D-limonene and geranial fractionation from lemon essential oil by molecular distillation

d-limonene and geranial are, respectively, the most abundant terpenic and oxygenated compounds found in lemon essential oil. the main objective of this research work is to study the technical feasibility of molecular distillation, in order to separate and concentrate those thermal labile compounds of lemon essential oil and to determine the best evaporation temperature and feed flow rate values which will lead to high separation efficiency. the highest temperature analyzed allowed to obtain a residue poor in d-limonene and enriched in geranial, with low geranial yield (between 35-50%). regarding d-limonene, the highest temperature (30 °c) used, led to higher yields of d-limonene. lower feed flow rate (0.6 ml min-1) led to low concentrations of d-limonene (320 g kg-1) and geranial (70 g kg-1) in the residue, with low yield for geranial (23.5%). a high yield of geranial in the residue (76.4%) can be obtained by using a feed flow rate of 1.3 ml min-1, which leads to the highest geranial concentration (113 g kg-1 ).