Process of producing adamantanols

Details Process of producing adamantanols Process of producing adamantanols

2000-01-28

2001-02-13

Shippen, Michael L. (Department: 1621)

Organic compounds -- part of the class 532-570 series

Organic compounds

Oxygen containing

Reexamination Certificate

active

06187967

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process of producing adamantanols useful as raw materials for high performance polymers, synthetic lubricants and plasticizers, and as intermediates for preparing organic chemicals such as pharmaceutical compounds and agricultural compounds.
BACKGROUND OF THE INVENTION
As the method of producing adamantanepolyols, Japanese Patent Application Laid-Open No. 2-104553 discloses a method using chromic acid. Japanese Patent Application Laid-Open No. 3-118342 and Japanese Patent No. 2678784 teach methods of hydrolyzing a brominated adamantane. Japanese Patent Application Laid-Open Nos. 8-38909, 9-327626 and 10-286467 disclose oxidization of adamantane compounds by oxygen in the presence of imide compound catalyst. Japanese Patent Application Laid-Open No.9-87216 discloses a metalloporphyrin-catalyzed oxidization of adamantane compounds by air. Japanese Patent Application Laid-Open No. 5-51334 uses ruthenium catalysts and peroxy acids. J. Am. Chem. Soc., 111, 6749 (1989) discloses a method of using dioxirane derivatives. However, the major problems of the proposed methods are in the complicated reaction systems and low yields.
An object of the present invention is to provide a method of selectively producing adamantanols from adamantane compounds in high yields.
Another object of the present invention is to provide a method of selectively producing adamantanols from adamantane compounds in high yields, where the extraction of adamantanediols is easy.
Still another object of the present invention is to provide a method of selectively producing adamantanols from adamantane compounds in high yields, where ruthenium compound is efficiently recovered.
SUMMARY OF THE INVENTION
As a result of extensive studies on the above problems in the known methods, the inventors have found that adamantanols are obtained with high selectivity and in high yields by hydroxylation of adamantane compounds catalyzed by a ruthenium compound in a specific two-phase solvent system of water and an organic solvent.
The inventors have further found that the adamantanediols transfers into an organic phase to make the extraction operation easy by adding a specific alcohol to a reaction liquid after the hydroxylation of the adamantane compounds. In addition, it has been found that the ruthenium compound catalyst is easily recovered from the reaction liquid by treating the reaction liquid with alkali prior to the addition of the alcohol. The present invention has been accomplished based on these findings.
Thus, in a first aspect of the present invention, there is provided a process of producing adamantanols comprising a step of hydroxylating an adamantane compound in the presence of a ruthenium compound and hypochlorous acid or its salt.
In a second aspect of the present invention, there is provided a process of producing adamantanols in which the hydroxylation is carried out in two-phase solvent system of water and an organic solvent.
In a third aspect of the present invention, there is provided a process of producing adamantanediols comprising a step of hydroxylating an adamantane compound in a two-phase solvent system of water and an organic solvent in the presence of a ruthenium compound and hypochlorous acid or its salt to obtain a reaction liquid; and a step of adding an alcohol having 4 to 8 carbon atoms to the reaction liquid, thereby transferring adamantanediols into the organic phase.
DETAILED DESCRIPTION OF THE INVENTION
Adamantane compounds used in the present invention as the starting materials are represented by the following formula:
wherein Rn is independently alkyl group, aryl group, cycloalkyl group, alkoxyl group, aryloxy group, acyloxy group or halogen atom, and suffix “n” is an integer from 0 to 14, with the proviso that at least two bridge-head carbons are not substituted by R
n
.
In the above formula, the alkyl group may be C
1
-C
10
alkyl such as methyl, ethyl, propyl, butyl and hexyl, preferably C
1
-C
6
alkyl and more preferably C
1
-C
4
alkyl. The aryl group may be phenyl and naphthyl, and the cycloalkyl may be cyclohexyl or cyclooctyl. The alkoxyl group may be C
1
-C
10
alkoxyl such as methoxyl, ethoxyl, propoxyl, butoxyl and hexyloxy. The aryloxy group may be phenoxyl. The acyloxy group may be C
2
-C
6
acyloxy such as acetyloxy, propionyloxy and butyryloxy. The halogen atom may be chlorine, bromine and iodine.
The adamantanols referred to in the present invention may include adamantanemonol, adamantanediol, adamantanetriol and adamantanetetraol, and more specifically, 1-adamantanol, 1,3-adamantanediol, 1,2-adamantanediol, 1,4-adamantanediol, etc. The adamantanols may have substituent R
n
mentioned above.
In the present invention, the adamantane compounds are hydroxylated by a ruthenium compound of high oxidation state of VI to VIII which is generated by the reaction of a ruthenium compound and hypochlorous acid or its salt. The ruthenium compound usable in the present invention may include metallic ruthenium, ruthenium dioxide(IV), ruthenium tetraoxide(VIII), ruthenium(III) hydroxide, ruthenium(III) chloride, ruthenium(III) bromide, ruthenium(III) iodide, ruthenium(IV) sulfate, and hydrates thereof. The ruthenium compound may be used alone or in combination of two or more. The ruthenium compound is used in an amount of 0.001 to 2 mol, preferably 0.01 to 2 mol, more preferably 0.01 to 0.4 mol, and particularly preferably 0.05 to 0.4 mol per one mol of the adamantane compound. An amount less than the above range decreases the reaction rate, and an amount more than the above range results in the use of a large amount of expensive ruthenium compound, each being undesirable for industrial process.
The salt of hypochlorous acid may include sodium salt and potassium salt, and sodium hypochlorite is preferably used in view of easy availability and low cost. Hypochlorous acid and its salt are usually used in the form of aqueous solution having a concentration regulated within a range of 0.01 to 4.7 mmol/g, preferably 0.07 to 2 mmol/g. Commercially available is 12% by weight (1.6 mmol/g) aqueous solution of sodium hypochlorite. The concentration of aqueous solution of hypochlorous acid or its salt largely affects the selectivity of the adamantanediols. When the concentration is lower than the above range, the extraction efficiency of the adamantanediols is poor due to a large amount of water phase. When higher than the above range, the increase in the concentration of the adamantanediols in the organic phase accelerates side reactions to reduce the yield. If appropriate, in place of hypochlorous acid or its salt, peracetic acid, periodic acid, bromic acid and salts thereof may be used.
Hypochlorous acid or its salt is used in an amount of 0.5 to 4 mol, preferably 1 to 3 mol per one mol of the adamantane compound. When the addition amount is larger than the above range, the selectivity from the adamantane compounds to the adamantanols is extremely low, and the reaction is inefficient due to a large amount of the adamantane compounds remaining unreacted when smaller than the above range. Hypochlorous acid or its salt may be added intermittently or continuously.
The organic solvent usable in the present invention may be selected from solvents which are less compatible with water, capable of well dissolving the ruthenium compound with high oxidation state and inert to the reaction of the present invention. If highly compatible with water, the recovery of the solvent becomes costly, and the reaction hardly proceeds if the organic solvent is poor in dissolving the ruthenium compound with high oxidation state. Examples of the organic solvent are alkyl halides such as dichloromethane, 1,2-dichloroethane, chloroform, carbon tetrachloride, 1,1,2-trichloroethane, 1,4-dichlorobutane, and 1,6-dichlorohexane; esters such as methyl acetate, ethyl acetate such as isopropyl acetate; aryl halides such as hexachlorobenzene and 1,1,1-trifluorotoluene; and hydrocarbons such as hexane, heptane and octane. Of the above organic solvents, 1,2-dichloroethane an

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