Atmospheric ozonolysis study of methyl acrylate and methyl 3-methyl acrylate

Abstract

Detailed reaction mechanisms of methyl acrylate (MA) and methyl 3-methyl acrylate (M3MA) with ozone have been investigated using quantum chemistry calculations based on the CCSD(T)/6-31G(d)+CF//B3LYP/6-31+G(d,p) level of theory. Possible reaction channels and products have been presented and discussed. The temperature-dependent and pressure-independent overall and site-specific rate constants are calculated by employing multichannel RRKM theory. The obtained overall rate constants (in cm3 molecule−1 s−1) based on the CCSD(T)+CF energies can be described as: $$ k_{{({\text{MA}} + {\text{O}}_{ 3} )}} = 3. 7 4 \times 10^{ - 1 3} { \exp }\,( - 3 7 4 6. 1 2/T) $$ and $$ k_{{({\text{M3MA}} + {\text{O}}_{ 3} )}} = 5. 1 2 \times 10^{ - 1 3} { \exp }( - 3 3 5 4. 8 7/T) $$ at 200–400 K and 760 Torr. Under atmospheric conditions, the dominant products of ozonolysis of MA and M3MA are methyl glyoxylate and formaldehyde, methyl glyoxylate and acetaldehyde, respectively. The results of theoretical study are in good agreement with the available experimental measurements. Researches on branching ratios and atmospheric lifetimes also have been obtained as complement to the experimental results.