Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-01-12
2003-01-14
Keys, Rosalynd (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S047000
Reexamination Certificate
active
06506943
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a process for producing an aldehyde. Specifically, the present invention relates to a process for producing a corresponding aldehyde by oxidative cleavage of a 1,2-diol (vic-diol).
BACKGROUND ART
Processes using periodic acid or lead tetraacetate are known as processes for forming a corresponding aldehyde by oxidative cleavage of a 1,2-diol. However, the process using periodic acid can be applied only to a narrow range, as the oxidizing agent is insoluble in an organic solvent. In addition, the above processes require large amounts of compounds containing iodine or lead, and require a complicated aftertreatrment and are not desirable from viewpoints of resources and environmental issues.
On the other hand, catalytic oxidation processes using oxygen as an oxidizing agent are employed as processes for oxidizing substrates without using large amounts of halogen compounds or metallic compounds. However, there are few processes for efficiently obtaining a corresponding aldehyde by oxidative cleavage of a 1,2-diol with oxygen.
DISCLOSURE OF INVENTION
Accordingly, it is an object of the present invention to provide a process for efficiently obtaining a corresponding aldehyde by oxidative cleavage of a 1,2-diol with oxygen.
After intensive investigations to achieve the above object, the present inventors found that the use of a catalyst including a ruthenium compound supported on a carrier can yield a corresponding aldehyde by oxidative cleavage of a 1,2-diol. The present invention has been accomplished on the basis of these findings.
Specifically, the present invention provides a process for producing an aldehyde. The process includes the step of allowing a 1,2-diol to react with oxygen in the presence of a ruthenium catalyst supported on a carrier to oxidatively cleave a bond between two carbon atoms, where hydroxyl groups are combined with the carbon atoms, to thereby yield a corresponding aldehyde. The carrier includes, for example, an activated carbon. An organic ruthenium complex or the like can be used as a catalytic component to be supported on an activated carbon.
BEST MODE FOR CARRYING OUT THE INVENTION
[Ruthenium Catalyst Supported on a Carrier]
The ruthenium catalyst supported on a carrier is not specifically limited as far as it is a catalyst including a ruthenium compound supported on a carrier. The term “ruthenium compound” as used in the present description also includes elementary ruthenium. The ruthenium compound includes, but is not limited to, metallic ruthenium, ruthenium oxide, ruthenium sulfide, ruthenium hydroxide, ruthenium fluoride, ruthenium chloride, ruthenium bromide, ruthenium iodide, ruthenium sulfate, ruthenic acid or salts thereof (e.g., ammonium ruthenate), perruthenic acid or salts thereof (e.g., tetrapropylammonium perruthenate), inorganic ruthenium complexes [e.g., ruthenium hydroxyhalides (e.g., ruthenium hydroxychloride), hexaamminerutherium halides (e.g., hexaammineruthenium chloride), nitrosylruthenium, hexahaloruthenic acids or salts thereof (e.g., sodium hexachlororuthenate)], and other inorganic compounds; ruthenium cyanide, organic ruthenium complexes [e.g., dodecacarbonyltriruthenium(0), dicarbonyltris(triphenylphosphine)ruthenium(II), diacetatodicarbonylbis(triphenylphosphine)ruthenium(II), dichlorotris(triphenylphosphine)ruthenium(II), dihydridotetrakis(triphenylphosphine)ruthenium(II), dichlorobis(acetonitrile)bis(triphenylphosphine)ruthenium(II), ruthenocene, and other organic compounds.
The ruthenium may have any valency of 0 to 8. The valency of ruthenium is preferably from 0 to 4, of which a valency of 2 is typically preferably.
Preferred ruthenium compounds include metallic ruthenium, perruthenic acid or salts thereof, and ruthenium complexes. Among them, metallic ruthenium and ruthenium complexes are typically preferred, of which organic ruthenium complexes, especially organic ruthenium complexes each having a phosphine such as triphenylphosphine as a ligand [e.g., dichlorotris(triphenylphosphine)ruthenium(II)] are specifically preferred. Each of these ruthenium compounds can be used alone or in combination.
