Tetraalkylammonium graphite

The first catalysts reported for the electroreduction of C02 were metallophthalocyanines (M-Pc).126 In aqueous solutions of tetraalkylammonium salts, current-potential curves at a cobalt phthalocyanine (Co-Pc)-coated graphite electrode showed a reduction current peak whose height was proportional to the C02 concentration and to the square root of the potential sweep rate at a given C02 concentration. On electrolysis, oxalic acid and glycolic acid were detected, but formic acid was not. Mn and Pd phthalocyanines were inactive, while Cu and Fe phthalocyanines were slightly active. At the potentials used for C02 reduction, M-Pc catalysts would be in their dinegative state, and the occupied dz2 orbital of the metal ion in the metallophthalocyanine was suggested to play an important role in the catalytic activity. 

In principle, the negatively charged, presumably planar network I can be combined with one molar equivalent of tetraalkylammonium ion IGN"1" of the right size as interlayer template to yield a crystalline inclusion compound of stoichiometric formula (IGN+) I C(NIG ) ICO2 that is reminiscent of the graphite intercalates. Anionic network n, on the other hand, needs twice as many monovalent cations for charge balance, and furthermore possesses honeycomb-like host cavities of diameter 700 pm that must be filled by... 

Amalgrams are alloys between mercury and a metal however, compounds that are not proper amalgams but function in a way similar to amalgams are also treated in this chapter. Thus, alloys between tetraalkylammonium and mercury or some other metals and also some interstitial compounds, for example, with graphite, are included in this review, even if these compounds have only a limited lifetime and are formed only as intermediates during direct electrolysis. 

TAA ions may make interstitial compounds with graphite [23,24] that have reducing properties similar to those of the tetraalkylammonium metals. 

Nonporous and porous graphitized carbon black solid beds (NPGC and PGC, respectively) are also used for herbicide isolation from water samples. Chlorophenoxy herbicides (requiring online derivati-zation with tetraalkylammonium salts), acetanilides, neutral diphenyl ethers, triazines, phenyl ureas, triazoles, benzimidazoles, phenoxyalkanoic acids, and quats (paraquat, diquat, difenzoquat) are readily isolated on graphitized carbon beds. 

Dane, C. Insertion cathodique des ions tetraalkylammonium dans le graphite et le platine reactivite, fonctionnalisation et applications., Ph.D. thesis. Universite de Rennes 1, 1998. 

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