Use of limonene in countercurrent chromatography: a green alkane substitute

Anal Chem. 2013 May 7;85(9):4644-50. doi: 10.1021/ac4002854. Epub 2013 Apr 15.

Abstract

Counter-current chromatography (CCC) is a preparative separation technique working with the two liquid phases of a biphasic liquid system. One phase is used as the mobile phase when the other, the stationary phase, is held in place by centrifugal fields. Limonene is a biorenewable cycloterpene solvent coming from orange peel waste. It was evaluated as a possible substitute for heptane in CCC separations. The limonene/methanol/water and heptane/methanol/water phase diagrams are very similar at room temperature. The double bonds of the limonene molecule allows for possible π-π interactions with solutes rendering limonene slightly more polar than heptane giving small differences in solute partition coefficients in the two systems. The 24% higher limonene density is a difference with heptane that has major consequences in CCC. The polar and apolar phases of the limonene/methanol/water 10/9/1 v/v have -0.025 g/cm(3) density difference (lower limonene phase) compared to +0.132 g/cm(3) with heptane (upper heptane phase). This precludes the use of this limonene system with hydrodynamic CCC columns that need significant density difference to retain a liquid stationary phase. It is an advantage with hydrostatic CCC columns because density difference is related to the working pressure drop: limonene allows one to work with high centrifugal fields and moderate pressure drop. Limonene has the capability to be a "green" alternative to petroleum-based solvents in CCC applications.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkanes / chemistry*
  • Countercurrent Distribution
  • Cyclohexenes / chemistry*
  • Hydrodynamics
  • Limonene
  • Methanol / chemistry
  • Molecular Structure
  • Terpenes / chemistry*
  • Water / chemistry

Substances

  • Alkanes
  • Cyclohexenes
  • Terpenes
  • Water
  • Limonene
  • Methanol