Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Reexamination Certificate
2001-06-08
2002-05-14
Barts, Samuel (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
Reexamination Certificate
active
06388136
ABSTRACT:
TECHNICAL FIELD
Present invention relates to a method of preparation of 4-aminodiphenylamine (4-ADFA) through an intermediary preparation of 4-nitrodiphenylamine and/or 4-nitrosodiphenylamine and/or their salts in which aniline reacts with nitrobenzene in a liquid medium, whereby precursors of 4-ADFA are formed, i.e. 4-nitrosodiphenylamine (4-NODFA), 4-nitrodiphenylamine (4-NO
2
DFA) an/or their salts which, after hydrogenation, result in 4-ADFA.
BACKGROUND ART
4-aminodiphenylamine (4-ADFA) is widely used as an intermediate product in the production of alkylated derivatives having outstanding properties as antiozonants, antioxidants and stabilizers.
Present methods of industrial production of 4-ADFA start with hydrogenation of the intermediates, 4-NODFA or 4-NO
2
DFA. However, production of these intermediates, consisting in several technologically demanding steps, is accompanied by a number of side products, organic and inorganic waste which must be liquidated, this being one of the greatest problems of this production method.
Alternative methods of preparation of 4-ADFA intermediates which are ecologically and economically preferred consist in the direct reaction of aniline with nitrobenzene. The reaction is initiated by bases which form an anilide anion through the reaction which anion subsequently substitutes hydrogen in nitrobenzene by nucleophilic addition [A. Wohl et al., Ber. 34, 2442-2450, 1901; and A. Wohl, Ber. 36, 4135-4138, 1903], wherein if solid potassium hydroxide has been used as the base, mostly phenazine and phenazine oxide result, if sodium hydroxide has been used, also 4-NODFA is obtained.
In fifties, a number of authors have studied and described mechanism of the Wohl-Aue nucleophilic reaction of aniline and its derivatives with aromatic nitrocompounds by the action of bases (NaOH, KOH, eventually NaNH
2
) in the medium of benzene, toluene and xylene, wherein phenazine derivatives are formed. Besides them also further reaction products like 4-nitrosodiphenylamine, 4-nitrosubstituted diphenylamines, azobenzenes, azoxybenzenes [E. I. Abramova et al., Zhur. Obshchei Khim. 22, 502-509, 1953; S. B. Serebryanyi, Uspekhi Khimii 24, 313-345, 1955; S. B. Serebryanyi, Ukrain. Khim. Zhur. 21, 350-360, 1955; V. P. Chemetskii et al., Zhur. Obshchei Khim. 25, 2161-2170, 1955] have been isolated and decribed at the same time.
It is known [N. R. Ayyangar et al., Tetrahedron Letters 31, 3217-3220, 1990] that 4-NODFA and 4-NO
2
DFA arise by the reaction of nitrobenzene with acetanilide in the presence of dipolar aprotic solvent, dimethyl sulfoxide (DMSO), by the action of sodium hydroxide and potassium carbonate, as well as [A. A. Frimer et al., J. Org. Chem. 48, 1700-1705, 1983] that 4-NO
2
DFA arises with a yield of up to 24% by the reaction of aniline with nitrobenzene in the presence of bases, in this case of potassium butoxide or potassium peroxide in the medium of benzene and in the presence of a crown ether.
Similarly [D. J. Stuehr et al., J. Org. Chem. 50, 694-696, 1985], by the reaction of aniline and N-methylaniline in DMSO with potassium peroxide, together with 18-crown-6-ether, as well as with tertiary potassium butoxide a mixture of 4-NODFA, 4-NO
2
DFA, 4-ADFA, azobenzene, 4-phenylazodiphenylamine and phenylformamide has been obtained as the reaction product (no yields given).
Preparation of 4-ADFA through oxidation of aniline by ferricyanide in strongly alkaline medium is known [U.S. Pat. No. 4,760,186 and GB patent 1 440 767], wherein head-foot linking of two aniline molecules comes into effect, but with a low yield only.
U.S. Pat. No. 5,574,187 describes the 4-ADFA preparation by substitution of phenylhydroxylamine by aniline in the presence of an acidic catalyst. The product has been obtained with average yields only (max. of 51.2%).
