Diphenylamine naphthylamine

The Sandmeyer procedure and its Gattermann variant (see page 259) often give poor yields when applied to diphenylamines, naphthylamines, or phen-anthrenamines, but good results can be obtained by the method worked out by Schwechten1239 as a variant of the Schiemann reaction (thermal decomposition of diazonium fluoroborates, see below). 

Preparation of aniline black from aniline naphthylamine violet from naphthylamine salts alizarine from anthraquinone—Toluidene—Alethyl-aniline— Diphenylamine— Methyl-diphenylamine—Naphthylamine.60-62... 

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. 

Abstract Hazardous effects of various amines, produced in the environment from the partial degradation of azo dyes and amino acids, adversely affect the quality of human life through water, soil and air pollution and therefore needed to be degraded. A number of such studies are already available in the literature, with or without the use of ultrasound, which have been summarized briefly. The sono-chemical degradation of amines and in the combination with a photocatalyst, TiC>2 has also been discussed. Similar such degradation studies for ethylamine (EA), aniline (A), diphenylamine (DPA) and naphthylamine (NA) in the presence of ultrasound, Ti02 and rare earths (REs) La, Pr, Nd, Sm and Gd, in aqueous solutions at 20 kHz and 250 W power have been carried out and reported, to examine the combinatorial efficacy of ultrasound in the presence of a photocatalyst and rare earth ions with reactive f-electrons. 

Cytotoxicity of methylamine [45], kidney liver and myocardial damage due to ethylamine [46], hepatosplenomegaly and eosinophilia due to aniline [47], euphoria, dyspnea, teratogenicity, renal failure, hematuria, proteinurea, anorexia and methanoglobinemia due to a-naphthylamine and diphenylamine have been reported in the literature [48-54]. Therefore the remediation and mineralization of amines is... 

Fig. 12.14 Delocalisation of electrons in aniline, naphthylamine and diphenylamine molecules...

Aniline, methyl aniline, 1-naphthylamine, and diphenylamine at trace levels were determined using this technique and electrochemical detection. Two electrochemical detectors (a thin-layer, dual glassy-carbon electrode cell and a dual porous electrode system) were compared. The electrochemical behavior of the compounds was investigated using hydrodynamic and cyclic voltammetry. Detection limits of 15 and 1.5nmol/l were achieved using colourimetric and amperometric cells, respectively, when using an in-line preconcentration step. 

High values of the inhibition coefficient (/= 12-28) were detected for the first time in the oxidation of cyclohexanol [1] and butanol [2] inhibited by 1-naphthylamine. For the oxidation of decane under the same conditions, /= 2.5. In the case of oxidation of the decane-cyclohexanol mixtures, the coefficient / increases with an increase in the cyclohexanol concentration from 2.5 (in pure decane) to 28 (in pure alcohol). When the oxidation of cyclohexanol was carried out in the presence of tetraphenylhydrazine, the diphenylaminyl radicals produced from tetraphenylhydrazine were found to be reduced to diphenylamine [3]. This conclusion has been confirmed later in another study [4]. Diphenylamine was formed only in the presence of the initiator, regardless of whether the process was conducted under an oxygen atmosphere or under an inert atmosphere. In the former case, the aminyl radical was reduced by the hydroperoxyl radical derived from the alcohol (see Chapter 6), and in the latter case, it was reduced by the hydroxyalkyl radical. 

Polyorthoamino phenol (2 wt. percent) and polyorthoaminophenol + phenyl-p-naphthylamine (0.7 wt. percent of each) acted as antirads, preventing any significant cross-linking on exposure to 24 krad (240 Gy).201,202 The addition of a diphenylamine derivative gave a reasonable protection to radiation up to 22 Mrad (220 kGy).202... 

Amines have been used for the following purposes related to expls,propellants, pyrotechnic compositions and fuels a)Stabilizers for NC propellants(eg, diphenylaniine, nitro-diphenylamine and phenyl-/d-naphthylamine, the last examined in France(Ref 3) b)Sensi-tizers for some expl and propellent compns (Ref 4 and addnl ref d) c)Smoke-producing compds (Addnl Ref d) d)Liquid fuels for rockets in conjunction with strong oxidizers, such as nitric acid(sonte of these are hyper-golic) (Refs 6 8 and addnl refs e,g,i,k l) e)Additives to gasoline and other motor fuels (Addnl refs a,b,c f)... 

