Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-04-05
2001-03-27
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06207867
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for purifying &bgr;-phenylethyl alcohol. More particularly, the present invention relates to a method for purifying &bgr;-phenylethyl alcohol having a characteristic that nasty smell components can be selectively separated and removed from crude phenylethyl alcohol efficiently by only a simple operation without requiring complicated apparatuses and operations, to obtain high purity &bgr;-phenylethyl alcohol having excellent fragrance for an aromatic and the solvent used in the process can be re-used economically.
BACKGROUND OF THE INVENTION
&bgr;-Phenylethyl alcohol is a valuable substance widely used in detergents, cosmetics and the like as a rose type aromatic, and in use thereof, products having high purity and excellent fragrance are required. In general, aromatic components degrade in commercial value even if a small amount of impurities influencing the original fragrance is present, therefore, the purification method thereof are particularly noticed. As the purification method of &bgr;-phenylethyl alcohol, there are a method in which &bgr;-phenylethyl alcohol is derived to a borate or organic acid ester for purification, a method in which impurities are adsorbed on silica gel for purification, a method of purification using higher stages purification column, as well as other methods. However, these methods have respective defects and have problems as industrial methods. Namely, the esterification method has economical disadvantages that a process for esterifying &bgr;-phenylethyl alcohol and a hydrolysis process for liberating &bgr;-phenylethyl alcohol from the ester are required, and further, an acid should be recycled, and the like. The method for adsorbing impurities has problems in that purification effect is low, and further, silica gel is recycled. In the distillation method, even if a fractionating column having higher stages is used, when components having near boiling points or azeotropic components are present, &bgr;-phenylethyl alcohol having satisfactory quality can not be obtained easily.
SUMMARY OF THE INVENTION
The present inventors have intensively studied a purification method having no problems as described above, and resultantly found that nasty smell components can be selectively separated and removed from crude &bgr;-phenylethyl alcohol efficiently by only a simple operation without requiring complicated apparatuses and operations, to obtain high purity &bgr;-phenylethyl alcohol having excellent fragrance for an aromatic, by purifying and distilling the crude &bgr;-phenylethyl alcohol with a solvent, and that the extraction solvent used for extracting the crude phenylethyl alcohol can be recycled by extracting the solvent with other solvent, and have completed the present invention.
Namely, the present invention relates to a method for purifying &bgr;-phenylethyl alcohol, comprising
an extractive distillation process in which crude &bgr;-phenylethyl alcohol is extractive-distilled using an extraction solvent (A), and
an extracting process in which the extraction solvent (A) after use in the extractive distillation process is extracted using other extraction solvent (B).
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As the crude &bgr;-phenylethyl alcohol which is a raw material in the present invention, those obtained by, for example, hydrogen reduction of styrene oxide, reaction of benzene with ethylene oxide, hydrogen reduction of phenylacetic acid, and oxidation reaction of an aromatic hydrocarbon compound, and the like, can be used.
Further, crude &bgr;-phenylethyl alcohol which has been washed with an alkali can also be used. As the alkaline aqueous solution, ammonia water and sodium hydroxide water are preferable, and a sodium hydroxide aqueous solution is more preferable from the standpoint of easy handling. The concentration of the alkaline aqueous solution is usually from about 1 to 50% by weight. For the washing with an alkali, it may be advantageous that crude &bgr;-phenylethyl alcohol and an alkaline aqueous solution are mixed, and then, they are separated into oil and water. The temperature in the washing is usually from room temperature (about 20° C.) to 100° C., and the amount of the alkaline aqueous solution used is preferably from 5 to 50 parts by weight based on 100 parts by weight of the crude &bgr;-phenylethyl alcohol.
The extractive distillation process in the present invention is a process in which crude -phenylethyl alcohol is extractive-distilled using an extraction solvent (A). As the extraction solvent (A), at least one solvent system selected from the group consisting of the following (I), (II) and (III) is preferable from the standpoint of removal efficiency of odor components.
(I) water.
(II) a mixture of water with 1,2-ethane diol, 1,2-propane diol or 1,3-propane diol.
(III) a mixture of water with 1,2-ethane diol monomethyl ether, 1,2-ethane diol monoethyl ether, 1,2-propane diol monomethyl ether, 1,2-propane diol monoethyl ether, 1,3-propane diol monomethyl ether or 1,3-propane diol monoethyl ether.
When the solvent system is a mixture of two or more solvents, it is preferable that the weight ratio of water to divalent alcohol or divalent alcohol monoalkyl ether is from 1:9 to 7:3. As the extractive distillation method, there is for example a method in which a raw material crude &bgr;-phenylethyl alcohol is extractive-distilled by using a mixture of extraction solvents (A), water and divalent alcohol or divalent alcohol monoalkyl ether, to distilled off extraction solvents (A) having higher volatility and impurities having nasty odor from the column top, and to extract &bgr;-phenylethyl alcohol from the column bottom. As the extractive distillation conditions, usual distillation conditions are adopted, for example, it is conducted under reduced pressure, at a temperature from 50 to 200° C. and at a refluxing ratio of 0.1 to 50. The positions for feeding crude &bgr;-phenylethyl alcohol and extracting solvent on the extractive distillation column can be controlled at will if necessary.
The extracting process in the present invention is a process in which the extraction solvent (A) after use in the extractive distillation process is extracted using other extraction solvent (B) for purification. Namely, by extracting an extraction solvent (A) containing impurities having nasty odor distilled from the extractive distillation apparatus, by using an extraction solvent (B), the extraction solvent (B) containing the impurities having nasty odor is distilled off from the column top and on the other hand, the purified extraction solvent (A) is recovered from the column bottom. As the extraction solvent (B), hydrocarbon oils are preferable, among them, aromatic oils are preferable, further among other, aromatic hydrocarbon oils containing benzene, toluene and/or xylene are preferable, from the stand points of easy availability and efficiency for removing the impurities having nasty odor.
It is preferable to recycle the extraction solvent (A) after purification in the extracting process into the extractive distillation process, for re-use, from the standpoints of economical use of solvents, reduction in post-treatment cost after the used solvents. On the other hand, the extraction solvent (B) containing impurities having nasty odor can be purified easily, for example, known operations such as usual distillation in an aromatic plant.
The &bgr;-phenylethyl alcohol after the extractive distillation process can be made into the final product, &bgr;-phenylethyl alcohol by, for example, performing post-treatment such as distillation and the like.
According to the present invention, it is possible to provide a method for purifying &bgr;-phenylethyl alcohol in which nasty smell components can be selectively separated and removed from crude &bgr;-phenylethyl alcohol efficiently by only a simple operation without requiring complicated apparatuses and operations, to obtain high purity &bgr;-phenylethyl alcohol having excellent fragrance for an aromatic and the extraction sol
Kamaya Kazuhiko
Onodera Yoshimitsu
Birch & Stewart Kolasch & Birch, LLP
Shippen Michael L.
Sumitomo Chemical Company Limited
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