JPH0747568B2 - Process for producing alkylaminoalkyl ester of acrylic acid or methacrylic acid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid.

Since alkylaminoalkyl esters of acrylic acid or methacrylic acid have an amino group in the molecule, they can be used as fiber dyeability modifiers, plastic antistatic agents, etc.
A polymer obtained by polymerizing or copolymerizing these monomers is useful as a paper strength enhancer, a toner binder, an ultraviolet curing printing material, a coating resin, a polymer coagulant, an ion exchange resin and the like.

(Prior Art) A method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid by a transesterification reaction between a methyl ester of acrylic acid or methacrylic acid and an alkylamino alcohol is already known.

(Problems to be Solved by the Invention) The transesterification reaction between a methyl ester of acrylic acid or methacrylic acid and an alkylamino alcohol is an equilibrium reaction, and therefore, in order to obtain a target product in a high yield, a by-product is usually used. It is necessary to remove such methanol outside the reaction system or to charge the starting material methyl ester of acrylic acid or methacrylic acid in excess with respect to the alkylamino alcohol.

The excess ratio of methyl ester of acrylic acid or methacrylic acid is usually 1.
It is in the range of 5 to 10 mol. However, the higher the molar ratio of the methyl ester of acrylic acid or methacrylic acid to the alkylaminoalcohol, the larger the volume of the reactor and the poor volumetric efficiency, and the slower initial reaction rate. There is.

On the contrary, when the molar ratio is lowered, the initial rate of the reaction becomes faster, but in the latter half of the reaction, the reaction becomes difficult to proceed and the reaction temperature becomes high, so that there are disadvantages that the amount of by-products is increased.

(Means for Solving Problems) As a result of repeated studies on such problems, the present inventors add a methyl ester of acrylic acid or methacrylic acid as a raw material to the reaction system over time. As a result, they have found that the initial rate of the reaction can be increased, the reaction rate in the latter half of the reaction can be increased, and the production of reaction by-products can be suppressed, and the present invention has been completed.

That is, the present invention relates to a methyl ester of acrylic acid or methacrylic acid and a general formula (1) R ₁ R ₂ N (CH ₂ ) nOH (1) (wherein R ₁ is hydrogen or an alkyl group having 1 to 6 carbon atoms, R ₂ is an alkyl group having 1 to 6 carbon atoms, and n is an integer of 2 to 6)
In producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid by transesterification with an alkylamino alcohol represented by, it is characterized by reacting while adding a methyl ester of acrylic acid or methacrylic acid to the reaction system. A method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid.

Hereinafter, the method of the present invention will be described in detail.

The method of the present invention, while adding a methyl ester of acrylic acid or methacrylic acid to a mixed solution of a methyl ester of acrylic acid or methacrylic acid and an alkylaminoalcohol, while heating, stirring, to proceed the reaction, the desired acrylic It produces an alkylaminoalkyl ester of an acid or methacrylic acid.

For example, when methacrylic acid dimethylaminoethyl ester is produced from methyl methacrylate and dimethylaminoethanol as raw materials, this transesterification reaction is represented by the following formula.

_{CH 2 = C (CH 3)} COOCH 3 + (CH 3) 2 N (CH 2) 2 OH CH 2 = C (CH 3) COO (CH 2) 2 N (CH 3) 2 + CH 3 OH transesterification reaction On the other hand, the following reaction rate equation holds.

_{r = dC DM / dt = k} 1 C MMA C DMAE- k 2 C DM C MEOH where C is the molar fraction, subscript MMA is methyl methacrylate, DMAE is dimethylaminoethanol, DM is dimethylaminoethyl methacrylate Ethyl ester and MEOH represent methanol, and K ₁ and K ₂ are rate constants.

According to the formula, C _MMA / C which maximizes the initial velocity of this reaction
_{The DMAE} ratio is 1, and the initial rate is highest when the molar ratio of methyl methacrylate and dimethylaminoethanol is 1.

When the initial velocity is actually measured in this system, the maximum is obtained when the molar ratio of methyl methacrylate and dimethylaminoethanol is 1, and when the molar ratio is 3, the initial velocity is less than half that in the case of the molar ratio of 1. In the transesterification reaction between a methyl ester of acrylic acid or methacrylic acid and an alkylamino alcohol, when the early and late stages of the reaction are compared, the molar ratio of the methyl ester of acrylic acid or methacrylic acid to the alkylamino alcohol is 1 in the initial stage. The closer the reaction is, the faster the reaction is. On the contrary, the latter reaction is an equilibrium reaction.

The method of adding the methyl ester of acrylic acid or methacrylic acid, which is a raw material, to such a contradictory problem to the reaction system does not decrease the reaction rate in the latter half while keeping the initial rate of the reaction sufficiently, and The amount of product can also be reduced.

The amount of the methyl ester of acrylic acid or methacrylic acid added in the method of the present invention is ineffective if the amount is small, and if the amount is too large, the reaction volume required becomes large. It is in the range of 70%, preferably 25 to 50%.

The amount of methyl ester of acrylic acid or methacrylic acid used is 1.5 to 1 per 1 mol of alkylamino alcohol.
It is 0 mol, preferably 2 to 5 mol.

