JP2008127293A - Carbamic acid ester compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carbamic acid ester compound solving various problems in a conventional production of an isocyanate compound by thermal decomposition of the carbamic acid ester compound, and to provide a method for producing an isocyanate compound by using the carbamic acid ester compound. <P>SOLUTION: The carbamic acid ester compound is represented by formula (1) (wherein, R<SP>1</SP>is a linear or branched 1-12C alkyl group; Q<SP>1</SP>and Q<SP>2</SP>are each an ether group containing an aromatic group having a substituent, and provided that an aromatic hydroxy compound having ≥250°C standard boiling point and a structure obtained by adding a hydrogen atom to each group). The method for producing the isocyanate compound by the thermal decomposition of the carbamic acid ester compound is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a novel carbamic acid ester compound and a method for producing an isocyanate compound using the carbamic acid ester compound.

  Isocyanate compounds are useful as raw materials for producing polyurethane foams, paints, adhesives, etc., and the main industrial production method is a reaction between amines and phosgene (phosgene method). However, this production method uses highly toxic phosgene and produces a large amount of highly corrosive hydrogen chloride as a by-product, and the isocyanate compound produced by the phosgene method often contains hydrolyzable chlorine. Therefore, there is a problem that the weather resistance and heat resistance of polyurethane products using the isocyanate compound are often adversely affected. Against this background, in recent years, a method by thermal decomposition of a carbamic acid ester compound has been proposed as one method for producing an isocyanate compound that does not use phosgene (see, for example, Patent Document 1).

It has long been known that an isocyanate and a hydroxyl compound can be obtained by thermal decomposition of a carbamic acid ester compound (see, for example, Non-Patent Document 1). However, the thermal decomposition reaction of the carbamate ester is reversible, and its equilibrium is advantageous on the isocyanate and hydroxyl compound side at high temperatures, but is biased toward the carbamate side at low temperatures. Therefore, in the production method of isocyanate by thermal decomposition of a carbamic acid ester compound, since the carbamic acid ester is produced by the reverse reaction of the produced isocyanate and the hydroxyl component, not only the yield and selectivity of the isocyanate are lowered, but also the polymer. In some cases, the long-term operation becomes difficult, for example, the reactor is blocked by the precipitation of the solid solid.
Japanese Patent No. 3382289 Berchte der Deutschen Chemischen Gesellshaft, 3, 653, 1870

  An object of the present invention is to provide a carbamate compound capable of solving the above-mentioned problems when an isocyanate compound is produced by thermal decomposition of a carbamate compound, and a method for producing an isocyanate compound using the carbamate compound. It is to provide.

  As a result of intensive studies on the above problems, the present inventor has found that the problem can be solved by a carbamic acid ester compound having a specific structure, and has completed the present invention.

（式中：
Ｒ¹は直鎖状または分岐状の炭素数１〜１２のアルキル基を表し、Ｑ¹及びＱ²は、

式（２）、（３）で示される置換基を有する芳香族基を含む基であって、該基を構成するＡｒ¹−Ｏ−及びＡｒ²−Ｏ−に各々水素原子が付加した構造を有する芳香族ヒドロキシ化合物Ａｒ¹ＯＨ及びＡｒ²ＯＨの標準沸点が２５０℃以上である。）、
[２] Ｑ¹及びＱ²を構成するＡｒ¹−Ｏ−及びＡｒ²−Ｏ−に各々水素原子が付加した構造を有する芳香族ヒドロキシ化合物Ａｒ¹ＯＨ及びＡｒ²ＯＨが、１価の芳香族ヒドロキシ化合物であることを特徴とする[１]記載のカルバミン酸エステル化合物、
[３] 一般式（１）におけるＲ¹が、直鎖状の炭素数６のアルキル基であることを特徴とする[１]又は[２]に記載のカルバミン酸エステル化合物、
を提供する。 That is, in the first aspect of the present invention,
[1] Carbamate compound represented by the following formula (1):

(Where:
R ¹ represents a linear or branched alkyl group having 1 to 12 carbon atoms, Q ¹ and Q ² are

A group containing an aromatic group having a substituent represented by formulas (2) and (3), wherein a hydrogen atom is added to each of Ar ¹ —O— and Ar ² —O— constituting the group. The normal boiling point of the aromatic hydroxy compounds Ar ¹ OH and Ar ² OH is 250 ° C. or higher. ),
[2] The aromatic hydroxy compounds Ar ¹ OH and Ar ² OH each having a structure in which a hydrogen atom is added to Ar ¹ —O— and Ar ² —O— constituting Q ¹ and Q ² are monovalent aromatic A carbamate compound according to [1], which is a hydroxy compound;
[3] The carbamic acid ester compound according to [1] or [2], wherein R ¹ in the general formula (1) is a linear alkyl group having 6 carbon atoms,
I will provide a.

