Of diphenylamine

Prepare two solutions, one containing i g. of diphenylamine in 8 ml. of warm ethanol, and the other containing 0-5 g. of sodium nitrite in i ml. of water, and cool each solution in ice-water until the temperature falls to 5°. Now add o 8 ml. of concentrated hydrochloric acid steadily with stirring to the diphenylamine solution, and then without delay (otherwise diphenylamine hydrochloride may crystallise out) pour the sodium nitrite solution rapidly into the weil-stirred mixture. The temperature rises at once and the diphenylnitrosoamine rapidly crystallises out. Allow the mixture to stand in the ice-water tor 15 minutes, and then filter off the crystals at the pump, drain thoroughly, wash with water to remove sodium chloride, and then drain again. Recrystallise from methylated spirit. Diphenylnitrosoamine is thus obtained as very pale yellow crystals, m.p. 67 68° yield, 0 9-1 o g. 

Coloured oxidation products, a) Dissolve a few small crystals of diphenylamine in 1 ml. of cone. H2SO4. Add 2 drops of cone. HNO3 to about 10 ml. of water, shake, and add i drop of this diluted HNO3 to the diphenylamine solution an intense purple-blue coloration is produced. Monomethylaniline merely turns a dirty brown when treated in this way. 

Pure bromoform is somewhat unstable and darkens on keeping it may be stabilised by the addition of 4 per cent, of its weight of ethyl alcohol or of a small quantity of diphenylamine. 

Miscellaneous Reactions. The A/-hydrogen atom of diphenylamine is reactive and readily replaced by deuterium by treating with C2H OD. The addition of acid cataly2es the exchange of the hydrogen atoms on the ring system (11). 

According to the U.S. International Trade Commission s Synthetic Organic Chemicals, Production and Sales, 1987, the three manufacturers of diphenylamine are Rubicon, Inc., Aristech Chemical Corp., and Uniroyal Chemical Co. No production figures have been given siace 1974, but U.S. production ia the range of 5,000—10,000 t/yr appears reasonable. 

Diarylamiaes are of the greatest iadustrial importance as stabili2ers and antioxidants (qv) for polymers, stabili2ers for explosives, polymeri2ation inhibitors, and ia dyes. Today, the use of these materials as antioxidants is essentially limited to derivatives of diphenylamine siace /V-phenyl-2-naphthylamine is ao longer used. 

Typical recipes for an antioxidant dispersion and an ultra-accelerator dispersion are given below. The antioxidant recipe is for Aminox (Uniroyal, Inc.), alow temperature reaction product of diphenylamine and acetone. 

DuPont in the U.S. developed about 1909, a smokeless powder from cotton of relatively low nitrogen that was quite soluble in ether alcohol. A small amount of diphenylamine was used as a stabilizer. After forming the grains and removing the liquid, a coating of graphite was added to make the smokeless powder that was used in the U.S. Other double-base types contain about 25% nitroglycerin. Cotton lint for nitration has been replaced by purified wood cellulose. 

Mention should be made of one of the earliest internal indicators. This is a 1 per cent solution of diphenylamine in concentrated sulphuric acid, and was introduced for the titration of iron(II) with potassium dichromate solution. An intense blue-violet coloration is produced at the end point. The addition of phosphoric(V) acid is desirable, for it lowers the formal potential of the Fe(III)-Fe(II) system so that the equivalence point potential coincides more nearly with that of the indicator. The action of diphenylamine (I) as an indicator depends upon its oxidation first into colourless diphenylbenzidine (II), which is the real indicator and is reversibly further oxidised to diphenylbenzidine violet (III). Diphenylbenzidine violet undergoes further oxidation if it is allowed to stand with excess of dichromate solution this further oxidation is irreversible, and red or yellow products of unknown composition are produced. 

Acid-treated clay catalyst Engelhard F-24 was found to be very effective for the alkylation of diphenylamine (DPA) with an olefin such as a-methyl styrene (AMS) to obtain a mixture of mono and dialkylated diphenylamines (Chitnis and Sharma, 1995). For example, alkylation of DPA with AMS produced a mixture of 4-(a,a-dimethyl benzyl) diphenylamine, i.e. monocumyl-diphenylamine (MCDPA) and 4,4 -bis(a,a-dimethylbenzyl) diphenylamine, i.e. dicumyldiphenylamine (DCDPA) (Eqn.(l 1)). The dialkylated diphenylamine, i.e. DCDPA, is indu.strially important as an antioxidant and heat stabilizer. DCDPA is reported to be an ideal antioxidant for many materials like polyethylene, polypropylene, polyether polyol, polyacetals, nylon 6, synthetic lubricants, hot melt adhesives, etc. 

