KR101610470B1 - Method for Preparing Diureido Compounds - Google Patents

Abstract

The present invention relates to a process for producing diureido by reacting a diamine having 2 to 13 carbon atoms with urea, characterized by using an alcohol having 3 to 12 carbon atoms as a reaction solvent and using tetraalkylammonium hydroxide as a catalyst By weight. According to the production method of the present invention, diureido can be produced in a high yield in a short time.

Description

[0001] The present invention relates to a method for preparing diureido compounds,

The present invention relates to a process for preparing a diureido compound. More specifically, the present invention relates to a method for producing diureido in a short time and in high yield by using tetraalkylammonium hydroxide as a catalyst in the production of diureido by reacting a diamine with urea in an alcohol.

Isocyanates, which are used as intermediates for the production of polyurethanes, adhesives and pesticides, have been synthesized from amines and phosgene, but these methods require not only the use of toxic phosgene, but also the production of a large amount of pollutant, hydrogen chloride (HCl) There has been a demand for a new environmentally friendly method that does not use phosgene. As a part of this method, a method of synthesizing carbamate first and pyrolyzing it to produce isocyanate has been mainly studied.

Examples of the carbamate include a method of reacting a nitro compound or amine with carbon monoxide and alcohol in the presence of a catalyst at a high temperature and a high pressure, a method of synthesizing a carbamate from the reaction of an amine and a dialkyl carbonate, a method of reacting an amine with ethylene or propylene carbonate A method of synthesizing an alkylurea by reacting an amine with urea, and reacting the alkylurea with an alcohol to prepare a carbamate in two steps.

U.S. Pat. Nos. 3,461,149 and 3,979,427 use a metal halide such as iron chloride as a cocatalyst to increase the reaction rate with palladium or rhodium catalysts when preparing carbamates using nitro or amine compounds. The excess cocatalyst is not only difficult to separate after the reaction but also causes corrosion problems of the apparatus.

U.S. Patent No. 4,178,455 discloses that when a carbamate is produced from an aromatic nitro compound using a catalyst such as platinum, the reaction rate and selectivity can be increased by adding a primary amine. However, Because of the use of iron chloride as a redox active metal halide, this method also has problems with separation and corrosion.

In order to solve such a corrosion problem, U.S. Patent Nos. 4,169,269, 4,219,661, 4,262,130 and 4,339,592 disclose that a tertiary amine such as pyridine is added to the reaction without using a redox active metal halide to form an aromatic nitro compound Carbamate. As the catalyst, a Group VIII element such as palladium and platinum can be used. In the same conditions, US Pat. Nos. 3,338,956, 3,993,685 and 4,705,883 use a carbonyl compound of rhodium or ruthenium as a catalyst. The pyridine used in this case is excessive as compared with the catalyst used and sometimes used as a reaction solvent. However, this method is not economical due to difficulty in the process due to the use of pyridine having a strong odor and recovery of noble metal catalyst.

U.S. Patent Nos. 4,297,502, 4,304,992 and 4,474,978 disclose the use of palladium in which PdCl ₂ and a phosphine ligand are coordinated as a catalyst to react a primary amine or urea with an aromatic nitro compound in the presence of CO and an alcohol to form a carbamate However, there is a problem that the catalyst is excessively expensive, the use of carbon monoxide, which is a toxic gas, and the catalyst recovery after the reaction are not easy.

Japanese Patent Application Laid-Open No. 54-145601 discloses a method using a transition metal compound such as palladium or palladium compound as a catalyst and a method using palladium, ruthenium, rhodium and a Lewis acid and a tertiary amine as a catalyst, Have a problem of not only using a noble metal catalyst having a low catalytic activity and an expensive noble metal but also producing large amounts of urea compounds and N-alkylated amines.

In Chemistry Letters (1972) 373-374, there is disclosed a method of synthesizing a carbamate by carbonylating an amine on a selenium catalyst. However, since an equivalent amount of selenium is used, not only is there a large loss of catalyst, There is a drawback that the reaction hardly proceeds.