In the second aspect of the present invention,
[4] A method for producing an isocyanate compound, which comprises thermally decomposing a carbamic acid ester compound of the general formula (1),
I will provide a.

  According to the present invention, when an isocyanate compound is produced by thermal decomposition of a carbamic acid ester compound, the yield of the isocyanate compound can be improved.

  The following embodiment is an example for explaining the present invention, and is not intended to limit the present invention only to this embodiment. The present invention can be implemented in various forms without departing from the gist thereof.

（式中：
Ｒ¹は直鎖状または分岐状の炭素数１〜１２のアルキル基を表し、Ｑ¹及びＱ²は、

式（２）、（３）で示される置換基を有する芳香族基を含む基であって、該基を構成するＡｒ¹−Ｏ−及びＡｒ²−Ｏ−に各々水素原子が付加した構造を有する芳香族ヒドロキシ化合物Ａｒ¹ＯＨ及びＡｒ²ＯＨの標準沸点が２５０℃以上である。） The carbamic acid ester compound of the present invention is a carbamic acid ester represented by the following formula (1).

(Where:
R ¹ represents a linear or branched alkyl group having 1 to 12 carbon atoms, Q ¹ and Q ² are

A group containing an aromatic group having a substituent represented by formulas (2) and (3), wherein a hydrogen atom is added to each of Ar ¹ —O— and Ar ² —O— constituting the group. The normal boiling point of the aromatic hydroxy compounds Ar ¹ OH and Ar ² OH is 250 ° C. or higher. )

Q ¹ and Q ² in the above formula (1) include aromatic hydroxy compounds Ar ¹ OH having a structure in which hydrogen atoms are added to Ar ¹ -O— and Ar ² —O— constituting Q ¹ and Q ² , respectively. Ar ² OH is preferably a monovalent aromatic hydroxy compound. Examples of such Ar ¹ OH and Ar ² OH include octylphenol (each isomer), nonylphenol (each isomer), decylphenol (each isomer), undecylphenol (each isomer), dodecylphenol (each Isomers), dibutylphenol (each isomer), dipentylphenol (each isomer), dihexylphenol (each isomer), diheptylphenol (each isomer), dioctylphenol (each isomer), dibutylmethylphenol (each Isomers), dimethylmethoxyphenol (each isomer), naphthol (each isomer), phenylphenol (each isomer), phenoxyphenol (each isomer), and the like.

（式中：
Ｒ²、Ｒ³は、各々独立に、直鎖状又は分岐状の炭素数１〜１６のアルキル基、炭素数５〜１２のシクロアルキル基、直鎖状又は分岐状の炭素数２〜１２のアルケニル基、無置換若しくは置換された炭素数６〜１９のアリールと、直鎖状又は分岐状の炭素数２〜１４のアルキル基及び炭素数５〜１４のシクロアルキル基からなる群から選ばれるアルキルとからなる炭素数７〜２０のアラルキル基、又は無置換若しくは置換された炭素数６〜２０のアリール基を示す。） The production method of the carbamic acid ester compound of the present invention is not particularly limited, but preferred examples include the carbamic acid ester compound A represented by the following formula (4), the Ar ¹ OH and / or Ar ² OH described above. The method of manufacturing by heating in the compound to contain can be mentioned. The method will be described below.

(Where:
R ² and R ³ are each independently a linear or branched alkyl group having 1 to 16 carbon atoms, a cycloalkyl group having 5 to 12 carbon atoms, or a linear or branched carbon group having 2 to 12 carbon atoms. An alkyl selected from the group consisting of an alkenyl group, an unsubstituted or substituted aryl having 6 to 19 carbon atoms, and a linear or branched alkyl group having 2 to 14 carbon atoms and a cycloalkyl group having 5 to 14 carbon atoms And an aralkyl group having 7 to 20 carbon atoms or an unsubstituted or substituted aryl group having 6 to 20 carbon atoms. )

