JP3242213B2 - Method for producing N- (meth) acryloylmorpholine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a new process for producing N- (meth) acryloylmorpholine.

[0002]

2. Description of the Related Art The following method is known as a method for synthesizing N, N-dialkyl (meth) acrylamide. (1) acrylic acid, methacrylic acid and esters thereof,
When an amide is reacted with an amine, Michael addition of a double bond is likely to occur. Therefore, when these compounds are used as a raw material, 2-mol of the amine is reacted, and then 3-dialkylamino- (2-methyl) produced -N, N-dialkylpropionamide is thermally decomposed to give N, N-dialkyl (meth) acrylamide. (J. Am. Ch
em. Soc. 74, 6281, (1952), JP-B-47-40777, JP-B-48-31086, JP-A-58-18346, JP-A-61-1.
45151, JP-A-4-208258)

(2) To suppress the addition of Michael to the double bond of acrylic acid and methacrylic acid, acrylic acid, methacrylic acid and its ester are first formed into an adduct by a Diels-Alder reaction with cyclopentadiene. After protecting the double bond with an amine in the presence of a strong basic catalyst to lead to an amide, the cyclopentadiene is removed by thermal decomposition to obtain the corresponding (meth) acrylamide derivative. (Japanese Patent Laid-Open No. 49-66625,
(3) An alcohol is eliminated from a β-alkoxy-substituted carboxylic acid amide to obtain an N-substituted unsaturated carboxylic acid amide. (4) Further, as a method for producing N- (meth) acryloylmorpholine, acrylamide is reacted with a halogen-substituted compound in a polar aprotic solvent in the presence of a strongly basic substance to form N- (meth) acryloylmorpholine. For obtaining N, N-dialkylacrylamide derivatives (JP-A-1-287078)

[0004] However, in the method (1), the amine is used twice in mole, so that an amine recovery step is required.
In addition, since the reaction rate of thermal decomposition is slow, severe reaction conditions such as high temperature and long time are necessary, and the yield of N, N-dialkyl (meth) acrylamide produced is lowered due to polymerization and increase of various side reactions. Inevitable. The method (2) involves three steps of introducing a protecting group, amidating, and removing a protecting group, so that the entire process becomes complicated and it is hard to say that the operability is excellent. Further, since the protecting group is eliminated at a high temperature, there is a high risk of polymerization. In the method (3), β-
Alcohol-substituted carboxylic acid must be derived before dealcoholization, which increases the number of steps. In addition, the method (4) cannot be said to be an excellent method, because a strongly basic substance which is troublesome to handle must be used.

[0005] Therefore, the present invention provides a method in which a protective group is introduced from a (meth) acrylic acid enol ester and morpholine in the middle of a reaction step, or a N-deprotection reaction is not required in one step.
An object of the present invention is to provide a method for producing (meth) acryloylmorpholine.

The present invention provides a compound represented by the general formula (I):
A (meth) acrylic acid enol ester represented by

Embedded image Reacting with morpholine to produce a Michael adduct represented by general formula (II),

Embedded image Then, the amine is rearranged from the Michael adduct (II) to give an α, β unsaturated amide (III)

Embedded image In a method for producing N- (meth) acryloylmorpholine.

According to the present invention, a 1: 1 mixture of (meth) acrylic acid enol ester represented by the general formula (I) and morpholine is used.
And the resulting Michael adduct 3
This is a method in which N- (meth) acryloylmorpholine is obtained by producing a morpholino-propionic acid enol ester and treating it.

In general, when N, N-dialkyl (meth) acrylamide is synthesized by reacting a dialkylamine with a (meth) acrylic acid ester, the addition of Michael occurs predominantly. When acrylate is reacted at a molar ratio of 1: 1, 3- (N, N-dialkylamino)-(2-methyl) propionate is produced in high yield, and N, N-
It is difficult to obtain dialkyl (meth) acrylamide. For this reason, 2 moles of dialkylamine are reacted,
A method of producing N, N-dialkyl-3- (N, N-dialkylamino)-(2-methyl) propionamide and then synthesizing N, N-dialkyl (meth) acrylamide by reverse Michael addition reaction by heat. I have to take. However, this method has the drawback that it requires severe conditions of high temperature and long-time heating, and the yield is low.

