JPH0680034B2 - Method for producing pivalic acid (meth) acrylate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing pivalic acid (meth) acrylate having a highly reactive carboxyl group and one ethylenically unsaturated group in the molecule.

Pivalic acid (meth) acrylate can be widely applied as a raw material for synthetic resins, paints, adhesives, functional materials, etc., and also as a modifier or modifier, and is practically applicable to various molecular designs. It is a compound useful as an intermediate raw material.

(Prior Art) Pivalic acid (meth) acrylate is a compound represented by the following formula.

(In the formula, R is hydrogen or a methyl group.) Pivalic acid (meth) acrylate is described in US Pat.
Is described as one of the trivalent chromium coordination compounds of Werner complex salt, and this Werner complex salt is obtained by reacting an aqueous solution of a chromium salt with an alcohol and an ω unsaturated carboxylic acid.

(Problems to be Solved by the Invention) The object of the present invention is to provide useful pivalic acid (meta) as described above.
It is to provide a method for efficiently producing an acrylate by an esterification reaction.

(Means for Solving Problems) As a result of intensive studies on the method for producing pivalic acid (meth) acrylate by the esterification reaction, the present inventors have used an acidic catalyst, an inert solvent and a polymerization inhibitor. In the presence of the above, it was found that pivalic acid (meth) acrylate is produced by carrying out an esterification reaction under reflux while blowing dry air, and arrived at the present invention.

That is, the present invention relates to 1) hydroxypivalic acid
Pivalic acid (meth), characterized in that an esterification reaction of hydroxypivalic acid and acrylic acid or methacrylic acid is carried out in the presence of a polymerization inhibitor using 0.02 to 1% by weight of an acidic catalyst while blowing dry air. Method for producing acrylate, and 2) Pivalic acid (meth) as described in the preceding paragraph, wherein esterification reaction is carried out under reflux by adding an inert solvent more than twice the reaction mixture of hydroxypivalic acid and acrylic acid or methacrylic acid. This is a method for producing acrylate.

Examples of the acidic catalyst used in the present invention include mineral acids such as sulfuric acid, hydrochloric acid and phosphoric acid, and organic acids such as p-toluenesulfonic acid, m-xylenesulfonic acid and methanesulfonic acid. To organic acids are preferred. The amount of acidic catalyst used is 0.02 to 1% by weight, preferably 0.02 to 0.1% by weight, based on the raw material hydroxypivalic acid.
Used in proportion.

The addition ratio of hydroxypivalic acid and (meth) acrylic acid is 1 to 5 mol of (meth) acrylic acid with respect to 1 mol of hydroxypivalic acid. Also, in the reaction, hydroquinone, p-methoxyphenol, 2,4-dimethyl-6-t
-Butylphenol, 3-hydroxythiophenol,
2-nitroso-β-naphthol, p-benzoquinone, 2,
5-dihydroxy-p-quinone, phenothiazine, N-
Polymerization inhibitors such as nitroso-diphenylamine, copper salts,
It is preferable to add about 0.01 to 1% by weight to the product. Furthermore, it is also useful for preventing the polymerization to carry out the reaction while blowing dry air.

It is preferable to add a solvent inert to the reaction during the esterification reaction, for example, n-hexane, n-butane, n-
Saturated aliphatic hydrocarbons such as pentane, n-heptane and cyclohexane, saturated alicyclic hydrocarbons or aromatic hydrocarbons such as benzene, toluene and xylene are added to the reaction mixture in an amount of at least 2 times.

The reaction temperature of the esterification reaction is 150 ° C. or lower, and the esterification reaction is carried out using the above-mentioned inert solvent having a boiling point of 150 ° C. or lower while extracting the produced water under reflux of the solvent.

(Effect of the Invention) Since pivalic acid (meth) acrylate has two kinds of different functional groups, which are a highly reactive carboxy group and an ethylenically unsaturated group, in one molecule, it can be variously prepared by the method of the present invention. It is possible to efficiently obtain a compound having the characteristics of.

That is, the carboxy group in the molecule is easily modified or crosslinked by esterification, epoxidation, amidation, imidization and the like.

On the other hand, one ethylenically unsaturated group has a high radical polymerizability, and has a characteristic that it is polymerized by simply heating to form a polymer compound.

For example, it can be easily reacted with alcohols, phenols, epoxies, and further polyesters, polyethers, polyglycidyl and the like.

Therefore, the pivalic acid (meth) acrylate of the present invention can be widely applied as a raw material for synthetic resins, paints, adhesives, functional materials, etc., and as a modifier or modifier.

For example, when it is used as one of the raw materials for paints, it is possible to impart a coating film having excellent heat resistance, light resistance, chemical resistance, and particularly metal adhesion under a suitable crosslinking density.

(Example) Example 1 Hydroxypivalic acid was placed in a four-necked flask having an internal volume of 1 in which a reflux condenser, a water separator, a stirrer, and a thermometer were set.
8 parts, acrylic acid 147 parts, catalyst p-toluenesulfonic acid
11.0 parts, hydroquinone 1.3 parts, benzene 160 parts, and cyclohexane 40 parts are added, and dry air is blown into the mixture while heating to raise the temperature. The mixture was reacted under reflux (84 to 88 ° C) while removing water. The reaction time was terminated when the amount of water taken out reached a predetermined amount (about 18 parts), and the reaction was carried out for 5 hours.