As a method for solving such a problem, a method of reacting a dialkyl carbonate and an amine under relatively mild conditions has been proposed. For example, Japanese Patent Publication No. 51-33095 discloses a method using a Lewis acid such as uranyl acetate or antimony trichloride as a catalyst. However, these catalysts accelerate the alkylation reaction of amines with carbonic acid diesters in addition to the carbamate-forming reaction, resulting in increased by-products of N-alkylated amines. The uranium compound gives comparatively good results, but it is not practically usable because it is difficult to handle radioactive elements.

Japanese Patent Laid-Open Publication No. 57-82361 discloses a method using a neutral or basic compound of zinc, titanium or zirconium as a catalyst. This method is industrially undesirable because of the high yield of carbamate but requires high temperature and long reaction time and difficulty in catalyst separation after the reaction.

Methods using Lewis acids such as aluminum chloride, tin chloride, iron chloride, zinc chloride, and rhodium chloride as catalysts are also disclosed in Gazz. Ital 115,275. According to this document, although the reaction using these catalysts gives good results, there is a problem that the reaction is carried out in the presence of an excess amount of amine relative to the dialkyl carbonate, which requires a large amount of energy for recovery of amine and purification of carbamate.

As a method of using a base as a catalyst, Japanese Unexamined Patent Publication No. 2-311452 discloses a method of using an alcohol of an alkali metal and an alkaline earth metal. However, a base may remain in the carbamate obtained by this method. The residual base may be polymerized or colored when the carbamate is converted into isocyanate by pyrolysis, so it must be neutralized with acid before pyrolysis process.

Japanese Unexamined Patent Publication (Kokoku) No. 5-85854 discloses that if an excess of amine is used for the dialkyl carbonate, the reaction proceeds rapidly even in the absence of a catalyst, and the carbamate can be produced with high selectivity at a high yield. This method has the advantage that it is not necessary to add a substance other than the reaction raw material to the reaction system and the carbamate can be obtained in a short time in a high yield. However, it requires a lot of energy for the recovery of the amine used and the purification of the carbamate In addition, when dicarbamate is produced using diamine as a raw material, there is a problem that the yield of dicarbamate is excessively low.

Korean Patent Laid-Open Publication No. 1999-0079326 discloses a method of producing a carbamate in a high yield by reacting an amine with an alcohol and a mixed gas of CO / O _{2 in} the presence of a selenium catalyst system. However, the problem of toxicity of carbon monoxide and selenium There is a problem that the post-selenium catalyst must be recovered.

International Patent Publication No. WO 2007/082818 discloses a process for producing diabodies by reacting diamines with urea to prepare diureido and reacting them with an alcohol at a high temperature in a two step process, Toluene or the like, which is a volatile organic solvent, is used in the production reaction, and the reaction temperature is relatively high at 170 to 220 ° C, which is economically and environmentally undesirable.

The inventors of the present invention have conducted intensive researches to solve the above-mentioned problems of the prior art in the synthesis of diureido. As a result, it has been found that when the reaction of diamine and urea proceeds in the presence of a tetraalkylammonium hydroxide catalyst, Diureido can be obtained in high yield, and the present invention has been completed.

Accordingly, an object of the present invention is to provide an economical and environmentally friendly preparation method of producing diureido from a diamine and a urea in a short time in a high yield.

The present invention relates to a process for preparing diureido by reacting a diamine having 2 to 13 carbon atoms with urea, which process comprises reacting tetraalkylammonium hydroxide represented by the following formula (1) as a catalyst with an alcohol having 3 to 12 carbon atoms as a solvent And a method for producing the same.

[Chemical Formula 1]

In the above formulas,

R ₁ represents an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, a hydroxyalkyl group having 1 to 8 carbon atoms, or a benzyl group,

R ₂ represents an alkyl group having 1 to 4 carbon atoms.

