JPS6033097B2 - Method for producing methacrylic acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing methacrylic acid esters from methacrylamide and alcohol.

Methacrylic acid ester is an important compound as an industrial raw material. Currently, methacrylic acid ester is produced from acetone cyanohydrin, water and alcohol in the presence of equimolar sulfuric acid, but the supply of raw material acetone cyanohydrin is limited and a more stable solution is needed. In addition, it is desired to switch to a cheaper raw material that can be supplied in large quantities, and the above production method has the major problem of creating a large amount of ammonium sulfate, which makes it difficult to dispose of it. The present inventors have discovered that methacrylamide is produced by the hydration reaction of methacrylonitrile obtained by ammoxidation of isobutylene, that the production method has been technically established, and that it can be supplied in large quantities at low cost. Since there is no by-product of ammonium sulfate when producing methacrylic acid ester from alcohol and alcohol, they conducted extensive research into the production method.

On the other hand, a method for producing a carboxylic acid ester by reacting a certain kind of carboxylic acid amide with an alcohol has been known, for example, a method for obtaining a Q-hydroxyisobutyric acid ester by alcoholysis of Q-hydroxyisobutyramide was proposed by Tokuseki Akira. It is disclosed in Japanese Patent No. 52-3015.

However, the alcoholysis catalysts described in these known documents, such as alkali catalysts such as caustic potash, sodium methoxide, and lithium hydroxide, and metals, oxides, and hydroxides of copper, zinc, and cobalt, are not suitable for the alcoholysis of methacrylamide. As a catalyst, the activity is too low and the yield and selectivity of methacrylamide are also low, making it insufficient. Therefore, an object of the present invention is to provide a method for producing methacrylic acid ester from methacrylic acid amide and alcohol in high yield and high selectivity, and above all, to provide the most suitable reaction catalyst.

This purpose is to combine methacrylamide and primary alcohol with at least one member selected from the group consisting of nickel and cobalt halides, nitrates, and organic acid salts, and phenols, aldehyde groups, ketone groups, carboxyl groups, and bases. This is achieved by carrying out the reaction in the presence of a catalyst comprising a combination of at least one compound selected from the group consisting of compounds containing at least one type of nitrogen-containing group.

Next, the present invention will be specifically explained. Examples of the nickel and cobalt compounds used as catalysts in the present invention include halides, nitrates, organic acid salts, and the like.

Examples of halides include chloride, bromide, iodide, and fluoride; examples of organic acid salts include formic acid, acetic acid, propiosic acid,
Salts such as stearic acid are used. As other components of the catalyst of the present invention, a compound having any one of a phenol group, an aldehyde group, a ketone group, a carboxyl group, and a basic nitrogen-containing group is employed, and a compound containing a plurality of the above groups, and Also includes polymer compounds having these groups.

Specific examples of these compounds include phenols, aldehydes, ketones, carboxylic acids, and basic nitrogen-containing compounds. Examples of phenols include phenol, chirotechol, hydroquinone,
Examples of aldehydes include P-phenylphenol, nitrophenol, methyl m- or P-oxybenzoate, and examples of aldehydes include benzaldehyde, salicylaldehyde, m-hydroxybenzaldehyde, methoxybenzaldehyde, 0-, m-, or P-methylbenz aldehyde, P
Monophenylbenzaldehyde and ketones include acetophenone. As the carboxylic acids, benzoic acid, oxybenzoic acid, methoxybenzoic acid, and nitrobenzoic acid are used. Basic nitrogen-containing compounds include primary, secondary, and tertiary amines, such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, butylamine, dibutylamine, triptylamine, monoethanolamine, Diethanolamine, triethanolamine, N-methylpiverazine, pyrrolidine, diethylenetriamine, aniline, monomethylaniline, dimethylaniline, aminophenolpyridine and pyridine derivatives, e.g.
-Pyridine methanol, 3-pyridine methanol, nicotinic acid, pyridine 2-aldehyde, pyridine 3-aldehyde, and amino acids such as glycine and alanine are used. The alcohol used in the present invention is a primary alcohol such as methanol, ethanol, propanol, n-butanol, etc.

In the present invention, the above-mentioned catalyst is added to methacrylamide and the above-mentioned alcohol, and the reaction is carried out at an appropriate temperature and pressure in the absence or presence of a reaction medium. However, the activity of the catalyst is maintained.

Note that ammonia is produced by the reaction, and removing the produced ammonia from the reaction system intermittently or continuously improves the coloring, yield, and selectivity of the methacrylic acid ester product. This is preferable in that it allows

Ammonia can be removed by introducing a gas that does not participate in the reaction, such as nitrogen or air, into the reaction system as a carrier gas to effectively remove the generated ammonia, or by removing the ammonia from the reaction system together with the reaction medium. The method will be adopted. The amount of alcohol used relative to methacrylamide is 2 to 5 qmol.