Similarly, reactions which are substantially enhanced by the use of PTC can be carried out even with reduced use of PTC with substantial enhanced rates of reaction as has been demonstrated by Sivakumar and Pandit (2000) in the case of conversion of benzamide to benzonitrile. In the case of A-alkylation of diphenylamine with benzyl bromide, in the presence of KOH as the anion source and PEG methyl ether as the PTC, some improvement in the rate has been observed. (Cains et al., 1998). Metal catalysed hydrogenations, such as those based on Ni, Pd/C, and Ru/C also benefit from ultra-sound. 

The 5,168-acre Alabama Army Ammunition Plant tract, on the banks of the Coosa River in Talladega County, AL, is 4 miles north of Childersburg, AL (4). Plant operations, between 1942 and 1945, left residues from the manufacture of diphenylamine, TNT, DNT, and tetryl. Some of these compounds have been found on the site, and others are suspected. The shallow water table, draining to the Coosa River, is probably contaminated, but only deeper, uncontaminated aquifers would be used as the source for... 

Time Percentage degradation of diphenylamine under different experimental conditions... 

Fig. 12.7 Degradation of diphenylamine with different rare earths...

Drzyzga O, Jannsen S, Blotevogel KH (1995) Toxicity of diphenylamine and some of its nitrated and aminated derivatives to the luminescent bacterium vibrio fischeri. Environ Safety 31(12) 149-152... 

DeAtley WW (1970) Spectrophotometric determination of diphenylamine, 2-nitrodipheny-lamine, and 4-nitrodipheylamine by oxidation with ferric ion. Anal Chem 42(6) 662-664... 

Phenothiazines are well-known as intermediates for pharmaceuticals, and are also active as insecticides and antioxidants. These compounds are usually prepared by the thiation of diphenylamines with elemental sulfur. In this context, the group of Toma has elaborated a synthesis of 3-phthalimidophenothiazine, as shown in Scheme 6.265 [455]. Using a variety of high-boiling solvents under conventional thermal reflux conditions, low isolated yields of the desired product were obtained. The highest conversion and isolated product yield (55%) was achieved by microwave irradiation of a mixture of the starting N-(4-phenylaminophenyl)phthalimide with... 

The reaction proceeds further on refluxing 104 with a second equivalent of diphenylamine [Eq. (118)]. 

The use of a sulphonic acid derivative of diphenylamine overcomes the problem of low indicator solubility. 

The oxidative coupling/cyclization process occurs via stoichiometric carbo-palladation using a Pd(II) species, typically Pd(OAc)2. In an early example, submission of diphenylamines 3 to the palladium(II)-promoted oxidative intramolecular cyclization conditions yielded carbazoles 4 [15-... 

J. Cho, A. Kimoto, M. Higuchi, and K. Yamamoto, Synthesis of diphenylamine-substituted phenylazomethine dendrimers and the performance of organic light-emitting diodes, Macro Chem. Phys., 206 635-641 (2005). 

This is a spectrophotometric assay based on the reaction of diphenylamine with the deoxyribose moiety of DNA to produce a complex that absorbs at 600 nm. The reaction is specific for deoxyribose and RNA does not interfere. It can be used on relatively crude extracts where direct spectrophotometric determinations of DNA concentration are not possible. 

Due to the high interest in metalation reactions with lithium amide or alkyllithiums, an indicator scale of lithium ion pairs in THF has been developed119. Aggregation studies have indicated that organolithium species exist predominantly, if not exclusively, as monomers in the 10-3-10-4 M concentration range. Particular attention has been devoted to the lithium and caesium ion-pair acidities of diphenylamine in THF120 that, at 25 °C, have been found to be 19.05 and 24.20, respectively. 

Needless to say, the Buchwald-Hartwig reaction can also be usefully employed in ways other than the efficient preparation of diphenylamines. Given the respective substitution, it should be possible to bring about the phenazine skeleton by Pd-catalyzed ring formation as well. There are two ways to proceed either the substituent pattern required by the intramolecular Buchwald-Hartwig reaction is elaborated after the formation of the diphenylamine (121 124), or the starting material already contains the substituents necessary for the two JV-arylations. A reasonable starting point is the intermolecular JV-arylation of an o-haloaniline... 

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