The diamine having 2 to 13 carbon atoms used in the production method of the present invention includes an aliphatic diamine having 2 to 13 carbon atoms, a cycloaliphatic diamine having 3 to 13 carbon atoms and an aromatic diamine having 5 to 13 carbon atoms, (EDA), 1,3-propanediamine (PDA), 1,4-butanediamine (BDA), 1,6-hexanediamine (HDA), 1,8- Cyclohexanediamine (1,2-CHDA), 1,3-cyclohexanediamine (1,3-CHDA), 1,4-cyclohexanediamine (1,4-CHDA), 1,2- (1,2-CHBMA), 1,3-cyclohexane bismethylamine (1,3-CHBMA), 1,4-cyclohexane bismethylamine (1,4-CHBMA), isophoronediamine , 4'-methylenebiscyclohexylamine (H12MDA), m-xylene diamine (MXDA), o-xylene diamine (OXDA), p- xylene diamine (PXDA) But are not limited thereto.

The alcohol having 3 to 12 carbon atoms used in the production method of the present invention is, for example, n-propanol, n-butanol, isobutanol, n-pentanol, n-hexanol, (MEG), 2-ethoxyethanol (EEG), 2-propoxyethanol (PEG), 2-isopropoxyethanol, 2-methoxyethanol (EEG), 2- (2-methoxyethoxy) ethanol (MEEG), 2- Diethylene glycol monomethyl ether (EDEG), diethylene glycol monobutyl ether (BDEG), triethylene glycol monomethyl ether (MTEG), and diethylene glycol monomethyl ether ), Triethylene glycol monoethyl ether (ETEG), triethylene glycol monobutyl ether (BTEG), tetraethylene glycol monomethyl ether (MTTEG), tetraethylene glycol monoethyl ether (ETTEG) Include but not limited.

In the production process according to one embodiment of the present invention, the amount of the urea to be used is preferably 2 to 10 moles, more preferably 2.2 to 6.6 moles per 1 mole of diamine as a starting material. When the amount of urea is less than 2 mol, the yield of diureido is markedly decreased. When the amount of urea is more than 10 mol, more urea than necessary is used, resulting in an increase in the amount of urea and urea derivative to be recovered after the reaction do.

The amount of the alcohol to be used is preferably 2 to 20 moles, more preferably 4 to 10 moles, per 1 mole of the starting diamine. If the amount of alcohol used is less than 2 moles, the reaction proceeds too slowly to lower the conversion of diamine and the yield of the diureido compound and increase the production of alkylated amine byproducts. If the amount of alcohol exceeds 20 moles, Resulting in a large amount of alcohol to be recovered, which is uneconomical.

In the production method according to one embodiment of the present invention, the tetraalkylammonium hydroxide of Formula 1 used as a catalyst is reacted with an alkoxide ion (RO) generated from the reaction of a hydroxyl ion (OH ^- ) or an alcohol with an alcohol ^- ) interacts with the diamine of the raw material to increase the nucleophilicity of the diamine, thereby promoting the reaction between the diamine and the urea.

The amount of the tetraalkylammonium hydroxide to be used is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.01 mol, based on 1 mol of the starting diamine. When the amount of the catalyst used is less than 0.0001 mol, the catalytic function of the tetraalkylammonium hydroxide is insignificant and the effect of increasing the reaction rate is insignificant. When the amount of the catalyst is more than 0.1 mol, The possibility of adversely affecting the production process of the baramate is increased.

In the production method according to an embodiment of the present invention, since tetraalkylammonium hydroxide used as a catalyst is extremely small, there is no need for a separate separation and removal process after the reaction. Also, the alcohol solution containing a small amount of catalyst after the reaction provides an advantage that it can be used as it is in a carbamate synthesis reaction using diureido as a raw material.

The reaction temperature can be selected in the range of 50 to 150 ° C, but it is preferably selected in the range of 80 to 130 ° C in consideration of the reaction rate, yield and selectivity of diureido. When the reaction temperature is lower than 50 ° C, the production rate and yield of diureido is remarkably lowered, and when it is higher than 150 ° C, the production of by-products and unnecessary energy are excessively consumed, which is uneconomical.

The reaction time can be selected within the range of 1 to 10 hours, but it is preferably selected within the range of 2 to 6 hours in consideration of the yield of the diureido and the economical efficiency of the reaction.

