title: Stability of nicotinate and dodecyl sulfate in a Lewis acidic ionic liquid for aluminum electroplating and characterization of their degradation products.
abstract: Plating bath additives are essential for optimization of the morphology of electroplated layers. The ionic liquid 1-ethyl-3-methylimidazolium (EMIM) chloride plus 1.5 mol equivalents of AlCl3 has great potential for electroplating of aluminum. In this study, the chemical and electrochemical stability of the additives EMIM-nicotinate and sodium dodecyl sulfate and their effect on the stability of EMIM was investigated and analyzed. Nicotinate and its electrochemical decomposition product β-picoline could be detected and we show with a single HPLC-UV-MS method that EMIM is not affected by the decomposition of this additive. An adapted standard HPLC-UV-MS method together with GC-MS and ion chromatography was used to analyze the decomposition products of SDS and possible realkylation products of EMIM. Several volatile medium and short chain-length alkanes as well as sulfate ions have been found as decomposition products of SDS. Alkenium ions formed as intermediates during the decomposition of SDS realkylate EMIM to produce mono- up to pentasubstituted alkyl-imidazoles. A reaction pathway involving Wagner-Meerwein rearrangements and Friedel-Crafts alkylations has been suggested to account for the formation of the detected products.
authors: Institute for Chemistry and Technology of Materials, Graz University of Technology, NAWI Graz, Graz, Austria.
authors: Patrick
authors: P
authors: Kosmus
authors: Institute for Chemistry, Analytical Chemistry, University of Graz, NAWI Graz, Graz, Austria.
authors: Oliver
authors: O
authors: Steiner
authors: Institute for Chemistry, Analytical Chemistry, University of Graz, NAWI Graz, Graz, Austria.
authors: Walter
authors: W
authors: Goessler
authors: Institute for Chemistry and Technology of Materials, Graz University of Technology, NAWI Graz, Graz, Austria.
authors: Bernhard
authors: B
authors: Gollas
authors: VARTA Micro Innovation GmbH, Graz, Austria.
authors: Gisela
authors: G
authors: Fauler
mesh_terms: D000535:Aluminum / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid; D004595:Electroplating / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry; D052578:Ionic Liquids / Q000737:chemistry*; D009525:Niacin / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*
chemical_list: D052578:Ionic Liquids; D009525:Niacin; D012967:Sodium Dodecyl Sulfate; D000535:Aluminum; C028913:dodecyl sulfate
keywords: Additive; Aluminum electroplating; GC MS; HPLC MS; Ionic liquids