JPH06329589A - Production of beta-hydroxypropionic acid ester - Google Patents

Abstract

PURPOSE:To provide a process capable of easily producing, in high yield and purity, a beta-hydroxypropionic acid ester which has been difficult to produce. CONSTITUTION:A beta-hydroxypropionic acid ester is produced by reacting (A) a beta-acyloxypropionic acid or its ester or an acrylic acid oligomer or its ester with (B) an alcohol in the presence of a transesterification catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel process for producing β-hydroxypropionic acid esters. The compound is useful as a raw material for polymers and various intermediates.

[0002]

2. Description of the Related Art Conventionally, as a method for producing β-hydroxypropionic acid ester, a method has been considered in which β-hydroxypropionic acid is obtained and then esterified with alcohol. However, the method for producing β-hydroxypropionic acid cannot be said to be easy, and thus it was similarly difficult to obtain the ester. For example, Zh.Org.Khim., Volume 19 P
As described in 33-37 (1983) that β-hydroxypropionic acid can be obtained from acrylic acid and water in a yield of about 28%, β-hydroxypropionic acid as a raw material of ester is low in yield. Can only be manufactured. Further, this method has a problem that the conversion rate of the starting acrylic acid cannot be sufficiently increased due to the equilibrium reaction, and therefore the isolation of β-hydroxypropionic acid becomes complicated.

On the other hand, another method route for producing β-hydroxypropionic acid and its ester has been proposed. For example, German Patent No. 4107987 discloses 1,3-
A method for obtaining propanediol by oxygen oxidation in the presence of a Pd catalyst, and U.S. Pat. No. 4,973,741 discloses ethylene oxide, carbon monoxide, hydrogen, and alcohol as raw materials.
A method of obtaining an ester thereof using a catalyst containing h and Ru is disclosed. However, these methods have the same problems as the methods described in the above literatures, use of expensive precious metals, and disadvantages such as the use of a homogeneous catalyst that is difficult to recover. All of these methods are easy methods to carry out industrially. It is hard to say.

In addition, the Journal of Chemi
Cal Society) Volume 70, P1004-1006 (1948), it is shown that it is synthesized by the reaction of β-propiolactone with an alcohol in the presence of a base catalyst. Lactone has the disadvantages that it is expensive, highly toxic, and difficult to handle.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances of the prior art. That is, the object of the present invention is to obtain β-
It is to provide a new industrial production method for producing a hydroxypropionic acid ester.

[0006]

That is, the present invention is based on β
There is provided a method for producing a β-hydroxypropionic acid ester, which comprises reacting an acyloxypropionic acid or its ester, or an acrylic acid oligomer or its ester with an alcohol in the presence of a transesterification catalyst.

A feature of the present invention is that a β-acyloxypropionic acid or its ester and an alcohol can be easily obtained by adding a carboxylic acid to the double bond of acrylic acid or its ester to form a transesterification catalyst. The point is to react in the presence to produce β-hydroxypropionic acid ester. The reaction formula is shown below.

[0008]

[Chemical 1]

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a secondary butyl group, a tertiary butyl group, a hexyl group, an octyl group and a 2-ethylhexyl group. Examples of the alkenyl group include, but are not limited to, a vinyl group, an allyl group, an isopropenyl group, a hexenyl group and the like.

A feature of the present invention is that an acrylic acid oligomer or its ester and an alcohol (the term "acrylic acid oligomer in the present invention" has a repeating unit of acrylic acid as shown in the formula (2)). In the presence of a transesterification catalyst to produce a β-hydroxypropionic acid ester. The reaction formula is shown below.

[0011]

[Chemical 2]

Examples of the alkyl group are the same as above.

These reactions can proceed in a high yield by appropriately selecting a catalyst from known transesterification catalysts and appropriately selecting reaction conditions. Also β obtained in this way
-Hydroxypropionic acid ester is volatile (methyl ester bp.184 ℃ / 760mmHg, 79 ℃ / 12mmHg) unlike its acid form, so it can be easily isolated as a highly pure product by distillation. it can.

As the raw material used in the present invention, various β-acyloxypropionic acids or their esters as shown in the reaction formula (1) or (2) or acrylic acid oligomers or their esters can be used. For example, β-acetoxypropionic acid obtained from acetic acid and acrylic acid, β-propionyloxypropionic acid obtained from propionic acid and acrylic acid, and β-acryloyloxypropionic acid which is an acrylic acid dimer are preferable. Further, it is possible to use as long as it contains these, for example, waste oil (containing a considerable amount of acrylic acid dimer) from an acrylic acid production plant can be used. As the acrylic acid oligomer or its ester, acrylic acid trimer, acrylic acid tetramer and the like can also be preferably used.

