Flash point of binary mixtures of chlorinated hydrocarbons with toluene and their predictability with existing mixing rule

• Published in: Process safety progress Vol. 39; no. 3
• Main Authors: Fayet, Guillaume, Tribouilloy, Benoit, Rotureau, Patricia
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.09.2020; John Wiley and Sons, Limited; Wiley
• Subjects: Binary mixtures; Chlorinated hydrocarbons; chlorinated solvents; Chlorination; Dichloromethane; Environmental Engineering; Environmental Sciences; Flammability; Flash point; Hydrocarbons; Liquid surfaces; Mixing rules; mixtures; Solvents; Toluene; Trichloroethylene; UNIFAC; Vapors; FLASH POINT; MIXTURES; CHLORINATED SOLVENTS; UNIFAC
• ISSN: 1066-8527; 1547-5913
• DOI: 10.1002/prs.12127

The flash points of binary mixtures of toluene with two chlorinated hydrocarbons (trichloroethylene and dichloromethane) at different concentrations were investigated to evaluate their predictability by existing mixing rules. Measurements were performed using both open and closed cup flash point testers highlighting complex ignition phenomena. Beyond a certain level of concentration in chlorinated compound, no proper flash is observed, in our test conditions when the flame is presented, but specific behaviors are observed that did not allow the definitive determination of a flash point. The observed phenomena can be attributed to the formation of halogenated radicals, presenting flame‐retardant behaviors, by decomposition of the chlorinated vapors at the contact of the flame. Existing mixing rules are based on the consideration of the vapor‐liquid equilibrium defining the amount of flammable vapors above the liquid surface. So, the application of such mixing rule failed predicting this specific phenomenon, more likely related to a specific reactivity problem. This work also confirms that the sole consideration of the flash point to investigate the flammability of such mixtures may lead to an underestimation of their actual hazard. Additional experimental tests should be conducted to investigate deeper the flammability of such liquid mixtures.