The effect of selected solvents on the relative volatility of the binary system: 1–octene – 2–hexanone with the aim of separating the azeotropic mixture

Abstract

The removal of oxygenates from olefins has tremendous industrial significance. This study dealt specifically with potential azeotropic and extractive distillation processes for the purification of higher alpha olefins. An Othmer type vapour liquid equilibrium still was used to study the influence of selected solvents on the l-octene I 2-hexanone system. These screening tests were performed under conditions of a fixed solvent concentration of 66% with the azeotropic ratio of l-octene to 2-hexanone. The resulting data was used to identify solvent properties and theoretical models which correlate well with actual performance. It is evident that specific available solvent properties and principles can indeed be successfully utilized to predict the effect of a solvent. Although many of these guidelines are not strictly quantitative, they agree well with theoretical understandings of sol vent action and can save much time in future solvent searches. The large difference in polarity between the two components .appears to be the main factor on which the sol vents discriminate. Differences in molar volume and complex forming ability are also meaningful. Related sol vent properties are consequently important when selecting a solvent for similar systems. Effective solvents (such as dimethyl formamide and methanol) all have high values for properties {such as the dielectric constant and polar solubility parameter) which are associated with the strength of solvent solute interaction. Binary vapour liquid equilibrium data was also measured for some sol vents. The data was regressed and used to simulate actual distillation schemes. This verified that chosen solvents are indeed able to efficiently effect a high separation between the two components.