The addition time of the methyl ester of acrylic acid or methacrylic acid is equal to the reaction time and is usually 2.5 to 7 hours, although it varies depending on the amount of raw materials used, pressure, temperature, catalyst and the like.

Examples of the alkylamino alcohol used in the method of the present invention include methylaminoethanol, ethylaminoethanol, n-butylaminoethanol, iso-butylaminoethanol, t-butylaminoethanol,
Examples thereof include dimethylaminoethanol, methylethylaminoethanol, diethylaminoethanol, di-n-propylaminoethanol and di-n-butylaminoethanol.

Any known catalyst may be used as the catalyst used in the method of the present invention. For example, it is an alkali metal carbonate such as potassium carbonate, rubidium carbonate or cesium carbonate. In this case, the amount of the catalyst used is 0.01 to 2% by weight based on the total amount of the methyl ester of acrylic acid or methacrylic acid and the alkylamino alcohol. It is in the range, and more preferably in the range of 0.02 to 1.0% by weight.

The transesterification reaction can be carried out under normal pressure, but the reaction pressure is usually under reduced pressure to suppress side reactions such as polymerization, and preferably in the range of 100 to 760 mmHg.

The reaction temperature is determined by the boiling point of the reaction system at that pressure, and is preferably in the range of 50 to 120 ° C. at which the reaction rate is sufficiently high and the polymerization can be sufficiently suppressed.

In order to obtain the desired product in high yield, it is desirable to remove the by-product methanol from the reaction system. Specifically, it can be distilled out of the system by azeotropic distillation with unreacted acrylic acid or methacrylic acid methyl ester.

During the reaction, a polymerization inhibitor is usually added to prevent polymerization. As the polymerization inhibitor, a well-known polymerization inhibitor for unsaturated ester, for example, hydroquinone, hydroquinone monomethyl ether, phenothiazine or the like is used. The amount added is preferably in the range of 0.05 to 2% by weight with respect to the reaction solution.

After completion of the reaction, the reaction solution is depressurized to distill off unreacted acrylic acid or methacrylic acid methyl ester,
An objective alkylaminoalkyl ester of acrylic acid or methacrylic acid is obtained. The target product is purified by distillation or the like.

(Operation and Effect of the Invention) According to the method of the present invention, the reaction can be allowed to proceed promptly as compared with the case where the same amount of the methyl ester of acrylic acid or methacrylic acid is charged all at once at the start of the reaction.

Further, as compared with the case of the same charge amount, the reaction by-product is less and a highly pure alkylaminoalkyl ester of acrylic acid or methacrylic acid can be produced in a high yield.

(Examples) Hereinafter, the method of the present invention will be specifically described with reference to Examples.

Example 1 A flask having an inner volume of 1 equipped with a stirrer, a thermometer and a fractionation tower was charged with 133.7 g (1.5 mol) of dimethylaminoethanol, 225.2 g (2.25 mol) of methyl methacrylate, and 0.7 g of phenothiazine as a polymerization inhibitor. The mixture was heated with stirring at a reaction pressure of 400 mmHg. When reflux started, potassium carbonate dissolved in methanol as a catalyst was continuously added to the reaction system using a microtube pump. At the same time, methyl methacrylate was added to the reaction system. Regarding the addition rate and the addition time, potassium carbonate was 0.4 g / hour for 2.7 hours, and methyl methacrylate was 25.0 g / hour for 3 hours. The added and by-produced methanol was distilled as a methanol-methyl methacrylate azeotrope at a reflux ratio of 0.5 to 5 while maintaining the overhead temperature of the fractionating column at 48 to 51 ° C. The reaction was completed in 3 hours, and then the pressure was reduced to 20 mmHg to distill methyl methacrylate, and dimethylaminoethyl methacrylate was distilled at a pressure of 10 mmHg and a distillation column overhead temperature of 62 to 65 ° C. . The obtained methacrylic acid dimethylaminoethyl ester was 226.5 g, and the purity was 99.8%. The yield is 96 based on the charged dimethylaminoethanol.
%Met.

Examples-2 to 3 The same apparatus as in Example-1 was used, and the amounts of methyl methacrylate added and added were changed by the same method. The results are shown in Table-1.

Comparative Examples-1 and 2 Table-2 and FIG. 1 show a comparison with the case where the same apparatus as in Example-1 was used and methyl methacrylate was not added except for charging.

The conversion C of amino alcohol was calculated from A = charged amino alcohol (mol) B = unreacted amino alcohol (mol) C = [(AB) / A] × 100 (%).

[Brief description of drawings]

FIG. 1 is a diagram showing the change with time of the conversion rate of amino alcohol.

Claims (1)

[Claims] 1. A methyl ester of acrylic acid or methacrylic acid and a general formula (1) R ₁ R ₂ N (CH ₂ ) nOH (1) (wherein R ₁ is hydrogen or an alkyl group having 1 to 6 carbon atoms, R ₂ is an alkyl group having 1 to 6 carbon atoms, and n is an integer of 2 to 6)
In producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid by transesterification with an alkylamino alcohol represented by, it is characterized by reacting while adding a methyl ester of acrylic acid or methacrylic acid to the reaction system. A method for producing an alkylaminoalkyl ester of acrylic acid or methacrylic acid.