Evaporation Path in a Liquid Crystal/Hydrocarbon Emulsion in the System Toluene, 5‐Phenylvalerate, 4‐Pentylphenol and Water

The evaporation path in emulsions of a water/5‐phenylvalerate/4‐pentylphenol lamellar liquid crystal in toluene was calculated using an algebraic method to extract information from a partial phase diagram. The equations for the tie lines between the emulsion phases and the evaporation path were established and used to evaluate the variation in the composition of the liquid crystal during the evaporation. The evaporation lead to significant changes in the composition of the liquid crystal and the modification of the vapor pressure during the process was estimated from published values for similar systems. The deviation of water pressure from the value for p was too small to influence the evaporation path to a significant degree, but the departure from the native toluene pressure were sufficient to cause a discernable change in the evaporation path. These deviations were small in comparison with the ones caused by the relative humidity on the evaporation path. The results also gave an example of a situation in which the assumption of equilibrium between the vapor and the compound in the emulsion is no longer valid providing an example for which the phase diagram approach to evaporation is not relevant.

Keywords:

• Phase diagrams
• evaporation
• emulsions
• naphtenic acids
• liquid crystals