Polyynes production in a solvent-submerged electric Arc between graphite electrodes. III. Chemical reactivity and stability toward air, ozone, and light

Since polyynes are easily accessible with the submerged electric arc synthesis between graphite electrodes, the chemical behavior of polyynes solutions in different solvents has been explored. It has been found that surprisingly the polyynes solutions, with polyynes having up to 16 carbon atoms arranged in a chain, are, stable in air over 1 week time in the dark. These solutions react relatively slowly with ozone while add rapidly and completely bromine. The polyynes solutions are instead quit e easily photolyzed under the action of UV radiation both in air and under N-2. Two different light sources were used in the study: a low pressure mercury lamp emitting almost a monochromatic radiation at 254 nm and an high pressure mercury lamp emitting in a broad wavelength range in the ultraviolet. With the former monochromatic light source, it has been demonstrated the possibility to perform a selective photolysis of selected polyynes in a mixture of homologous series.