Although it is preferable from the viewpoint of yield that water not coexist in the reaction system, the reaction can be carried out even if water is present in an amount of 1q sound molar relative to methacrylamide. Regarding the amount of the catalyst used, the first component, copper, cobalt, and nickel alone or in combination, is used in an amount of 0.1 to 100 mol % based on methacrylamide.

If it is less than 0.1 mol%, the yield of methacrylic acid ester will decrease, which is not preferable.

The amount of the second catalyst component added is 0.1 to 1 molar, more preferably 0.5 to 5 times the molar amount of the first component.

The reaction temperature is 50 to 300°C, more preferably 100 to 300°C.
The reaction pressure is adjusted appropriately depending on the type and amount of alcohol used, the amount of water, and the reaction temperature, but is preferably 5 to 100 k9', more preferably 10 to 50 k9'.
9/Earth is used.

Although the reaction time cannot be generalized because it varies depending on the reaction temperature, the charging ratio of raw materials, the amount of catalyst, etc., it is 1 to 1 m hours, more preferably 3 to 6 hours. The catalyst used in the present invention is expected to be an excellent catalyst not only for the alcoholysis of methacrylamide but also for the alcoholysis of other general carboxylic acid amides.

Examples are shown below.

Example 1 500 cc of methacrylamide 85 mL, methanol 250 mL, cobalt nitrate 5 mL and triethanolamine 2 mL
The mixture was charged into a volumetric autoclave, the pressure was maintained at 20k9/kg, and the mixture was reacted for 4 hours at 170qo under a rice cooker.

During this time, nitrogen gas was blown into the reactor at a rate of 2 per minute.
The generated ammonia was released from the pressure holding device together with nitrogen gas. After the reaction, the reaction solution was cooled and the reaction product was analyzed by gas chromatography, and the following results were obtained. Example 2 500cc of methacrylamide 85ml, propanol 300ml, nickel acetate 5x, tri-n-butylamine 2x
The mixture was charged into an autoclave and reacted for 4 hours at a pressure of 200 qo while maintaining the pressure at 30 k9/kg.

The reaction product was analyzed using the same treatment method as in Example 1, and the following results were obtained. Example 3 Methacrylamide 85%, methanol 250%, water 30%
The mixture was reacted under the same reaction conditions as in Example 1, and the following results were obtained.

Example 4 Methacrylamide 85 times, ethanol 300 times, nickel acetate 2 times, triethanolamine 1 night, benzoic acid 0.
5 ml was reacted under the same reaction conditions as in Example 1.

The results are as follows. Example 5 A reaction was carried out under the same reaction conditions as in Example 1 using 85 days of methacrylamide and 300 hours of methanol, using various catalysts shown in Table 1 below, using catalyst 11 for 5 days and catalyst [2} for 2 nights. became.

The results are shown in Table 1. Table 1 Comparative Example 1 85 parts of methacrylamide, 250 parts of methanol, and 1 part of sodium methylate were charged into a 500 cc autoclave, and a reaction was carried out in the same manner as in Example 1.

The results were as follows. Comparative Example 2 A reaction was carried out in the same reaction method as in Example 1 using 85 ml of methacrylamide, 250 ml of methanol, and 5 ml of various catalysts shown in Table 2.

The results are shown in Table 2. Table 2 Comparative Example 3 A reaction was carried out in the same reaction method as in Example 1 using 85 tons of methacrylamide, 300 tons of methanol, and 5 tons of copper benzoate.

Claims (1)

[Scope of Claims] 1. Methacrylamide and a primary alcohol, at least one member selected from the group consisting of nickel and cobalt halides, nitrates, and organic acid salts, a phenol group,
A methacrylic acid ester characterized in that the reaction is carried out in the coexistence of a catalyst consisting of a combination with at least one kind selected from the group consisting of compounds containing at least one kind of an aldehyde group, a ketone group, a carboxyl group, and a basic nitrogen-containing group. manufacturing method. 2. The method for producing a methacrylic acid ester according to claim 1, wherein the reaction is carried out while the ammonia produced by the reaction is removed from the reaction system intermittently or continuously. 3. At least one compound selected from the group consisting of compounds containing at least one of a phenol group, an aldehyde group, a ketone group, a carboxyl group, and a basic nitrogen-containing group, consisting of nickel and cobalt halides, nitrates, and organic acid salts. 0.1 to 10 for at least one species selected from the group
A method for producing a methacrylic acid ester according to claim 1, which is used at twice the molar ratio.