems, these methods should be used as much as possible. Is not preferred.

  In the prior art, carbonate is used as an alternative raw material for carbon dioxide, and in another prior art, as a method using a carbonic acid compound as a catalyst, carbonate and alkanolamine are used as raw materials. And a method of synthesizing a urea compound using potassium carbonate as a catalyst has been proposed (Patent Documents 1 and 2). However, this type of method is different from the direct synthesis method from carbon dioxide.

  And, in the ammonia synthesis method, high pressure conditions and water removal by heating are indispensable, and it is necessary to increase the reaction pressure to increase the yield, and when the reaction pressure is low, the yield decreases. In the synthesis method, there are problems in improving the yield of monomers and searching for lower temperature conditions. Therefore, in this technical field, compared with conventional methods, development of a new low environmental load type urea compound synthesis process that can synthesize urea compounds in a shorter time and in a more environmentally friendly manner under low pressure conditions. Was strongly requested.

JP 59-59657 A Japanese Patent No. 3324191

R. Nomura, Y. et al. Hasegawa, M .; Ishimoto, T .; Toyosaki, H .; Matsuda, J. et al. Org. Chem. 1992, 57, 7339. H. Ogura, K .; Takeda, R.A. Tokyo, T .; Kobayashi, Synthesis, 1987, 394. C. F. Cooper, S.M. J. et al. Falcon, Synth. Commun. 1995, 25, 2467. N. Yamazaki, F.A. Higashi, T .; Iguchi, Tetrahedron Lett. , 1974, 13, 1191. J. et al. Fournier, C.I. Brunau, P.A. H. Dixneuf, S.M. Lecolier, J. et al. Org. Chem. 1991, 56, 4456.

  Under such circumstances, the present inventors can solve the problems of the above-mentioned conventional technology in view of the above-mentioned conventional technology, and can be manufactured at a low pressure and in a short time compared to the conventional method, and energy As a result of investigating the reaction system using various alkaline water solvents, water solvents, and solvent-free, while earnestly researching with the goal of developing a new low-environmentally friendly synthesis process of urea compounds, The inventors have found that the intended purpose can be achieved by a method that breaks the conventional common sense of using water, and further research has been completed to complete the present invention.

  An object of this invention is to provide the method of synthesize | combining the urea compound corresponding to the said amine raw material by chemically fix | immobilizing a carbon dioxide to an amine raw material by a carbon dioxide fixation process. The present invention also provides a novel synthesis technique for these compounds that makes it possible to synthesize urea compounds corresponding to the raw materials from the amine compounds of the raw materials by immobilizing carbon dioxide contained in the medium. It is for the purpose. Another object of the present invention is to provide a novel carbon dioxide immobilization process technology that makes it possible to synthesize a urea compound corresponding to the amine compound by immobilizing carbon dioxide in the medium to the amine compound as a raw material. To do.

The present invention for solving the above-described problems comprises the following technical means.
(1) A reaction system using a medium containing at least carbon dioxide as a reaction medium, using a water-soluble salt as a catalyst, reacting a carbon dioxide raw material with an amine compound raw material, and chemically fixing carbon dioxide to the amine compound A method for producing a urea compound for synthesizing a urea compound corresponding to the amine compound raw material,
Using water in which carbon dioxide is dissolved as a reaction medium, using the base capable of adjusting pH by dissolving or dispersing in water as the water-soluble salt, the amine compound raw material has the formula: at least an amine compound containing one or more consisting of a primary amine represented by R- NH ₂ (wherein, R, also acyclic or cyclic a alkyl group having a carbon number of 1 to 20 carbon number 1 to 10 And a corresponding urea compound is synthesized using the above-mentioned aryl group .
(2) The method for producing a urea compound according to (1) above, wherein water having a pH of 7 or more and 14 or less is used as a medium.
(3) The urea compound according to the above (2), wherein a hydroxide prepared from an alkali metal or an alkaline earth metal, or water prepared by dissolving or dispersing a carbonate is used as a base in adjusting pH. Manufacturing method.
(4) As a hydroxide or carbonate composed of an alkali metal or an alkaline earth metal, lithium hydroxide, lithium carbonate, lithium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, sodium hydroxide, sodium carbonate, Sodium bicarbonate, rubidium hydroxide, rubidium carbonate, rubidium bicarbonate, cesium hydroxide, cesium bicarbonate, cesium carbonate, magnesium hydroxide, magnesium carbonate, calcium hydroxide, calcium carbonate, strontium hydroxide, strontium carbonate, barium hydroxide The method for producing a urea compound according to any one of (1) to (3), wherein water containing at least one selected from barium carbonate is used.
(5) The method for producing a urea compound according to any one of (1) to (4), wherein the partial pressure of carbon dioxide is normal pressure or higher and 20 MPa or lower, and the temperature is 40 ° C or higher and 300 ° C or lower.

