Question

What would happen if we attempted fractional or simple distillation of lemon grass to obtaincitral

Answer 1

In lemongrass oil in addition with citral some other constituents are also present (i.e. some other hydrocarbons, esters, ketones, alcohols etc.). So if we want to citral we have to do distillation. But the boiling point of citral and the other impurities are close enough. If we perform the fractional distialltion the citral will never come out as pure compound rather we get the distillate which will be the mixture of different compound. Hence fraction distillation is used for the compounds which are non volatile and have significantly different boiling point.

In this case in order to extract citral we have to do steam distillation as citral is steam volatile.