Can fractional distillation be used to distinguish between: 1) d/l form of a compound 2) geometrical isomers of a compoun (Cis and Trans)
- The boiling point of an (R)-isomer is the same as the one of the enantiomer, the (S)-isomer. Since the condensor does not offer a chiral environment to the chiral molecules, there is no discern of them and consequently, neither "single" nor "fractional distillation" separates them.
(You may expose the molecules to a chiral surface to adsorb, though, and separate the enantiomers by chiral gas chromatography; a specialized approach in analytical chemistry and -- because of the scale of amount typically accessible -- much less frequently deployed on a preparative one (a review).)
- A successful separation of (cis)-(trans)-isomers by distillation of course depends on how different the boiling points of the pure compounds are. Looking up the data for (trans)-stilbene (bp 305 C reference) and (cis)-stilbene (307 C at 1 atm reference) suggests other separation techniques may be much more suitable since less demanding. This especially becomes relevant if you need a technique easy to scale, to manage and to be run continously (e.g., distillation).
fraction distillation means seperation of compounds on the basis of specificity of boiling point.so we cannot find the geometrical and stero isomerism using fractional distillation. But we can find the form of the substance wheather it is gas or solid or liquid using fractional distillation.