Oxidation Processes. XXI.¹ The Autoxidation of the p-Phenylenediamines

On the early reaction stages of ozone with N,N′-substituted p-phenylenediamines (6PPD, 77PD) and N,N′,N″-substituted-1,3,5-triazine “Durazone®”: An electron spin resonance (ESR) and electronic absorption spectroscopy study

“…The relatively complex equilibria occurring in Ss-PPDs solutions are known over a long period [32,33] and were revisited and studied in more detail and in different contexts also in more recent times [7,8,18,22,[24][25][26][27][28][29][30]. Also the final oxidation products of PPD are known [4,31,34,35].…”

“…The SsPPDs radical cation obtained by this single electron oxidation is stable for several days or even several weeks [32] and is characterized by specific and well characterized electronic transitions in the visible or in the near infrared which are useful for the qualitative and quantitative detection [7,8,18,22,[24][25][26][27][28][29][30][31][32]. The stability of the Ss-PPDs radical cation is essentially due to resonance stabilization (see Scheme1), so that the radical cation, can be also represented as a semiquinone radical as shown in Scheme 1 [32][33][34]. The SsPPDs semiquinone radical has a certain tendency to dimerize and is stabilized in polar solvents in slight acid media with appropriate counter anion (Scheme 1) [32].…”

Oxidative transformation processes and products of para-phenylenediamine (PPD) and para-toluenediamine (PTD)—a review

“…Especially, the equilibrium between PPD, SBQDIR, and BQDI seems to be very easily influenceable [74]. Hints for autocatalytic reaction steps were deduced from examinations of the correlation between oxygen consumption and BB formation at pH values >8.5 [75]. Thus it can be inferred that the reproducibility of determined product composition is very low.…”

Genomic organization and full‐length cDNA sequence of human collagen X

“…Although this dA-rich region (47 of 50 bases are A) is not as well conserved in other species it might be a remnant of a former poly(A) tail. If the collagen type X gene arose by reintegration of a processed collagen transcript, as had been suspected before [19], it would One would have to require that the integration happened into the gene locus of a different gene before type VIII and type X genes developed separately. The integration of a reverse transcript into another gene, yielding a new functional genetic entity, is certainly a rare event.…”