Abstract:
The technique of IR LPHP has previously been shown to be of considerable benefit to the elucidation of gas phase pyrolysis decomposition mechanisms. This study used the IR LPHP technique in conjunction with copyrolysis experiments, bromo-substituted compounds, detailed product analyses, and theoretical calculations to investigate the thermal decomposition of selected azines and 5-membered ring species important from environmental perspectives. The decomposition reactions for the majority of azine species were found to proceed via radical C-H bond fission whereas the analogous initiation reactions of the 5-membered ring species varied from radical C-H fission to C-heteroatom bond scission depending on the relative 'aromaticity' of the ring structure. The IR LPHP technique has also been investigated in conjunction with tuneable diode laser spectroscopy in order to investigate a novel method of generating transient precursors for high resolution infrared spectroscopy. Numerous preliminary results indicate that this technique is an effective and efficient method of generating transient species, possessing numerous advantages over conventional thermal generative techniques. Initial spectroscopic investigations include the preliminary derivation of spectral constants for the v2 band of 2H2-ketene, whereas the equivalent band of 1H2-ketene appears to be heavily perturbed. Future applications of the IR LPHP method look certain to include solution injection laser pyrolysis (SILP) enabling the pyrolysis of involatile and possibly ionic precursors.