  Examples of the carbamic acid ester compound A represented by the above formula (4) include N, N′-hexanediyl-bis-carbamic acid dimethyl ester, N, N′-hexanediyl-bis-carbamic acid dimethyl ester, N , N′-hexanediyl-bis-carbamic acid dimethyl ester, N, N′-hexanediyl-bis-carbamic acid diethyl ester, N, N′-hexanediyl-bis-carbamic acid dipropyl ester (each isomer), N, N′-hexanediyl-bis-carbamic acid dibutyl ester (each isomer), N, N′-hexanediyl-bis-carbamic acid dipentyl ester (each isomer), N, N′-hexanediyl-bis- Carbamic acid dihexyl ester (each isomer), N, N′-hexanediyl-bis-carbamic acid diheptyl Ester (each isomer), N, N′-hexanediyl-bis-carbamic acid dioctyl ester (each isomer), N, N′-hexanediyl-bis-carbamic acid dinonyl ester (each isomer), N, N'-hexanediyl-bis-carbamic acid didecyl ester (each isomer), N, N'-hexanediyl-bis-carbamic acid diundecyl ester (each isomer), N, N'-hexanediyl-bis- Carbamic acid didodecyl ester (each isomer), N, N′-hexanediyl-bis-carbamic acid dicyclopentyl ester, N, N′-hexanediyl-bis-carbamic acid dicyclohexyl ester, N, N′-hexanediyl- Bis-carbamic acid dicyclooctyl ester, N, N′-hexanediyl-bis-carbamic acid dicyclohexane Chiruesuteru and the like.

In the method for producing the carbamic acid ester compound A represented by the above formula (4) by heating in the above-mentioned compound containing Ar ¹ OH and / or Ar ² OH, it is represented by the above formula (4). The amount of Ar ¹ OH and / or Ar ² OH in the compound containing Ar ¹ OH to the carbamic acid ester compound A is preferably 1 to 500 times, more preferably 2 to 100 times in terms of stoichiometric ratio, 50 times is more preferable. Moreover, 100 to 250 degreeC is preferable and the temperature at which this reaction is implemented has more preferable 150 to 230 degreeC.

  In the reaction, a known catalyst can be used to accelerate the reaction. The catalyst is used in an amount of 0.01 to 30% by weight, preferably 0.5 to 20% by weight, based on the weight of the carbamic acid ester compound A represented by the above formula (4). Suitable for use are organometallic catalysts such as dibutyltin dilaurate, lead octylate, stannous octoate, and amines such as 1,4-diazabicyclo [2,2,2] octane, triethylenediamine, triethylamine, among others, dilauric acid Organometallic catalysts such as dibutyltin, lead octylate, stanaoctate are preferred. These compounds may be used alone or as a mixture of two or more.

  The carbamic acid ester compound of the present invention is a compound suitable for the production of an isocyanate compound by thermal decomposition of the carbamic acid ester compound, and an implementation method thereof will be described. The temperature at which the thermal decomposition reaction of the carbamic acid ester compound of the present invention is carried out is preferably from 100 ° C to 350 ° C, more preferably from 150 ° C to 300 ° C. At high temperatures exceeding 350 ° C., there are cases where the yield of isocyanate decreases due to side reactions. Although the reaction is carried out under atmospheric pressure or reduced pressure, it is preferably carried out under reduced pressure from the viewpoint of quickly recovering the isocyanate produced by thermal decomposition. A catalyst for promoting the thermal decomposition reaction is not particularly required, but a catalyst can also be used. When the catalyst is used, preferable use conditions are 0.01 to 30% by weight, preferably 0.5 to 20% by weight, based on the weight of the carbamate compound. Suitable catalysts include, for example, organometallic catalysts such as dibutyltin dilaurate, lead octylate, stannous octoate, and amines such as 1,4-diazabicyclo [2,2,2] octane, triethylenediamine, and triethylamine. Of these, organometallic catalysts such as dibutyltin dilaurate, lead octylate, and stanaoctate are preferred. These compounds may be used alone or as a mixture of two or more.

  Moreover, it is not necessary to use a solvent in the thermal decomposition reaction, but a solvent can be used for the purpose of facilitating the reaction operation. Preferred solvents include alkanes such as hexane (each isomer), heptane (each isomer), octane (each isomer), nonane (each isomer), decane (each isomer), benzene, toluene, Xylene (each isomer), ethylbenzene, diisopropylbenzene (each isomer), dibutylbenzene (each isomer), aromatic hydrocarbons such as naphthalene and alkyl-substituted aromatic hydrocarbons, chlorobenzene, dichlorobenzene (each isomer) , Aromatic compounds substituted with halogen or nitro group such as bromobenzene, dibromobenzene (each isomer), chloronaphthalene, bromonaphthalene, nitrobenzene, nitronaphthalene, diphenyl, substituted diphenyl, diphenylmethane, terphenyl, anthracene, di Benzyltoluene (each isomer) etc. Polycyclic hydrocarbon compounds, aliphatic hydrocarbons such as cyclohexane, cyclopentane, cyclooctane and ethylcyclohexane, ketones such as methyl ethyl ketone and acetophenone, esters such as dibutyl phthalate, dihexyl phthalate, dioctyl phthalate and benzyl butyl phthalate, Examples thereof include ethers and thioethers such as diphenyl ether and diphenyl sulfide, sulfoxides such as dimethyl sulfoxide and diphenyl sulfoxide, and silicone oil. These solvents can be used alone or as a mixture of two or more.

