JP2001058986A - Production of vinyloxazoline or isopropenyloxazoline derivative - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce the subject compound in high yield by subjecting (A) cyclopentadiene and (B) a (meth)acrylic ester to a Diels-Alder reaction, amidating the obtained Diels-Alder adduct, dehydrating the amidation product to provide an oxazolylnorbornene derivative, and thermally decomposing the derivative. SOLUTION: (A) Cyclopentadiene and (B) a (meth)acrylic ester are subjected to a Diels-Alder reaction, and the obtained Diels-Alder adduct is amidated with (D) aminoethanol by using a catalyst preferably a sodium methylate or the like at 20-80 deg.C to provide an amide adduct. The amide adduct is heated preferably under a reduced pressure to 160-250 deg.C to carry out dehydration cyclization and to provide (E) an oxazolylnorbornene derivative of formula I (R1 is H or methyl; R2 to R5 are each an alkyl or an aryl), and the obtained oxazolylnorbornene derivative is thermally decomposed in vapor phase preferably at 200-500 deg.C to provide the objective compound of formula II.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a bifunctional monomer having a polymerizable double bond and an oxazoline group in its molecule.
The present invention relates to a method for producing a vinyloxazoline or isopropenyloxazoline derivative useful as a water-based paint, an adhesive, a resin modifier, or a crosslinking agent.

[0002]

2. Description of the Related Art A method for producing a vinyloxazoline or isopropenyloxazoline derivative is disclosed in
No. 24977, 2-alkyl-2
-Condensation of oxazoline with formaldehyde to give 2-
There is a method of obtaining (α-hydroxymethylalkyl) -2-oxazoline and dehydrating it in the presence of an alkali catalyst. According to this method, the condensation yield for isopropenyloxazoline is 96.5%, and the dehydration yield is 97.8%.
However, the yield of vinyloxazoline is not clear, and the final isolation method and isolation yield of any monomer are not described at all. In addition, the yield is based on formaldehyde.In this method, excess alkyloxazoline is inevitably distilled and recovered because excess alkyloxazoline is used relative to formaldehyde, and it is estimated that the yield based on oxazoline is extremely low. Is done.

On the other hand, a Diels-Alder adduct obtained by reacting a double bond such as methyl acrylate with cyclopentadiene or the like is subjected to aminolysis with an amine or the like, and then the product is thermally decomposed (reverse Diels-Alder reaction). ) To obtain an N-substituted acrylamide,
Although these are described in JP-A-47-34311, they are all limited to relatively simple N-alkyl-substituted acrylamides, and no mention is made of cyclic compounds having an active reactive group such as oxazoline. Not been.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to establish a process for producing a vinyloxazoline or isopropenyloxazoline derivative with high purity and high yield.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, after amidating a Diels-Alder adduct of cyclopentadiene and (meth) acrylate with aminoethanol, The crude monomer obtained by thermally decomposing the oxazolyl norbornene derivative represented by the formula (1) obtained by dehydration can be converted into vinyloxazoline or isopropenyl in high purity and high yield by relatively simple distillation. The inventors have found that an oxazoline derivative can be obtained, and have completed the present invention.

Hereinafter, the present invention will be described in detail. The Diels-Alder reaction between cyclopentadiene and (meth) acrylate is performed by adding (meth) acrylate to a three-necked flask equipped with a stirrer, a thermometer, and a dropping device, and gradually adding cyclopentadiene thereto. Allow the reaction to take place. As the acrylate, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate and the like can be used.

The amount of cyclopentadiene added is (meth)
Although an equimolar amount is used based on the acrylate ester, an excess of cyclopentadiene may be used to complete the reaction. The excess amount is preferably 20 mol% or less. Although a further excess accelerates the completion of the reaction, it is not preferable because cyclopentadiene itself is condensed into two molecules to produce a large amount of by-products of dicyclopentadiene.

[0008] The reaction temperature may be any temperature, but it is preferably carried out at 60 ° C or lower. Higher temperatures are not preferred because dicyclopentadiene by-products increase.

The thus obtained ester adduct is, if necessary, purified by collecting unreacted acrylate or cyclopentadiene and dicyclopentadiene as a by-product by distillation under reduced pressure.

Next, the ester adduct is reacted with an amino alcohol to obtain an amide adduct. Amino alcohols include 2-aminoethanol, 2-amino-1-propanol, 1-amino-2-propanol, 3-amino-2-butanol, and homologs thereof. Aminoethanol is usually used in an equimolar amount or more based on the ester adduct to complete the reaction. The excess amount is 50 mol% or less, preferably 20 mol%.

The catalyst used in the reaction is an alkali metal hydroxide or an alkali metal alcoholate, and preferably sodium methylate. The catalyst is used in an amount sufficient to catalyze the amidation of the ester adduct with the amino alcohol, but is usually 0.1 mol% or more and 10 mol% or less and 0.5 mol % Or more and 2 mol% or less is preferable.

[0012] The amidation reaction is carried out at a temperature of not lower than 20 ° C and not higher than 80 ° C. Preferably it is 60 ° C. or lower. If the temperature is too high, it is not preferable because by-products such as two molecules of the ester adduct reacted with the amino alcohol are formed.

After the reaction, the produced alcohol and excess aminoethanol are recovered by distillation to obtain an amide adduct.

Next, the amide adduct is dehydrated and ring-closed,
An oxazolyl norbornene derivative is obtained. Known catalysts such as zinc salts such as zinc oxide, zinc chloride, zinc acetate and zinc sulfate, and iron salts such as ferric sulfate and ferric chloride can be used as the catalyst in the dehydration ring closure reaction. The amount of the catalyst is 1% by weight or more and 30% by weight or less, preferably 5% by weight or more and 15% by weight or less based on the amide adduct.

