Before starting each set of experiments, the mixing tank and the
shock tube are cleaned thoroughly with acetone. Subsequent to the
cleanup, the mixing tank, connecting tubes, and the shock tube are
heated to 100 C overnight and turbomolecular pumped to
0.9 lTorr to ensure no residuals are left prior to performing the
experiments. The mixtures used in the experiments were prepared
while the stainless steel mixing vessel is uniformly heated to 50 C.
A double-dilution process was utilized when preparing mixtures
for fuel + OH rates measurements to obtain more accurate concentrations
in the mixing tank [26]. The mixtures are left to mix for 2 h
prior to performing the experiments. Hydroxyl radicals were
produced by rapid thermal decomposition of the OH precursor
tert-butyl hydroperoxide (TBHP), where TBHP is known to be a
clean OH precursor and have been validated in many studies
[24,26,29–34]. The TBHP decomposition rates are also very wellknown
[30]. A 70% TBHP in water solution, 2-butanone (P99.7%),
and 3-buten-2-one (P99.7%) were obtained from Sigma Aldrich.
Research grade argon (99.999%) and research grade oxygen
(99.999%), supplied by Abdullah Hashim Gases (AHG), were used
to make test mixtures.