JPS5865245A - Preparation of glycol monoester - Google Patents

Abstract

PURPOSE:To improve the selectivity and yield advantageously without requiring expensive corrosion-resistant materials in obtaining the titled compound from an aldehyde as a raw material, by carrying out the reactiok in the presence of an alkaline earth metallic oxide. CONSTITUTION:An aldehyde of formulaI(R1 and R2 are the same or different 1-5C alkyl) is catalytically reacted in the presence of an alkaline earth metallic oxide, e.g. barium oxide or magnesium oxide, at 50-150 deg.C for 0.5-4hr to give a compound of formula II. The amount of the alkaline earth metallic oxide is preferably in the range of 0.5-10wt%, and isobutyraldehyde, 2-methylbutyraldehyde, etc. may be cited as the aldehyde. Preferably, the moisture content in the aldehyde is 5wt% or less, and the acid content in the therein is 2wt% or less.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved process for the production of glycol monoesters. More specifically, in the presence of an alkaline earth metal oxide, the present invention provides a compound having the general formula (r) (wherein R8 and R8 are the same or different and have a carbon number of 1-
5 represents an alkyl group. ) The present invention relates to a method for producing a glycol monoester represented by the general formula (It) OHR* (wherein R1 and R2 have the same meanings as above) from an aldehyde represented by the formula (It).

BACKGROUND ART Conventionally, Maki's method is known as a method for producing glycol monoester from an aldehyde using a catalyst. For example, methods using alkali or alkaline earth hydroxide catalysts (USF, 3291821, USF, 3718689
．． JP-A-54-59215, etc.), a method using an alkali or alkaline earth hydroxide catalyst in the coexistence of alcohol or acid (Japanese Patent Publication No. 52-15581, JP-B-Sho 52)
-15582, JP-A-54-148716, etc.), Alcolade system, method using a catalyst (Japanese Patent Publication No. 1987-148716, etc.)
-22857 Publication, Japanese Patent Publication No. 52-155809, Japanese Patent Publication No. 52-15581, Japanese Patent Publication No. 47-376
No. 09, etc.) are known.

However, when an alkali or alkaline earth hydroxide catalyst is used when producing a glycol monoester from an aldehyde, the reaction rate is generally low. Further, when an alkali or alkaline earth hydroxide catalyst is used in the coexistence of alcohol or acid, the following problems occur.

That is, when adding alcohol, it is necessary to separate unreacted aldehyde after the reaction and then separate and recover the alcohol by distillation or steam distillation. When an acid is used, after one reaction, the salt must be separated by neutralization with an alkali, washing with water, or distillation, and depending on the acid concentration and temperature, expensive corrosion-resistant materials are required.

Furthermore, when an alcoholade catalyst is used, there is a drawback that the reaction rate decreases if an aldehyde containing a large amount of water is used as a raw material.

The present inventors conducted various studies on methods for producing glycol monoester from aldehydes in high yield and high selectivity.
The present invention was completed by discovering that the glycol monoester represented by the general formula (II) can be produced from the aldehyde represented by 1) in high yield and high selectivity.

The present invention will be explained in detail below.

Examples of the aldehyde represented by the general formula (1) include isobutyraldehyde, 2-methylbutyraldehyde, 2-ethylbutyraldehyde, 2-methylpentanal, and 2-ethylpentanal.

As for the aldehyde, the lower the acid and water content in the aldehyde, the more preferable the aldehyde is.
Any aldehyde having a weight of less than - can be used as the raw material aldehyde of the present invention.

Barium oxide, magnesium oxide, etc. are used as the alkaline earth metal oxide.

The amount of alkaline earth metal oxide is preferably in the range of 0.5-10% by weight relative to the aldehyde. The catalytic reaction is carried out at 50-150°C for 0.5-4 hours. After the reaction, to obtain the target product from the reaction solution, filter the reaction solution! After first separating the catalyst, the target product can be separated and purified by distilling the F liquid using a conventional distillation method.

Examples of the present invention are shown below.

Example 1゜ 100 # of anhydrous isobutyraldehyde (isobutyraldehyde: 99.85% by weight, water: 0.03% by weight, isobutyric acid: 0.12% by weight) was placed in a reactor, and barium oxide (BaO) was added as a catalyst. (manufactured by Wako Junkei Co., Ltd.) was added in an amount of 1% by weight based on the aldehyde, and the mixture was reacted at 85° C. for 2 to 5 hours with stirring.

After the reaction, the reaction solution was cooled to room temperature, and then p was removed from the reaction solution.
After separating the peroxide catalyst, the F solution was analyzed by gas chromatography (5).The results are as follows.

Reaction rate of isobutyraldehyde: s2.3%2, 2.4
- ) Selectivity to dimethyl-1,3-bentanediol monoimbutyrate: 94.9% Example 2 In a reactor, hydrated isobutyraldehyde (794.48% by weight of isobutyraldehyde, water: 2% by weight, isobutyric acid :
Add 100g of 1.522% by weight, and use Ba, O as a catalyst.
(Wako Tsumugi Yaku M) was added in an amount of 3% by weight based on the aldehyde, and the mixture was reacted at 120° C. for 1.5 hours with stirring. Example 1 below
In the same way, we obtained the following results.

Reaction rate of isobutyraldehyde: 80% 2.2.4-)
Selectivity to samethyl-1,3-bentanediol monoisobutyrate: 90.0% (6)

Claims (1)

[Claims] In the presence of an alkaline earth metal oxide,
5 represents an alkyl group. ) from the aldehyde represented by the general formula (If) OHR. A method for producing a glycol monoester represented by the formula (wherein R1 and R2 have the same meanings as above).