Excellent Thermal Stability and Environmental Sustainability of Trifluorodimethyl Sulfide as a Potential Alternative Refrigerant

Trifluorodimethyl sulfide (CH 3 SCF 3 ) has been proposed to be a potential alternative refrigerant based on various rigorous quantum chemistry calculations. It is revealed that the half F-substitution is capable of tuning the stability and reactivity of dimethyl sulfide (CH 3 SCH 3 ) significantly. The strength of both S–C bonds is enhanced. The bond dissociation energies increase by 5–6 kcal/mol with respect to CH 3 SCH 3, and decomposition temperature of CH 3 SCF 3 is predicted to be 875 K. Meanwhile, the existence of CH 3 group keeps the good reactivity of CH 3 SCF 3 toward OH radicals in the troposphere. Complex-forming H-abstraction to produce H 2 O and CF 3 SCH 2 radicals is the predominant mechanism accompanied by minor S–O association/elimination pathways. The atmospheric lifetime and radiative efficiency of CH 3 SCF 3 is 0.2–1 years and 0.25 Wm 2– ppb –1, respectively, leading to a global warming potential of 9–90 for a 100-year time horizon. The possible degradation products of CH 3 SCF 3 in the atmosphere include both radicals, e.g., CF 3 SCH 2 OO, CF 3 SCH 2 OONO, CF 3 SCH 2 OONO 2, CF 3 SCH 2 O, CF 3 S, and molecules, e.g., (CF 3 SCH 2 OO) 2, CF 3 SCH 2 OOH, CH 2 O, and CH 3 S(O)CF 3 . The present computational work not only provides interesting insights into the dramatic impact of the partial fluorination on stability and reactivity of sulfides but also demonstrates that CH 3 SCF 3 should be a viable refrigerant replacement for hydrofluorocarbons and even hydrofluoroolefins with excellent thermal stability and environmental sustainability.