JPS591273B2 - ether methacrylic sun ester - Google Patents

Description

[Detailed description of the invention] The present invention is based on the general formula R, CH2■muCOOCH2-V(■) (However, in the formula, R1 represents hydrogen or a methyl group.

) The present invention relates to a method for producing acrylic esters and methacrylic esters containing an ether group as shown in the following. Acrylic esters and methacrylic esters containing ether groups are useful monomers that have a wide range of uses such as paints and crosslinking agents.

These compounds are conventionally produced by dehydration condensation and esterification reactions of acrylic acid, methacrylic acid, and their methyl esters with alcohols represented by the formula HOCH2,
Alternatively, it is produced by transesterification.

However, in this conventional method, since the reaction is carried out with active double bonds intact, there is always a risk of polymerization. Moreover, the alcohols containing ether groups used in the present invention are said to be susceptible to autooxidation by oxygen in the air, and as a result, produce peroxides. Even compared to methacrylic acid esters, they are more likely to cause problems such as polymerization and coloring.

In order to solve this problem, many patents have been published using various antioxidants, polymerization inhibitors, etc., but this has not yet reached the point where polymerization is completely prevented, and a considerable amount of monomer is wasted as polymerized products. It is consumed by many people, becomes industrial waste, and causes problems in the process. The inventors of the present invention have conducted extensive studies on methods to solve these problems, and as a result, have completed the present invention. That is, the feature of the present invention is that compound (I) is obtained by thermally decomposing compound (I) as shown below. (However, in the formula, R represents hydrogen or a methyl group.) Surprisingly, the product obtained by thermally decomposing compound starch I) consists of only two types, compound (■) and cyclopentadiene. and no by-products are obtained that adversely affect the process. Moreover, since compound (■) and cyclopentadiene have a boiling point difference of more than 100°C at normal pressure,
Separation by distillation is extremely easy, and it is possible to obtain a highly pure compound starch. In addition, cyclopentadiene can be recovered and reused any number of times, making it possible to save resources. The present invention will be explained in more detail. Compound I) used as a raw material in the present invention can be synthesized extremely easily and with high yield by a conventional method.

That is, methyl acrylate or methyl methacrylate and cyclopentadiene are subjected to a Diel s-Alder reaction to protect the double bond of methyl acrylate or methyl methacrylate. If necessary, it is also effective to use general-purpose organic solvents such as benzene, toluene, methanol, and chloroform, use sulfuric acid, hydrochloric acid, aluminum chloride, etc. as catalysts, and add polymerization inhibitors such as hydroquinone and catechol. It is.

The compound m represented by the general formula (where R1 represents hydrogen or a methyl group) obtained by the above Diels-Alder reaction is transesterified with tetrahydrofurfuryl alcohol in the presence of a catalyst. , Compound (I) can be easily obtained in a yield of 85% or more.

As a catalyst, it is preferable to use a base catalyst such as NaOCH3, NaOC2H5, NaOH, etc. in an amount of 1 to 2 Omol%, preferably 3 to 1 Omol%, based on Compound D. If necessary, it is also effective to reduce the pressure in the system to promote distillation of methanol and advance the reaction. This reaction also does not cause any side reactions, and furthermore, there is a considerable difference in the boiling points of the product (1) and the unreacted raw material (9), so the recovery of the raw material and the purification of the product (I) are difficult. The thermal decomposition of compound wax I), which is a feature of the present invention, is carried out in the gas phase or liquid phase at a temperature in the range of 200°C to 500°C. Pyrolysis products (
) is immediately taken out of the reaction system and rapidly cooled.

The residence time is at most a few seconds, so there is little possibility of polymerization.

ιWhen thermally decomposed in the gas phase, the vaporized compound (I)
is introduced into a tube heated to 200°C to 500°C and is thermally decomposed in an extremely short time.

The pyrolysis tube is filled with glass, stainless steel, or porcelain Raschig rings as necessary to facilitate heat exchange. It is also effective to dilute the vaporized compound (I) with an inert gas such as nitrogen. Yang combination carried out in the liquid phase, compound f
! ff! ! Jl) is directly heated above its boiling point, or compound I) is introduced into a container in which a highly thermally stable inert fluid such as terphenyl, varafine, etc. has been heated to the required temperature, thermal decomposition is carried out, and the product is A method is used in which the gas is distilled off at the same time as it is produced.

At this time, it is convenient to include a polymerization inhibitor such as hydroquinone or catechol in the inert fluid in order to prevent polymerization of decomposition products. Since the thermal decomposition product Compound 1) and cyclopentadiene have a large difference in boiling point, they are easily decomposed and pure compound () can be obtained. As mentioned above, the esterification reaction and the transesterification reaction are carried out after protecting the active double bond with cyclopentadiene, and
Since the thermal decomposition, which is a feature of the present invention, is carried out in an extremely short time, side reactions such as polymerization do not occur at all. Furthermore, unreacted raw materials and cyclopentadiene can be recovered, recycled, and used any number of times, so that not only is the yield high, but a manufacturing process that produces almost no waste is possible.

The present invention will be specifically explained below with reference to Examples.

Example Production of tetrahydrofurfuryl acrylate (
b) Production of 5-norbornene-2-carboxylic acid methyl ester After stirring using a reflux condenser, thermometer, and stirring, put methyl acrylate 1729 into a 500 ml flask equipped with a dropping load, and add cyclopentadiene 1329 while adjusting the temperature to 40°C. was reacted dropwise to quantitatively obtain 5-norbornene-2-carboxylic acid methyl ester.

→ Production of 5-norbornene-2-carboxylic acid tetrahydrofurfuryl ester 152 g of 5-norbornene-2-carboxylic acid methyl ester, tetrahydrofurfuryl alcohol 10 Sodium methylate 1629 as a 2θ catalyst was heated and stirred at 110°C to 115°C. While doing so, the pressure inside the system was reduced, and the methanol produced was successively distilled off to allow the reaction to proceed.

After the reaction, it was neutralized with 1.479 sulfuric acid, and then distilled under reduced pressure (13
0 to 1357 C/5 mmHg) to obtain 200 g of 5-norbornene-2-carboxylic acid-tetrahydrofurfuryl ester.

'→ Production pressure of tetrahydrofurfuryl acrylate 10m7! 5-Norbornene-2-carboxylic acid tetrahydrofurfuryl ester 2229 was heated and evaporated at LHg, and passed through a Pyrex glass pyrolysis tube heated to 450°C to obtain tetrahydrofurfuryl acrylate (Bp92C/20m77!Hg). ) 1489 and cyclopentadiene 62,89 undecomposed raw material 1069 were obtained.

Claims (1)

[Claims] 1. A method for thermally decomposing a compound (I) represented by the general formula ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (in the formula, R_1 represents hydrogen or a methyl group). Characteristic general formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (II) (However, R_1 in the formula represents hydrogen or methyl group.) Acrylic ester or methacrylic ester containing an ether group Production method. 2. Acrylic acid ester or methacrylic acid containing an ether group according to claim 1, wherein compound (I) is obtained by transesterification reaction between compound (IV) and tetrahydrofurfuryl alcohol (III). Method for producing esters. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(IV) (However, R_1 represents hydrogen or a methyl group.)