Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2000-04-21
2001-08-07
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
Reexamination Certificate
active
06271420
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a process for preparing quinonediimines from their corresponding phenylenediamines using hydrogen peroxide in the presence of a catalyst.
BACKGROUND OF THE INVENTION
The class of cyclic enones is well known in organic chemistry. Best known examples of cyclic enones are quinones such as, for example, the benzoquinones, naphthoquinones, anthraquinones, phenanthraquinones, and the like. 1,4-Benzoquinone is commonly referred to as quinone. Quinones are generally brightly colored compounds and have versatile applications in chemical synthesis, biological uses, as redox materials, as well as in industry. There are several review articles on the chemistry and applications of quinones including, for example,
Kirk-Othmer Encyclopedia of Chemical Technology
, Third ed., Vol. 19, pages 572-605, John Wiley & Sons, New York, 1982.
The synthesis of quinones is well documented. See, for example, J. Cason,
Reactions of Benzoquinones by Oxidation, in Organic Synthesis
, Vol. IV, page 305, John Wiley & Sons, New York (1948). Quinones generally are prepared by oxidizing the appropriately disubstituted aromatic hydrocarbon derivatives, the substituents being hydroxyl or amino groups in the ortho or para positions. 1,4-Benzoquinone, for example, can be made from the oxidation of hydroquinone, p-aminophenol or p-phenylenediamine, or from quinic acid. The reagents generally used for the oxidation are dichromate/sulfuric acid mixture, ferric chloride, silver (II) oxide or ceric ammonium nitrate. In these cases, oxidation of the aminoaromatic compound is accompanied by hydrolysis to the corresponding quinone. Some processes may take several hours for completion of the reaction.
Thus, some of the prior art processes utilize a catalytic agent to achieve an acceptable reaction rate while other processes proceed without catalysts. The process according to the present invention utilizes hydrogen peroxide in the presence of a catalytic agent which provides extremely high conversion, high selectivity, and fast reaction rates to prepare the quinonediimine.
A prior art process which utilizes a catalyst in the preparation of a quinoneimine compound is disclosed by Desmurs, et al. in U.S. Pat. No. 5,189,218. The process of Desmurs, et al., which converts N-(4-hydroxyphenyl)aniline into N-phenylbenzoquinone-imine, utilizes a manganese, copper, cobalt, and/or nickel compound as a catalyst in an oxidation type reaction.
Other processes are known which use oxidizing agents to convert phenylenediamines into their corresponding quinonediimines. For example, EP 708,081 (Bernhardt et al), which describes the conversion of phenylenediamines to phenylenediimines by oxidation of the diamine in an alkali/alcoholic solution, gives a general description of such processes in its background. The EP '081 process suffers from various disadvantages including long reaction times and low yields. Additional oxidation conversion processes are described by Wheeler in U.S. Pat. No. 5,118,807 and by Haas et al, in EP 708,080. However, the use of a hydrogen peroxide in the presence of a catalytic agent in the conversion of diamino compounds to give highly selective yields of diimino compounds has not heretofore been suggested.
As such, the current invention is based on the problem of providing a simple and economic process for the preparation of N,N′-disubstituted quinonediimines in high yields and with high purity.
SUMMARY OF THE INVENTION
It has been discovered that phenylenediamine compounds can be converted with extremely high selectivity into the corresponding quinonediimine by reaction of the diamine with hydrogen peroxide in the presence of a catalytic agent. Conditions are revealed in which nearly quantitative yields have been obtained.
In contrast to prior art, an advantage of the present invention is that the conversion of phenylenediamine to the corresponding quinonediimine is nearly quantitative. Thus, very little waste material remains upon completion of the reaction.
Another advantage is that the hydrogen peroxide/catalytic agent combination, as set forth herein, provides an extremely high conversion, high selectivity and faster more complete reaction compared to prior art processes.
Still further advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description of the preferred embodiments.
DETAILED DESCRIPTION OF THE INVENTION
The object of the present invention is to provide an effective process for converting phenylenediamines into their corresponding quinonediimines.
In accordance with the object of the invention, a phenylenediamine (ortho or para) according to Formula I:
wherein R
1
, R
2
and R
3
are the same or different radicals selected from hydrogen, hydroxyl, halogen, alkyl, alkoxy, aryl, aralkyl, alkaryl, cycloalkyl, heterocycle, acyl, aroyl, carbamyl, carboxylic acids, esters, ethers, ketones, alcohols, thiols, alkylthiols, and cyano, is reacted with hydrogen peroxide in the presence of a catalytic agent.
The reaction produces a corresponding quinonediimine according to Formula IIa or IIb:
wherein R
1
, R
2
and R
3
are the same as in the compound according to Formula I.
The reaction is represented as follows:
Examples of satisfactory radicals for R
1
, R
2
and R
3
are linear or branched alkyls such as methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and the like; aryls such as phenyl, naphthyl, anthracyl, tolyl, ethylphenyl, 1-ethyl-3-methylpentyl, 1-methylheptyl, and the like; cycloalkyls such as cyclobutyl, cyclopentyl, cyclohexyl, cyclooctyl, and the like. Other examples include allyl and isobutenyl; 1,3,5-sym-triazinyl, 2-benzothiazolyl, 2-benzimidazolyl, 2-benzoxazolyl, 2-pyridyl, 2-pyrimidinyl, 2,5-thiadiazolyl, 2-pyrazinyl, adipyl, glutaryl, succinyl, malonyl, acetyl, acrylyl, methacrylyl, caproyl, 3-mercaptopropionyl, benzoyl, phthaloyl, terephthaloyl, aminocarbonyl, carbethoxy, carbonyl, formyl, and the like. These are merely exemplary radicals and are in no way intended to limit the scope of the invention.
The hydrogen peroxide used in the reaction according to the present invention is typically present in an amount ranging from 1.05 to 2.05 parts per equivalent of phenylenediamine. Use of less than one equivalent will tend to produce blends of quinonediimine and unreacted phenylenediamine. The strength of the hydrogen peroxide can range from 5% to 85%. The strength is preferably between 10% and 35%.
Catalytic agents which are used along with the hydrogen peroxide include, but are not limited to, carbon supported catalysts such as Pt/C and Pd/C; modified activated carbon catalysts such as those produced by removing surface oxides therefrom as set forth in U.S. Pat. No. 4,624,937, the disclosure of which is incorporated herein by reference; water soluble ionic metal catalysts; activated carbon; metal oxides, such as iron oxide (FeO
2
), manganese oxide (MnO
2
), and copper (II) oxide (CuO
2
); and metals, such as silver (Ag).
The catalysts of the present invention cause the conversion reaction in the process according to the present invention. Even in systems where the oxidizing agent, aqueous hydrogen peroxide, is soluble in the solvent solution of phenylenediamine (i.e. acetronitrile in N,N-dimethylformamide) there is no reaction until the catalyst is added. It is advantageous to utilize solid catalysts in the reaction according to the present invention as there is ease in recovery of the solid catalysts, via filtration, and the solid catalysts can be reused in the process. There are also advantages with respect to environmental containment, and there is less likelihood that there will be contamination by the catalyst in the final isolate of quinonediimine. Further, the catalysts give high conversion and excellent selectivity.
The reaction, according to the present invention, takes place in either a homogeneous or two-phase solvent system. Water soluble organic solvents are used for the homogeneous reaction while
Barts Samuel
Flexsys America LP
Morris Louis A.
LandOfFree
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