On the other hand, since the bond between an acyl group and a vinyloxy group is easily cleaved, the enol ester reacts with an amine under a very mild condition without a catalyst or under acidic conditions such as sulfuric acid to produce a corresponding amide. (Industri
al & Engineering Chem. 41 volumes, 2
920 (1949), US Pat. No. 2,472,633)

The inventors of the present invention have conducted intensive studies on a method of using (meth) acrylic acid enol ester represented by the formula (I) and morpholine in synthesizing N- (meth) acryloylmorpholine, and have found the following facts. The present invention has been completed.

When an equimolar mixture of (meth) acrylic acid enol ester and morpholine is reacted at 0 ° C. to 30 ° C., the enol of the Michael reaction adduct, 3-morpholino- (2-methyl) propionate, is obtained in high yield. Esters (formula (I
It is surprising that this compound is aged at 100 to 200 ° C. or treated in a solvent in the presence of an acidic or basic catalyst to rearrange the morpholino group to give N-. (Meth) acryloylmorpholine was formed. The rearrangement of the morpholino group from the Michael adduct does not occur under these reaction conditions when using a usual (meth) acrylate.

The present invention is characterized in that an enol ester of (meth) acrylic acid is used in the production of N- (meth) acryloylmorpholine. The method of the present invention comprises:
It has the following advantages over the conventional method for producing N- (meth) acryloylmorpholine.

(1) The amount of morpholine charged may be equimolar to that of the (meth) acrylic acid enol ester. In a conventional method for preparing a 2-mol adduct using twice the mole of morpholine with respect to (meth) acrylic acid ester and then removing morpholine to synthesize N- (meth) acryloylmorpholine, morpholine is used. However, the method of the present invention does not require the recovery of morpholine, and is excellent in operability.

(2) When the Michael adduct is aged, morpholine rearrangement occurs at a relatively low temperature. For this reason, it can be industrially carried out as a liquid phase reaction. The conventional method of adding 2 mol of morpholine from a (meth) acrylic ester and then desorbing 1 mol of morpholine usually requires a high temperature of 200 ° C. or higher, and in some cases, a gas phase reaction.

Next, the manufacturing conditions of the present invention will be described. The reaction between (meth) acrylic acid enol ester and morpholine can be performed by adding (meth) acrylic acid enol ester in morpholine without solvent or by adding morpholine in (meth) acrylic acid enol ester, The reaction can be similarly performed in the presence of a solvent. The charged molar ratio of the (meth) acrylic acid enol ester to morpholine may be in the range of 1 to 1.2: 1, preferably 1:
It is one.

As the solvent, any solvent which does not basically react with morpholine and (meth) acrylic acid enol ester can be used. Particularly preferred solvents are high boiling hydrocarbons such as toluene, xylene, cumene and the like. The reaction temperature can be arbitrarily set in the range of 0 to 90 ° C., but the Michael addition reaction is an exothermic reaction,
Considering that there is a risk that the enol acrylate polymerizes, it is preferable to carry out the reaction in the range of 0 to 70 ° C.

(2-methyl)-represented by the general formula (II)
The conversion of morpholinopropionic acid enol ester to N- (meth) acryloylmorpholine can be carried out in the absence of a catalyst or in the presence of an acidic or basic catalyst, in the absence of a solvent or in a state diluted with a solvent. In the absence of a catalyst, the reaction temperature is between 100 and 200 ° C. If the temperature is lower than 100 ° C., the efficiency of the thermal reaction is low, and if the temperature is higher than 200 ° C., the risk of polymerization increases.

When a solvent is used, any solvent may be used as long as it has a boiling point higher than the reaction temperature and does not react with morpholine or (2-methyl) -3-morpholinopropionic acid enol ester. Particularly preferred solvents are high boiling hydrocarbons such as toluene, xylene and cumene.