The carrier includes conventional carriers for supporting catalysts, such as silica, alumina, silica-alumina, zeolite, titania, magnesia, and other inorganic metal oxides, as well as activated carbon. Among them, activated carbon is preferred from viewpoint of catalytic activity. Activated carbons obtained from a variety of materials (e.g., vegetable, mineral, or resinous materials) can be used as the activated carbon. The activated carbon may be any of gas-activated carbon or chemically activated carbon. The carrier has a specific surface area of, for example, about 10 to 3000 m
2
/g, and preferably about 50 to 3000 m
2
/g.
The amount of the ruthenium compound to be supported is, for example, about 0.1 to 50% by weight, preferably about 1 to 20% by weight, and more preferably about 2 to 10% by weight, relative to the weight of the carrier. The catalyst can be prepared by a conventional technique such as impregnation, precipitation, or ion exchange.
The amount of the ruthenium catalyst supported on a carrier is, for example, about 0.001 to 1 mole, preferably about 0.01 to 0.6 mole, and more preferably about 0.02 to 0.4 mole in terms of a ruthenium compound per 1 mole of the substrate 1,2-diol.
In the present invention, a base can be used as a promoter (co-catalyst). The concurrent use of a base may improve a reaction rate or a reaction selectivity in some cases. Particularly, the use of a base can remarkably enhance the reaction rate upon oxidation of a cyclic 1,2-diol. Such bases include, for example, hydroxides, carbonates, and hydrogencarbonates of alkali metals (e.g., sodium and potassium), hydroxides and carbonates of alkaline earth metals (e.g., magnesium and calcium), and other inorganic bases; triethylamine, piperidine, N-methylpiperidine, N-methylpyrrolidine, N,N-dimethylaniline, and other amines, pyridine, quinoiine, and other aromatic nitrogen-containing heterocyclic compounds, and other organic bases. Preferred bases include, carbonates and hydrogencarbonates of alkali metals, and carbonates of alkaline earth metals, of which potassium carbonate, and other carbonates of alkali metals are specifically preferred.
The amount of the base is, for example, about 0.001 to 1 mole, preferably about 0.005 to 0.2 mole, and more preferably about 0.01 to 0.1 mole, per 1 mole of the substrate 1,2-diol.
[1,2-Diol]
The 1,2-diol (vic-diol) for use as a reactant (substrate) includes terminal vic-diols, chain internal vic-diols, and cyclic vic-diols. Such 1,2-diols include, but are not limited to, a compound represented by the following formula (1):
(wherein each of R
a
and R
b
is, identical to or different from each other, a hydrogen atom, a hydrocarbon group, or a heterocyclic group, where R
a
and R
b
may be combined to form a ring with adjacent two carbon atoms).
In the formula (1), the hydrocarbon group in R
a
and R
b
includes aliphatic hydrocarbon groups, alicyclic hydrocarbon groups, aromatic hydrocarbon groups, and groups each including these groups combined with each other. Such aliphatic hydrocarbon groups include, but are not limited to, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, pentyl, hexyl, decyl, docecyl, and other alkyl groups each having about 1 to 20 (preferably 1 to 10) carbon atoms; vinyl, allyl, 1-butenyi, and other alkenyl groups each having about 2 to 20 (preferably 2 to 10) carbon atoms; ethynyl, propynyl, and other alkynyl groups each having about 2 to 20 (preferably 2 to 10) carbon atoms.
The alicyclic hydrocarbon groups include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, and other cycloalkyl groups each having about 3 to 20 members (preferably 3 to 15 members, and more preferably 5 to 8 members); cyclopentenyl, cyclohexenyl, and other cycloalkenyl groups each having about 3 to 20 members (preferably 3 to 15 members, and more preferably 5 t
Ishii Yasutaka
Nakano Tatsuya
Daicel Chemical Industries Ltd.
Keys Rosalynd
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