The UV spectrum of acetyl and the kinetics of the chain reaction between acetldehyde and chlorine

Time resolved UV spectroscopy has been used to investigate the role of acetyl radical in the photolytically initiated chain reaction of acetaldehyde with chlorine. At a resolution of 2 nm, acetyl has a broad, unstructured, absorption in the 200–280 nm range, with a peak cross section of (1.07 ± 0.11) × 10−17 cm2 at 217 nm. The chain propagation reaction between acetyl and molecular chlorine has a measured rate constant of k2 = 2.8−0.8+1.1×10−11 e(−47±91)/T cm3 s−1 while the chain terminating self reaction proceeds with a rate constant of k3 = 3.9−1.4+2.3×10−12 e(450±120)/T cm3 s−1.