Ethane tritium-labelled

CH4 + H2 — CH3 H reaction and the a -term to the exchange with radiation-activated H2 or to reactions involving radicals or excited states. Besides tritium-labelled methane, labelled ethane, ethylene, propane, i-C4Hio, n-C4Hio, Mel and higher hydrocarbons have also been isolated. 

Reactions (8) to (10) not only explain qualitatively the formation of the three major products, but allow a rough evaluation of the abundance of labeled methyl ions former", from the decay. Assuming, in the absence of more detailed information, a statistical distribution of tritium between the products of reaction (9), the activity of HT from reaction (9) is equivalent to 2/5 of the activity contained in the ethyl ions, eventually isolated as tritiated ethane. Therefore, the yield of HT from reaction (9) can be calculated to be 7-0 x 2/5 = 2-8%, and the fraction of the methyl ion undergoing reaction (9), 9-8%. Comparing this figure with the fraction (78%) of labeled methyl ions that react with CgHg to yield... 

Radioactive decay of tritium in H-labelled ethane leads to the formation of ethyl ions ( 80%) and fragments of ethane (s 20%). Because the recoil energy is too low to break C-C bonds, fragmentation of the ethane molecule must be due to excitation effects. 

---