Investigation of europium(III) uptake from highly sulphate solution via cloud point extraction by mono-Schiff base combined with Triton X-100.

Owing to its unique physico-chemical properties, europium is one of the most precious and sought-after rare earth elements in the field of high technology. The major economic and commercial importance of such an element, combined with the pollution risks associated with its intensive use, require the development of efficient and eco-compatible recovery and recycling processes. This study focuses on the recovery of europium from highly saline sulphate media (0.5 mol/L) using an environmentally friendly two-phase aqueous extraction technique (known as cloud point extraction (CPE)), using 2((phenylimino)methyl)phenol mono-Schiff base (HPIMP) as the extractant and Triton X-100 as the non-ionic surfactant. The influence of key experimental parameters such as pH, extractant concentration, surfactant concentration and separation temperature on the europium extraction process was systematically studied and optimized. Under optimum experimental conditions, a quasi-quantitative extraction with a minimal volume fraction of surfactant-rich phase (φs = 0.025), and concentration factor of (CF = 38) was achieved at pH 9.8, in one stage. The analysis of the extraction data revealed that the CPE of europium(III) takes place by a cation exchange-solvation mechanism. The stoichiometry of the complex extracted into the surfactant-rich phase was ascertained to have a composition of 1:2 [Eu:HPIMP] with the slope analysis method. A higher extraction constant was obtained for CPE compared with conventional solvent extraction, confirming the feasibility and usefulness of CPE for Eu(III) recovery. On the other hand, this new HPIMP/Triton X-100 chelating system showed superior extractability for Eu(III) in the CPE process relative to other systems reported previously.

Synthesis of a series of new platinum organometallic complexes derived from bidentate Schiff-base ligands and their catalytic activity in the hydrosilylation and dehydrosilylation of styrene.

The synthesis and properties of a novel class of platinum complexes containing Schiff bases as O,N-bidentate ligands is described as are the solution and solid state properties of the uncomplexed ligands. The platinum complexes were prepared from [PtBr2(COD)] (COD = 1,5-cyclooctadiene) and N-(2-hydroxy-1-naphthalidene)aniline derivatives in the presence of base (NaOBu(t)). Instead of a substitution reaction to afford cationic species, the addition of the Schiff base ligands results in both the formal loss of two equivalents of bromide and addition of hydroxide to the COD ligand of the complexes. It is proposed that this reaction proceeds through a cationic platinum complex [Pt(N-O)(COD)]Br which then undergoes addition of water and loss of HBr. An example of a dinuclear platinum complex in which two cyclo-octene ligands are bridged by an ether linkage is also reported. The platinum complexes were evaluated as catalysts for the hydrogenative and dehydrogenative silylation of styrene, the resulting behaviour is substituent, time and temperature dependent.