Nuclear radiation-induced cracking of n-hexadecane

A representative paraffin hydrocarbon in the gas oil range, n-hexadecane, has been irradiated in the Industrial Reactor Laboratories' 5 mw. nuclear research reactor. In the vapor phase radiation-induced cracking proceeded efficiently, and G values for radiation conversion of n-hexadecane were 200 to 1,200 at temperatures near 750°F. Total conversions of n-hexadecane were less than 3 wt. % and were due only in part to the radiation effect. The distributions of products which were obtained were similar to those which result from thermal cracking of n-hexadecane. There were however significant increases in the yields of hydroger., reductions in the yields of very light hydrocarbons and small yields of high molecular weight products. At temperatures above 850°F. extensive thermal cracking obscured the effects of radiation. In liquid phase radiation-induced cracking at 750°F. conversions of n-hexadecane up to 15 wt. % have been obtained at liquid spaces velocities near 4 v./hr./v. In many exposures nearly one-half of this conversion was attributed to the direct utilization of radiation. The corresponding G values were 30 to 60. The products obtained have been accounted for by adding together the products which would be expected from a radiation-induced reaction producing primarily dimer, from radiation-initiated chain propagated cracking, and thermally initiated chain cracking. The product distribution from these reactions can be changed by variation of the cracking temperature and/or radiation dose.