Benzaldehyde is not soluble in water. I wouldn't have expected that anyway, given that ring in the compound. The presence of other compounds in the mixture might improve their ability to mix, much as you have with a ternary of benzene, ethanol, and water (the classic azeotropic distillation example). A separation between benzaldehyde and water? My first response would be to use a simple decanter, but I think we don't know enough about your particular problem to say much that is useful. What other compounds are present, and what does your process look like? For VLE calculations, I imagine a liquid activity model, such as NRTL, would be applied. However, obtaining the interaction parameters for that binary would be difficult, given the insolubility. Parameters regressed from a ternary with something else might be possible. Provide details; then perhaps we can help.