According to the process for producing diureido of the present invention, by using alcohol as a reaction solvent and tetraalkylammonium hydroxide as a catalyst in the production of diureido from the reaction of diamine and urea, di Ureido can be prepared. The diureido alcohol solution obtained according to the present invention can be directly used as a starting material for the production process of dicarbamate without separate separation and purification process. Therefore, when the present invention is combined with the production process of dicarbamate, Can be greatly improved. In addition, since tetraalkylammonium hydroxide used as a catalyst is extremely small, there is no need for a separate separation and removal process after the reaction.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these embodiments are for illustrative purpose only and that the scope of the present invention is not limited to these embodiments.

Example 1:

(HDA; 58 g, 0.5 mol), urea (66.0 g, 1.1 mol) and 2-methoxyethanol (152 g, 2.0 mol) were added to a 500 mL three-necked flask equipped with a reflux condenser and a thermometer, , Benzyltrimethylammonium hydroxide (0.167 g, 0.001 mol) were charged and reacted at 100 DEG C for 3 hours. The precipitate obtained by cooling the reaction mixture to room temperature was filtered, dried and weighed. The composition was analyzed by ¹ H NMR. As a result, the conversion of 1,6-hexanediamine was found to be 98%, 1,6-hexane diureido was found to be 97.2 %. ≪ / RTI >

The conversion of diamine and the yield of diureido were calculated as follows.

Conversion ratio of diamine (%) = (amount of reaction of diamine / amount of diamine used) × 100

Yield (%) of diureido = (amount of diureido / amount of diamine used) x 100

Examples 2 to 6:

In order to examine the effect of the catalyst, the molar ratio of urea to HDA was fixed at 2.2 and the reaction was carried out under the same conditions as in Example 1 while varying the molar ratio of the catalyst and HDA. The results are shown in Table 1 below.

Example Molar ratio (catalyst / HDA) HDA conversion (%) Diureido yield (%) 2 0.0001 75.1 74.4 3 0.001 96.8 95.9 4 0.005 99.4 98.7 5 0.05 99.9 99.9 6 0.1 97.4 99.9

Examples 7 to 12:

To investigate the effect of alcohol, the reaction was carried out under the same conditions as in Example 1 while changing the molar ratio of urea to HDA to 2.2 and changing the molar ratio of MEG to HDA. The results are shown in Table 2 below.

Example Molar ratio (MEG / HDA) HDA conversion (%) Diureido yield (%) 7 2 90.2 89.1 8 3 94.4 93.2 9 5 99.9 98.9 10 6 100 99.3 11 15 100 99.4 12 20 100 99.7

Examples 13-17:

The reaction was carried out under the same conditions as in Example 1 while changing the molar ratio of 2-methoxyethanol and HDA to 4 and changing the mole ratio of urea to HDA. The results are shown in Table 3 below.

Example Molar ratio (urea / HDA) HDA conversion (%) Diureido yield (%) 13 2 94.3 94.8 14 3 99.9 98.9 15 4 100 99.7 16 6 100 99.9 17 10 100 99.9

Examples 18-22:

The reaction was carried out under the same conditions as in Example 1 while changing the reaction temperature. The results are shown in Table 4 below.

Example Reaction temperature (캜) HDA conversion (%) Diureido yield (%) 18 50 54.2 53.7 19 80 85.7 85.2 20 120 99.7 99.9 21 130 100 98.1 22 150 100 97.3

Examples 23 to 26:

The reaction was carried out under the same conditions as in Example 1 while changing the reaction time. The results are shown in Table 5 below.

Example Reaction time (h) HDA conversion (%) Diureido yield (%) 23 One 66.8 66.2 24 2 89.7 89.1 25 6 99.9 99.7 26 10 100 99.9

Examples 27 to 35:

The reaction was carried out under the same conditions as in Example 1 while varying the kind of diamine. The results are shown in Table 6 below.

Example Diamine Diamine conversion (%) Diureido yield (%) 27 EDA 99.7 98.9 28 BDA 98.5 97.8 29 ROOM 94.8 93.7 30 1,2-CHDA 93.8 92.7 31 IPDA 94.2 93.7 32 H12MDA 93.2 92.2 33 MXDA 90.2 89.1 34 PXDA 89.9 88.9 35 1,3-CHBMA 93.3 92.1

Examples 36 to 48:

The reaction was carried out under the same conditions as in Example 1 with different kinds of alcohols, and the results are shown in Table 7 below.

