JPH02145554A - Production of isocyanatoalkyl unsaturated carboxylate - Google Patents

Abstract

PURPOSE:To obtain a compound useful as various synthetic intermediates in good yield without containing noxious impurities by reacting an imidazole derivative with phosgene and then with a monoalkanolamine and further esterifying the resultant product. CONSTITUTION:An imidazole derivative is reacted with phosgene in a solvent, such as dichloromethane, to provide a reaction product, which is then reacted with a monoalkanolamine. The resultant product is subsequently reacted with an unsaturated carboxylic acid, chloride or ester thereof at <=100 deg.C temperature, as necessary, under reduced pressure to afford the objective substance expressed by the formula (R is H, lower alkyl, aryl or vinyl; R' is H or methyl; A is 2-4C alkylene). A functional molecule having active hydrogen atom is added to the isocyanate group to synthesize a novel functional monomer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention provides a method for producing - machining allowance (i), which is useful as a variety of synthetic intermediates.
) This invention relates to an improved method for producing an unsaturated carboxylic acid isocyanatoalkyl ester represented by:

In formula C, R is a hydrogen atom, a lower alkyl group, an aryl group,
or represents a vinyl group, Ro represents an aqueous atom or a methyl group, and A represents a linear or branched fullkylene group having carbons a2 to 4,] general formula [! ] The unsaturated carboxylic acid isocyanatoalkyl ester represented by - has a C═C double bond and an incyanato group simultaneously in the molecule.

(A) Polymerized alone or with other vinyl monomers to provide pendant incyanato groups on the polymer chain.

(B) A so-called macromonomer is synthesized by adding it to a polymer having a functional group having active hydrogen such as -OH or -NH2.

(C) Functional molecule with active hydrogen in the incyanato group (
For example, by adding physiologically active substances, etc.

Synthesize a new functional 7-mer.

It is an extremely useful compound industrially, and can be used for various purposes. In particular, in formula 1 [I], R=H, R'=
CH, n=2(7) compound (methacrylic acid-2-isocyanatoethyl ester) is used as a raw material for manufacturing distinctive products in the fields of photoresists, paints, adhesives, etc.

[Conventional technology]

As a method for producing an unsaturated carboxylic acid isocyanatoalkyl ester, the following method has been proposed.

(i) Synthesize hydroxycarbamic acid ethyl ester from monoalkanolamine, ethyl chloroformate, and a basic compound (K2CO2), react this with an unsaturated carboxylic acid chloride to form a urethane ester, and convert this into phosphorus pentachloride or chloride. A method of converting thionyl into incyanate (U.S. Pat. No. 2,718,516) This method has the problem that phosphorus and sulfur remain as impurities, and side reactions that are thought to be based on double bonds (e.g. monopolymerization, MCI addition) is likely to occur, making it difficult to obtain the target product in high yield.

(2) A method of synthesizing unsaturated carboxylic acid aminoalkyl ester hydrochloride from unsaturated carboxylic acid chloride and monoalkanolamine hydrochloride and reacting it with phosgene to produce incyanate (U.S. Pat. No. 2,821, 544
No.) This method has the disadvantage of low yield.

(3) Reaction of 2-flukenylomerosacillin and phosgene (JP-A-54-5921) This method uses an expensive oxazoline compound as a raw material, and the process is long, so the product obtained is also expensive. I have no choice but to become

In addition, each of the methods (i) to (3) contains chlorine as an impurity in the product, and is therefore unsuitable for use as a 1M lubricant material.

(4) By reaction of dimethyl-, diethyl-1 or diviropyl carbonate with ethanolamine.

A method of synthesizing hydroxyurethane, converting it into a urethane ester with an unsaturated carboxylic acid, or its chloride or ester, and thermally decomposing it (JP-A-62-1953)
54) In this method, it is difficult to thermally decompose the urethane ester; for example, even at a high temperature of 400°C, the decomposition rate is 50-60%.
It is. However, unsaturated carboxylic acid isocyanatoalkyl esters are extremely easy to polymerize, so if they are exposed to such high temperatures, they tend to polymerize and cause problems such as reduced yields and blockages in thermal decomposition reactors, making them difficult to industrialize. It cannot be said that it is necessarily easy.