The alcohol used in the present invention includes:
Various ones can be used. Primary alcohol such as methyl alcohol, ethyl alcohol, and n-propyl alcohol
Is particularly preferable because of its high reaction rate. The amount used is preferably 1 to 50 equivalents relative to 1 equivalent of the raw material β-acyloxypropionic acid, acrylic acid oligomer or esters thereof. Since it is governed by the equilibrium, the more it is used, the more advantageous it is to the product side, but in consideration of practicality such as productivity and reaction rate, 2 to 20 equivalents are preferable.

As the catalyst used in the present invention, any known catalyst used in transesterification can be used. For example, catalysts particularly suitable for transesterification reactions such as sulfuric acid and organic sulfonic acids, as well as hydrochloric acid, nitric acid,
A strong acid such as phosphoric acid or a sulfonic acid type ion exchange resin can be used. The amount used is 0.00 per 1 equivalent of raw material
01 to 1 equivalent is preferred. Reaction temperature is 50-200
C., preferably 80 to 150.degree. Below that, the reaction is slow, and above that, adverse reactions due to side reactions occur.

As the transesterification catalyst, 2B, 4
Group A, 4B, 5B elements (the symbols A and B attached to the group are I
UPAC (International Union of Pure and Applied C
Hemistry) nomenclature committee of inorganic chemistry (1965)) oxides, hydroxides, organic compounds effectively act in the reaction of the present invention. For example, stannic oxide, dialkyltin oxide, lead monoxide, germanium oxide, germanium tetraalkoxide, antimony trioxide, zinc oxide, zinc hydroxide, zinc acetate, zinc dialkoxide, cadmium oxide, titanium tetraalkoxide. Sides are effective. Particularly preferred are tin-based and zinc-based materials. The amount used is 0.0001 to 1 with respect to 1 equivalent of the raw material.
It is an equivalent, preferably 0.001 to 0.2 equivalent. The reaction temperature is 80 to 250 ° C, preferably 100 to 200 ° C. At low temperature, the reaction rate is slow, and at high temperature, the production of by-product β-alkoxypropionic acid ester increases.

The use of the solvent is not particularly limited, but it is not preferable to use alcohol or water other than the raw materials because it will reduce the yield of the desired product.

The contents of the present invention will be more specifically described below with reference to examples, but the present invention is not limited thereto.

[0020]

【Example】

Example 1 An electromagnetic stirring type 1-liter SUS autoclave was used for 3-
Acetoxypropionic acid 200 g, methyl alcohol 5
00 g and 2 g of p-toluenesulfonic acid were charged, and after the atmosphere was replaced with nitrogen, the internal temperature was raised to 120 ° C. with stirring and kept at the same temperature for 5 hours. After cooling, the content was analyzed by gas chromatography to find that methyl β-hydroxypropionate 1
The presence of 49 g was confirmed. This amount is 9 based on the theoretical yield.
This corresponds to 4.6%.

Example 2 A magnetic stirring type 1-liter SUS autoclave was used for 3-
200 g of ethyl acryloyloxypropionate, 500 g of ethyl alcohol, and 2 g of dibutyltin oxide were charged, and after substituting with nitrogen, the internal temperature was raised to 150 ° C. with stirring and kept at the same temperature for 6 hours. After cooling, the content was analyzed by gas chromatography, whereupon the presence of 132 g of ethyl β-hydroxypropionate was confirmed. This amount corresponds to 96.2% of the theoretical yield.

Example 3 400 g of an acrylic acid oligomer (average degree of polymerization: 3.2), 950 g of methyl alcohol, and 7.0 g of zinc oxide were charged into an electromagnetic stirring type 2 liter autoclave made of SUS, and nitrogen was charged. After the replacement, the internal temperature was raised to 150 ° C. with stirring and kept at the same temperature for 6 hours. After cooling the contents, the light boiling materials were cut with an evaporator, and then the internal pressure was 7 to 11 mmH with a fractionating device.
332 g of a distillate having a distillation temperature of 60 to 69 ° C. was obtained. This fraction contained 98% by weight of methyl β-hydroxypropionate. This represents an isolated yield of 81.9% of theoretical yield.

Example 4 200 g of waste oil from an acrylic acid production plant (containing about 50% by weight of acrylic acid dimer), 500 g of methyl alcohol were added to an electromagnetic stirring type 1 liter autoclave made of SUS.
g, and 2 g of dibutyltin oxide were charged, and after substituting with nitrogen, the internal temperature was raised to 150 ° C. with stirring and kept at the same temperature for 6 hours.
After cooling, the content was analyzed by gas chromatography, whereupon the presence of 84 g of methyl β-hydroxypropionate was confirmed.

[0024]

Industrial Applicability According to the method of the present invention, β-hydroxypropionic acid ester, which has not been easy in the past, can be produced with a simple operation, high yield and high purity.

Claims (1)

[Claims] 1. A method for producing a β-hydroxypropionic acid ester, which comprises reacting β-acyloxypropionic acid or its ester, or acrylic acid oligomer or its ester with an alcohol in the presence of an ester exchange catalyst. .