Radiofrequency discharge reaction

This reaction provides a third indication of the usefulness of a radiofrequency discharge in the synthesis of compounds of low thermal stability. The more-stable (CFaljTej had been prepared by the interaction of CFj radicals, formed in the pyrolysis of (CF3)2CO, with a tellurium mirror (19). The less-stable (CFsljTe was not, however, observed in that experiment. 

Thus, there are at least two important chemical differences between these reactions in (a) the radiofrequency discharge in an annular ozon-izer-type reactor at pressures near 200 torr, and (b) the microwave discharge in a cylindrical reactor at pressures of 12 or 50 torr. Under the microwave conditions, C2H2 is always produced (together with CH4) from H2 + CO and H2 + C02 (without cooling) form CO but no hydrocarbons. Obviously, it would be extremely useful to understand these phenomena. We have explored this situation a bit further, in the following manner. 

The work described here is an attempt to systematize the study of benzene reactions in radiofrequency discharges. The only products isolated in these reactions were diphenyl, a liquid polymer and a solid polymer. The polymers appear to be polystyrenes. 

Some routes to (SN), that do not involve (SN)2 as an intermediate are available (see 15.2.12.3). The polymer is obtained in high yield from the reaction of (NSC1)3 with trimethylsilyl azide in acetonitrile - , by the electrochemical reduction of [(SN)5] salts ", and by radiofrequency discharge through (SN)4 vapors in a helium plasma. Other reactions that produce (SN), include the reduction of S2N" with azide ion, the solid state polymerization of impure S4N2 (recrystallized S4N2 does not polymerize) , and the oxidation of (SN)J with certain electrophiles . 

Bis(trifluoromethyl)mercury is useful in the preparation of numerous CF3 derivatives, especially of group IV elements. It was first prepared in 1949 by irradiation of CF3I and Hg in the presence of Cd. Alternative routes include radiofrequency discharge methods, for example, reaction of CF3 radicals witli HgXz or elemental mercury. Preparative scale quantities are best obtained by decarboxylation of mercury trifluoroacetate in the presence of carbonate. ... 

A reaction in N2 similar to (51) and (52) has been proposed by Lund and Oskam from mass spectrometric studies of the time dependences of the ionic species present in the afterglows of pulsed radiofrequency discharges in nitrogen. Specifically, they suggest... 

High yields of gaseous hydrocarbons from H2 + CO have now been shown to occur in low-frequency [50 Hz. (8) and 60 Hz. (24)] discharges between electrodes, and electrodeless radiofrequency (2-110 MHz.) (6) and microwave (2450 MHz.) discharges. However, in all of these cases, the reaction does not appear to be an extremely rapid one, such as is the case for dissociation of diatomic molecules in a discharge, for instance. 

The significance, if any, of the values calculated for Ku etc., and the temperature numbers is not known. However, there are chemical differences between the reactions under microwave and radiofrequency conditions, and perhaps this is reflected in the difference between these numbers for different discharges. 

In recent years, benzene has been subjected to direct electrode discharge (20) and glow discharges induced by microwave (22, 23) and radiofrequency (21) energy. In this paper, we report some of our observations for the reaction of benzene in a corona discharge. 

DRC Dynamic reaction cell RF-GDMS Radiofrequency glow discharge mass... 

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