Para-phenylenediamine

H2N.C6H4.NH2, mw 108.14, N 25.91%. There are three isomers ortho-, meta- and para-. Phenylenediamines were first prepd in the 1860 s by P. Griess and then by A.W. Hofmann. Inasmuch as some confusion existed in regard to the structure of these compds, it is difficult to say which isomers they were... 

A -( 1,3-dimethylbutyl)-iV -phenyl-para-phenylenediamine. Tetrahydro-l,3,5-tri-(n)-butyl-(S)-triazinethione. 

Ivan et al. [95] reported that 3,5-di-tert-butyM-hydroxybenzylcyanoacetate is a nonstaining antiozonant that affords similar protection to NR and to cw-polyisoprene compounds such as N-isopropyl-N -phenyl-para-phenylenediamine does (see Figure 15.12). This product lasts longer than conventional nonstaining antiozonants, like the styrenated phenols. 

No in vitro assays that are based on proliferation of naive lymphocytes upon sensitizer exposure have been developed as yet. Using haptenized DC, proliferation can be induced but only for strong sensitizers such as trinitrophenol and fluorescein iso-thiocyanate, or with para-phenylenediamine in only a limited proportion of the experiments. 

Nitro-para-phenylenediamine see l,4"Diamino-2-nitrobenzene) 2-Nitropropane... 

Rubber antioxidants are commonly of an aromatic amine type, such as dibeta-naphthyl-para-phenylenediamine and phenyl-beta-naphthylamine. Usually, only a small fraction of a percent affords adequate protection. Some antioxidants arc substitute phenolic compounds (butylatcd hydro -vamsole, di-tert-butyl-para-cresol, and propyl gallate). 

PARA-PHENYLENEDIAMINE HYDROCHLORIDE Trade Names Diamine H, P.D.H. 

Other Uses for Aniline. Aniline currently is used as a raw material in most of the major groups of rubber-processing chemicals accelerators, antioxidants and stabilizers, and anti-ozonants. The most important of these are the thiazole derivatives and substituted para-phenylenediamines. The demand for aniline in these rubber-processing uses is expected to grow at less than 1 percent/year. In agricultural chemicals, the major use for aniline is as a raw material in the manufacture of amide herbicides for controlling annual... 

The chemistry associated with the oxidation of primary intermediates is now reasonably well known. For para-phenylenediamine and para-aminophenol, this involves the process outlined in Fig. 13.40. It can be seen that dye formation is a two-step process involving oxidation and self-coupling. 

Polyimide surface modification by a wet chemical process is described. Poly(pyromellitic dianhydride-oxydianiline) (PMDA-ODA) and poly(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) polyimide film surfaces are initially modified with KOH aqueous solution. These modified surfaces are further treated with aqueous HC1 solution to protonate the ionic molecules. Modified surfaces are identified with X-ray photoelectron spectroscopy (XPS), external reflectance infrared (ER IR) spectroscopy, gravimetric analysis, contact angle and thickness measurement. Initial reaction with KOH transforms the polyimide surface to a potassium polyamate surface. The reaction of the polyamate surface with HC1 yields a polyamic acid surface. Upon curing the modified surface, the starting polyimide surface is produced. The depth of modification, which is measured by a method using an absorbance-thickness relationship established with ellipsometry and ER IR, is controlled by the KOH reaction temperature and the reaction time. Surface topography and film thickness can be maintained while a strong polyimide-polyimide adhesion is achieved. Relationship between surface structure and adhesion is discussed. 

Here we report a wet surface modification of PMDA-ODA and poly-(bisphenyl dianhydride-para-phenylenediamine) (BPDA-PDA) with KOH or NaOH solution. The modified surfaces are identified with contact angles, XPS spectra and ER IR spectra. Polymer thickness and weight changes are also studied. The depth of modified layer is measured by a non-destructive technique using ER IR and ellipsometry. Relationship between surface structure and adhesion strength is discussed. 

Benzocaine can cause sensitization, and being a para-aminobenzoic acid derivative it can cross-react with para-phenylenediamine, sulfonamides, aniline dyes, and related local anesthetics. However, in a recent retrospective study of 5464 patients it was concluded that benzocaine allergy is not common in the UK, confirming earlier reports that benzocaine should not be used as a single screening agent for local anesthetic allergy (27). 

M. Sir Hashim, Y.O.Hamza, B.Yahia, F.M.Khogali, G.I.Sulieman. Poisoning from henna dye and para-phenylenediamine mixtures in children in Khartoum. Annals of Tropical Paediatrics 1992 12 3-6... 

Evans R G, Klymenko O V, Hardacre C, et al. Oxidation of N,N,N, N -tetraalkyl-para-phenylenediamines in a series of room temperature ionic liquids incorporating the bis(trifluoromethylsulfonyl)imide anion. J. Electroanal. Chem. 2003. 556, 179-188. 

Dimethyl-para-phenylenediamine is obtained finm methyl orange either by reduction with tin metal and hydrochloric acid as shown in (a) above or by treatment with sodium dithionite (Na2S204) as depicted in ib) above. 

Some henna, particularly that marketed as "black henna," is mixed with the compound para-phenylenediamine (PPD), a black hair dye that frequently causes skin sensitization and has been responsible for numerous cases of allergic contact dermatitis, some of which have caused permanent scarring... 

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