A comprehensive review on flash point behavior of binary ignitable mixtures: Trends, influencing factors, safety and fuel design implications, and future directions

The flash point (FP) behavior of binary ignitable mixtures, which are the simplest form of mixtures and fundamental building blocks, is essential for understanding multicomponent mixture behavior. This knowledge plays a vital role in process and chemical safety as well as in fuel design. In the present review, the FP of 245 independent binary ignitable mixtures, composed of 102 individual pure compounds derived from 69 published articles, was investigated. The mixtures based on their chemical class were categorized. Investigations on their ideal or extreme FP behaviors revealed that certain combinations have a higher potential for demonstrating extreme FP behaviors such as alcohol + aromatic hydrocarbon, alcohol + ester, alcohol + alkane, aromatic hydrocarbon + organic acid, alcohol + organic acid, phenol + alcohol, phenol + ketone, and phenol + pyridine. It was found that the occurrence of extreme FP behaviors is not only related to the chemical class but also to the molecular structure, the non-ideality of binary mixture, and the temperature gap between FP values of the pure constituents in each binary blend. These findings can be utilized to enhance the safety level of processes or operations involving these binary mixtures. Furthermore, this information can be valuable in fuel design for specific purposes and improve combustion, thanks to a comprehensive knowledge regarding the FP tendencies of each binary category and the potential for extreme FP behaviors.