( 6 ) The purity of carbon dioxide is 50% or more and 100% or less, and any one of the above (1) to ( 5 ) using a mixed gas composed of at least one gas selected from nitrogen, oxygen, and hydrogen. A method for producing a urea compound according to Item .

Next, the present invention will be described in more detail.
The present invention relates to a new method for synthesizing a urea compound that synthesizes a urea compound from a high-pressure carbon dioxide gas up to a pressure of 20 MPa and an amine compound. In the present invention, since an inexpensive water-soluble salt is used as the catalyst, it is possible to easily remove the catalyst by washing or the like, and it is essential to remove water by heating at a high pressure of about 10 MPa to 50 MPa. Compared to the conventional method, since an aqueous medium is used as a medium, there is an advantage that an environment-friendly low environmental load type process technology can be constructed.

  The present invention relates to a method for producing a urea compound, which is a reaction between a raw material amine compound and carbon dioxide using a medium containing carbon dioxide, that is, water in which carbon dioxide is dissolved, or carbon dioxide containing water as a medium. By performing the above, carbon dioxide contained in water is chemically fixed, and a urea compound corresponding to the raw material can be synthesized.

  According to the present invention, from a raw material amine compound, a urea compound useful for an air cleaner, a deodorizing agent, a flame retardant, a flame retardant aid, a pharmaceutical, a pharmaceutical intermediate, etc., without using an organic solvent, water as a medium, It is environmentally friendly and can be synthesized efficiently.

Carbon dioxide is used as the departure material, preferably dissolved in water, in the present invention, water containing dissolved carbon dioxide is needed use as the reaction medium. The water used at that time absorbs more carbon dioxide and is a medium for obtaining a urea compound from an amine compound in a high-concentration carbon dioxide atmosphere. In order to absorb, water is preferably neutral to basic, that is, pH = 7 to 14.

  Normally, when water absorbs carbon dioxide, the pH becomes acidic at 6. Therefore, it is necessary to adjust the pH by adding a base in addition to the amine to be added. The base to be added may be an inorganic base or an organic base without limitation on the type, but it must be a base whose pH can be adjusted by dissolving or dispersing in water. Preferred are hydroxides, hydrogen carbonates and carbonates made of a similar metal.

  Specifically, as hydroxide, carbonate or bicarbonate, lithium hydroxide, lithium carbonate, lithium bicarbonate, potassium hydroxide, potassium carbonate, potassium bicarbonate, sodium hydroxide, sodium carbonate, sodium bicarbonate, Rubidium hydroxide, rubidium carbonate, rubidium bicarbonate, cesium hydroxide, cesium bicarbonate, cesium carbonate, magnesium hydroxide, magnesium carbonate, calcium hydroxide, calcium carbonate, strontium hydroxide, strontium carbonate, barium hydroxide, barium carbonate Used.

  Among these, a salt containing at least one kind can be dissolved or dispersed in water and used for the production of a urea compound consisting of a reaction between an amine compound and carbon dioxide. The concentration of the base can be adjusted and used without limitation as long as the pH is neutral or higher. However, when carbon dioxide is added, the concentration of 1 mM or more and 5 M or less is provided so that water is not biased toward the acidic side. It is preferable that the base be added at a concentration of 10 mM or more and 5 M or less, and most preferably 10 mM or more and 3 M or less.

  Carbon dioxide used in the production of the urea compound is preferably dissolved in water and used, or is preferably used by dispersing water in liquefied carbon dioxide, supercritical carbon dioxide, etc. , Preferably under a temperature of 40 ° C. or more and 300 ° C. or less and having a partial pressure of carbon dioxide of normal pressure or higher and 20 MPa or lower, more preferably safer normal pressure or higher and 10 MPa or lower, and most preferably It is above normal pressure and below 7.3 MPa which is the critical pressure of carbon dioxide.

  The temperature condition at that time is preferably 40 ° C. or more and 300 ° C. or less. However, since the reaction is extremely slow, 100 ° C. or more and 300 ° C. or less, more preferably 150 ° C. or more and 300 ° C. or less, and most preferably 150 ° C. or more and 200 ° C. It is below ℃.

