ABSTRACT
Electrodes in Water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 15.4 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 336 Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 337
The bulk synthesis of cyanopolyynes (called also cyano-and dicyanoacetylenes) is quite a complicated task. Hopf and Witulski have reviewed the organic synthesis of these molecules proposing the best synthetic route [1]. However, monocyanopolyynes and dicyanopolyynes can be easily produced in very small quantities by laser ablation of graphite targets in a He carrier gas in the presence of certain reactants [2,3]. For instance, when acetonitrile was added to the system, monocyanopolyynes were detected, but when N2 was used as reagent dicyanopolyynes were formed [2,3]. With an excess of H2 instead the exclusive products were hydrogen-terminated polyynes [2,3]. The synthesis of polyynes with laser ablation is an approach sufficient to feed a mass spectrometer to identify the products but is not useful for bulk synthesis. Cyanopolyynes were obtained in larger quantities when cyanogen gas at low pressure was admitted to the chamber confining the carbon arc working under the Kratschmer-Huffman conditions [4,5]. In the present chapter the production of monocyanopolyynes and dicyanopolyynes produced with the submerged electric arc technique is reported. Thus, data will be presented concerning the formation of polyynes R-(CC)n-R0 with R¼H andR0 ¼CN (monocyanopolyynes) and with R¼R0¼CN (dicyanopolyynes) in the electric arc under special conditions.
