JPS6111212B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing methacrylic acid ester from methacrylamide and alcohol. Methacrylic acid ester is an important compound as an industrial raw material, and currently, this methacrylic acid ester is produced from acetone cyanohydrin and alcohol in the presence of equivalent moles of sulfuric acid. The supply of acetone cyanohydrin, a raw material, is becoming limited, and there is a desire to switch to a cheaper raw material that can be supplied more stably and in large quantities.In addition, since the above production method uses concentrated sulfuric acid, the reaction equipment is The material is expensive and a large amount of ammonium sulfate is produced as a by-product.
There is a major problem in that it is difficult to process it. The present inventors discovered that methacrylamide is produced by the hydration reaction of methacrylonitrile obtained by ammoxidation of isobutylene, and can be supplied in large quantities at low cost. As a result of extensive research into a manufacturing method that does not use concentrated sulfuric acid, the present invention has been completed. Hitherto, methods for producing carboxylic acid esters from certain carboxylic acid amides and alcohols have been known. However, the esterification catalysts described in these known documents, such as caustic soda, potassium carbonate, calcium hydroxide, and sodium methylate, have low activity and low yield in the alcoholysis of methacrylamide, and it is difficult to increase the conversion rate. At present, this problem has not been sufficiently solved technically, resulting in a significant drop in selectivity. The reason for this is thought to be that the starting material, methacrylamide, and the product, methacrylic ester, are easily polymerized, and addition of alcohol to unsaturated double bonds, addition of produced ammonia, and other reactions occur. As a result, it was difficult to obtain methacrylic acid ester in high yield and high selectivity. The present inventors have achieved high yield and high selectivity without producing a polymer from methacrylamide and alcohol.
As a result of studying the catalysts to be used, we found that by using the catalyst described below, methacrylic acid esters can be produced extremely advantageously in high yield and high selectivity without inducing the above polymerization reaction or side reactions. Achieved an invention. That is, the present invention uses Y, Pr,
Nd, Pm, Eu, Gd, Tb, Dy, Ho, Er, Tm,
The present invention relates to a method for producing methacrylic acid ester, characterized in that the reaction is carried out using at least one selected from the group consisting of halides, inorganic acid salts, and organic acid salts of Yb and Lu. The reaction of the present invention is carried out between methacrylamide and alcohol in the presence of the above catalysts, with or without a reaction medium. As the halides, chlorides, bromides, iodides, and fluorides are used, and as the inorganic acid salts, sulfates, nitrates, phosphates, borates, etc. are used. As the organic carboxylic acid salt, monocarboxylic acid or dicarboxylic acid is used, and for example, salts of formic acid, acetic acid, propionic acid, succinic acid, glutaric acid, fumaric acid, benzoic acid, phthalic acid, etc. are used. The alcohol used in this reaction is a primary alcohol such as methanol, ethanol, propanol, n-butanol, etc., and these alcohols are used in an amount of approximately 2 to 50 times the molar amount of methacrylamide. The amount of catalyst used is 0.01 mol% or more based on methacrylamide, preferably 0.1 to
It is 100 mol%. The reaction temperature is preferably 50° to 300°C, more preferably 100° to 250°C. The reaction time is the reaction temperature,
Although it varies depending on the catalyst etc., the time is from 1 hour to 10 hours, more preferably from 2 to 6 hours. The absence of water in the reaction system of the present invention gives a higher yield.
Although preferred from the viewpoint of selectivity, a small amount of water, e.g.
The reaction proceeds satisfactorily even if it is present in an amount less than 3 times the molar amount of methacrylamide. The reaction pressure is appropriately determined depending on the type and amount of alcohol used, the amount of water, and the reaction temperature, but is 5 to 100 Kg/cm ² , more preferably 10 to 50 Kg/cm 2 .
Kg/ ^cm2 . During the reaction, it is preferable to remove the generated ammonia from the reaction system intermittently or continuously from the viewpoint of coloration of the methacrylic ester, yield, and selectivity. Removal methods include introducing a gas that does not participate in the reaction, such as nitrogen, air, or argon, into the reaction system as a carrier gas to effectively remove the generated ammonia, or removing it from the reaction system together with the reaction medium. It is also possible to remove the Further, this reaction can be carried out in the presence of an inert organic solvent, such as dioxane, tetrahydrofuran, n-hexane, cyclohexane, benzene, toluene, and the like. Example 1 85 g of methacrylamide, 250 g of methanol, and 5 g of dysprosium nitrate were charged into a 500 c.c. autoclave, the pressure was kept at 20 Kg/cm ² and the mixture was heated at 170°C with stirring.
The reaction was carried out for 5 hours. During this time, nitrogen gas was blown into the reactor at a rate of 2 per minute, and the generated ammonia was discharged from the pressure holding device together with the nitrogen gas. After the reaction, the reaction solution was cooled and the reaction product was analyzed by gas chromatography. The results are shown below.