  The carbon dioxide used for the reaction with the amine compound can be pure carbon dioxide or carbon dioxide mixed with other gases such as nitrogen, oxygen, hydrogen, etc. If the purity of carbon dioxide is too small, the reaction is remarkably slow, so that the purity is preferably 50% or more and 100% or less, more preferably 80% or more and 100% or less, and most preferably 95% or more and 100% or less. It is desirable to use carbon dioxide of a purity of

The amine compound used in the present invention, wherein: R- amine compound containing at least one or more consisting of a primary amine represented by NH ₂ (wherein, R is an acyclic carbon number 1-2 or cyclic a alkyl group, aralkyl group or an aryl group having a carbon number of 1-10.), and the like.

In the present invention, the yield of the synthesis reaction of the urea compound is relatively low under a low pressure condition of 5 MPa or less. In this case, the yield is improved when water is used as a medium, and alkali salts such as carbonates are added. When added to make the pH alkaline, the yield is further improved. As a result of examining the effect of various alkaline water solvents, water solvents, and no solvent on the selectivity of the target product, for example, 1M Na ₂ CO _{3 was} reacted with decylamine at 180 ° C. under a low pressure of 5 MPa for 3 hours. With 3M Cs ₂ CO ₃ , it was confirmed that a urea compound could be synthesized with a selectivity of 80% or more.

  Furthermore, in the case of using decylamine at 180 ° C. and 5 MPa for 5 hours, in the case of carbonate, water solvent, or no solvent, the conversion rate was 98%, the selectivity was 93%, and the yield was 90% or more. It was confirmed that it was obtained. Further, the obtained urea compound was stirred in a carbonate aqueous solution at 180 ° C. under a pressure of 5 or 10 MPa for 3 or 5 hours, and the stability was examined. As a result, the urea compound was obtained under the above reaction conditions. It was chemically stable, and it was confirmed that the equilibrium was tilted to the right in the following reaction formula of Chemical Formula 2 (see FIG. 4).

The present invention has the following effects.
1) It is possible to provide a new industrial production technology for urea compounds that makes it possible to synthesize a urea compound corresponding to the amine compound from an amine compound as a raw material by a carbon dioxide fixation process.
2) It is possible to synthesize urea compounds in an environmentally friendly process at a temperature of 300 ° C. or lower, for example, 150 ° C. or higher and 200 ° C. or lower, using carbon dioxide and an amine compound as starting materials. It is possible to provide a technology for synthesizing a low environmental load urea compound.
3) The target urea compound can be synthesized at a high selectivity exceeding 80% by adding a base composed of carbonate, bicarbonate or carbonate to the reaction system.
4) Compared with solvent-free conditions and water solvents alone, urea compounds can be synthesized in a shorter time and at a lower pressure and at milder reaction temperature conditions by using an aqueous solvent with carbonate added. Technology that can be done can be provided.

The conversion of decylamine is shown. The selectivity of the product (N, N'-didecylurea) is shown. The selectivity of the target compound by various alkaline water solvents, water solvents, and no solvent is shown. The stability of urea compounds under various alkaline water solvent conditions is shown.

  EXAMPLES Next, although this invention is demonstrated concretely based on an Example, this invention is not limited at all by the following Examples.

  In this example, sodium carbonate aqueous solution was used as a solvent, and these were reacted from carbon dioxide and raw material decylamine to synthesize didecylurea. Decylamine 0.5g (3.17mmol), 1M sodium carbonate aqueous solution 5ml was added to a 50mL capacity pressure vessel, the inside of the vessel was replaced with carbon dioxide under normal pressure, and preheated at 180 ° C for 90 minutes.

  Thereafter, carbon dioxide was charged until the inside of the container reached a pressure of 5 MPa, and the mixture was reacted for 5 hours at 180 ° C. while stirring with a magnetic stirrer. After completion of the reaction, the container was cooled to about 4 ° C. with ice water, and then the carbon dioxide in the container was gradually removed to return to normal pressure. The solid substance deposited in the container was separated by suction filtration to obtain 0.63 g of fine brown crystals (wet crude yield> 100%) as a reaction product.

  In order to analyze the product, the conversion rate of the raw material decylamine and the selectivity of the target product didecylurea in the above reaction were analyzed using Shimadzu HPLC. The analysis conditions were Imtakt ODS column Cadenza CD-C18 (250 mm × 4.6 mm, particle size 3 μm), column oven 40 ° C., chloroform: methanol = 80: 20 eluent, and the product was supplied at a flow rate of 0.8. Separation was performed at 35 ml / min, and detection was performed using a detector: ELSD 300S manufactured by SofTA. As a result of the analysis, the selectivity for the target product in the product was 89.0%, and the conversion rate of the raw materials was 94.0%.

