JPS6310772A - Production of 2-alkenyl-2-oxazoline - Google Patents

Abstract

PURPOSE:To produce the titled compound useful as surface active agent, etc., directly and efficiently, the reacting an alkenylnitrile with ethanolamine in the presence of a metallic salt catalyst supported on a solid carrier in an aprotic organic solvent. CONSTITUTION:An alkenylnitrile (e.g. methacrylonitrile, etc.) is reacted with ethanolamine in an aprotic organic solvent such as benzene, toluene, dioxane, tetrahydrofuran, methylene chloride, etc., in the presence of a metallic salt catalyst (especially effectively cadmium acetate or zinc chloride) supported on a solid catalyst (e.g. alumina, silica, active carbon, etc.) preferably at 50-100 deg.C to give a 2-alkenyl-2-oxazoline (e.g. 2-isopropenyl-2-oxazoline, etc.). USE:A monomer for polymerization or copolymerization or an intermediate for various syntheses.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing 2-alkenyl-2-oxazoline by reacting an alkenyl nitrile with ethanolamine.

(Prior art and its problems) The 2-alkenyl-2-oxazoline of -C formula (1) itself has uses as a surfactant, a corrosion inhibitor, etc., and can also be polymerized or copolymerized depending on the alkenyl group. Unsaturated carboxylic acid 2-aminoethyl ester, which is attracting attention as a difunctional monomer by reaction with phosgene, can be used as a polymer or as a variety of synthetic intermediates, such as unsaturated carboxylic acid 2-aminoethyl ester by hydrolysis, and unsaturated carboxylic acid 2-isocyanatoethyl ester, which is attracting attention as a bifunctional monomer by reaction with phosgene. It is a useful compound with a variety of uses.

Conventionally, N-(β-hydroxyalkyl) can be easily obtained by reacting carboxylic acid halide with ethanolamine.
A method for obtaining 2-alkyl-2-oxazolines by ring-closing carboxamides is known, but this method was applied to the production of 2-alkenyl-2-oxazolines, using an unsaturated carboxylic acid as a raw material to obtain N-(β -hydroxyalkenyl) carboxamide and ring-closing it by a known method, an addition reaction of the alkenyl group to the double bond occurs, making it difficult to obtain the desired product in high yield.

Therefore, in the past, 2-alkyl-2-oxazoline was first prepared, this was further reacted with formaldehyde under anhydrous conditions to form 2-(α-hydroxymethylalkyl)-2-oxazoline, and then this was oxidized with an alkali or alkaline earth metal. A method was developed to obtain the desired 2-alkenyl-2-oxazoline by reacting it with a substance and dehydrating it (
Japanese Patent Publication No. 54-5921, Japanese Patent Publication No. 59-24977). However, although this method has good selectivity in each step, the yield for each reaction angle is small due to the low conversion rate, and it is not suitable for industrial processes due to the complexity of reaction operations associated with achieving anhydrous conditions and multi-stage steps. It is hard to say that this is completely satisfactory in practical terms.

Another known method is to obtain 2-alkyl-2-oxazolines by heating alkylnitrile and ethanolamine in the presence of a small amount of cadmium acetate or zinc chloride catalyst (Annaren der Hemi, 1974). , p. 996) and applied this method to unsaturated nitriles to obtain 2
If -alkenyl-2-oxazoline can be obtained in high yield, the above-mentioned difficulties can be overcome, but this has the following problems.

That is, when an unsaturated nitrile is used as a raw material, Michael addition of ethanolamine to the unsaturated nitrile tends to occur, and β-hydroxyethylaminoalkyl nitrile or one molecule of this is likely to occur in addition to the target 2-alkenyl-2-oxazoline. 2-(β-hydroxyethylaminoalkyl)-
2-oxazoline etc. are produced.

(However, in the formula, R represents a lower alkyl group.) Liebigs Annaren der Hemi-996-1009 True (
(1974), the reaction products of l) and 2) are B
) and C), and it is also known that ^) can be obtained by thermal decomposition of C), but the reaction conditions for obtaining C) and A) are significantly different, so 1) and 2 )
It was not predicted at all that the target A) could be obtained all at once using these as raw materials.

(Means for Solving the Problems) The present inventor has completed the present invention as a result of various studies aimed at producing 2-alkenyl-2-oxazoline directly and efficiently from alkenylnitrile and ethanolamine.

