Fig. 2. (a) OH sensitivity analysis, SOH=(∂XOH/∂ki)/(XOH/ki)SOH=(∂XOH/∂ki)/(XOH/ki). (b) ΔOH sensitivity, SΔOH=(∂ΔXOH/∂ki)/(ΔXOH/ki)SΔOH=(∂ΔXOH/∂ki)/(ΔXOH/ki).Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 3. Uncertainty analysis for the measured rate constant of CH3CHO + OH.Figure optionsDownload full-size imageDownload as PowerPoint slide
4. Summary of results
A total of 61 reflected shock wave experiments were performed to determine the overall rate constants for the reactions of OH with four aldehydes (CH2O, CH3CHO, C2H5CHO and n-C3H7CHO) at near-pseudo-first-order conditions. Experiments were carried out over the temperature range of 950–1400 K at pressures of 1–2 atm using different initial fuel and TBHP concentrations. Results Glimepiride summarized in Table 1.
As expected, the uncertainties in the rate constant measurement were seen to decrease at higher aldehyde/TBHP ratio (Fig. 4). However, though Ordovician extinction was tempting to use even higher aldehyde/TBHP ratio, the increased uncertainties from the thermal decomposition of aldehydes at very high temperatures and from the manometric preparation of very dilute TBHP mixtures eventually limited the measurement accuracy. The current choices of aldehyde/TBHP had already accounted for the tradeoff between these different uncertainty sources. Despite the variations in uncertainty limits, all data points followed the same trend and were seen to be very consistent. Experiments at a higher pressure (∼4 atm) were included, and no pressure dependence was observed, which suggested that the overall OH + aldehydes rates measured in the current study were probably dominated by H-abstraction.