THE MERCURY-PHOTOSENSITIZED DECOMPOSITION OF PROPANE: A MASS SPECTROMETRIC STUDY AT LOW PRESSURES: PART I

Abstract

It is found that the primary decomposition involves the cleavage of a C—H bond. Both primary and secondary hydrogen atoms are lost. The relative rates of the two processes could not be determined accurately but are estimated to be approximately 1:1. It is found that at least 70% of the secondary reactions involves the interaction of hydrogen atom with a propyl radical. The main reaction is the re-formation of propane. An important disproportionation of hydrogen atoms with propyl radicals leading to propylene is shown to occur. The atomic cracking reaction H + C3H7 → C3H8* → C2H5 + CH3 is also observed. Using mixtures of C3H8 and C3D8 the relative cracking rate of n-propyl- to isopropyl-derived propane is determined to be equal to 5. This result is compared with theoretical predictions.