Feasibility of fractional distillation of Eucalyptus hybrida essential oil for the separation of valuable compounds

Abstract

Raw essential oil (EO) of Eucalyptus hybrida extracted from the leaves of trees found in Uttarakhand state and nearby areas consists of a mixture of monoterpenoids, sesquiterpenoids and several different volatile compounds of which 1,8-cineole i.e., eucalyptol, a monoterpenoid cyclic ether is a major component. The eucalyptol rich EO also holds antimicrobial, anti-inflammatory, broncholytic and mucolytic potential. In this work experimental tests were done to evaluate the feasibility of batch fractionation or fractional distillation (FD) technique in performing value addition of eucalyptus essential oil. The proximity of boiling points of eucalyptol, limonene and p-cymene act as a barrier in separating these compounds. A two-stage FD procedure was devised, which recovers relatively light terpene fractions in first stage and provides eucalyptol rich fractions in second stage. The GC-MS analysis of the fractionated samples revealed good separation results with three stage-B fractions (B8, B9 and B10) containing >90% purity of eucalyptol, while two stage-A fractions (A1 and A2) containing >90% purity of pinene mixture (α-pinene and β-pinene). FD thus proved to be an effective method for adding value to the eucalyptus EO.