  The reaction vessel in which the thermal decomposition reaction of the carbamic acid ester compound of the present invention is performed is not particularly limited, and a known reactor can be used. For example, conventionally known reactors such as a stirring tank, a pressurized stirring tank, a reduced pressure stirring tank, a tower reactor, a distillation tower, a packed tower, and a thin film distillation apparatus can be used in appropriate combination. The material of the reactor is not particularly limited, and a known material can be used. For example, glass, stainless steel, carbon steel, Hastelloy, glass lining on the base material, or Teflon (registered trademark) coating can be used.

EXAMPLES Hereinafter, the present invention will be specifically described based on examples, but the present invention is not limited to these examples.

<Analysis method>
1) NMR analysis method Apparatus: JNM-A400 FT-NMR system manufactured by JEOL Ltd.
Preparation of ¹ H and ¹³ C-NMR analytical samples:
0.3 g of the sample solution is weighed, and about 0.7 g of deuterated chloroform (manufactured by Aldrich, 99.8%) is added and mixed uniformly as an NMR analysis sample.

[Reference Example 1]
Production of N, N'-hexanediyl-bis-carbamic acid diethyl ester Into a four-necked flask with an internal volume of 5000 mL, 1888 g (16 mol) of diethyl carbonate (manufactured by Aldrich) and a stirrer were placed. Two dropping funnels were attached. One dropping funnel was charged with 228 g (2 mol) of hexamethylenediamine (manufactured by Aldrich), and warm water heated to about 60 ° C. was passed through the dropping funnel jacket to heat the dropping funnel. The other dropping funnel was charged with 38.6 g of sodium methoxide (28% methanol solution, manufactured by Wako Pure Chemical Industries, Ltd.), and the dropping funnel was not heated. After the system was purged with nitrogen, the 4-necked flask was immersed in an oil bath (OBH-24 manufactured by Masuda Rika Kogyo Co., Ltd.) heated to 70 ° C., and hexamethylenediamine and sodium methoxide were added dropwise over about 5 hours. . After completion of the dropwise addition, heating was further performed for 2 hours. The obtained solution was washed with water, and an oil bath (manufactured by Masuda Rika Kogyo Co., OBH-24), a vacuum pump (manufactured by ULVAC, G-50A) and a vacuum controller (manufactured by Okano Manufacturing Co., Ltd.) VC-10S) was connected to a rotary evaporator (R-144, manufactured by Shibata Kagaku Co., Ltd.), and the oil bath temperature was 80 ° C. and distillation was performed at 5 kPa. The obtained solid was washed with hexane to obtain 426 g of a white solid. As a result of ¹ H and ¹³ C-NMR analysis, the obtained solid was N, N′-hexanediyl-bis-carbamic acid diethyl ester.

[Example 1]
Production of N, N′-hexanediyl-bis-carbamic acid di (nonylphenyl) ester N, N′-hexanediyl-bis-carbamic acid diethyl ester obtained in Reference Example 1 in an eggplant-shaped flask having a volume of 1000 mL 6 g (0.11 mol), nonylphenol (manufactured by Wako Chemical Co., isomer mixture) 397 g (1.8 mol) and dibutyltin dilaurate (manufactured by Wako Pure Chemical Industries, Ltd., for chemical use) 3.5 g (5.5 mmol) , Three-way cock, Helipak No. A distillation column packed with 3 and a fractionation head with a reflux condenser connected to a distillate receiver and a thermometer were attached, and the inside of the system was purged with nitrogen. The flask was immersed in an oil bath heated to 240 ° C. and heated under atmospheric pressure nitrogen. When heated for about 70 minutes, 6.2 g of distillate was recovered. As a result of ¹ H and ¹³ C-NMR analysis, the distillate was ethanol. The temperature of the oil bath was lowered to 130 ° C., a vacuum pump and a vacuum controller were attached, and excess nonylphenol was distilled off under reduced pressure at 1 Torr. 65 g of solid was obtained in the flask, and as a result of ¹ H and ¹³ C-NMR analysis, it was N, N′-hexanediyl-bis-carbamic acid di (nonylphenyl) ester.

