Production method for isocyanate compound

Abstract

The present invention provides a process for producing an isocyanate compound such as 3-methyl-2-methoxymethyl-1-isocyanate benzene and the like. By reacting 3-Methyl-2-methoxymethyl aniline and the like with phosgene in the presence of a tertiary amine at 10 C. to 14 C. in one or more solvents selected from the group consisting of toluene and xylene, isocyanate compounds such as 3-methyl-2-methoxymethyl-1-isocyanate benzene and the like can be produced at high yield.

Claims

1. A process for producing an isocyanate compound of formula (2): ##STR00005## wherein R.sup.1 represents a methyl group, a cyclopropyl group, a chlorine atom, a bromine atom, an ethyl group, or a methoxy group, and R.sup.2 represents an alkyl group having one to six carbon atoms, which comprises reacting a compound of formula (1): ##STR00006## wherein R.sup.1 and R.sup.2 are the same as defined above, with phosgene in the presence of a tertiary amine at 9 C. to 16 C. in one or more solvents selected from the group consisting of toluene and xylene.

2. The process according to claim 1 wherein the reaction is carried out at 10 C. to 14 C.

3. The process according to claim 1 wherein R.sup.1 represents a methyl group and R.sup.2 represents a methyl group.

4. The process according to claim 1 wherein the tertiary amine is triethylamine.

5. The process according to claim 1 wherein the solvent is toluene.

Description

MODE FOR CARRYING OUT THE INVENTION

(1) The process for producing an isocyanate compound represented by formula (2) is described.

(2) The isocyanate compound represented by formula (2) can be produced by reacting a compound represented by formula (1) (hereinafter, sometimes referred to as Compound (1)):

(3) ##STR00004##
wherein R.sup.1 and R.sup.2 are the same as defined above, with phosgene in the presence of a tertiary amine at 9 C. to 16 C. in one or more solvents selected from the group consisting of toluene and xylene.

(4) Examples of an alkyl group having one to six carbon atoms as R.sup.2 group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, and hexyl group. The preferable alkyl group having one to six carbon atoms as R.sup.2 group is methyl group and ethyl group.

(5) The solvent to be used in the reaction is toluene, xylene or mixtures thereof, and preferably toluene. The use amount of the solvents is usually 3 to 20 times by weight relative to the compound (1).

(6) The use amount of phosgene is usually 0.95 to 1.5 moles, preferably 1.0 to 1.3 moles, relative to 1 mole of the compound (1).

(7) Examples of the tertiary amine to be used in the reaction include triethylamine, diisopropylethylamine, N-methylmorpholine, N-methylpiperidine, diazabicycloundecene, and the like. The tertiary amine is preferably trialkylamine such as triethylamine and diisopropylethylamine, more preferably triethylamine.

(8) The use amount of the tertiary amine is usually 1.8 to 3.0 moles, preferably 2.0 to 2.6 moles, relative to 1 mole of the phosgene.

(9) The reaction temperature is 9 C. to 16 C., preferably 10 C. to 14 C.

(10) In the reaction, the order of mixing the compound (1), the phosgene, and the tertiary amine is preferably adding the compound (1) to solvent and the phosgene, followed by an addition of the tertiary amine. Each of the reactant compounds is preferably added dropwise in portionwise thereof in terms of the yield. Though the time of dropwise addition of each of the reactant compounds depends on the amounts thereof, it is usually 30 minutes to 24 hours. Preferably, the compound (1) is added dropwise over 2 to 24 hours, and the tertiary amine is added dropwise over 4 to 24 hours.

(11) After the completion of the dropwise addition of each of the reactant compounds, the reaction mixtures are usually stirred at 10 C. to 14 C. for 0.1 to 6 hours.

(12) After the completion of the reaction, the compound (2) can be isolated by carrying out a post-treatment procedure such as filtration of the reaction mixture. The compound (2) may be purified by further procedures such as distillation and chromatography.

EXAMPLES

Example 1

(13) Under nitrogen atmosphere, 382.0 g of Toluene was cooled to 10 C. At the same temperature, a dropwise addition of 78.6 g of 3-methyl-2-methoxymethylaniline and a bubbling of 61.7 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 126.3 g of triethylamine and 78.6 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 88.8 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 96.4%).

Example 2

(14) Under nitrogen atmosphere, 254.6 g of toluene was cooled to 12 C. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxymethylaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 59.5 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 96.8%).

Example 3

(15) Under nitrogen atmosphere, 254.6 g of toluene was cooled to 14 C. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxymethylaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 59.9 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 97.4%).

Example 4

(16) Under nitrogen atmosphere, 382.0 g of toluene was cooled to 9 C. At the same temperature, a dropwise addition of 78.6 g of 3-methyl-2-methoxymethylaniline and a bubbling of 61.7 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 126.3 g of triethylamine and 78.6 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 92.1 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 93.1%).

Example 5

(17) Under nitrogen atmosphere, 254.6 g of toluene was cooled to 15 C. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxymethylaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 57.9 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 94.3%).

Example 6

(18) Under nitrogen atmosphere, 254.6 g of toluene was cooled to 16 C. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxymethylaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of toluene was added dropwise to the resulting mixtures over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 57.1 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 92.9%).

Example 7

(19) Under nitrogen atmosphere, 254.6 g of xylene was cooled to 12 C. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxymethylaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of xylene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered, and a filtrate was analyzed with liquid chromatography to find that 58.9 g of 3-methyl-2-methoxymethyl-1-isocyanate benzene was contained in the filtrate (yield 95.9%).

Reference Examples

(20) Under nitrogen atmosphere, 254.6 g of toluene was cooled to each of the temperatures shown in the Table below. At the same temperature, a dropwise addition of 52.4 g of 3-methyl-2-methoxyaniline and a bubbling of 41.2 g of phosgene were carried out concurrently over 3 hours, and after the completion of the procedures, the reaction mixture was stirred at the same temperature for 1.5 hours. A mixture of 94.7 g of triethylamine and 52.4 g of toluene was added dropwise to the resulting mixture over 5 hours, and the mixture was stirred for 3 hours to precipitate out crystals. The obtained crystals were filtered and a filtrate was analyzed with liquid chromatography to find that 3-methyl-2-methoxymethyl-1-isocyanate benzene was obtained at each of the yields shown in the Table 1 below.

(21) TABLE-US-00001 TABLE 1 Reference Reference Example 1 Example 2 Reaction 8 C. 20 C. temperature Yield 85.2% 67.0%

INDUSTRIAL APPLICABILITY

(22) According to the present invention, isocyanate compounds such as 3-methyl-2-methoxymethyl-1-isocyanate benzene and the like can be produced.