Electrolysis competence, comparative

As a further possibility the ac electrolysis may lead to other products than those of the photolysis. In this case an excited state mechanism is, of course, excluded. Although there is a certain similarity between the electronic structure of an excited state and the reduced or oxidized form of a molecule, they are not identical. Consequently, it is not surprising when photolysis and electrolysis do not yield the same product. Another reason for such an observation may be the different lifetimes. An excited state can be extremely short-lived. Non-reactive deactivation could then compete successfully with a photoreaction. The compound is not light-sensitive. On the contrary, the reduced and oxidized intermediates generated by ac electrolysis should have comparably long life times which may permit a reaction. The ac electrolysis of Ni(II)(BABA)(MNT) (BABA = biacetyl-bis(anil) and MNT - = disulfidomaleonitrile) is an example of this reaction type (63). 

There is still no reliable basis for the calculation of prices. In connection with the production of protein from molecular hydrogen and carbon dioxide, an electrical biomass equivalent has been calculated (Schlegel, 1969). It is based on the experimental data with respect to the amount of hydrogen consumed and biomass produced. The hydrogen which can theoretically be produced from 1 kWh by electrolysis of water is equivalent to 66 g biomass or at least 33 g bacterial protein. If, for comparative purposes, one considers the costs of other unconventional crude materials such as hydrocarbons or methane and includes costs for oxygen, carbon dioxide and mineral salts, biomass production on the basis of hydrogen can compete successfully with the processes mentioned. 

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