Theoretical Insights into the Atmospheric Chemistry of 1,1-Difluoroacetone: Reactions with OH Radicals and Cl Atoms and Its Further Degradation

Abstract

This study investigates the atmospheric chemistry of 1,1-difluoroacetone (DFA), a potential alternative to harmful halogenated compounds. Using high-level computational methods, CCSD(T)/aug-cc-pVTZ//M06-2X/6-311++G(d,p), we explored the reaction mechanisms, rate coefficients, atmospheric lifetime, and global warming potential (GWP) of DFA. DFA primarily undergoes H-abstraction reactions with OH radicals and Cl atoms, with rate coefficients values of 1.04 × 10^–13 and 3.45 × 10^–13 cm³ molecule^–1 s^–1, respectively, at 298 K. Its atmospheric lifetime is estimated to be 0.30 years. GWP values are 37.7, 10.7, and 3.25 over 20-, 100-, and 500-year horizons. The COF₂, CO, CO₂, and HCOH are key degradation products. Notably, difluoromethylglyoxal (DMGLY) was identified as one of the possible degradation products, with a calculated rate coefficient for the reaction with OH radicals amounting to 0.54 × 10^–11 cm³ molecule^–1 s^–1. These findings offer insights into DFA’s atmospheric behavior and environmental impact, supporting its consideration as an alternative to more harmful compounds.