Poly(o-toluidine), poly(m-toluidine), and poly(o-ethylaniline) have been synthesized chemically and electrochemically. The polymers were characterized by elemental analysis, UV-vis spectroscopy, and cyclic voltammetry. Elemental analysis data suggest that the protonated polymers are derived from bases containing ca. 37-54% oxidized (imine) units. Upon treatment with 1 M HC1, conductivities of the polymers increase dramatically from ca. 10~8 S/cm to ca. 1CT1 S/cm for polytoluidines and to ca. 1CT3 S/cm for poly(oethylaniline). The conductivities, UV-vis spectra, and electrochemical reactions of the polymers are compared with those of polyaniline and are shown to be consistent with a reduction in -conjugation of the alkyl derivatives caused primarily by steric effects.

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Gas holdup (εg) and power correlations in gas–liquid (G–L) systems, apart from the physicochemical properties of the liquid phase, are dependent on impeller–sparger–vessel geometry. To date, reported correlations do not specifically address this issue, and it must be investigated with a unified approach. Here, we propose a correlation via the use of a normalized εg that involves the impeller–sparger system geometry for a vessel of standard geometry expressed as a function of an easily measurable and independent operational parameter, that is, (1 – P g/P l), where P g/P l is the gassed to ungassed power ratio. Furthermore, our work demonstrates that P g/P l can be used as a tool for the identification of hydrodynamic regimes. Radial and axial impellers with ring spargers were used in a stirred and sparged contactor (SSTC) of 0.25 m diameter containing 1 × 10–2 m3 water. The oxygen flowrate (Q g) was varied from 2.5 to 40 LPM or (4.17 to 66.7) × 10–5 m3 s–1, and the agitation intensity (N 0) was varied from 1.67 to 50 rps at the temperature (θ) = 313 K under atmospheric pressure. This novel correlation is easy to use, offers reasonable precision, and can serve as a valuable alternative to more complex correlation models.