The gas phase reactions of hydroxyl radicals with a series of esters over the temperature range 240–440 K

✍ Scribed by Timothy J. Wallington; Philippe Dagaut; Renzhang Liu; Michael J. Kurylo

• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 485 KB
• Volume: 20
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.550200210

✦ Synopsis

Absolute rate constants were determined for the gas phase reactions of OH radicals with a series of esters using the flash photolysis resonance fluorescence technique. Experiments were performed over the temperature range 240-440 K at total pressures (using Ar diluent gas) between 25-50 torr. The kinetic data for methyltrifluoroacetate (k,) over the complete temperature range, and for methylacetate (kz), and ethylacetate (k,) over the range 296-440 K were used to derive the Arrhenius expressions;

molecule-' s-' At 296 K, the measured rate constants (in units of cm3 molecule-' s-') were: k , = (0.52 ? 0.08), k, = (3.41 t 0.29), and k3 = (15.1 ? 1.4). Room temperature rate constants for the OH reactions with several other aliphatic esters were also measured. These were (in the above units): methylformate, (2.27 t 0.34); ethylformate, (10.2 f 1.4); n-propylformate, (23.8 ? 2.7); n-butylformate, (31.2 ? 3.3); npropylacetate, (34.5 ? 3.4); i-propylacetate, (37.2 f 2.9); n-butylacetate, (41.5 * 3.0); s-butylacetate, (56.5 f 5.9); methylpropionate, (10.3 t 0.4); ethylpropionate, (21.4 ? 3.0); n-propylpropionate, (40.2 t 3.2); methylbutyrate, (30.4 2 3.3); ethylbutyrate, (49.4 ? 3.8); n-propylbutyrate, (74.1 ? 3.21, and n-butylbutyrate, (106 ? 131, error limits represent 2 a from linear least-squares analyses. The results are discussed in terms of the reaction mechanisms and are compared to previous literature data.