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

Abstract

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.

Evaporation Kinetics of Liquid Mixtures and Safe Handling

“…Incorporation of the data pair for n -butyl acetate makes no change in the parametric values. The result observed for the pair C 2 HCl 3 /Ph-CH 3 was not included in the fitting . The T f value reported for this binary mixture, although doubtlessly dependable, may not be mechanistically accounted for solely on volatility but rather in terms of reactivity causes like the formation of flame-retardant products in the decomposition of these types of halogenated molecules …”

“…The result observed for the pair C 2 HCl 3 /Ph-CH 3 was not included in the fitting. 40 The T f value reported for this binary mixture, although doubtlessly dependable, may not be mechanistically accounted for solely on volatility but rather in terms of reactivity causes like the formation of flame-retardant products in the decomposition of these types of halogenated molecules. 40 Despite the few data in Table 2, one finds an average absolute difference in T f of around 4 °C between the divulged and calculated flash-point values, in a range from −17 to 63.2 °C.…”

“…40 The T f value reported for this binary mixture, although doubtlessly dependable, may not be mechanistically accounted for solely on volatility but rather in terms of reactivity causes like the formation of flame-retardant products in the decomposition of these types of halogenated molecules. 40 Despite the few data in Table 2, one finds an average absolute difference in T f of around 4 °C between the divulged and calculated flash-point values, in a range from −17 to 63.2 °C. This average absolute difference of 4 °C can be compared to the value of 12 °C determined by Radnoff 32 on the discrepancies between disclosed and measured T f values for 83 products in commercial SDS, although one must take into consideration that the uncertainty for her laboratory results was reported as ± 5 °C.…”

Chemoinformatics for the Safety of Energetic and Reactive Materials at Ineris

“…In 1982, Gmehling and Rasmussen [83] proposed to combine a vapor-liquid equilibrium model (UNIFAC [84] ) and the Le Chatelier rule (to account for the flammability of vapor mixtures). More recently, this method was adapted by Liaw [85] and successfully applied to various types of mixtures including ternary [86] , partially miscible [87] and aqueous mixtures [88] , even if some limits were also evidenced, notably for chlorinated mixtures [89] . Moreover, these mixing rules require knowledge on data on their constituents, and in particular their individual flash points.…”

“…More recently, this method was adapted by Liaw [85] and successfully applied to various types of mixtures including ternary, [86] partially miscible [87] and aqueous mixtures, [88] even if some limits were also evidenced, notably for chlorinated mixtures. [89] Moreover, these mixing rules require knowledge on data on their constituents, and in particular their individual flash points.…”