Photochlorination of propane

The chlorination of propane was studied in a tubular flow reactor, with outside illumination, at atmospheric pressure. At chlorine concentrations of less than 1.5 mole % (and inert nitrogen above 94%) a second‐order (in chlorine) rate expression was indicated. At higher chlorine or propane concentrations propane affects the rate. Two rate equations, based upon different termination steps for the chain carriers, were found to fit the data. For the low concentration region the apparent activation energy for the overall reaction was 3.4 kcal./g.‐mole. Most of the measurements were carried out with polychromatic light, but data taken with a narrow band of radiation, over the range 2,200 to 5,400Ā, showed an increase in rate with decreasing wave length. As a first step toward reactor design, differential reactor data were used to predict the conversion for laminar flow, integral reactor conditions. A reactor model which included the effects of residence time distribution and radial variation in light intensity gave good agreement with experimental data. A plug‐flow model was less satisfactory.