TY  - JOUR
A1  - Träger, Juliane
A1  - Klamroth, Tillmann
A1  - Kelling, Alexandra
A1  - Lubahn, Susanne
A1  - Cleve, Ernst
A1  - Mickler, Wulfhard
A1  - Heydenreich, Matthias
A1  - Müller, Holger
A1  - Holdt, Hans-Jürgen
T1  - Complexation of Palladium(II) with unsaturated Dithioethers a systematic development of highly selective ligands for solvent extraction
JF  - European journal of inorganic chemistry : a journal of ChemPubSoc Europe
N2  - There is a demand for new and robust PdII extractants due to growing recycling rates. Chelating dithioethers are promising substances for solvent extraction as they form stable square-planar complexes with PdII. We have modified unsaturated dithioethers, which are known to coordinate PdII, and adapted them to the requirements of industrial practice. The ligands are analogues of 1,2-dithioethene with varying electron-withdrawing backbones and polar end-groups. The crystal structures of several ligands and their palladium complexes were determined as well as their electro- and photochemical properties, complex stability and behaviour in solution. Solvent extraction experiments showed the superiority of some of our ligands over conventionally used extractants in terms of their very fast reaction rates. With highly selective 1,2-bis(2-methoxyethylthio)benzene (4) it is possible to extract PdII from a highly acidic medium in the presence of other base and palladium-group metals.
KW  - Renewable resources
KW  - Palladium
KW  - Chelates
KW  - Ligand design
KW  - S li-gands
Y1  - 2012
U6  - https://doi.org/10.1002/ejic.201101406
SN  - 1434-1948
IS  - 14
SP  - 2341
EP  - 2352
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Träger, Juliane
A1  - König, Jana
A1  - Städtke, Anja
A1  - Holdt, Hans-Jürgen
T1  - Development of a solvent extraction system with 1,2-bis(2-methoxyethylthio) benzene for the selective separation of palladium(II) from secondary raw materials
JF  - Hydrometallurgy : an international journal devoted to all aspects of the aqueous processing of metals
N2  - The chelating dithioether 1,2-bis(2-methoxyethylthio)benzene. a novel solvent extractant for Pd(II), is aimed to be utilised in the selective recovery of palladium from spent automotive catalysts. For that, the extraction system has been further customised, including the choice of an appropriate diluent (1,2-dichlorobenzene) as well as an effective stripping agent (0.5 M thiourea in 0.1 M HCl), which both have been selected from a number of potential agents. It is shown in batch experiments that the selectivity for Pd(II) is maintained when the organic phase (10(-2) M 1,2-bis(2-methoxyethylthio)benzene in 1,2-dichlorobenzene) is used several times to extract an oxidising leach solution. According to the McCabe-Thiele plot two theoretical stages are needed to extract more than 98% of the Pd(II) contained in that solution. The calculation of the thermodynamic quantities Delta H degrees. Delta S degrees and Delta G degrees reveals that the reaction is entropy driven - the temperature has only a slight influence on the extraction yield. It is demonstrated that the mono-oxidised extractant has a catalytic effect on the extraction kinetics when the aqueous phase contains highly concentrated hydrochloric acid. HPLC measurements prove the presence of small quantities of 1-(2-methoxyethylsulfinyl)-2-(2-methoxyethylthio) benzene in the organic phase.
KW  - Solvent extraction
KW  - Palladium
KW  - S ligands
KW  - Extraction system development
KW  - Stripping
Y1  - 2012
U6  - https://doi.org/10.1016/j.hydromet.2012.07.002
SN  - 0304-386X
SN  - 1879-1158
VL  - 127
IS  - 5
SP  - 30
EP  - 38
PB  - Elsevier
CY  - Amsterdam
ER  -