Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2002-05-30
2002-11-19
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
Reexamination Certificate
active
06482995
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for producing an alicyclic unsaturated alcohol and a high purity tetrahydrobenzyl alcohol. Specifically, the present invention relates to a process for producing an alicyclic unsaturated alcohol used for a great variety of industrial applications, for example, as raw chemicals for synthesizing drugs; agricultural chemicals, perfumes, dyes, etc. more specifically, the present invention relates to a process for producing, with high selectivity, an appropriate alicyclic unsaturated alcohol such as tetrahydrobenzyl alcohol useful as an intermediate raw material for epoxy resins, and the like, and a high purity tetrahydrobenzyl alcohol having a low acid value and a low water content.
2. Description of the Related Art
As a process for producing an alicyclic unsaturated alcohol such as tetrahydrobenzyl alcohol by hydrogenating an unsaturated cyclic aldehyde such as tetrahydrobenzaldehyde, that is, a process for obtaining an alicyclic unsaturated alcohol by selectively reducing a carbonyl moiety in the unsaturated cyclic aldehyde, conventionally, the process for obtaining a corresponding unsaturated alcohol using a reducing reagent, for example, by reducing using lithium aluminum hydride (A. Guiotto. et al., Farmaco. Ed. Sci. 72 (12), 1045-52 (1972)), or by reducing using sodium borohydride (Neth. Appl. 790242 (Sep. 18, 1979)) is known.
The method using LiAlH
4
, NaBH
4
, or the like as a reducing reagent is one which is capable of producing, with high-selectivity, the alicyclic unsaturated alcohol, for example, in which the conversion is 98 mol % or more, the selectivity of the desired alicyclic unsaturated alcohol is 97 to 98 mol %, the by-produced alicyclic saturated alcohol is 2 to 3 mol %, and a little saturated cyclic aldehyde is produced. However, the method is very disadvantageous for the industrial applications, since the reducing reagent used is very expensive and a large quantity of the reducing reagent must be used. Also, a large quantity of waste water is generated, because the method requires a large quantity of water for the reaction. Thus, there has been the problem of requiring very high cost for disposing of waste water. Moreover, the method has had the disadvantage in that it is difficult to apply the method to the industrial application because of its economic inferiority. Therefore, the method of synthesizing the alicyclic unsaturated alcohol without using such reducing reagents is sought.
Furthermore, the method of performing a hydrogen migration reaction using tetrahydrobenzaldehyde and alcohols as well as a catalyst is known (JP 63-275538 A).
Although the above-mentioned method can achieve the high selectivity, there is a problem in that the method requires aluminum alcoholate and alcohols of more than equimolar amount of the main raw material and also an equimolar amount of ketones is by-produced.
Therefore, the various methods of hydrogenating using a catalyst have been investigated as the method of synthesizing the alicyclic unsaturated alcohol without using the reducing reagents. For example, the method of hydrogenating using a copper-chromite catalyst, for example, the reaction using a copper-chromite as a catalyst under compression of hydrogen gas (Neth. Appl. 6, 603, 211 (Sep. 13, 1966)) and the reaction using a copper-chromite as a catalyst as well as cyclohexane, tetrahydrofuran as a solvent under compression of hydrogen gas (Ger. 1, 101, 409 (Mar. 9, 1961), J. Falbe. et. al., Chem. Ber. 98 (6), 1928-37 (1965)), and the method of hydrogenating using catalysts carried by Co, Rh-Sn, Ru-Sn, or the like on alumina, silica, zeolite, or the like under compression of hydrogen gas, for example, “The synthesis of crotyl alcohol by selectively hydrogenating crotonaldehyde using an alumina-carried bimetallic catalyst” (Nippon kagaku kaishi (Japanese), 1994 (5), 487-489: SAITAMA UNIVERSITY), and “The selective vapor phase hydrogenation of crotonaldehyde on an Ru-Sn-carried catalyst” (the 76th Catalyst Society of Japan Meetings, 3E15,228 (1995): KOBE UNIVERSITY), are known.
