Highly efficient extraction of Eucommia ulmoides gum by IL-organic solvent biphasic system

A biphasic solvent system consisting of ionic liquids (IL) and petroleum ethers was applied in the extraction of Eucommia ulmoides gum (EUG) from pericarp. Effects of IL and extraction parameters on the yield and purity of EUG were investigated. The results showed that the addition of IL could enhance the yield and purity of EUG extracted from pericarp comparing with the traditional alike pretreatment method. FTIR, XRD and 1H NMR characterization conformed the chemical structure of EUG. DSC analysis reviewed the partial destruction of crystal structure and the disappearance of β-crystal phase of EUG extracted by biphasic solvent system, resulting in the decrease of the melting point and increase of glass transition temperature. Moreover, the extracted EUG exhibited high tensile strength of 27.68 MPa, excellent elongation at break of 1069%, and thus high toughness of 181.45 MJ∙m−3. Additionally, the excellent reusability of IL and petroleum ethers showed the extraction method of the biphasic solvent system promise as a feasible method to replace the traditional alkali pretreatment.