Although a solvent is not always necessary, it is effective for adjusting the slurry concentration of the reaction system, and it is preferable to use sulfolane, polypropylene glycol, aliphatic hydrocarbon, aromatic hydrocarbon, or the like as an inert solvent.

In the reaction, a slurry solution composed of an amide adduct, a catalyst and a solvent is heated at 160 to 250 ° C. under reduced pressure, whereby a ring-closed oxazolyl norbornene derivative is distilled out together with water generated by dehydration. . The degree of pressure reduction depends on the reaction temperature and the reaction rate, but is usually 20 mmHg.
This is done below.

The thermal decomposition of the oxazolyl norbornene derivative represented by Chemical formula 1 is desirably performed in a gas phase at about 200 to 500 ° C. To facilitate heat exchange, glass, stainless steel, porcelain Raschig rings or the like are filled as necessary in a heating tube, and the vaporized chemical vapor as it is or diluted with an inert gas such as nitrogen. A method such as passing through is used. The decomposed product is cooled with water to condense the crude vinyl oxazoline, and the other cyclopentadiene is recovered in an acetone-dry ice bath. Hydroquinone, to suppress the polymerization of crude vinyl oxazoline,
It is preferred to add a polymerization inhibitor such as p-methoxyphenol, phenothiazine, 4-t-butylpyrocatechol. In addition, at the time of thermal decomposition, cuperone (N-nitrosophenylhydroxylamine), nitric oxide, or the like can be used to prevent polymerization in the gas phase.

Since crude vinyl oxazoline contains almost no by-products other than cyclopentadiene, vinyl oxazoline and unreacted raw materials, it is possible to obtain high-purity vinyl oxazoline by simple distillation by utilizing the difference in boiling points. It is.

[0019]

The present invention will be described in more detail with reference to the following examples. Example 1 Production of Ester Adduct In a 3000 ml three-necked flask equipped with a stirrer, a thermometer, and a dropping device, 1300 g of methyl acrylate was charged, and 1000 g of cyclopentadiene was gradually added dropwise with stirring. Meanwhile, the temperature of the reaction mixture was 35 ° C.
Kept below. After the addition was completed, the reaction mixture was stirred at 35 ° C. or lower overnight. The unreacted product and the by-produced dicyclopentadiene were recovered by distillation under reduced pressure to obtain the ester adduct 225.
7 g were obtained. The yield was 98%.

Preparation of amide adduct In a similar reactor, 2200 g of ester adduct, 2
1060 g of aminoethanol and 52 g of a 30% sodium methylate solution were charged and reacted at 60 ° C. for 6 hours. Thereafter, by-product methanol was recovered by distillation under reduced pressure to complete the reaction. After the reaction solution was neutralized with the added sodium methylate and an equivalent amount of concentrated sulfuric acid, excess aminoethanol was recovered by distillation to obtain 2490 g of an amide adduct. The yield was 95%.

Dehydration of amide adduct The amide adduct 200 was placed in a reactor equipped with a stirrer and a distillation column.
0 g, 2000 g of polypropylene glycol, 200 g of basic zinc carbonate, and 4 g of MHQ as a polymerization inhibitor, and 160 to 19 with a mantle heater under reduced pressure of 2 mmHg.
Oxazolyl norbornene 126
0 g was obtained. The yield was 70%.

Thermal decomposition of oxazolyl norbornene 1200 g of oxazolyl norbornene was converted to 60 mmHg
Was heated and vaporized with an evaporating tube under reduced pressure, and passed through a stainless steel pyrolysis tube (inner diameter 21.4 mm, length 600 mm) heated to 400 to 420 ° C. to perform pyrolysis. The running time was about 12 hours. The product of pyrolysis is about 5
The mixture was trapped by a condenser kept at 0 ° C. and a condenser cooled to −60 ° C., to obtain 696 g of crude vinyloxazoline from the former, and 479 g of cyclopentadiene from the latter. The oxazolyl norbornene thermal decomposition rate was 96.9%, and the vinyl oxazoline yield was 88%.

Next, the crude vinyl oxazoline was subjected to simple distillation under reduced pressure through a rectification column packed with 20 cm of McMahon packing (boiling point: 50 ° C./25 mmHg). As a result, 460 g of a fraction having a purity of 99% or more (distillation yield: 94%) was obtained. The overall yield was 54%.

Example 2 In Example 1, methyl methacrylate was used as a raw material instead of methyl acrylate, and the reaction in each step was carried out in the same manner. As a result, isopropenyl oxazoline was converted to a total yield of 51%.
I got it. Purity was over 99%.

[0025]

The oxazolyl norbornene derivative obtained by amidating a Diels-Alder adduct of cyclopentadiene and (meth) acrylic acid ester with aminoethanol and then dehydrating the resultant is subjected to gas phase thermal decomposition. The vinyl oxazoline derivative could be produced in high yield with almost no by-products.

Claims (1)

[Claims] 1. A method comprising subjecting a Diels-Alder adduct of cyclopentadiene and (meth) acrylic acid ester to amidation with aminoethanol, followed by dehydration to thermally decompose the oxazolylnorbornene derivative represented by Chemical Formula 1. A process for producing a vinyl oxazoline or isopropenyl oxazoline derivative represented by Chemical Formula 2. Embedded image (Wherein, R1 represents hydrogen or a methyl group;
To R5 represent hydrogen, an alkyl group or an aryl group. ) (Wherein, R1 represents hydrogen or a methyl group;
To R5 represent hydrogen, an alkyl group or an aryl group. )