However, the methods using those catalysts are still insufficient for selectivity of the desired unsaturated alcohol, and there is a problem in that the saturated cyclic aldehyde and alicyclic saturated alcohol, which are by-products, are produced in an amount of more than that of the desired product.
As the method of improving the above-mentioned method, the reaction using an alumina-carried cobalt catalyst under compression of hydrogen gas is known (JP 10-236995 A). In the method, the catalyst obtained by adding to the above-mentioned alumina-carried cobalt catalyst containing the second metals (Pt, Ru, Fe, Cu, Rh, etc.) is used to hydrogenate an unsaturated aldehyde using a polar solvent such as an alcohol, and then, the carbonyl moiety in the unsaturated aldehyde having a double bond in the molecule is selectively hydrogenated to selectively produce a corresponding unsaturated alcohol.
However, the hydrogenation according to the above-mentioned method indispensably requires the presence of the polar solvent, and has poor productivity and is not sufficient for the industrial application.
When tetrahydrobenzyl alcohol as the alicyclic unsaturated alcohol is used as an example, impurities at the time of production of the alcohol include tetrahydrobenzaldehyde (3-cyclohexenecarboaldehyde) which is a raw material, and hexahydrobenzyl alcohol, cycrohexanecarboaldehyde, and the like, which are by-products. In general, those impurities are industrially separated by rectification.
The boiling points of the impurities contained in the desired unsaturated alcohol (3-cyclohexenemethanol; boiling point: 183° C.) are 163° C. (for 3-cyclohexenecarboaldehyde), 161° C. (for cyclohexanecarboaldehyde), and 181° C. (for cyclohexanemethanol).
The boiling point of the unsaturated cyclic aldehyde as the raw material which is one of the impurities, is relatively low compared to the alicyclic unsaturated alcohol, and they have the difference of boiling points of from 20 to 30° C. Thus, they can be separated by rectification. However, the boiling point of the alicyclic saturated alcohol which is another by-product, is almost equal to that of the alicyclic unsaturated alcohol. As a result, the industrial-scale separation is substantially impossible, and thus, the by-products, which are difficult to separate, are provided with being contained in the article.
However, when the above-mentioned unsaturated alcohol is used as a perfume, the regulation on the concentration of the saturated alcohol which is an impurity is very strict, and it is pointed out that even the product having the overspeck of 0.1 mol % can not be the article.
Moreover, the alicyclic unsaturated alcohol such as tetrahydrobenzyl alcohol may be used as raw materials for polymers by being subjected to the modification described in the following a) to d), for example.
a) esterifying a hydroxyl group in the alicyclic unsaturated alcohol with an ethylenically unsaturated acid such as acrylic acid and/or methacrylic acid;
b) esterifying a hydroxyl group in the alicyclic unsaturated alcohol with an ethylenically unsaturated acid such as acrylic acid and/or methacrylic acid, and epoxidizing the double bond;
c) converting the double bond in the alicyclic unsaturated alcohol to a hydroxyl group, and esterifying the produced hydroxyl group with the above-mentioned ethylenically unsaturated acid, or the like to form diester or triester; or
d) epoxidizing the double bond in the alicyclic unsaturated alcohol, and further converting the hydroxyl group to glycidyl group.
In the above-mentioned case, the low purity due to the remaining alicyclic saturated alcohol as well as saturated and unsaturated aldehyde, and the like causes those impurities to remain as the unreacted components in polymerization, and thus it is not preferable.
Furthermore, much water content inhibits the reaction when the double bond is epoxidized, which is very not preferable.
Moreover, the free car
Fujitani Kango
Kihara Yoshihiro
Okumura Koichi
Tanigawa Hiroto
Uenoya Masaya
Daicel Chemical Industries Ltd
Morgan & Finnegan , LLP
Shippen Michael L.
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