JP2002234886A - Method for producing acetal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for easily and efficiently producing a high-quality acetal in a short time. SOLUTION: This method for producing an acetal comprises reaction between a polyhydric alcohol and a ketone or aldehyde in the equivalent ratio of the ketone or aldehyde to the to-be-acetalized hydroxy groups in the polyhydric alcohol of (0.5-4):2 in the presence of a solid acid catalyst without conducting a substantial dehydration, and distillation of the resultant reaction liquid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a raw material for producing emulsifiers and humectants for cosmetics, industrial emulsifiers, surfactants and food additives, and ketals of polyhydric alcohols useful as intermediates in various organic syntheses. Or, it relates to a method for producing acetal (hereinafter simply referred to as acetal).

[0002]

2. Description of the Related Art As a method for producing an acetal, a polyhydric alcohol and a ketone or an aldehyde are prepared under the conditions of dehydration using an azeotropic dehydration solvent such as petroleum ether or hexane in the presence of an acid catalyst. A method of reacting (for example, JP-A-60-87282) and a method of performing a reaction using a water catching agent (for example, US Pat. No. 3,535,888) are known. However, these methods require selection of dehydration conditions, and have a problem that the reaction for acetalization is rate-determined by dehydration, so that a long reaction time is required to obtain a high conversion.

[0003] even without dehydration by azeotropic dehydration solvent and water-capturing agent, etc., in addition to a ketone or aldehyde of large excess in order to increase the reaction rate (15 times by mole or more based on the polyhydric alcohol) reaction Is known (for example, WO9
811087). However, this method requires a large amount of ketone or aldehyde to be removed after neutralization in order to obtain an acetal, so that the productivity is poor and cannot be said to be a method suitable for industrialization.

An object of the present invention is to provide a method for efficiently and efficiently producing an acetal in a short time.

[0005]

According to the present invention, a polyhydric alcohol and a ketone or an aldehyde are added at a ratio of 0.5 to 4 equivalents of the ketone or the aldehyde to 2 equivalents of the hydroxyl group to be acetalized of the polyhydric alcohol. This is a method for producing an acetal in which a reaction is carried out in the presence of an acid catalyst without substantial dehydration, and an acetal is obtained from the reaction solution by distillation.

[0006]

DETAILED DESCRIPTION OF THE INVENTION The polyhydric alcohol used in the present invention is a compound having two or more hydroxyl groups, and is ethylene glycol, propylene glycol, butylene glycol, glycerin, erythritol, sorbitol, trimethylolpropane, pentaerythritol, arabinose, xylose. Glucose, mannose, galactose, fructose, inositol, sucrose, lactose, maltose, cellopose, dextrin, starch, cellulose, glucosazone, glucosamine, gluconic acid, tartaric acid, adenosine, ascorbic acid, uridine, auxin, monoglyceride, diglycerin, triglyceride Glycerin, monoglyceryl ether and the like can be mentioned, and glycerin is preferable.
These polyhydric alcohols may be obtained by dehydrating a water-containing product.

The ketone used in the present invention includes acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methyl-n-propyl ketone,
Methyl-n-butyl ketone, methyl-sec-butyl ketone, methyl-t-butyl ketone, methyl-n-hexyl ketone, methyl-2-furyl ketone, diethyl ketone,
Ethyl-n-propyl ketone, di-n-hexylbenzyl ketone, acetophenone, n-butyrophenone, benzoin and the like are mentioned, and aldehydes are formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde and the like. Of these ketones or aldehydes, acetone is preferred.

In the present invention, from the viewpoint of efficiently obtaining an acetal, a ketone or aldehyde is added in an amount of 0.5 to 4 with respect to 2 equivalents of the hydroxyl group to be acetalized of the polyhydric alcohol.
The reaction is performed in an equivalent amount, preferably in a ratio of 0.5 to 2 equivalents, without causing substantial dehydration.

In the present invention, not substantially performing dehydration means not only not performing dehydration but also not performing dehydration for the purpose of performing an acetalization ratio of 90% or more. Therefore, a small amount of dehydration may be performed within a range not aiming at the purpose.

Further, the polyhydric alcohol which is the raw material, ketones, aldehydes, may be used after water, because the reaction is an equilibrium reaction which produces water, it is acetalization moisture is less in the reaction In order to improve the efficiency, it is preferable to use a raw material which has been previously dehydrated and reduced in water content.

The acid catalyst used in the present invention is not particularly limited, and examples thereof include inorganic acids such as hydrochloric acid and sulfuric acid, and organic acids such as paratoluenesulfonic acid and benzenesulfonic acid.
Acid catalyst, relative to the polyhydric alcohol, preferably 0.0
It is used in an amount of from 0.01 to 50% by weight, more preferably from 0.05 to 1.0% by weight.

