The shock tube pyrolysis of pyridine

Fossil fuels such as coal and heavy fuel oils contain up to about 2 per cen t by weight of fuel nitrogen, most of this being present in pyridine or pyr olic aromatic structures. Under pyrolytic conditions these ring structures decompose to give HCN and CH3CN. For present day computer modelling of NO, formation in flames it is necessary to know the mechanism and rates of reac tion. A number of previous studies of pyridine pyrolysis have been undertak en using shock tubes or flow reactors. In this present study a shock tube w as used to obtain the kinetics of pyridine decomposition in the range 1590- 2335 K and with pressures between 2.2 and 3.4 atm. Two independent sets of data were obtained. One set of results was found to be represented by an Ar rhenius rate constant k = 10(9.7+/-0.5) exp ( - 220.0 kJ mol(-1) RT-1)s(-1) . For the other work k = 10(9.8+/-0.5) exp (-228.191 +/- 18.42 kJ mol(-1) R T-1)s(-1). In addition, the pyrolysis mixtures of pyridine plus toluene have also been studied to understand the synergistic effects. The results indicated the s trong involvement initiated by fission of the pyridine ring system. Copyrig ht (C) 2000 John Wiley & Sons, Ltd.