How to make a green product greener: use of ionic liquids as additives during essential oil hydrodistillation

Abstract

The effect of addition of ionic liquids (ILs) during hydrodistillation of the essential oil of Rosmarinus officinalis L. on its yields has been evaluated. Four different chloride based ILs have been used, namely a hydroxyl functionalized imidazolium salt, 1-hydroxyethyl-3-methylimidazolium chloride (IL-1), a morpholinium salt, N,N-butylmethylmorpholinium chloride (IL-2), a Brønsted acidic ionic liquid, N-methylimidazolium chloride (IL-3) and an ammonium salt, choline chloride (IL-4). ILs 1–3 permitted to obtain higher yields of essential oil with respect to the classic hydrodistillation. In particular, IL-1 permitted to improve the essential oil yield by about 25%. Noteworthy, no appreciable changes were observed in the composition of the essential oils when the ILs were added.