Jump to main content
Jump to site search

Issue 11, 2017
Previous Article Next Article

Development of a lipase-mediated epoxidation process for monoterpenes in choline chloride-based deep eutectic solvents

Author affiliations

Abstract

Chemical syntheses in contemporary process industries today are predominantly conducted using organic solvents, which are potentially hazardous to humans and the environment alike. Green chemistry was developed as a means to overcome this hazard and it also holds enormous potential for designing clean, safe and sustainable processes. The present work incorporates the concepts of green chemistry in its design of a lipase-mediated epoxidation process for monoterpenes; the process uses alternative reaction media, namely deep eutectic solvents (DESs), which have not been reported for such an application before. Choline chloride (ChCl), in combination with a variety of hydrogen bond donors (HBD) at certain molar ratios, was screened and tested for this purpose. The process was optimized through the design of experiments (DoE) using the Taguchi method for four controllable parameters (temperature, enzyme amount, peroxide amount and type of substrate) and one uncontrollable parameter (DES reaction media) in a crossed-array design. Two distinct DESs, namely glycerol : choline chloride (GlCh) and sorbitol : choline chloride (SoCh), were found to be the best systems and they resulted in a complete conversion of the substrates within 8 h. Impurities (esters) were found to form in both the DESs, which was a concern; as such, we developed a novel minimal DES system that incorporated a co-substrate into the DES so that this issue could be overcome. The minimal DES consisted of urea·H2O2 (U·H2O2) and ChCl and exhibited better results than both the GlCh and SoCh systems; complete conversions were achieved within 2 h for 3-carene and within 3 h for both limonene and α-pinene. Product isolation with a simple water/ethyl acetate based procedure gave isolated yields of 87.2 ± 2.4%, 77.0 ± 5.0% and 84.6 ± 3.7% for 3-carene, limonene and α-pinene respectively.

Graphical abstract: Development of a lipase-mediated epoxidation process for monoterpenes in choline chloride-based deep eutectic solvents

Back to tab navigation

Supplementary files

Publication details

The article was received on 13 Apr 2017, accepted on 04 May 2017 and first published on 05 May 2017


Article type: Paper
DOI: 10.1039/C7GC01127J
Citation: Green Chem., 2017,19, 2576-2586
  •   Request permissions

    Development of a lipase-mediated epoxidation process for monoterpenes in choline chloride-based deep eutectic solvents

    S. Ranganathan, S. Zeitlhofer and V. Sieber, Green Chem., 2017, 19, 2576
    DOI: 10.1039/C7GC01127J

Search articles by author

Spotlight

Advertisements