Skeletal transformations of cyclic hydrocarbons

Huang et al. reacted the mixture of 97% n-octane plus 3% propyl-[1-ring C]-cyclopentane on Pt/KL zeolite.The radioactive label appeared 

Reacting ring-labelled and side chain labelled ethylbenzene and m-xylene on industrial Pt/A Os gave further information on the possible pathways of xylene isomerisation discussed in the previous section. The reaction of labelled ethylbenzene gave a considerable amount of [ C] label in the aromatic ring of xylene products, indicating the importance of ring 

Initial Label Position H2 Pressure, MPa Distribution of the Methyl Group Label Ring 

All the studies mentioned determined the position of the label as CO2 after proper oxidation processes. Another possible method can be pyrolysis of alkanes.Pulses of various [ C] labelled hydrocarbons (butadiene, pentene, cyclopentadiene, alkanes, alkylbenzenes) were introduced into an inert gas stream, then passed through a heated reactor, and the pyrolysis products (methane, Ci fragments and benzene) were analysed by a gas chromatograph equipped by a mass and a radioactivity detector. The temperature was kept between 873 and 1050 K, while the decomposition of aromatics required higher temperatures. With conversions between 5 and 90%, an accuracy of 5% could be reached. 

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