In this example, dipentylurea was synthesized by reacting carbon dioxide and pentylamine with an aqueous sodium carbonate solution as a solvent. Pentylamine 0.87 g (10 mmol) and 1M sodium carbonate aqueous solution 1.1 g were added to a 50 mL capacity pressure vessel, and the inside of the vessel was replaced with CO ₂ gas under normal pressure, and preheating was performed at 180 ° C. for 90 minutes.

Thereafter, CO ₂ gas was charged until the pressure in the container reached 10 MPa, and the reaction was carried out at 180 ° C. for 16 hours while stirring with a magnetic stirrer. After the reaction, the container was cooled to about 4 ° C. with ice water, and then the CO ₂ in the container was gradually removed to return to normal pressure. The solid substance deposited in the container was separated by filtration to obtain 1.02 g of a slightly yellow crystal (wet crude yield 51.0%) as a reaction product.

  In order to analyze the product, the conversion rate of the raw material pentylamine in the reaction and the selectivity of the target product dipentylurea were measured using a GC manufactured by VARIAN under the conditions of a column oven of 300 ° C. and a temperature increase of 20 ° C. per minute. analyzed. As a result of the analysis, the selectivity for the desired product in the product was 90.4%, and the conversion rate of the raw materials was 38.3%.

  In this example, didecylurea was synthesized by reacting carbon dioxide and decylamine with water as a solvent. Decylamine 0.5 g (3.17 mmol) and water 5 ml (27.8 mmol) were added to a 50 mL capacity pressure vessel, and the inside of the vessel was replaced with carbon dioxide under normal pressure, and preheated at 180 ° C. for 90 minutes.

  Thereafter, carbon dioxide was charged until the pressure in the container reached 10 MPa, and the mixture was reacted at 180 ° C. for 3 hours while stirring with a magnetic stirrer. After completion of the reaction, the container was cooled to about 4 ° C. with ice water, and then the carbon dioxide in the container was gradually removed to return to normal pressure. The solid substance deposited in the container was separated by suction filtration to obtain 0.66 g of colorless crystals (wet crude yield> 100%) as a reaction product.

  In order to analyze the product, the conversion rate of the raw material decylamine in the reaction and the selectivity of the target product didecylurea were analyzed using Shimadzu HPLC. The analysis conditions were Imtakt ODS column Cadenza CD-C18 (250 mm × 4.6 mm, particle size 3 μm), column oven 40 ° C., chloroform: methanol = 80: 20 eluent, and the product was supplied at a flow rate of 0.8. Separation was performed at 35 ml / min, and detection was performed using a detector: ELSD 300S manufactured by SofTA. As a result of the analysis, the selectivity for the target product in the product was 91.1%, and the conversion rate of the raw materials was 98.7%.

In this example, dipentylurea was synthesized by reacting carbon dioxide and pentylamine with water as a solvent. 2.50 g (28.6 mmol) of pentylamine and 2.59 g (143 mmol) of H ₂ O are added to a pressure vessel with a volume of 50 mL, and the inside of the vessel is replaced with CO ₂ gas under normal pressure, at 180 ° C. for 90 minutes Preheated.

  Thereafter, carbon dioxide was charged until the inside of the container reached a pressure of 10 MPa, and the mixture was reacted at 180 ° C. for 16 hours while stirring with a magnetic stirrer. After the reaction, the container was cooled to about 4 ° C. with ice water, and then the carbon dioxide in the container was gradually removed to return to normal pressure. The solid precipitated in the container was filtered off to obtain 3.66 g (wet crude yield> 100%) of fine brown crystals as a reaction product.

  In order to analyze the product, the conversion rate of the raw material pentylamine in the reaction and the selectivity of the target product dipentylurea were measured using a GC manufactured by VARIAN under the conditions of a column oven of 300 ° C. and a temperature increase of 20 ° C. per minute. analyzed. As a result of the analysis, the selectivity for the target product in the product was 87.6%, and the conversion rate of the raw materials was 31.5%.