That is, the present invention provides a method for producing 2-alkenyl-2-oxazoline, which comprises reacting alkenylnitrile and ethanolamine in an aprotic organic solvent in the presence of a metal salt catalyst supported on a solid carrier. This is what we intend to provide.

The method of the present invention will be explained in more detail below.

Examples of effective metal salt catalysts used in the method of the present invention include zinc chloride, zinc iodide, zinc sulfate, zinc bromide, zinc acetate, cadmium acetate, cobalt acetate, manganese acetate, and lithium chloride. Among them, cadmium acetate and zinc chloride are effective.

As the solid carrier, for example, alumina, silica, silica alumina, activated carbon, etc. are used. The amount of metal salt catalyst supported is not necessarily limited, but it is usually 0.5 to 3%.
It can be said that the degree is appropriate.

The solvent is not particularly limited as long as it is an aprotic organic solvent that is stable under the reaction conditions, but typical examples include the following. Aromatic hydrocarbons such as benzene and toluene, and dioxane.

Ethers such as tetrahydrofuran, chlorinated hydrocarbons such as methylene chloride and chloroform. There are no particularly strict restrictions on the reaction conditions, but in general, the molar ratio of raw materials is nitrile:ethanolamine = 1:0.5 to 1.5, preferably 1:0.8 to 1.2, and the temperature is 40 to 300°C. , preferably about 50 to 200°C.

The principle of the present invention is to obtain A by causing the nitrile adsorbed on the solid surface to react with ethanolamine in the liquid in the liquid phase to promote the cyclization reaction while suppressing Michael addition. Therefore, although it is possible to carry out the reaction in a batchwise manner, from an industrial standpoint, a continuous reaction method is more effective. In other words,
This is a method in which raw materials are continuously passed through the catalyst bed. However, in this case, there are many opportunities for reaction between both of them, which exist in a free state, and therefore the by-formation of B and C is unavoidable. In order to suppress the by-formation of B and C as much as possible, the temperature conditions of the catalyst layer are set in two stages, taking advantage of the fact that the production reaction of B and the production of A are reversible reactions, and the production of C is an irreversible reaction. All you have to do is select , and convert the once generated C to A. The product is the target A
and B, C, and ethanolamine, but A
A suitable method is to separate by distillation by taking advantage of its low boiling point, and to recycle the remainder.

Hereinafter, typical examples will be shown and more specifically explained about the method of the present invention, but these are representative examples for illustrative purposes only, and the method of the present invention is not limited to these. Needless to say.

Example 1 A catalyst was prepared in which 1% cadmium acetate was adsorbed on coconut shell activated carbon. Water was completely removed by vacuum drying. The above catalyst 1
00g was placed in a 300mJ glass flask. 30 g of methacrylonitrile is dissolved in 1001111 benzene and stirred for 10 minutes.

The temperature was maintained at 60° C., and 20 g of ethanolamine was added dropwise over 1 hour. Thereafter, 111rFx stirring was continued. Activated charcoal was used to collect oral fluid. 50 pieces of collected activated carbon
Wash the solution twice with ml of methylene chloride. After distilling off the solvent at normal pressure, 7 distillations were carried out under reduced pressure until the boiling point was 92°C/
25.6 g of 2-isopropenyl-2-oxazoline was obtained.

Yield 51.5%.

In addition, boiling point 120-125℃ 10.3) 1g of 2-<2
5 g of -C2-hydroxyethylaminoco-1-methyl-ethyl>-2-oxazoline was recovered.

Example 2 100 m7 of silica alumina catalyst capable of retaining 1% cadmium acetate and 0.5% zinc chloride! The mixture was divided into two stages and filled into a stainless steel tube with an inner diameter of 24mm.

(Cross-sectional area: 4.52 cm) The upper 1Qcm catalyst layer was maintained at 70°C. Lower berth 12
cm of catalyst layer was heated to 200°C.

From the top of the catalyst bed, 20 g/hour of methacrylonitrile and 25 g/hour of ethanolamine were fed from separate feed lines. The results of analysis of the product after a steady state was reached after 3 hours are shown.

(% by weight) Methacrylonitrile 8.72-Isopropenyloxaprine 51.9 Under the analysis conditions of gas chromatography, 3-(N-β-hydroxyethylamino)propionitrile decomposes into methacrylonitrile and ethanolamine. Measured.

Claims (1)

[Claims] 2-Alkenyl-2-, which is characterized by reacting an alkenyl nitrile with ethanolamine in an aprotic organic solvent in the presence of a metal salt catalyst supported on a solid carrier.
Method for producing oxazoline.