JPH0977861A - Fumarate production method - Google Patents

Abstract

(57) Abstract: In order to obtain an unsaturated polyester resin using maleic anhydride, which has a high isomerization ratio of maleic acid ester to fumaric acid ester, unsaturated polyester resin is used. The production of fumaric acid ester that can be placed during production is performed. In the process of producing an unsaturated polyester resin, maleic anhydride is subjected to ring-opening addition reaction with polyhydric alcohol to form maleic acid ester, which is isomerized to fumaric acid ester in the presence of acid chloride. [Effect] The maleic acid ester can be efficiently isomerized to the fumarate ester at a relatively low temperature regardless of the type of polyhydric alcohol or polybasic acid anhydride used or the ester production temperature.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to efficient isomerization reaction of maleic acid ester to fumaric acid ester which occurs during the production of unsaturated polyester resin using maleic anhydride. In the present specification, the unsaturated polyester resin is an unsaturated polyester resin,
Vinyl ester resins and resins obtained by chemically modifying these esters are collectively referred to.

[0002]

2. Description of the Related Art Unsaturated polyester resins are thermosetting, and their curing and molding are carried out by radical reaction at room temperature to high temperature by using a metal reaction accelerator and a polymerization initiator in the resin alone or in combination. Maleic anhydride is widely used as a raw material for polybasic acid anhydrides of unsaturated polyester resins, and maleic acid ester isomerizes to fumaric acid ester when a resin is produced using this. The isomerization rate is known to vary depending on the type of saturated polybasic acid or polyhydric alcohol used or the production temperature,
Unsaturated groups of maleic acid ester have poor reactivity with reactive diluents such as styrene, so unsaturated polyester resins with a low isomerization rate to fumaric acid ester do not undergo sufficient curing reaction and are obtained. Many physical properties such as mechanical properties, chemical resistance, water resistance, weather resistance, and heat resistance of the molded product may be remarkably deteriorated.

Therefore, when a sufficient isomerization rate cannot be obtained, it is a conventional method to use fumaric acid instead of maleic anhydride, but when the reaction is insufficient and unreacted fumaric acid remains. , The resin becomes cloudy and various physical properties are deteriorated. Therefore,
Often unsuitable for the production of unsaturated polyester resins with high acid values. Another problem is that the use of fumaric acid increases costs.

Heretofore, as a method of isomerizing a maleic acid ester to a fumaric acid ester, A. R. Hands
By using a triphenylphosphine catalyst (J.
Chem. Soc, 1181 (1964)), S.S. M.
Spatz, H .; Method using thiourea catalyst by Stone (J. Org. Chem, 23, 1559, (1
958)), Michael Dymicky, Rob
ert L.E. Fuchanan chloride catalyzed method by Buchanan (Organic Preparat
ions and Procedures Int.
17 (2), 121, (1985)) and the like, but all of them are organic chemistry findings and have not been applied to unsaturated polyester resins.

[0005]

The present invention, when producing an unsaturated polyester resin using maleic anhydride, irrespective of the polyhydric alcohol or polybasic acid anhydride or ester production temperature used, The purpose is to achieve a high isomerization rate of maleic acid ester to fumaric acid ester.

[0006]

Means for Solving the Problems That is, according to the present invention, in the process of producing an unsaturated polyester resin, maleic anhydride is subjected to a ring-opening addition reaction with a polyhydric alcohol to form a maleic acid ester, and the maleic acid ester is present in the presence of an acid chloride. It is a method for producing a fumarate which is characterized by isomerizing to a fumarate below.

More specifically, in the middle stage of the production of the unsaturated polyester resin, the polyhydric alcohol is mixed with maleic anhydride in an equimolar amount to the hydroxyl group, either alone or in combination with another polybasic acid anhydride. We propose a procedure to produce polybasic acid ester obtained by ring-opening addition reaction of anhydride and to efficiently isomerize maleic acid ester of polybasic acid ester to fumaric acid ester in the presence of acid chloride. It is a thing. After this operation, various unsaturated polyester resins can be finally synthesized by reacting with glycols, epoxy resins and the like.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Here, as the polyhydric alcohol raw material, ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,6- Examples thereof include, but are not limited to, hexanediol, hydrogenated bisphenoel A, bisphenol A propylene oxide adduct, bisphenol A ethylene oxide adduct, pentaerythritol allyl ether, and trimethylolpropane.

Polybasic acid anhydrides other than maleic anhydride include phthalic anhydride, tetrahydrophthalic anhydride,
Examples thereof include, but are not limited to, methyltetrahydrophthalic anhydride, endomethylenetetrahydrophthalic anhydride, and succinic anhydride. The acid chloride used as the isomerization catalyst is the same as Michael Dyckky and Robe mentioned above.
rt L. Buchanan uses fumaric acid chloride or fumaric acid monoalkyl ester acid chloride, but according to the study by the present inventors, it is not limited to them, but diacid chlorides such as isophthalic acid chloride and succinic acid chloride or their monochlorides are used. It was found that the alkyl ester acid chloride also has a similar catalytic effect at an addition amount of 0.5 to 1%. The reaction temperature is suitably 80 to 120 ° C, and more preferably 90 to 100 ° C. If it is less than that, the time required for isomerization becomes long, and if it is more than that, the acid gas volatilizes and the efficiency of isomerization becomes poor.