In the present invention, under reduced pressure or normal pressure, preferably 10 to 200 ° C., more preferably 20 to 100 ° C.
The acetalization of the polyhydric alcohol is carried out at the reaction temperature of 1 without dehydration. After completion of the reaction, the acid catalyst is neutralized, unreacted ketone or aldehyde and generated water are removed by a method such as distillation under reduced pressure, and the acetal is obtained by distillation.

Further, in the present invention, it is preferable to perform the same acetalization using the ketone or aldehyde recovered before the above-mentioned distillation and the residual liquid containing the polyhydric alcohol after the recovery of the acetal.

[0014]

Industrial Applicability According to the present invention, raw materials for producing emulsifiers and humectants for cosmetics and the like, industrial emulsifiers, surfactants and food additives, and acetal of polyhydric alcohols useful as intermediates for various organic synthesis can be shortened. It is possible to simply and efficiently synthesize in a short time.

[0015]

EXAMPLES The percentages in the examples are by weight unless otherwise specified.

Example 1 Acetone was used as a ketone and glycerin was used as a polyhydric alcohol at the ratios shown in Table 1, and 0.1% of sulfuric acid was added to the polyhydric alcohol, followed by a reaction at a temperature of 65 ° C. for 1 hour. . Then neutralize the catalyst with sodium hydroxide, was distilled off under reduced pressure and acetone, subjected to vacuum distillation at 80 to 100 ° C. at 1.33 kPa, the desired product 2,2-dimethyl-1,3
-Dioxolane-4-methanol was obtained. Table 1 shows the charge weight yield {[acetal formed g / (glycerin g + acetone g)] × 100 (wt%)}.

[0017]

[Table 1]

As is evident from Table 1, when the acetone is used in an amount of 0.5 to 4 times mol of glycerin, the charged weight yield is high.

Example 2: Synthesis of 2,2-dimethyl-1,3-dioxolan-4-methanol In a 3L four-necked flask, 920.9 g of glycerin (1
(0.0 mol), 1162.0 g (20.0 mol) of acetone and 1.04 g of sulfuric acid, and reacted at a temperature of 65 ° C. for 1 hour. Then the catalyst is neutralized with sodium hydroxide,
After acetone was distilled off under reduced pressure, with 1.33 kPa 80 to 10
Vacuum distillation was carried out at 0 ° C. to obtain 528.6 g of 2,2-dimethyl-1,3-dioxolan-4-methanol as a fraction as a fraction. Gas chromatography purity: 99.6 area%, charge weight yield: 25.4 wt%. Total synthesis time 5 hours.

Acetone distilled off under reduced pressure (containing 7% of water)
100 g was distilled in a rectification column having 10 theoretical plates and a reflux ratio of 2 to obtain 95 g of recovered acetone (containing 1% of water). 58 g of the recovered acetone (containing 1% of water) and 0.05 g of sulfuric acid were charged into 46 g of the residual liquid (mainly composed of glycerin) from the above vacuum distillation, and a reaction was carried out at a temperature of 65 ° C. for 1 hour. Next, the catalyst was neutralized with sodium hydroxide, acetone was distilled off under reduced pressure, and then vacuum distillation was performed at 1.33 kPa at 80 to 100 ° C.
As a fraction, 24.0 g of 2,2-dimethyl-1,3-dioxolan-4-methanol, which was the target substance, was obtained. Gas chromatography purity 99.2 area%.

Comparative Example 1: Synthesis of 2,2-dimethyl-1,3-dioxolan-4-methanol In a 1-L four-necked flask, 50 g (0.54 mol) of glycerin and 630.7 g (10.86 mol) of acetone were added. 3.4 g of sulfuric acid was charged and reacted for 4 hours under reflux. Next, the catalyst was neutralized with sodium hydroxide, and acetone was distilled off under reduced pressure. Thus, 71 g of 2,2-dimethyl-1,3-dioxolan-4-methanol, which was a target substance, was obtained as a fraction. Gas chromatography purity: 95area%, charge weight yield: 10.4wt%. 6 hours total synthesis time.

Claims (3)

[Claims] Claims: 1. A polyhydric alcohol and a ketone or aldehyde are converted to 2 equivalents of a hydroxyl group to be converted into a ketal or an acetal (hereinafter simply referred to as an acetal) of the polyhydric alcohol.
Using a ketone or aldehyde in a ratio of 0.5 to 4 equivalents,
A method for producing an acetal, comprising reacting in the presence of an acid catalyst without substantial dehydration to obtain an acetal by distillation from the reaction solution. 2. The method according to claim 1, wherein the ketone or aldehyde is a ketone or aldehyde recovered before distillation. 3. The method according to claim 1, wherein the polyhydric alcohol is contained in a residual liquid after the acetal is recovered.