Aromaticity potential curves

Polarographic reduction studies of aromatic hydrocarbons [Wawzonek ft at, (18-21), Hoijtink et ed. (22-27) and potentiometric titration experi-naents (2S) proved that besides mononegative ions, dinegative ions of aromatic hydrocarbons can also be formed. The polarographic current-potential curves showed in many instances two one-electron waves, indicating that the two following reactions occurred ... 

Schematic representation of typical curves for hydrogen uptake and catalyst potential for the hydrogenation of aromatic halonitro compounds.

Figure 1. Thermodynamic equilibrium in atmospheres of varying elemental proportions. The ternary diagram shows all compositions of systems containing carbon, hydrogen, and oxygen (each point represents 100% of the three components). Lower curves indicate the potential formation of solid carbon if equilibrium could be attained. Dashed curve holds at 500°K., the continuous one at 700°K. The upper lines indicate the asphalt threshold, the dashed one at 500° K., and the continuous one at 700° K. Above this threshold, thermodynamic equilibrium favors the formation of large proportions of polycyclic aromatic compounds ( asphalt ) ana a lesser increase of most of the other families of compounds. The dots through points A to C indicate the points used in the computations for Figure 2 (6).

Figure 3.16. The Stern-Volmer constant as a function of the half-wave potential E /2 for the reactions with trivalent phosphorus compounds (o), aromatic amines ( ), aliphatic amines ( ), and alkoxybenzenes (A)- The solid broken line represents the diffusional (horizontal) and kinetic branches of Ko for the irreversible reaction, while the dotted line is k from Eq. (3.22). The dashed curve represents Ko for reversible reactions. (From Ref. 121.)...

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