Figure 3. Four parameter, simplex-optimized SFC separation of a 12-component mixture. Chromatographic conditions as in Vertex 13 of Table II. Sample components isoquinoline, n-octadecane (n-CigH3g), naphthalene, quinoline, acetophenone, undecylbenzene, benzophenone, 2 -acetonaphthone, diphenylamine, o-dioctylphthalate, unidentified impurity, N-phenyl-1-naphthylamine, phenanthrene quinone. Other conditions as described in the experimental section.

Aromatic amines, such as phenyl- -naphthylamine or condensation products of diphenylamine with acetone condensates, are excellent antioxidants and antiozonants but cause color development. From the sterically hindered phenols, monocyclic phenols, such as 2,6-di-teit-butyl-p-cresol, are less effective antioxidants but remain white and nontoxic during aging. They are, however, volatile and provide poor protection at elevated processing temperatures. Polycyclic phenols, such as 2,2 -methylene-bis (4-methyl-6-teit-butylphenol), are relatively nonvolatile, but become discolored by oxidation to a conjugated system. O Shea... 

The numerous experiments which led to the formation of dyes at the anode, when aniline, toluidine, methylaniline,. diphenylamine, nethyldiphenylamine and naphthylamine or their salts were electrolyzed, have, however, not been scientifically investigated and, hence, still remain unsolved. The same holds true of Goppelsroder investigations concerning the oxidation of phenol and anthraquinone. The most important discovery is the fact that aniline salts smoothly yield aniline black at the anode the naphthylamine salts give naphtliylamine-violet.1... 

Fig. 24. Apparatus for large-scale distillation with superheated steam (for o-naphthylamine, diphenylamine, etc.) (1) inlet for superheated steam (2) distillation vessel with slow stirrer (3) coil condenser.

DianiIino-5,5 -binaphthalene-1,1-disulfonates can be efficiently synthesized (25-50% yield) from the corresponding naphthylamines [74], analogously to the coupling of diphenylamines (Table 5, number 3a). 

The attempted intramolecular cyclization of the substituted naphthylamines XVI failed and led only to an intermolecular coupling [92]. 4-Substituted diphenylamines form in a remarkable cyclodimerization 5,10-dihydro-5,10-diphenylphenazines [Eq. (10)] [84], One requirement is that all para positions must be substituted by groups that are not eliminated and not strongly electron withdrawing. Yields are increased by electrolyzing at low current densities. Di-(2-naphthyl)amine undergoes the same reaction anodically, but... 

Apart from the alkylated phenols, phenyl-p-naphthylamine, acetone diphe-nylamine reaction products and alkylated diphenylamines are also used in different industrial applications and they can absorb UV light. Using proper solvents, these antioxidants can be both qualitatively and quantitatively analysed. Table 5.1 shows the solvents and test conditions for determination of antioxidants. ... 

It has been demonstrated that the nitroxyl radical, X, reacts with a secondary alkyl radical to form XI which, under high-temperature conditions (>120°C), regenerates the original diphenylamine molecule, Reaction (4.36). In essence, this group of stabilisers acts catalytically by scavenging alternately peroxy (ROO-) and alkyl radicals (R-). As stated earlier, sterically hindered phenols deactivate only two peroxy radicals per phenol molecule. Hence, under high-temperature conditions, aromatic amines are far superior to their phenolic counterparts. As shown in Table 4.3, the stoichiometric factor of the diphenylamines depends on the substituents in the para position [33]. The efficacy of the diphenylamine antioxidant is improved by alkylating the para positions. The stabilisation mechanism for phenyl-a-naphthylamines. Reaction sequence (4.37) [34], is described as follows ... 

In contrast to the diphenylamine derivatives, transformation of the nitrogen radical (XII) to a nitroxyl radical, N-0-, has not been observed. Due to the longer lifetime of the nitrogen-centred radical (XII) by resonance stabilisation, dimerisation and oligomerisation take place whilst maintaining the -NH- function. Indications have been found that the products of Reaction (4.37) may result from direct reaction of phenyl-a-naphthylamine with oxygen [27, 35]. 

The importance of the cyclical regeneration of nitroxide in the aromatic series seems to be therefore questionable N,N -di-substituted PD, most probably not involved in this cycle, are generally more efficient chain-breaking antioxidants than both diphenylamine and N-phenyl-1-naphthylamine, potentially partly involved in the nitoxide cycle. It may, therefore, be supposed that the high antioxidant activity of PD more probably accounts for the positive cooperative effects of PD with its principal oxidative transformation product, BQDI. 

---