6697-95-6Relevant articles and documents
Simultaneous identification of Fenton degradation by-products of diclofenac, ibuprofen and ketoprofen in aquatic media by comprehensive two-dimensional gas chromatography coupled with mass spectrometry
Beldean-Galea, Mihail Simion,Coman, Virginia,Copaciu, Florina,Thiébaut, Didier,Vial, Jér?me
, p. 1021 - 1027 (2015/07/15)
Diclofenac, ibuprofen and ketoprofen are anti-inflammatory drugs intensively used both in human and animal treatment. Due to their high stability these compounds are partially removed by wastewater treatment plants and from this reason the development of some alternative treatments such as advanced oxidative processes are necessary. The main problems in the optimization of an advanced oxidative process rise from the difficulties which appear in the identification of degradation by-products necessary for the establishment of degradation pathway. In this paper a developed method for the simultaneous identification of Fenton degradation by-products of the three above mentioned pharmaceuticals is presented. The obtained results show the comprehensive two-dimensional gas chromatography coupled with mass spectrometry as a proper method for the analysis of the complex mixture of compounds resulted from the Fenton degradation process. Moreover, some compounds never mentioned in the scientific literature were identified. (Chemical Equation Presented).
Screw Sense Selective Polymerization of Achiral Isocyanides Catalysed by Optically Active Nickel(II) Complexes
Kamer, Paul C. J.,Nolte, Roeland J. M.,Drenth, Wiendelt
, p. 6818 - 6825 (2007/10/02)
Poly(isocyanides), (RN=Cn, can be prepared from isocyanides, , by the catalytic action of nickel(II) compounds.The main chain of these polymers is a rigid helix.This helical conformation results from a restricted rotation around the single bonds that connect the main-chain carbon atoms.Polymerization of achiral isocyanides generally gives a racemic mixture of left- and right-handed helices, whereas polymerization of optically active isocyanides results in helices with an excess of one screw sense.We describe a procedure for obtaining poly(isocyanides) with predominantly one screw sense, starting from an achiral monomer.A catalyst is prepared by adding an optically active amine to a tetrakis(isocyanide)nickel(II) perchlorate complex.Polymerization of various achiral isocyanides with this catalist yields optically active polymers with an enantiomeric excess up to 83percent.