Production of adamantanediols

Details Production of adamantanediols Production of adamantanediols

2001-09-19

2003-05-27

Shippen, Michael L. (Department: 1621)

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

Organic compounds

Oxygen containing

Reexamination Certificate

active

06570042

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process of producing adamantanediols 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.
2. Description of the Prior Art
The inventors have proposed in Japanese Patent Application Laid-Open No. 2000-219646 (U.S. Pat. No. 6,187,967) a method for producing adamantanols by the hydroxylation of adamantane compounds in a water/organic solvent two-phase system by hypochlorous acid or its salt in the presence of a ruthenium compound catalyst. In the proposed method, the hydroxylation is carried out by adding hypochlorous acid or its salt dropwise with the pH of the reaction system maintained at 0.1 to 11, and the adamantanediols are selectively produced in high yields. However, since the optimum pH for the hydroxylation largely depends on the chemical composition of the reaction system, the proposed method is still insufficient because of difficulty in controlling the hydroxylation.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method for producing adamantanediols in a high selectivity and a high yield by optimizing the conditions for the hydroxylation more accurately and easily.
The inventors have examined in more detail the production of the adamantanediols by the hydroxylation of an adamantane compound with a hypochlorite in the presence of a ruthenium compound catalyst in a water/organic solvent two-phase system. As a result thereof, the inventors have found that the adamantanediols are selectively produced in high yields by carrying out the hydroxylation with the concentration of the hypochlorite in the water phase maintained within the range of 0.001 to 2.0 mmol/g. The inventors have further found that the adamantanediols are produced more efficiently by regulating the variation of the hypochlorite concentration within 0.1 mmol/g or less. The present invention has been accomplished on the basis of these findings.
Thus, the present invention provides a method for producing an adamantanediol, which comprises a step of hydroxylating an adamantane compound in a water/organic solvent two-phase system in the presence of a ruthenium compound and a hypochlorite while regulating the concentration of the hypochlorite in the water phase within a limited range throughout the hydroxylation.
DETAILED DESCRIPTION OF THE INVENTION
The adamantane compound used in the present invention as the starting material is represented by the following formula:
wherein R or a plurality of R groups are independently alkyl group, aryl group, cycloalkyl group, alkoxyl group, aryloxy group, acyloxy group or halogen, and “n” is an integer from 0 to 14 with the proviso that at least two bridge-head carbon atoms 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, 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 may be chlorine, bromine and iodine.
The adamantanediols referred to in the present invention may include 1,3-adamantanediol, 1,2-adamantanediol, and 1,4-adamantanediol, which may be substituted by R in the above formula.
In the present invention, the adamantane compound is hydroxylated by a high-oxidation state ruthenium(VI to VIII) compound generated by the reaction between the ruthenium compound and the hypochlorite. The ruthenium compound usable in the present invention may include metallic ruthenium, ruthenium(IV) dioxide, ruthenium(VIII) tetraoxide, ruthenium(III) hydroxide, ruthenium(III) chloride, ruthenium(III) bromide, ruthenium(III) iodide, ruthenium(IV) sulfate, and hydrates of the above ruthenium compounds. The ruthenium compounds may be used alone or in combination of two or more. The ruthenium compound is used in an amount of preferably 0.001 to 2.0 mol, more 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 excessive use of the expensive ruthenium compound, each being undesirable for industrial process.
The hypochlorite may include sodium hypochlorite, lithium hypochlorite, potassium hypochlorite and calcium hypochlorite with sodium hypochlorite being preferred, which is added to the reaction system as an aqueous solution of 6 to 35% by weight. When the concentration of the hypochlorite is lower than 6% by weight, the extraction efficiency of the adamantanediols from the water phase is poor and a labor-intensive disposal of waste liquids are required because of a large amount of water phase. When higher than 35% by weight, the side reactions are likely to occur to reduce the yield of the adamantanediols.
In the method of the present invention, the hypochlorite is used in an amount of 1.5 to 4.0 mol, preferably 2.0 to 3.0 mol per one mol of the adamantane compound. When the addition amount is less than 1.5 mol, a large amount of the adamantane compound remains unreacted and a large amount of adamantanemonols is by-produced, thereby resulting in a low selectivity to the adamantanediols. When larger than 4.0 mol, a large amount of adamantanetriols is by-produced to reduce the selectivity to the adamantanediols.
In the present invention, to achieve a high selectivity to or a high yield of the adamantanediols, it is important to regulate the hypochlorite concentration in the water phase within a narrow limited range throughout the hydroxylation. Namely, the concentration of the hypochlorite in the water phase is preferably controlled within the range of 0.001 to 0.5 mmol/g, more preferably 0.001 to 0.2 mmol/g. If the concentration exceeds 0.5 mmol/g, the side reactions such as chlorination occur, thereby failing to produce the adamantanediols in good yields. If the concentration is less than 0.001 mmol/g, the hypochlorite added to the reaction system is readily decomposed to reduce the reaction efficiency. The variation of the hypochlorite concentration in the water phase is preferably regulated within 0.1 mmol/g or less.
The concentration of the hypochlorite in the water phase may be directly measured. If the direct measurement is difficult, the concentration may be indirectly controlled by measuring and controlling an indicative of the concentration of the hypochlorite, such as hydrogen ion concentration, oxidation-reduction potential, and absorbance.
For example, the concentration of the hypochlorite is controlled by the following methods.
(1) A hypochlorite solution and an acid solution are added to the reaction system in appropriate amounts for maintaining the pH within a limited range through a metering pump for hypochlorite supply and a metering pump for acid supply, each being connected to a pH controller.
(2) A hypochlorite solution is added to the reaction system in appropriate amount for maintaining the potential constant through a metering pump for hypochlorite supply which is connected to an oxidation-reduction potential controller.
(3) The hypochlorite consumption per unit time is calculated from the reaction rate measured in advance. The hypochlorite solution is added from a metering pump in an amount so as to make up for the consumed hypochlorite.
The control of the hypochlorite concentration by pH utilizes the phenomenon that the pH of the reaction system decreases with increasing consumption of the hypochlorite accompanied with the progress of the hydroxylation, and the hypochlorite is added to the reaction system when the pH becomes lower than the set value, thereby controlling the hypochlorite concentration in the water phase within a limited

Affiliated with

Also associated with

Rating

Production of adamantanediols does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Production of adamantanediols, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Production of adamantanediols will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3035615