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• Initial oxidative decomposition path and energy change of fluoroethane are obtained. • Energy changes of reactions of six active radicals with fluoroethane are compared. • Fluoroethane generates more than 20 products through two main radicals ·CH3 and ·CH2F. • Intermediates are easy to combine to form products rather than continue to decompose. Fluoroethane is a potential fluid or component of new environmentally friendly working fluids, but its flammability affects its direct application. The oxidative decomposition mechanism of the working fluid is the key to further study its flammability or stability. Therefore, the oxidative decomposition mechanism of fluoroethane was researched by density functional theory. Firstly, seven initial thermal decomposition paths of fluoroethane and four oxidative decomposition paths involving oxygen were obtained, among which the main initial decomposition products were CH 2 =CH 2 and HF, and the free radicals were ·CH 3 , ·CH 2 F, H·, HOO·, etc.; Secondly, the main reaction process of six typical active radicals generated by the chain reaction and fluoroethane was also studied, and it was found that the energy barrier of the hydrogen-extraction reaction was lower than that of the fluorine-extraction reaction, and most of the reactions were exothermic reactions; Finally, the subsequent reaction processes of the main radicals ·CH 3 and ·CH 2 F in the decomposition of fluoroethane were analyzed, and more than 20 possible products and their energy changes were obtained. The relevant results have guiding significance for weakening the flammability of fluoroethane, improving its thermal stability and evaluating its oxidative decomposition products from the deep mechanism. [ABSTRACT FROM AUTHOR]

[Display omitted] • Flammability limits of the new binary mixture R1234ze(E)/R32 was measured. • Oxidative decomposition and interaction mechanisms of R234ze(E)/R32 were studied. • R32 decomposes preferentially and R1234ze(E) is more likely to react with radicals. • CF 3 plays an important role in R1234ze(E) inhibiting flammability of R32. At present, mixed working fluids have received increasing attention due to their excellent comprehensive performance. Among them, R1234ze(E) (trans -1,3,3,3-tetrafluoropropene) and the R32 (difluoromethane) with excellent thermal properties can form a safe and environmentally friendly new mixture through advantageous complementarity. In this paper, the flammability of the binary mixture R1234ze(E)/R32 mentioned above was studied. Firstly, the flammability limits and critical concentration inhibition ratio of R1234ze(E)/R32 were tested at different ratios. Then, based on density functional theory (DFT), the interaction mechanism between the two components in the mixture was analyzed. The results show that with the increase of R1234ze(E), the flammable limit range becomes narrower. In the early stage of the reaction between R1234ze(E)/R32, R32 preferentially breaks the bond to generate H and F radicals, but the reactions between R1234ze(E) and free radicals are dominant. CF 3 radical is an important free radical for R1234ze(E) to inhibit the flammability of R32. The research results will have guiding significance for the internal interaction mechanism of the flammability of new binary mixtures and their safe applications. [ABSTRACT FROM AUTHOR]