JPS6058210B2 - Purification method of β-phenylethyl alcohol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for purifying β-phenylethyl alcohol, and more specifically to a method for purifying β-phenylethyl alcohol with high purity and excellent aroma for use in perfumery.
This invention relates to a purification method for obtaining phenylethyl alcohol.

β-Phenylethyl alcohol is a valuable substance that is widely used as a rose fragrance in detergents, cosmetics, etc. When it is used, products of high purity and excellent aroma are required. In general, the product value of perfume ingredients is significantly reduced if even a small amount of impurities that affect the original aroma are present, so special attention is paid to the purification method. The purification methods of β-phenylethyl alcohol that have been reported so far include a method of purifying β-phenylethyl alcohol by deriving it into boric acid or an organic acid ester, a method of purifying it by adsorbing impurities on silica gel, and a method of purifying β-phenylethyl alcohol by adsorbing impurities on silica gel. There is a method of purification using a rectification column with a number of plates. However, each of these methods has drawbacks and problems as an industrial method. That is, the esterification method requires an esterification step of β-phenylethyl alcohol and a hydrolysis step to liberate β-phenylethyl alcohol from the ester, and is economically disadvantageous because the acid must be recycled. . The method of adsorbing impurities has a small purification effect, and there is also a problem in that the silica gel must be regenerated before use. In the distillation method, even if a rectification column with a high number of plates is used, it is difficult to obtain β-phenylethyl alcohol of satisfactory quality if components with similar boiling points or azeotropic components are present. Therefore, the inventors of the present invention can
The present invention was developed as a result of extensive research into a method for selectively and efficiently separating and obtaining β-phenylethyl alcohol.

That is, the purpose of the present invention is to selectively separate and remove off-flavor components from crude β-phenylethyl alcohol, and to efficiently produce excellent quality β-phenylethyl by simple operations without requiring complicated equipment or operations. The goal is to separate and obtain alcohol. According to the invention, this object is then achieved by subjecting the crude β-phenylethyl alcohol to azeotropic distillation using a specific solvent as the selective solvent. That is, it is achieved by azeotropically distilling crude β-phenylethyl alcohol using a dihydric alcohol or a monoether of a dihydric alcohol as a selective solvent. The azeotropic distillation herein refers to a distillation method in which the added solvent is extracted as a distillate along with impurities. In the present invention, dihydric alcohols or monoethers of dihydric alcohols that can be used as azeotropic solvents include, for example, 1,2-ethanediol, 1●2-propanediol, 1●3-propanediol, 1●3 -butanediol, 2●3-butanediol, 2-hydroxyethyl methyl ether, 2-hydroxyethyl ethyl ether, 2-hydroxyethylpropyl ether, 2-hydroxyethyl isopropyl ether, 2-hydroxyethyl butyl ether, 2-hydroxyethyl isobutyl Ether, 1●2-propanediol-1-methyl ether, 1●2-propanediol-2-ethyl ether, 1●2-propanediol-1-ethyl ether,
1◆3-propanediol monomethyl ether, 1●3
Examples include -propanediol monoethyl ether, 1●3-butanediol-1-methyl ether, and 2●3-butanediol monoethyl ether.

These solvents may be used alone or in a mixture of two or more. The dihydric alcohol or monoether of the dihydric alcohol used in the azeotropic operation of the present invention is β-
It has particularly good selectivity for separating phenylethyl alcohol, and the present invention can be used to perform the operation of the present invention even with off-flavor components that could not be separated by simple rectification, even using a rectification column with a high number of plates. It becomes separable.

Next, the present invention will be specifically explained.

As the azeotropic distillation apparatus, for example, the one shown in FIG. 1 can be preferably used.

To explain based on FIG. 1, crude β-phenylethyl alcohol is transferred to the azeotropic distillation column 3 of the azeotropic distillation apparatus.
It is supplied through the supply pipe 1 provided in the middle of the tube.