  In this example, the effect of adding a base was examined. Experiments were performed using various carbonates under the same conditions as in Example 1 (reaction temperature 180 ° C., reaction time 5 hours). Two kinds of reaction pressures, 5 MPa and 10 MPa, were used. The conversion of decylamine is shown in FIG. 1, including Example 1, Comparative Example 1, an example in which neutral water was added, and an example in which no water was added, and selection of the product N, N′-didecylurea The rates are summarized and shown in FIG. As a result, the conversion rates were 10 MPa and 5 MPa, and the difference due to pressure was small. However, the selectivity of the obtained product was significantly different under the low pressure condition of 5 MPa, and the effect of adding a base was observed. That is, at 10 MPa, the water-only addition system was most excellent in the selectivity for producing the target product. In addition, at 5 MPa, the effect of adding water and carbonate in the selectivity was remarkably recognized as compared with the solventless system.

  In this example, the effects of water and base were examined. When decylamine is used, the reaction temperature is fixed at 180 ° C., the reaction pressure is 5 MPa, and the reaction time is 3 hours. When water is not used, when water is used, carbonate and cesium fluoride are used. Went. The selectivity of the obtained N, N′-didecyl urea is shown in FIG. From this, it was found that the selectivity for the urea compound was highest when sodium carbonate or cesium carbonate was used.

  Under the same conditions as in Example 1, studies using various amines were conducted, including examples in which the presence or absence of an aqueous medium and the presence or absence of carbonate were compared. Table 1 shows the results of studies using various amines. From this, a better yield was obtained when an amine having a longer alkyl chain was used as a raw material.

  As described above in detail, the present invention relates to a urea production method by carbon dioxide immobilization. According to the present invention, a urea compound corresponding to the amine compound is converted from a raw material amine compound by a carbon dioxide immobilization process. It is possible to provide a new industrial production technique for urea compounds that can be synthesized. A reaction system using carbon dioxide and an amine compound as a starting material makes it possible to synthesize a urea compound in an environment-friendly process at a temperature of 300 ° C. or lower, for example, 150 ° C. or higher and 200 ° C. or lower. A synthesis technique of a low environmental load type urea compound can be provided. By adding a base composed of carbonate, bicarbonate, or carbonate to the reaction system, the target urea compound can be synthesized with a high selectivity exceeding 80%. The present invention provides a new technology relating to synthesis of a urea compound by carbon dioxide immobilization, which makes it possible to synthesize a urea compound corresponding to the raw material amine compound by immobilization of carbon dioxide from the raw material amine compound and carbon dioxide. Useful as a thing.

Claims (6)

A reaction system using a medium containing at least carbon dioxide as a reaction medium, using a water-soluble salt as a catalyst, reacting a carbon dioxide raw material with an amine compound raw material, chemically fixing carbon dioxide to the amine compound, and A method for producing a urea compound for synthesizing a urea compound corresponding to a compound raw material,
Using water in which carbon dioxide is dissolved as a reaction medium, using the base capable of adjusting pH by dissolving or dispersing in water as the water-soluble salt, the amine compound raw material has the formula: at least an amine compound containing one or more consisting of a primary amine represented by R- NH ₂ (wherein, R, also acyclic or cyclic a alkyl group having a carbon number of 1 to 20 carbon number 1 to 10 And a corresponding urea compound is synthesized using the above-mentioned aryl group .   The method for producing a urea compound according to claim 1, wherein water having a pH of 7 or more and 14 or less is used as a medium.   3. The method for producing a urea compound according to claim 2, wherein, in adjusting the pH, a hydroxide prepared from an alkali metal or an alkaline earth metal or water prepared by dissolving or dispersing a carbonate is used as a base.   As hydroxides or carbonates composed of alkali metals or alkaline earth metals, lithium hydroxide, lithium carbonate, lithium hydrogen carbonate, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, sodium hydroxide, sodium carbonate, sodium hydrogen carbonate , Rubidium hydroxide, rubidium carbonate, rubidium bicarbonate, cesium hydroxide, cesium bicarbonate, cesium carbonate, magnesium hydroxide, magnesium carbonate, calcium hydroxide, calcium carbonate, strontium hydroxide, strontium carbonate, barium hydroxide, barium carbonate The manufacturing method of the urea compound as described in any one of Claim 1 to 3 using the water containing at least 1 or more types chosen from these.   The method for producing a urea compound according to any one of claims 1 to 4, wherein the partial pressure of carbon dioxide is from normal pressure to 20 MPa and the temperature is from 40 ° C to 300 ° C.   The urea compound according to any one of claims 1 to 5, wherein a mixed gas composed of at least one gas selected from nitrogen, oxygen, and hydrogen is used, the purity of carbon dioxide being 50% or more and 100% or less. Manufacturing method.