Study on pyrolysis behavior of long-chain n-alkanes with photoionization molecular-beam mass spectrometer

Abstract To understand the pyrolysis behavior of long linear alkanes, six n-alkanes (n-CnH2n+2, n = 10, 12, 13, 14, 15, 16) were conducted by pyrolysis coupled with photoionization molecular-beam mass spectrometer at pressure below 10 Pa and temperature between 200 °C and 1000 °C. Lots of important alkyl and alkenyl radicals (CH3, C4H9, C8H15, C9H19, C3H5, C5H9, etc.), which are the direct evidence to understand the pyrolysis reaction pathway, were real-time detected by mass spectral detector. The results suggested that the predominant pyrolysis mechanism of n-alkanes is a free-radical chain mechanism, beginning with the C C bond homolysis of n-CnH2n+2 to produce primary alkyl radicals (CmH2m+1, m