In the production of the polybasic acid ester before isomerization, it is necessary to completely carry out the ring-opening addition reaction with an equimolar amount of the polybasic acid anhydride with respect to the hydroxyl groups of the polyhydric alcohol. If the ring-opening addition reaction of the polybasic acid anhydride is insufficient and the hydroxyl group remains, the catalytic activity of the acid chloride decreases, making it impossible to carry out a sufficient isomerization reaction. Therefore, it is desirable to carry out the reaction in a relatively low boiling point organic solvent in order to completely perform the ring-opening addition reaction of the sublimable maleic anhydride with the polyhydric alcohol. Examples of the organic solvent used include, but are not limited to, benzene, toluene, xylene, and hexane.

When the polybasic acid ester isomerization reaction is carried out in the presence of acid chloride, the stainless steel reaction kettle and stirrer used may be corroded. It is desirable to carry out the reaction in a glass-lined device or in a device with stronger corrosion resistance, but in the case of a stainless steel reaction vessel, corrosion can be prevented by treating the surface with an aqueous solution of phytic acid. It was observed that it could be reduced. Hereinafter, the present invention will be described with reference to examples.

[0012]

EXAMPLES The present invention will be described below with reference to examples. The isomerization rate was measured by 1H-NMR, the apparatus was JOEL-90EX manufactured by JEOL Ltd., and the solvent was CD.
A mixture of Cl3 and DMSO-d6 at 20: 1 was used.

Comparative Example 1 Stirrer, Dimroth cooling pipe,
A 1 L 4-necked flask equipped with a thermometer and a nitrogen gas inlet tube was charged with 192.5 g of Mitsui Polyol KB280 (manufactured by Mitsui Toatsu Chemicals, Inc., hydroxyl equivalent 192.5), 98 g of maleic anhydride, and 32 g of toluene. The ring-opening addition reaction was carried out at 120 ° C. for 2 hours while introducing nitrogen gas. Then, the mixture was stirred for 3 hours while maintaining 120 ° C. The isomerization ratio of the obtained product to fumaric acid ester was 10%.

[Comparative Example 2] Stirrer, Dimroth cooling pipe,
In a 1 L 4-necked flask equipped with a thermometer and a nitrogen gas introduction tube, 106 g of diethylene glycol and 1 maleic anhydride.
96 g and 30 g of toluene were charged and a ring-opening addition reaction was carried out at 120 ° C. for 2 hours while introducing nitrogen gas. Then 12
The mixture was stirred for 3 hours while maintaining 0 ° C. The isomerization ratio of the obtained product to fumaric acid ester was 14%.

Example 1 Stirrer, Dimroth cooling pipe,
KB280 (manufactured by Mitsui Toatsu Chemicals, Inc.) 192.5 in a 1 L 4-necked flask equipped with a thermometer and a nitrogen gas introduction tube.
g, 98 g of maleic anhydride, and 32 g of toluene were charged, the ring-opening addition reaction was carried out at 120 ° C. for 2 hours while flowing nitrogen gas, and the mixture was allowed to cool to 90 ° C. and 3.2 g of fumaric acid chloride was added to the mixture at 95 to 105 ° C. for 3 hours. Stir for hours. The isomerization ratio of the obtained product to fumaric acid ester was 95%.

[Example 2] Stirrer, Dimroth condenser,
KB280 (manufactured by Mitsui Toatsu Chemicals, Inc.) 192.5 in a 1 L 4-necked flask equipped with a thermometer and a nitrogen gas introduction tube.
g, 98 g of maleic anhydride and 32 g of toluene were charged, a ring-opening addition reaction was carried out at 120 ° C. for 2 hours while flowing nitrogen gas, and the mixture was allowed to cool to 90 ° C. and isophthalic acid chloride 3.2.
g was added and the mixture was stirred at 95 to 100 ° C. for 3 hours. The isomerization ratio of the obtained product to fumaric acid ester was 88%.

[Embodiment 3] Stirrer, Dimroth condenser,
KB280 (manufactured by Mitsui Toatsu Chemicals, Inc.) 192.5 in a 1 L 4-necked flask equipped with a thermometer and a nitrogen gas introduction tube.
g, 98 g of maleic anhydride, and 32 g of toluene were charged, the ring-opening addition reaction was carried out at 120 ° C. for 2 hours while flowing nitrogen gas, and the mixture was allowed to cool to 90 ° C. and 3.2 g of succinic acid chloride was added to the mixture at 90 to 95 ° C. for 3 hours. Stir for hours. The isomerization ratio of the obtained product to fumaric acid ester was 84%.

[Embodiment 4] Stirrer, Dimroth condenser,
In a 1 L 4-necked flask equipped with a thermometer and a nitrogen gas introduction tube, 106 g of diethylene glycol and 1 maleic anhydride.
96 g of toluene and 30 g of toluene were charged and a ring-opening addition reaction was carried out at 120 ° C. for 2 hours while nitrogen gas was introduced.
For 3 hours. The isomerization ratio of the obtained product to fumaric acid ester was 96%.

[0019]

INDUSTRIAL APPLICABILITY In the case of producing an unsaturated polyester resin using maleic anhydride, maleic acid ester can be efficiently converted to fumaric acid regardless of the polyhydric alcohol, polybasic acid anhydride or ester production temperature used. It was possible to isomerize to the ester.

Claims (1)

[Claims] 1. In the process of producing an unsaturated polyester resin, maleic acid ester obtained by ring-opening addition reaction of maleic anhydride to polyhydric alcohol is isomerized to fumaric acid ester in the presence of acid chloride. A method for producing a fumaric acid ester, which is characterized.