Correlation of vegetable oil‐hexane solution vapor pressures

Summary Variations between commercial hexanes from different sources and boiling ranges of some solvents are sufficiently large to require specific data on vapor pressures for the solvent or solvent fraction in a miscella. Pressure‐concentration‐temperature relations, experimentally determined for three commercial hexanes and a heptane in soybean oil, have been correlated and presented graphically as a single set of curves, characteristic of n‐hexane. An example of a method is given by which these curves can be used to obtain specific data for any hexane solvent. A variation of ±5°F. in solvent boiling point is shown to cause a ±6% change in miscella concentration which can be corrected by a change of ±8°F. in operating temperature. This effect is due to a ± 7.5% variation in miscella vapor pressure, when the solvent boiling point varies by ±5°F., which is sufficiently greater than the uncertainty of pressures read from the correlation, about ±2%, to require consideration in design and operation of solvent recovery equipment.