Next, after cooling the liquid temperature to 50 ° C. or lower, 250 parts of benzene was added and diluted. Continue to add 300 parts of water, stir after stirring, separate into two phases, drain the lower phase water, and add the upper organic phase to further water.
It was washed with 300 parts of water, and this washing operation was repeated 4 times in total. From the reaction solution thus obtained, benzene and cyclohexane were distilled off under reduced pressure to obtain 143 parts of a target product as a distillate. The residual liquid was a pale yellow liquid having a slight viscosity.

The elemental analysis, acid value (mgKOH / g) and IR analysis of this product were as follows.

(1) Elemental analysis C 54.5%, H 7.2%, O 38.3% (theoretical value, C 55.8%, H 7.0%, O 37.2%) (2) Acid value (mgKOH / g) 315 (theoretical value 326) (3 ) IR analysis 2980,2860 (C-H) 1720 ( C = O) 1623,1610 (C = C) 1470,1400 (-CH 2 -) 1360 (-CH 3) 1290,1260,1150 (C-O) 1055 (C-O-C) Example 2 Hydroxypivalic acid was placed in a four-necked flask having an internal volume of 1 in which a reflux condenser, a water separator, a stirrer, and a thermometer were set.
8 parts, acrylic acid 88.2 parts, catalyst-toluenesulfonic acid
11.0 parts, hydroquinone 0.65 parts, and toluene 200 parts are added, and dry air is blown into the mixture while heating to raise the temperature. The mixture was reacted under reflux (100 to 116 ° C) while removing water.
The reaction time was terminated when the amount of water taken out reached a predetermined amount (about 18 parts), and the reaction was carried out for 3 hours.

Next, after cooling the liquid temperature to 50 ° C. or lower, 200 parts of toluene was added and diluted. Continue to add 300 parts of water, stir after stirring, separate into two phases, drain the lower phase water, and add the upper organic phase to further water.
It was washed with 300 parts of water, and this washing operation was performed three times in total. Toluene was distilled off from the reaction solution thus obtained under reduced pressure to obtain 145 parts of a residual liquid. The residual liquid was a pale yellow liquid having a slight viscosity.

The elemental analysis, acid value (mgKOH / g) and IR analysis of this product were as follows.

(1) Elemental analysis C 56.6%, H 7.3%, O 36.1% (theoretical value, C 55.8%, H 7.0%, O 37.2%) (2) Acid value (mgKOH / g) 300 (theoretical value 326) (3) ) IR analysis The absorption pattern was the same as in Example 1.

Example 3 Hydroxypivalic acid 118 in the same reactor as in Example 1
Parts, methacrylic acid 172 parts, methylsulfonic acid 11 parts,
0.7 parts of 2,4-dimethyl-6-t-butylphenol, 160 parts of benzene and 40 parts of cyclohexane were charged, and the reaction was carried out by blowing dry air in the same manner as in Example 1 until 18 parts of the produced water was distilled off. . The reaction temperature was 84 to 88 ° C, and the reaction time was 6 hours.

Next, after cooling the liquid temperature to 40 ° C. or lower, 500 parts of toluene was added and diluted. Subsequently, 300 parts of water was added and the mixture was washed under forced agitation and allowed to stand still to separate into two phases. The lower phase water was extracted, the upper organic phase was further washed with 300 parts of water, and this washing operation was performed 4 times in total.

From the reaction solution thus obtained, benzene and cyclohexane were distilled off under reduced pressure to obtain 157 parts of a residual liquid as a target substance.

The elemental analysis, acid value (mgKOH / g) and IR analysis of this product were as follows.

(1) Elemental analysis C 57.0%, H 7.3%, O 35.7% (theoretical value, C 58.1%, H 7.5%, O 34.4%) (2) Acid value (mgKOH / g) 272 (theoretical value 302) (3) ) IR analysis The absorption pattern was the same as in Example 1.

Example 4 Hydroxypivalic acid in the same reactor as in Examples 1 and 2
118 parts, methacrylic acid 172 parts, paratoluene sulfonic acid 9.5 parts, hydroquinone 0.65 parts, benzene 160
And 40 parts of cyclohexane were charged and reacted in the same manner as in Example 1 for 7 hours. At this time, the reaction temperature was 85 to 90 ° C, and the dehydration amount was 16 parts.

After the reaction was completed, the temperature was cooled to 50 ° C or lower, and 300 parts of benzene was added. Next, washing with 300 parts of water was performed three times in total. Subsequently, the solvent is removed under vacuum and the unreacted components are distilled off.
146 parts of residual liquid was obtained. This residual liquid is a yellow liquid.

The elemental analysis, acid value (mgKOH / g) and IR analysis of this product were as follows.

(1) Elemental analysis C 57.9%, H 7.9%, O 34.2% (theoretical value, C 58.1%, H 7.5%, O 34.4%) (2) Acid value (mgKOH / g) 251 (theoretical value 301) (3) ) IR analysis The absorption pattern was the same as in Example 1.

Claims (2)

[Claims] 1. An esterification reaction of hydroxypivalic acid with acrylic acid or methacrylic acid in the presence of a polymerization inhibitor while using 0.02 to 1% by weight of an acid catalyst based on hydroxypivalic acid in the presence of a polymerization inhibitor. Method for producing pivalic acid (meth) acrylate characterized by 2. A pivalic acid according to claim 1, wherein an esterification reaction is carried out under reflux by adding an inert solvent which is at least twice the amount of the reaction mixture of hydroxypivalic acid and acrylic acid or methacrylic acid. Method for producing (meth) acrylate