Nature of the next U.S. Pat. No. 5,420,354 consists in the reaction of nitrobenzene with aniline in the presence of hydrogen, hydrogenation catalyst, acidic catalyst and hydrogenation inhibitor, which reaction yields directly 4-ADFA, but with relatively low yields (max. of 12%) and at a low selectivity of the reaction, similarly to other above given procedures.
In the EP application 566 783, the AKZO N.V. describes a method of manufacture of 4-nitrodiphenylamine by the reaction of nitrobenzene with aniline in the medium of a polar aprotic solvent, particularly dimethyl sulfoxide and tertiary butanol in a strongly alkaline reaction system, wherein hydroxides of alkali metals and of alkaline-earth metals, alkoxides, amides and hydrides of alkali metals have been used as bases, eventually in the presence of a phase transfer catalyst, like tetrabutylammonium hydrogen sulfate. Relatively high yields have been achieved, but selectivity of the reaction is insufficient. Therefore, it is necessary to isolate the product (NO
2
DFA) from the side products by crystallization. Moreover, in the process of products isolation salts are obtained, thus causing further costs for their processing. Also lossless recycling of bases and solvent mixtures back to the process is questionable.
A further halogen free method of 4-ADFA preparation consists in the reaction of aniline with 4-phenylazodiphenylamine in the presence of strong bases, like tertiary potassium butoxide with crown ethers or with quaternary ammonium hydroxides [U.S. Pat. Nos. 5,382,691, 5,633,407, 5,618,979 and 5,451, 702]. Subsequent transformation of 4-FADFA to 4-ADFA can be performed either by a catalytic hydrogenation according to the U.S. Pat. No. 5,451,702] or by a nucleophilic substitution reaction of 4-FADFA with amine in the presence of strong bases [U.S. Pat. Nos. 5,382,691, 5,633,407 and 5,618,979]. 4-ADFA can be also [see the U.S. Pat. Nos. 5,618,979 and 5,633,407 and the paper M. K. Stern et al., J. Org. Chem. 59, 5627-5632, 1994] prepared in one step directly by the reaction of azobenzene, eventually azoxybenzene, with aniline in the presence of strongly alkaline catalysts. However, in all above given procedures the starting raw material is azobenzene which is technically less easily accessible raw material, and it must be prepared in advance. Moreover, much waste arises which must be necessarily further treated or liquidated.
In a number of patents of the firm Monsanto [U.S. Pat. Nos. 5,117,063, 5,453,541, 5,608,111, 5,623,088], there is described a method of 4-ADFA intermediates production by direct reaction of aniline with nitrobenzene in an aprotic solvent with a controlled amount of a protic solvent by the action of bases, which include alkali hydroxides, alkoxides, hydrides and quaternary ammonium hydroxides with alkyl-, aryl- and aralkylsubstituents, as well as alkylsubstituted diammonium hydroxides. Nevertheless, the reaction products could be obtained with high yields and with high selectivity only when using quaternary ammonium hydroxides. Also mechanism of the reaction is known [M. K. Stern et al., J. Am. Chem. Soc. 114, 9237-9238, 1992, and New J. Chem. 20, 259-268, 1996].
From a comparison of the respective bases, described in the above given patents and papers, used in the reaction of aniline with nitrobenzene it becomes clear that the alkali hydroxides give low yields of the 4-ADFA intermediates. The yields increase substantially when alkali hydroxides are used together with crown ethers. Nevertheless, taking into account their technically demanding preparation, their industrial utilization is not very probable. Also the reaction in the presence of potassium butoxide and in the presence of DMSO shows low selectivity. Contrary to this, if quaternary ammonium hydroxides are used as bases in the reaction, both high selectivity and high yields are achieved. Nevertheless, they have a disadvantage of lower stability, they decompose in a concentrated state and, therefore, they must be stored in diluted aqueous solutions only. An another disadvantage is also their low thermal stability, they easily decompose at higher temperatures [A. Cope et a
Be{haeck over (s)}ka Emanuel
Fiedler Karol
Hronec Milan
Pint{dot over (e)}r Jozef
Toman Peter
Barts Samuel
Duslo, A.S. Sala
Pennie & Edmonds LLP
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