Benefits of Ryegrass on Multicontaminated Soils Part 2: A Green Process to Provide Idrocilamide

Abstract

International audienceA restoration of highly contaminated garden soil is proposed as a greener alternative to the production of vegetables. Depending on potentially toxic elements and their concentration, ryegrass shoots accumulate these elements in sufficient quantity to be used as a catalyst in organic synthesis. The analysis of Cd, Pb, Zn, Cu, Fe, Mn, and Al in ashes issued from the calcination of ryegrass shoots revealed that the concentration of Zn was highest (>7000 mg kg–1). The ratios between potential Lewis acids (Zn, Cu, Fe, Mn, and Al) to carcinogenic metals (Cd or Pb) were 191 ± 7 for LA/Cd and 235 ± 13 for LA/Pb, making the shoots of ryegrass suitable for the production of Zn-rich polymetallic biosourced catalysts. This material was used in the synthesis of idrocilamide under free-solvent condition, providing the drug in a good yield (69.9%). Data show that a limitation of waste, a maximization of the material incorporation in the process, a minimization of the steps, and an optimization of the stoichiometric factor are the main innovative factors in the current process in comparison with those previously reporte