[Example 2]
Production of hexamethylene diisocyanate by thermal decomposition of N, N'-hexanediyl-bis-carbamic acid di (nonylphenyl) ester Molecular distillation apparatus having a jacket-type heating section by oil circulation (MS-300, manufactured by Shibata Kagaku Co., Ltd.) A vacuum pump and a vacuum controller were attached to), and a purge line of the vacuum controller was connected to a nitrogen gas line. The inside of the molecular distillation apparatus was purged with nitrogen, and the heating unit was heated to 200 ° C. 62.0 g (0.10 mol) of N, N′-hexanediyl-bis-carbamic acid di (nonylphenyl) ester produced in Example 1 was added to 250 g of benzylbutyl phthalate (manufactured by Wako Pure Chemical Industries, Ltd., first grade). Mixed with. While reducing the pressure in the molecular distillation apparatus to 1.3 kPa and rotating the wiper of the molecular distillation apparatus at about 300 rpm, the slurry liquid is charged into the molecular distillation apparatus at a rate of about 5 g / min. Thermal decomposition of '-hexanediyl-bis-carbamic acid di (nonylphenyl) ester was performed. 16.4 g of pyrolysis product was obtained in the sample receiver, and nothing was recovered in the low boiling point trap. As a result of ¹ H and ¹³ C-NMR analysis, what was recovered in the sample receiver was hexamethylene diisocyanate. The yield based on N, N′-hexanediyl-bis-carbamic acid diethyl ester was 88%.

[Comparative Example 1]
Preparation of hexamethylene diisocyanate by thermal decomposition of N, N'-hexanediyl-bis-carbamic acid diethyl ester 30 g (0.12 mol) of N, N'-hexanediyl-bis-carbamic acid diethyl ester and 200 g of benzylbutyl phthalate And 3.8 g of dibutyltin dilaurate was added to form a slurry, which was introduced at a rate of about 5 g / min using a liquid feed pump into a molecular distillation apparatus heated to 200 ° C. and reduced in pressure to 1.3 kPa in advance. . 2.4 g of liquid was obtained in the sample receiver, and as a result of ¹ H and ¹³ C-NMR analysis, this liquid was hexamethylene diisocyanate. The yield was 12%. After completion of the reaction, the inside of the molecular distillation apparatus was observed, and a brown deposit was observed in the heated portion.

  As described above, hexamethylene diisocyanate was obtained in a high yield in Example 2 in which pyrolysis of the carbamic acid ester produced by the method of Example 1 was carried out, but produced in Example 1. In Comparative Example 1 in which no carbamic acid ester was used, the yield of hexamethylene diisocyanate was low, and in Comparative Example 1, contamination was observed inside the reactor. From these results, the effect of the present invention is clear.

  According to the present invention, when an isocyanate compound is produced by thermal decomposition of a carbamic acid ester compound, the yield of the isocyanate compound can be improved.

It is a NMR analysis (< ¹ > H-NMR) figure of the carbamic acid ester compound manufactured in Example 1 of this invention. It is a NMR analysis ( ^13C -NMR) figure of the carbamic acid ester compound manufactured in Example 1 of this invention.

Claims (4)

Carbamate compound represented by the following formula (1):

(Where:
R ¹ represents a linear or branched alkyl group having 1 to 12 carbon atoms, Q ¹ and Q ² are

A group containing an aromatic group having a substituent represented by formulas (2) and (3), wherein a hydrogen atom is added to each of Ar ¹ —O— and Ar ² —O— constituting the group. The normal boiling point of the aromatic hydroxy compounds Ar ¹ OH and Ar ² OH is 250 ° C. or higher. ). Aromatic hydroxy compounds Ar ¹ OH and Ar ² OH each having a structure in which hydrogen atoms are added to Ar ¹ —O— and Ar ² —O— constituting Q ¹ and Q ² are monovalent aromatic hydroxy compounds. The carbamic acid ester compound according to claim 1, wherein The carbamic acid ester compound according to claim 1, wherein R ¹ in the general formula (1) is a linear alkyl group having 6 carbon atoms.   A method for producing an isocyanate compound, comprising thermally decomposing a carbamic acid ester compound of the general formula (1).

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