Promotion by SF6 of a Radiolytically Induced Chain Reaction for the Geometrical Isomerization of cis or trans-Butene-2 in Dilute Gaseous Mixtures
FOR several years SF6 has been used in radiolytic studies because of its high cross-section for capture of low-energy electrons and consequent effect on observable products resulting from positive-ion neutralization reactions. A reduced yield of H2 from irradiated propane has been reported1 and attributed to electron scavenging by the small proportions of SF6 present. On the other hand, SF6 does not affect the H2 yield from irradiated liquid unsaturates such as trans-butene-2 (ref. 2), indicating that ionic species may not be important with respect to H2 formation from these olefines.
Hydrogen Formation in the Radiolyses of Liquid Butene−1 and trans‐Butene−2
The effect of temperature and various electron or positive‐ion scavengers on hydrogen formation in the radiolyses of liquid butene−1 and trans‐butene−2 have been examined. The hydrogen formation is not appreciably affected by temperature and these additives, which indicates that thermal free radicals and ionic species may not play an important role in hydrogen formation from these olefins. The liquid‐phase radiolyses of C4H8−1—C4D8−1 and trans‐C4H8−2‐trans‐C4D8−2 mixtures have also been investigated. The data indicate that hydrogen for the most part may be formed by bimolecular processes. The results have led to the conclusion that the mechanism of the hydrogen formation may be interpreted in terms of the hydrogen‐atom abstraction reaction of hot hydrogen atoms or the equivalent formed by the direct excitation which may involve ``superexcitation.''
THE NITROUS OXIDE RADIATION DOSIMETER
The initial yield of nitrogen from nitrous oxide (1 atm, 20 deg C) irradiated with Co/sup 60/ gamma rays was G/sub N2/ = 12.8 plus or minus 0.4 molecules per 100 ev. The energy absorption was determined by ionization current measurements. Determination of the energy absorbed by the Fricke dosimeter gave G/sub N2/ = 12.0 plus or minus 0.4. The initial G/sub N2/ was independent of the pressure of N/sub 2/O between 200 and 760 mm Hg and of dose rate between 0.73 and 3.0 x 10/sup 14/ ev ml/sup -1/ min/sup -1/. G/sub N2/ was not independent of tot al dose but decreased at doses greater than about 2.4 x 10/sup 17/ ev ml/sup - 1/, having a value of 9.3 at 2.5 x 10/sup 18/ ev ml/sup -1/. The yields of nitrite, formed when the irradiated gas was extracted with sodium hydroxide solution, and of oxygen were determined. (auth)