Chemical reactions in high voltage discharges

Abstract

Ultra-violet light, radiations from radio-active materials and electrical energy have been used in various ways for synthesis of organic and inorganic compounds. Of these three, the latter is most useful since;- 1. reactions with ultra-violet light take place in a small volume because of radiation absorption; 2. radio-active materials are usually recovered only in small concentrations. It is thus difficult to obtain a curie (3.7 x 10 10 disintegration per second) of suitable material cheaply whereas a coulomb (amp-second) of electricity, corresponding to 6.3 x 10 18 electrons, can be readily realised with suitable equipment. Chemical syntheses involving electrolysis usually have high yields associated with them, but are limited to oxidation and reduction reactions. For more general reactions,a useful form of supply of electrical energy for synthetical reactions is the high voltage discharge. There are two fundamentally different types of electrical discharge, the silent or non-disruptive and the disruptive. The former includes a number of types such as: the ozoniser, semi-corona, corona and glow discharge. These have been used in numerous investigations oxygen to ozone: Anderegg. F. 0., J. Amer. Chem. Soc., 39, 2581 (1917), hydrocarbons: Jakosky J. J., Bur. Mines, Tech. Paper, 375, (1926) 21. C.A. 21, 1701, (1927) with a variety of substances. There is no doubt that in many cases atoms and radicals are formed by the decomposition of organic and inorganic compounds in these discharges Rice F. O. and Whaley F. R., J. Amer. Chem. Soc. 56, 1311 (1934). However, the situation is usually too complex to permit any accurate conclusions as to the rates of elementary reactions. On the other hand, the results are frequently of value as confirmatory evidence for postulated mechanisms and a means for synthesis. The best example of synthesis is of ozone from oxygen in the silent discharge.