Process for producing adamantanols

Details Process for producing adamantanols Process for producing adamantanols

2000-07-14

2001-12-25

Shippen, Michael L. (Department: 1621)

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

Organic compounds

Oxygen containing

Reexamination Certificate

active

06333438

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates to a process for producing adamantanols useful as raw materials for high performance polymers, synthetic lubricants and plasticizers, and as intermediates for preparing organic chemicals of pharmaceutical and agricultural use.
BACKGROUND OF THE INVENTION
As the method of producing adamantanepolyols, proposed are a method using chromic acid (Japanese Patent Application Laid-Open No. 2-104553), hydrolysis of a brominated adamantane (Japanese Patent Application Laid-Open No. 3-118342 and Japanese Patent No. 26787849), air-oxidation of adamantane compounds in the presence of imide compound catalyst (Japanese Patent Application Laid-Open Nos. 8-38909, 9-327626 and 10-286467), metalloporphyrin-catalyzed oxidization of adamantane compounds by air (Japanese Patent Application Laid-Open No. 9-87216), a method of using ruthenium catalysts and peroxy acids (Japanese Patent Application Laid-Open No. 5-51334), a method of using dioxirane derivatives (J. Am. Chem. Soc., 111, 6749 (1989)), etc. However, the major problems of the proposed methods are in the complicated reaction systems and low yields.
In U.S. patent application Ser. No. 09/493,207 (European Patent Application No. 00100253.4), the inventors have proposed a process for producing adamantanols in high yields by hydroxylation of adamantane compounds in a water/organic two-phase system in the presence of a ruthenium compound and a salt of hypochlorous acid. The ruthenium used in the process is a very expensive transition metal. Therefore, loss of the ruthenium compound must be minimized in the production of adamantanols and it is quite important for the industrial application of the process to ensure the recovery and reuse of the ruthenium compound.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a process for efficiently separating and recovering a ruthenium compound used as the catalyst in the process for producing adamantanols by hydroxylation of adamantane compounds in a water/organic two-phase system in the presence of a ruthenium compound and a salt of hypochlorous acid.
As a result of extensive study on the process for producing adamantanols by hydroxylation of adamantane compounds in a water/organic two-phase system in the presence of a ruthenium compound and a salt of hypochlorous acid, the inventors have found that the ruthenium compound is extracted into the organic phase by adding an oxidizing agent to the hydroxylation product liquid. It has been further found that the ruthenium compound is back-extracted into an aqueous phase by adding an aqueous alkali solution to the organic phase containing the extracted ruthenium compound. The present invention has been completed based on these findings.
Thus, in a first aspect of the present invention, there is provided a process for producing adamantanols, comprising the steps of (1) hydroxylating an adamantane compound in a water/organic two-phase system in the presence of a ruthenium compound and a salt of hypochlorous acid, thereby obtaining a hydroxylation product liquid; (2) mixing the hydroxylation product liquid with an oxidizing agent, thereby obtaining an extraction mixture; and (3) permitting the extraction mixture to separate into an organic phase and an aqueous phase, thereby extracting the ruthenium compound into the organic phase.
In a second aspect of the present invention, there is provided a process for producing adamantanols, in which the process mentioned above is followed by a step of mixing the organic phase containing the extracted ruthenium compound with an aqueous alkali solution, thereby back-extracting the ruthenium compound into an aqueous phase; and a step of recovering the ruthenium compound from the aqueous phase.
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the starting adamantane compounds are represented by the following formula:
wherein R is independently alkyl group, aryl group, cycloalkyl group, alkoxy 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.
In the above formula, the alkyl group may be C
1
-C
10
alkyl such as methyl, ethyl, propyl, butyl and hexyl. The aryl group may be phenyl and naphthyl, and the cycloalkyl may be cyclohexyl or cyclooctyl. The alkoxy group may be C
1
-C
10
alkoxy such as methoxy, ethoxy, propoxy, butoxy and hexyloxy. The aryloxy group may be phenoxy. 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 a substituent as mentioned in the definition of R.
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 a salt of hypochlorous acid. The ruthenium compound usable in the present invention may include metallic ruthenium, ruthenium oxides such as ruthenium dioxide (IV) and ruthenium tetraoxide (VIII); ruthenates such as sodium ruthenate (VI); ruthenium (III) hydroxide; ruthenium halides such as ruthenium (III) chloride, ruthenium (III) bromide and ruthenium (III) iodide; ruthenium (IV) sulfate; ruthenium (III) nitrate; ruthenium carboxylates such as ruthenium (III) acetate; and ruthenium complexes such as ammonium hexachlororuthenate (III), potassium hexachlororuthenate (III), ammonium pentachloroaquaruthenate (III), potassium pentachloroaquaruthenate (III), potassium pentachloronitrosylruthenate (III), hexaammineruthenium (III) chloride, hexaammineruthenium (III) bromide, hexaammineruthenium (III) iodide, nitrosylpentaammineruthenium (III) chloride, hydroxonitrosyltetraammineruthenium (III) nitrate, ruthenium (IV) ethylenediaminetetraacetate and ruthenium (0) dodecacarbonyl. The above ruthenium compounds may be anhydrous or hydrated. The ruthenium compound may be used alone or in combination of two or more. The ruthenium compound is used in an amount of 0.01 to 2.00 mol, preferably 0.05 to 0.40 mol per one mol of the starting adamantane compound.
Sodium hypochlorite is preferably used in the present invention as the salt of hypochlorous acid. Sodium hypochlorite is usually used as aqueous solution in a concentration of 0.01 to 2.00 mmol/g, preferably 0.07 to 1.00 mmol/g, and added 0.5 to 4.0 mol, preferably 1.0 to 3.0 per one mol of the starting adamantane compound.
The organic solvent usable in the present invention may be selected from good solvents for the ruthenium compound of high oxidation state, which are less compatible with water and inert to hydroxylation of the adamantane compounds. 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 of 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 and isopropyl acetate; aryl halides such as hexachlorobenzene and 1,1,1-trifluorotoluene; and hydrocarbons such as hexane, heptane and octane. The above organic solvent may be used alone or in combination of two or more. The amount of the solvent to be used is 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight per one part by weight of the starting adamantane compound.
The hydroxylation of the adamantane compound is carried out at 10 to 80° C., preferably 40 to 70° C. in a water/organic two-phase system. The weight ratio of water and the organic solvent in the two-phase system is preferably 1:2 to 1:20.
In the present invention, an oxidizing agent is added to the hydro

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