On the other hand, a dihydric alcohol or a monoether of a dihydric alcohol as a solvent is supplied from a supply pipe 2 provided below the supply pipe 1 . All of these are continuously supplied. Azeotropic distillation is performed in the distillation column 3, and the distillation tube 4 at the top of the column
Azeotropic solvents with higher volatility and impurities with off-odor are distilled out. β-phenylethyl alcohol is taken out from the bottom of the distillation column 3 through a withdrawal pipe 5. The purified β-phenylethyl alcohol is then supplied to the middle stage of the rectification column 6 and taken out from the distillation pipe 7 at the top of the column. Azeotropic distillation column 3 and rectification column 6
There are no particular restrictions on the operating conditions, and normal distillation conditions may be employed. For example, it is carried out under reduced pressure at a temperature of 50 to 200°C. - The reflux ratio is also carried out in the range of 0.1 to 50. The supply position of crude β-phenylethyl alcohol and dihydric alcohol or monoether of dihydric alcohol in the azeotropic distillation column 3 and the supply position of β-phenylethyl alcohol in the rectification column 6 are arbitrarily adjusted as necessary. .
The azeotropic solvent can also be mixed with crude β-phenylethyl alcohol and supplied to the distillation apparatus through the supply pipe 1. In the above explanation, a continuous treatment method for crude β-phenylethyl alcohol was exemplified, but the present invention can also be effectively applied to a batch treatment method.

Note that the purification method according to the present invention may be applied alone, but
It can also be applied in combination with other purification methods if necessary.

Other purification methods include esterification method, silica gel adsorption method,
Examples include rectification methods, acid treatment methods, and alkali treatment methods.
The crude β-phenylethyl alcohol used in the present invention may be produced by any production method, and the production method is not particularly limited.

For example, it may be produced by hydrogen reduction of styrene oxide, reaction of benzene and ethylene oxide, hydrogen reduction of phenylacetic acid, or oxidation reaction of aromatic hydrocarbon compounds. The β-phenylethyl alcohol obtained by the method of the present invention has no unpleasant odor and is of sufficiently satisfactory quality for perfume use.

Next, the present invention will be explained with reference to Examples and Comparative Examples. Example 1 Azeotropic distillation was carried out in the manner described in FIG.

The azeotropic distillation column 3 was a 3-size column, and the rectification column 6 was a 1-size column, and both were operated under reduced pressure. A mixture of crude β-phenylethyl alcohol and 1●2-propanediol (weight ratio 1:2) was continuously fed at a rate of 300 parts per hour. At this time, off-flavor components were distilled out together with 1,2-propanediol through the distillation pipe 4 at the top of the column at a rate of 208 parts per hour.
When β-phenylethyl alcohol taken out through the extraction pipe 5 at the bottom of the column was fed to the eighth stage from the top of the rectification column 6, purified β-phenylethyl alcohol was passed through the distillation pipe 7 at the top of the column per hour. It was distilled at the same speed. The purified β-phenylethyl alcohol obtained here had no unpleasant odor and was of a quality suitable for perfume use (purity 99.7%). Comparative Example 1 Distillation was carried out using the same apparatus as in Example 1.

Crude β-phenylethyl alcohol containing 2.5 wt% of impurities and having an off-odor was continuously fed into the distillation column 3 from the feed pipe 1 at a rate of 1 (1) part per hour to the second forge counted from the top of the column. , the distillate is taken off at a rate of 8 parts per hour through distillation tube 4 at the top of the column. On the other hand, when the liquid taken out through the extraction pipe 5 at the bottom of the tower was supplied to the eighth stage from the top of the rectification tower 6, β-phenylethyl alcohol was passed through the distillation pipe 7 at the top of the tower at a rate of 9? Distilled out. β− obtained here
The phenylethyl alcohol still had a strange odor and was not of a quality suitable for perfume use. Examples 2 and 3 The same procedure as in Example 1 was carried out using the same equipment and conditions, but with a different azeotropic solvent, and β-phenylethyl alcohol, which had no off-odor and was suitable for perfumes, was obtained.

The results are shown in Table 1.

[Brief explanation of the drawing]

FIG. 1 is an azeotropic distillation apparatus used in the practice of the present invention. 1: Raw material supply pipe, 2: Solvent supply pipe, 3: Azeotropic distillation column, 4
: distillation pipe, 5: extraction pipe, 6: rectification column, 7: distillation pipe.

Claims (1)

[Claims] 1 In purifying crude β-phenylethyl alcohol, 1,2-ethanediol, 1,2-propanediol, 1,3-propanediol, 1,2-ethanediol monomethyl ether, 1,2-ethanediol monoethyl One or more compounds selected from ether, 1,2-propanediol monomethyl ether, 1,2-propanediol monoethyl ether, 1,3-propanediol monomethyl ether, or 1,3-propanediol monoethyl ether A method for purifying β-phenylethyl alcohol, which comprises subjecting it to azeotropic distillation using as a selective solvent.