Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 25 for “"Homogene Katalyse"”.
-
Rhodium - katalysierte Hydroformylierung von 1-Dodecen mit zweizähnigen Liganden in Mikroemulsionssystemen
Die große Herausforderung für die homogene Katalyse liegt sowohl in der maximalen Ausbeute der Reaktion als auch in der Wiederverwendbarkeit des aktiven Katalysators. Für die Hydroformylierung langkettiger Olefine (> C6) werden in industriellen Verfahren Cobalt-Katalysatoren verwendet. In unseren …
-
Entwicklung neuer Methoden und Katalysatoren für die Hydroaminierung und die Hydroaminoalkylierung von Alkenen
Diese Arbeit befasst sich mit der Entwicklung neuer Methoden und Katalysatoren für Hydroaminierungs- und Hydroaminoalkylierungsreaktionen. Es wurde eine KOH-katalysierte Hydroaminierung von Styrolderivaten mit primären und sekundären Arylaminen und Phenylhydrazin entwickelt, die es ermöglicht, auf …
-
Asymmetrischer katalytischer Phenyltransfer zur Synthese von Diarylmethanolen und Diarylmethylaminen
Enantiopure diarylmethanols and diarylmethylamines are important intermediates in the synthesis of biologically active compounds, since their derivatives have e. g. antihistaminic properties. For example, the (S)-enantiomer of the commercially important non-sedating antihistamine agent Cetirizine …
-
Polymergebundene Homogenkatalysatoren : Untersuchungen zum Einfluss des Polymerrückgrates auf die Produktselektivität
Immobilized chiral catalysts, synthesized by means of ring opening metathesis polymerisation (ROMP), have been evaluated with respect to structural and conformational influences. Therefore, a number of different chiral precursors suitable for ROMP have been synthesized. Statistic copolymerisation …
-
Rutheniumkatalysierte Hydratisierung von terminalen Alkinen und deren Einsatz in Synthesestrategien
In the context of this work the ruthenium-catalyzed anti-Markovnikon-hydration of terminal alkynes was optimized. This covers the reaction conditions (catalyst loading, concentration, solvent/reaction media, equivalents of water, additives and exchange of the counterion) as well as the variation of …
-
Synthese und Untersuchung pentadentater Liganden und ihrer Lanthanoid(III)-Komplexe
Coordination compounds of lanthanide(III)salts show interesting properties and are used e.g. as lewis acid catalysts in organic synthesis. The precise knowledge about interactions between ligand and Ln(III)-cation as well as the investigation of new ligand systems with low coordination numbers is …
-
New strategies for multiphase catalysis using supercritical carbon dioxide
The work reported in this thesis deals with the development of an effective strategy for the recycling of a multipurpose catalyst. An immobilized metal complex acts as a "catalyst cartridge" applicable in a variety of catalytic reactions without using any volatile organic solvents but only carbon …
-
Asymmetrische Cycloisomerisierung von 1,6-Dienen
Within this thesis an highly selective and active catalyst system for the cycloisomerisation of 1,6-dienes towards exo-methylenecyclopentanes could be developed. The combination of [{Ni(allyl)Br}2], Wilke´s azaphospholene and Na[BARF] led to a catalyst, which transformed diethyl diallylmalonate to …
-
Beiträge zur Addition von Stickstoff- und Kohlenstoffnucleophilen an C-C-Doppelbindungen
The thesis at hand deals with the topic of palladium catalysts for the addition of nucelophiles to conjugated double bonds. The objective was the development of new ligands for the hydroamination of dienes and the creation of catalysts for homologous compounds. According to a model of the …
-
Metal based asymmetric catalysis in Baeyer-Villiger oxidations
One of the objectives of the present thesis was to improve the efficiency of an aluminium-catalyzed Baeyer-Villiger oxidation. This system was based on a mediating species formed by enantiopure 2,2'-dihydroxy-1,1'-binaphthyl (BINOL) and Me2AlCl and utilized a hydroperoxide as oxidant. A first …
-
Neutral and cationic complexes of the rare earth metals : synthesis, characterisation and polymerisation catalysis
The most common starting materials for the access to cationic complexes of the rare-earth metals are the homoleptic tris(trimethylsilylmethyl) precursors [Ln(CH2SiMe3)3(thf)2]. The principal objective of this work has been to substitute the well-known CH2SiMe3 group for other fragments, and study …
-
Allylcalcium complexes : synthesis, reactivity and application in homogeneous catalysis
The main objective of the present work is to study preparation, coordination behavior and basic reactivity patterns of allylcalcium compounds. Examples for catalytic reactions of the resulting calcium compounds are given to evaluate the scope of applications. The first part describes the isolation …
-
Studies on transition metal-catalysed oxidations with hydrogen peroxide as terminal oxidant
… inexpensive metals, such as iron, effects homogeneous liquid phase oxidations, producing water as the sole by-product. This "green" combination represents a highly desirable solution to the environmental issue. Following these guidelines, hydrogen peroxide was chosen as terminal oxidant for …
-
Derivatisierungsreaktionen von Cinchona-Alkaloiden und eine Cinchona-Alkaloid-katalysierte asymmetrische Synthese von 2,5-Diarylphopholanen
This thesis consists of two parts: The first part deals with the synthesis of structurally diverse cinchona alkaloid derivatives via nucleophilic addition of organometallic reagents. An addition of organolithium reagents leads to 2´-alkylated products. The reaction with Grignard reagents leads to …
-
Chirale Phosphortriamide und Phosphin-Phosphoramidite als Liganden für die asymmetrische Katalyse
Asymmetric catalysis with transition metal complexes containing chiral ligands is an efficient tool for the synthesis of enantioenriched compounds, which can be used as active pharmaceutical ingredients, agrochemicals, flavors or fragrances. The development of novel chiral ligands plays a major …
-
Katalytische Hydrierung in Mehrphasensystemen auf Basis von ionischen Flüssigkeiten und Kohlendioxid
Carbon dioxide (CO2) and ionic liquids (ILs) have been intensively studied as solvents in catalysis. The combination of ILs and CO2 and its interaction with third components has attracted only sparse interest in research. In the literature, the IL/CO2 system is discussed as a promising technique …
-
Synthesis and application of chiral phosphorous triamide ligands
In this thesis the synthesis and application of novel chiral monodentate phosphorous triamide (PTA) ligands is presented. First, a small library of chiral PTAs based on three different chiral diamine backbones has been prepared through a convenient modular synthetic approach. The study …
-
Selektive Hydrierung biogener organischer Disäuren mit Rutheniumphosphinkatalysatoren
In the scope of this work the hydrogenation of diacids was investigated in depth on the example of itaconic acid. Rutheniumcatalysts with phoshineligands were stable and active hydrogenation catalysts. Mono- and bydentate ligands catalyse the conversion towards the 2- and …
Page 1 of 2