[Table] Example 2 85 g of methacrylamide, 200 g of ethanol and 4 g of europium chloride were charged into a 500 c.c. autoclave, and the pressure was maintained at 350 Kg/cm ² while stirring at 285 g.
℃ for 33 hours. During this time, nitrogen gas was introduced into the reactor at a rate of 1/min, and the generated ammonia was released from the pressure holder together with the nitrogen gas. The results were as follows.

[Table] Example 3 Methacrylamide 85g, methanol 350g, water
40 g was reacted with 5 g of holmium nitrate under the same reaction conditions as in Example 1. The results were as follows. 〓〓〓〓

[Table] Example 4 85 g of methacrylamide, 160 g of methanol, 2 g of europium sulfate, and 2 g of neodymium nitrate were reacted under the same reaction conditions as in Example 1. The results were as follows.

[Table] Example 5 85 g of methacrylamide, 250 g of methanol, and 2 g of isotria nitrate were reacted under the same reaction conditions as in Example 1. The results were as follows.

[Table] Example 6 85 g of methacrylamide and 300 g of methanol were reacted under the same reaction conditions as in Example 1 using 5 g of the various catalysts shown in Table 1. Table 1 shows the results.

【table】

[Table] Example 7 Methacrylamide 85g, methanol 200g, water
20g, neodymium phosphate 3g, dioxane 100g
The mixture was placed in a 500 c.c. autoclave, and the reaction was carried out at 170° C. for 3 hours with stirring while maintaining the pressure at 22 Kg/cm ² . The results were as follows.

[Table] Example 8 Methacrylamide 85g, n-butanol 300g
g, 40 g of water, and 3 g of isotria borate were placed in a 500 c.c. autoclave, and the reaction was carried out at 150° C. for 6 hours while maintaining the pressure at 27 Kg/cm ² . The results were as follows.

[Table] Comparative example 1 Methacrylamide 85g, methanol 350g, water
Charge 30g of caustic soda and 3g of caustic soda into a 500c.c. autoclave, maintain the pressure at 20Kg/cm ² , and stir while stirring.
The reaction was carried out at ℃ for 4 hours. During this time, nitrogen gas was introduced into the reactor at a rate of 2 per minute, and the generated ammonia was discharged from the pressure holding device together with the nitrogen gas. The results were as follows. 〓〓〓〓

[Table] Comparative Example 2 85 g of methacrylamide, 250 g of methanol, and 4 g of sodium methylate were reacted under the same reaction conditions as in Example 1. The results were as follows.

[Table] 〓〓〓〓

Claims (1)

[Claims] 1. In producing methacrylic acid ester from methacrylamide and alcohol or alcohol and water, Y, Pr, Nd, Pm, Eu, Gd,
Production of methacrylic acid ester, characterized in that the reaction is carried out using at least one selected from the group consisting of halides, inorganic acid salts, and organic acid salts of Tb, Dy, Ho, Er, Tm, Yb, and Lu. Law. 2. The method for producing a methacrylic ester according to claim 1, wherein the reaction is carried out while removing ammonia produced by the reaction from the reaction system intermittently or continuously.