Search for dissertations about: "rhodium"

Showing result 11 - 15 of 67 swedish dissertations containing the word rhodium.

2. 11. Development of a regeneration procedure for commercial automotive three-wy catalysts

   Author : Henrik Birgersson; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; deactivation; fouling; sintering; poisoning; palladium; rhodium; regeneration; dispersion; thermal gas treatment; oxy-chlorine; TWC; automotive catalyst; Chemical process equipment; Kemisk apparatteknik;

   Abstract : Car exhaust catalysts were introduced in the early 1980’s, to limit the release of pollutants such as hydrocarbons, carbon monoxides and nitrogen oxides. These catalysts contain noble metals such as palladium (Pd), platinum (Pt) and rhodium (Rh) and are able to simultaneously abate all three of the above-mentioned pollutants, hence the name three-way catalyst (TWC). READ MORE

4. 12. Asymmetric transfer hydrogenation of ketones : Catalyst development and mechanistic investigation

   Author : Katrin Ahlford; Hans Adolfsson; Martin Wills; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Asymmetric catalysis; reduction; amino acid; rhodium; mechanistic investigation; kinetic study; Organic chemistry; Organisk kemi; organisk kemi; Organic Chemistry;

   Abstract : The development of ligands derived from natural amino acids for asymmetric transfer hydrogenation (ATH) of prochiral ketones is described herein. In the first part, reductions performed in alcoholic media are examined, where it is found that amino acid-derived hydroxamic acids and thioamides, respectively, are simple and versatile ligands that in combination with [RhCp*Cl2]2 efficiently catalyze this particular transformation. READ MORE

5. 13. Experimental Studies of NOx Catalysts; Storage, Reduction and Sulphur Deactivation

   Author : Annika Amberntsson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; barium oxide; NOx storage; platinum; rhodium; sulphur poisoning; NOx reduction;

   Abstract : The aim of this thesis work was to investigate how different gaseous compounds, present in an automotive exhaust from lean-tuned combustion, interact with so-called NOx storage catalysts containing Al2O3 as a support, BaO as the NOx storage compound and noble metals to provide oxidation and reduction functions. The investigations included model sample preparations, flow reactor studies with various gas mixtures and spectroscopic experiments (FTIR and XPS). READ MORE

6. 14. Transition metal-catalyzed reduction of carbonyl compounds : Fe, Ru and Rh complexes as powerful hydride mediators

   Author : Elina Buitrago; Hans Adolfsson; Robert Morris; Stockholms universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Asymmetric catalysis; amino acid; N-heterocyclic carbene; iron; ruthenium; rhodium; mechanistic investigation; kinetic study; asymmetric transfer hydrogenation; hydrosilylation; organisk kemi; Organic Chemistry;

   Abstract : A detailed mechanistic investigation of the previously reported ruthenium pseudo-dipeptide-catalyzed asymmetric transfer hydrogenation (ATH) of aromatic ketones was performed. It was found that the addition of alkali metals has a large influence on both the reaction rate and the selectivity, and that the rate of the reaction was substantially increased when THF was used as a co-solvent. READ MORE

7. 15. Platinum Group Elements in Birds of Prey

   Author : Kristine H. Ek; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; rhodium; bird of prey; platinum; laser ablation; palladium; ICP-MS; airborne particles;

   Abstract : The environmental concentrations of Pd, Pt and Rh (three of the platinum group elements, PGE) have increased since the introduction of exhaust catalysts on automobiles. A limited understanding of the environmental distribution and effects of the platinum group elements has raised concern over their potential biological availability. READ MORE