A simplified extractive metallurgy exercise to demonstrate selective extraction of copper

A laboratory activity is described for senior high school or 1st year undergraduate level students that illustrates key concepts linked to extractive metallurgy. This experiment demonstrates preferential binding of a methoxyphenolic oxime ligand to Cu2+ in the presence of other transition metal ions in aqueous solution. The students are tasked to investigate the importance of the spatial relationship between the oxime and phenol group of two potential ligands by performing a series of short and simple tests. The objective is achieved by identifying which methoxyphenolic oxime ligand selectively and rapidly forms an isolable precipitate with Cu2+ ions. Only one of the potential ligands exhibits a clear preference for binding to Cu2+ and this can easily be identified visually (and confirmed by UV-visible spectroscopy if desired). The experiment has successfully been employed as part of an extracurricular laboratory course involving groups of 25-30 high school students.PostprintPeer reviewe

Isothiourea-catalyzed [2+2] cycloaddition of C(1)-ammonium enolates and N-alkyl isatins

The research leading to these results has received funding from the EPSRC (EP/S019359/1, C. Y.; EP/T023643/1, J. D.; K. K.) as well as Syngenta and the EPSRC Centre for Doctoral Training in Critical Resource Catalysis [CRITICAT, EP/L016419/1 (W.C.H.)].Enantioselective [2+2] cycloaddition of C(1)-ammonium enolates generated catalytically using the isothiourea HyperBTM with N alkyl isatins gives spirocyclic β-lactones. In situ ring-opening with an amine nucleophile generates isolable highly enantioenriched products in up to 92:8 dr and in >99:1 er.Publisher PDFPeer reviewe