Example Alcohol Diamine conversion (%) Diureido yield (%) 36 n-propanol 97.4 96.8 37 n-pentanol 95.4 94.1 38 n-hexanol 91.8 90.8 39 Cyclohexanol 91.7 90.1 40 Benzyl alcohol 94.2 93.2 41 n-butanol 96.2 95.8 42 EEG 95.1 94.6 43 MPG 95.8 95.1 44 BEG 93.2 92.3 45 MEEG 94.4 92.5 46 EEEG 92.6 91.5 47 MTEG 89.4 88.2 48 MTTEG 86.3 85.8

Examples 49-53:

The reaction was carried out under the same conditions as in Example 1 while varying the kind of catalyst, and the results are shown in Table 8 below.

Example catalyst Diamine conversion (%) Diureido yield (%) R ₁ R ₂ 49 benzyl ethyl 96.7 96.1 50 Hydroxyethyl methyl 98.5 97.8 51 Hydroxyethyl Butyl 97.8 97.3 52 Cyclohexyl methyl 93.8 92.7 53 Butyl Butyl 94.2 93.7

Claims (8)

A process for producing a diureido compound by reacting a diamine having 2 to 13 carbon atoms with urea, which comprises reacting a tetraalkylammonium hydroxide represented by the following formula (1) as a catalyst with an alcohol having 3 to 12 carbon atoms as a reaction solvent A method for producing
[Chemical Formula 1]

In the above formulas,
R ₁ represents an alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 3 to 8 carbon atoms, a hydroxyalkyl group having 1 to 8 carbon atoms, or a benzyl group,
R ₂ represents an alkyl group having 1 to 4 carbon atoms. The process according to claim 1, wherein the diamines having 2 to 13 carbon atoms are selected from the group consisting of 1,2-ethanediamine (EDA), 1,3-propanediamine (PDA), 1,4-butanediamine (BDA), 1,6- HDA), 1,8-octanediamine (ODA), 1,2-cyclohexanediamine (1,2-CHDA), 1,3-cyclohexanediamine (1,3-CHDA), 1,4- (1,4-CHDA), 1,2-cyclohexane bismethylamine (1,2-CHBMA), 1,3-cyclohexane bismethylamine (1,3-CHBMA), 1,4- Amine (1,4-CHBMA), isophoronediamine (IPDA), 4,4'-methylenebiscyclohexylamine (H12MDA), m-xylene diamine (MXDA), o- xylene diamine (OXDA) Xylene diamine (PXDA). The process according to claim 1, wherein the alcohol having 3 to 12 carbon atoms is at least one selected from the group consisting of n-propanol, n-butanol, isobutanol, n-pentanol, n-hexanol, (EEG), 2-propoxyethanol (PEG), 2-isopropoxyethanol, 2-butoxyethanol (BEG), 2-ethoxyethanol (MPE), 2- (2-methoxyethoxy) ethanol (MEEG), 2- (2-ethoxyethoxy) ethanol (EEEG) (BEEG), diethylene glycol monomethyl ether (MDEG), diethylene glycol monoethyl ether (EDEG), diethylene glycol monobutyl ether (BDEG), triethylene glycol monomethyl ether (MTEG), triethylene glycol monoethyl ether (ETEG), triethylene glycol monobutyl ether (BTEG), tetraethylene glycol monomethyl ether (MTTEG) or tetraethylene glycol monoethyl ether (ETTEG). . The process according to claim 1, wherein the amount of urea used is 2 to 10 moles per mole of diamine. The production method according to claim 1, wherein the amount of alcohol used is 2 to 20 moles per 1 mole of diamine. The production method according to claim 1, wherein the amount of the catalyst to be used is 0.0001 to 0.1 mol per mol of the diamine. The process according to any one of claims 1 to 6, wherein the reaction temperature is from 50 to 150 ° C. 7. The process according to any one of claims 1 to 6, wherein the reaction time is 1 to 10 hours.