In the reaction using a catalyst, either an acidic or basic catalyst can be used. Examples of the acidic catalyst include inorganic acids such as sulfuric acid, hydrochloric acid and nitric acid, organic acids such as paratoluenesulfonic acid and acetic acid, solid acids such as ion exchange resins, and Lewis acids such as aluminum chloride and zinc chloride. Examples of the basic catalyst include tertiary amines such as pyridine and dimethylaminopyridine, and ion exchange resins having a tertiary amino group. Particularly preferred are acetic acid and nitric acid.

In the reaction using a catalyst, the reaction temperature is 30 to
The reaction temperature can be arbitrarily set between 170 ° C, but the preferred reaction temperature is 40 to 100 ° C. During these conversion reactions, by-product enol alcohol isomers such as acetaldehyde and acetone can be removed by distillation when the reaction temperature is higher than the boiling point of these compounds. It is also possible to remove sodium from the reaction solution by adding sodium.

The N- (meth) acryloylmorpholine may be taken out of the reaction solution by distillation from the reaction solution as it is, or may be taken out by solvent extraction from the reaction solution. In the distillation, N
-In order to prevent polymerization of (meth) acryloylmorpholine, hydroquinone, p-methoxyphenol, N-phenyl-N '-(1,3-dimethylbutyl) -p-phenylenediamine (manufactured by Ouchi Shinko Chemical Co., Ltd. Nocrack 6C) may be added.

The N- (meth) acryloyl morpholine produced by the present invention has excellent properties such as low viscosity and low primary skin irritation, and is useful for a wide range of applications as a diluent monomer for UV-electron curable coatings. Compound.

[0022]

Next, the present invention will be described specifically with reference to examples. In the examples, “parts” means parts by weight. Example 1 19.62 parts (0.2 mol) of vinyl acrylate was placed in a glass flask equipped with a stirrer, a dropping funnel, a thermometer, and a Dimroth condenser, and 0.04 of trade name "Nocrack 6C" was used as a polymerization inhibitor. Then, 17.42 parts (0.2 mol) of morpholine was added dropwise thereto over 30 minutes under air cooling. During the dropwise addition, the temperature of the reaction solution rose to 66 ° C. due to heat generation. The reaction solution was heated to 150 ° C. over 20 minutes and aged at the same temperature for 4 hours. Thereafter, the reaction solution was cooled, and N-acryloylmorpholine was quantified by high performance liquid chromatography. The yield of N-acryloylmorpholine produced by the reaction was 26.1% based on the charged morpholine.

Example 2 A glass flask equipped with a stirrer, a dropping funnel, a thermometer and a Dimroth condenser was charged with 8.71 parts (0.1%) of morpholine.
(mol) 0.02 parts of Nocrack 6C (trade name) as a polymerization inhibitor and 19.62 parts of xylene as a solvent were charged and heated to 128 ° C. At the same temperature, 9.81 parts of vinyl acrylate were added dropwise over 20 minutes. Subsequently, the reaction solution was aged at the same temperature for 10 hours. Thereafter, the reaction solution was cooled, and N-acryloylmorpholine was quantified by high performance liquid chromatography. The yield of N-acryloylmorpholine produced by the reaction was 29.1% based on the charged morpholine.

[0024]

According to the method of the present invention, N- (meth) acryloyl morpholine can be synthesized by using morpholine in an equimolar amount to the enol ester of (meth) acrylic acid, and the addition of Michael can be suppressed. This is a one-step reaction that does not require the introduction of a protecting group or the deprotection reaction to perform the reaction at a relatively low temperature, and thus is a very simple method for synthesizing N- (meth) acryloylmorpholine.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C07D 295/18 CA (STN) REGISTRY (STN)

Claims (2)

(57) [Claims] 1. A compound of the general formula (I) Reacting a (meth) acrylic acid enol ester represented by the formula with morpholine to give a compound of the general formula (II) And then the amine is rearranged from the Michael adduct (II) to give an α, β unsaturated amide (III) The method for producing N- (meth) acryloylmorpholine characterized by producing 2. The method according to claim 1, wherein the charged molar ratio of the (meth) acrylic acid enol ester to morpholine is 1 to 1.2: 1.