[Problems to be solved]

In view of the above circumstances, the present inventors have conducted various studies on methods for producing unsaturated carboxylic acid isocyanato alkyl esters in high yield and free of harmful impurities.

[Means to solve problems]

As a result, (i) reacting the imidazole derivative with phosgene; (d) reacting the obtained reaction product with a monoalkanolamine; By esterification using ester, a blocked isocyanatoalkyl ester of an unsaturated carboxylic acid can be synthesized in good yield, and by decomposition and distillation, 181. It was discovered that a highly pure product containing almost no harmful impurities such as phosphorus and sulfur could be obtained, and the present invention was completed.

The imidazole derivative used in the first step of the present invention is
Since it is necessary to react with phosgene to produce carbamic acid chloride, it must have a >N-H bond, and therefore N-a substituted derivatives cannot be used.

Further, since imidazole derivatives are relatively expensive, it is desirable to collect and reuse them, and therefore, it is preferable to use one that can be treated in a light manner.

From these viewpoints, the imidazole derivatives include imidazole (unsubstituted), 2-ethyl-4-methylimidazole, and 2-methylimidazole.

Phosgene to be reacted with the imidazole derivative, preferably 2-ethylimidazole, is preferably used in an amount equal to or more than the imidazole derivative, preferably 1.1 to 1.5 times the mole, in order to allow one reaction to proceed completely. Remaining reactive imidazole may cause undesirable side reactions.

The reaction must proceed to a sufficient degree of completeness.

This reaction is preferably carried out in a solvent in order to facilitate one reaction.The solvent must not react with phosgene, amines, alcohols, acids, incyanates, etc., and must not react with halogenated hydrocarbons such as dichloromethane, Aromatic hydrocarbons such as toluene are used.

After the reaction of imidazole derivatives with phosgene.

It is better to drive off the excess phosgene and hydrogen chloride that is formed; any excess phosgene or hydrogen chloride that remains will react with the alkanolamine during the next step reaction, giving undesirable by-products.

To remove phosgene and hydrogen chloride, an inert gas such as nitrogen may be blown in at normal pressure to slightly reduced pressure.

In the second step of reacting the reaction product (A) of phosgene and an imidazole derivative with an alkanolamine,
It is preferable to gradually add (A) to the alkaliamine. In this case, it is preferable that the alkanolamine be dissolved in the same solvent used for the synthesis of (A).
Sodium hydride, to remove hydrogen chloride generated.
It is desirable that HC cross-receptors such as potassium carbonate, triethylamine, pyridine, etc. coexist.

In order to convert the reaction product (B) of (A) and alkanolamine thus obtained into an ester of an unsaturated fatty acid, it can be esterified with an unsaturated fatty acid or its acid chloride in a conventional manner. , by transesterification with an ester of the acid. At this time, the temperature of one reactor is 100℃,
Preferably, the temperature should not exceed 80°C, and if necessary, the reaction should be carried out under reduced pressure, unless the temperature rises.

The product may decompose giving undesirable by-products.

After completion of the reaction, the resulting solution can be directly thermally decomposed, but before that, it is preferable to wash it with a weakly alkaline solution such as sodium hydrogen carbonate and water to remove inorganic acids and salts.

When the unsaturated fatty acid ester obtained in this way is thermally decomposed, the desired unsaturated fatty acid isocyanato ester is obtained, but as mentioned above, this is extremely easy to polymerize, so It must be decomposed by temperature. Furthermore, since this thermal decomposition reaction is an equilibrium reaction, it is preferable to carry out the reaction while constantly removing products.

From this point of view, it is desirable to carry out the thermal decomposition reaction in the form of reactive distillation, that is, after evaporating the solvent under \tc pressure, a catalytic amount of tertiary amine or organotin compound is added, and the reaction is heated for 90 minutes under reduced pressure. By distilling at ~120°C, 1 decomposition and distillation purification of the target product can be performed simultaneously.The residual liquid after the completion of the reaction can be used again in the first step.

Thereafter, if necessary, the solvent mixed as an impurity can be removed by distillation to obtain a product with even higher purity.

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples.

250 g of phosgene was blown into a mixture of 200 m of toluene and 218 g of 2-ethyl-4-methylimidazole at room temperature (about 1 hour), and then.

It was left for 18 hours. The reactor was immersed in an oil bath whose temperature was maintained at 40 to 50°C, and nitrogen gas was blown into the oil bath at a rate of 1/min for 8 hours.

The obtained mixture was added dropwise to a mixture of 122 g of monoethanolamine, 173 g of anhydrous potassium carbonate, and 100 g of toluene over 1 hour with thorough stirring. After continuing to stir for 8 WIf, the mixture was washed twice with 500 g of water.

Next, P-) Luenesulfone s 5g and acrylic% 15
0 g was added and refluxed for 8 hours under reduced pressure of 60 to 70 Torr in a vessel equipped with a Dean-Stark trap to perform esterification.

After the reaction is complete, add 500 mu of 5% sodium hydrogen carbonate aqueous solution.
Wash once with 500 m of water and twice with 500 m of water, then wash with 500 m of water.
After distilling toluene under a reduced pressure of ~60 Torr, 0.5 g of dibutyltin dilaurate was added, and the temperature of the heating bath was raised to 100 to 120°C, and reaction residence was carried out while gradually increasing the degree of vacuum.

As a result, 187 g of m2-incyanatoethyl acrylate was obtained. This contained about 5% (by weight) toluene.

Phosgenation and monoethanolamine reaction were carried out in the same manner as in Example 1, using 136 g of imidazole instead of 2-ethyl-4-methylimidazole.

15 g of imidazole, 4゜4-diazabisiful el (2,
2,2) Octane 10g and methyl methacrylate 7
Add 10g.

The reaction was carried out under reduced pressure of 200 to 250 Torr (D) while removing the generated methanol as a co-S mixture with methyl methacrylate. During the reaction, 200 g of methyl methacrylate was added twice every 8 hours, and after 24 hours of reaction, the reaction was blocked with imidazole. 2-incyanatomethyl methacrylate was produced in a yield of 62%.

Phosgenation and reaction with monoethanolamine were carried out in the same manner as in Example 1, using 164 g of 2-methylimidazole instead of 2-ethyl-4-methylimidazole. To this was added 218 g of 96% crotonic acid chloride, and an esterification reaction was carried out at 70 to 80°C for about 2.5 hours.

After the reaction was completed, washing and thermal decomposition were performed in the same manner as in Example 1.

As a result, 170 g of crude 2-incyanatoethyl crotonate was obtained. This contains approximately 5% toluene and 3-
It contained about 3% of chloro #'v1%-2°-isocyanatoethyl ester.

Substance 1 Esterification reaction was carried out in the same manner as in Example 3, except that 150 g of mono(2-hydroxypropyl)amine was used instead of monoethanolamine, and 351 g of 95% cinnamic acid chloride was used instead of crotonic acid chloride. I did it. As a result, cinnamic acid-2-isocyachitopropyl ester blocked with 2-methylimidazole was produced in a yield of 67%.

〔Effect of the invention〕

According to the present invention, unsaturated carboxylic acid isocyanatoalkyl esters containing no harmful impurities can be produced in high yield.

Claims (1)

[Claims] (i) reacting an imidazole derivative with phosgene, (ii) reacting the reaction product of (i) with a monoalkanolamine, and (iii) reacting the reaction product of (ii) with an unsaturated carboxylic acid. ,
A method for producing an unsaturated carboxylic acid isocyanatoalkyl ester represented by the general formula [I], which comprises esterifying the unsaturated carboxylic acid isocyanatoalkyl ester with the general formula [I] or its chloride or ester. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ [I] [In the formula, R is a hydrogen atom, a lower alkyl group, an aryl group,
or a vinyl group, and R' represents a hydrogen atom or a methyl group. Further, A represents a straight chain or branched alkylene group having 2 to 4 carbon atoms. ]