Sökning: "Lewis acid activation"

Visar resultat 1 - 5 av 13 avhandlingar innehållade orden Lewis acid activation.

1. 1. Crystallization of Metal Fluoride Hydrates from Mixed Acid Solutions

   Författare :Kerstin Forsberg; Åke Rasmuson; Alison Lewis; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; crystallization; crystal growth; b-FeF3.3H2O; iron fluoride trihydrate; CrF3.3H2O; pickling; pickle bath; hydrofluoric acid; nitric acid; stainless steel; Chemical engineering; Kemiteknik;

   Sammanfattning : In this work crystal growth and nucleation of b-FeF3×3H2O and crystallization of chromium (III), iron (III) and nickel (II) fluoride hydrates from mixed acid (1-3 mol/kg HNO3 and 1-6 mol/kg free HF) have been investigated. The solubility of b-FeF3×3H2O has been determined in solutions of different hydrofluoric acid (1-7mol/ kg) and nitric acid (0-7mol/ kg) concentrations at 30, 40 and 50°C. LÄS MER

3. 2. Development and Studies of the Processes Involved in Minor Enantiomer Recycling

   Författare :Anna Laurell Nash; Christina Moberg; Karl Anker Jørgensen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; asymmetric catalysis; biocatalysis; cyanohydrins; dual activation; Lewis acid; Lewis base; minor enantiomer recycling; recycling; titanium; Kemi; Chemistry;

   Sammanfattning : This thesis describes the development and rationalization of processes involved in a new methodology developed in our group, minor enantiomer recycling.The first part of the thesis addresses mechanistic studies of one of the reactions involved in minor enantiomer recycling, dual Lewis acid-Lewis base catalyzed acetylcyanation of aldehydes. LÄS MER

4. 3. New Methods for Chiral Cyanohydrin Synthesis

   Författare :Erica Wingstrand; Christina Moberg; Benjamin List; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; acyl cyanides; asymmetric synthesis; biocatalysis; cyanide; cyanohydrins; dual activation; enzymes; high-throughput screening; Lewis acid; Lewis base; metal catalysis; minor enantiomer recycling; salen; titanium; Chemistry; Kemi;

   Sammanfattning : This thesis deals with method development in asymmetric catalysis and specifically syntheses of enantioenriched O-functionalized cyanohydrins. The first part describes the development of a method for the synthesis of O‑alkoxycarbonylated and O-acylated cyanohydrins. LÄS MER

5. 4. Lewis Acid Mediated Alkylation and Diels-Alder Reactions of 2H-Azirines

   Författare :Erik Risberg; KTH; []
   Nyckelord :2H-azirines; Lewis acid activation; chiral ligandsorganolithium reagentsDiels-Alder reactions; DFT-calculations;

   Sammanfattning : This thesis describes the use of 2H-azirines as reactivesubstrates in Lewis acid catalysed nucleophilic additions andin the Diels-Alder reaction.A number of carbon nucleophiles have been added to aseries of 2H-azirines in the presence and absence ofBF3·Et2O. LÄS MER

7. 5. Lanthanide-mediated C-F Bond Activation Method Development and Mechanistic Investigation

   Författare :Mario Janjetovic; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; C-F bond activation; fluorine chemistry; lanthanides; single-electron transfer reagent; Lewis acid; chemoselectivity; synthetic method; catalysis;

   Sammanfattning : The use of transition-metals and main-group Lewis acids has proven to be an outstanding source for activation and subsequent functionalization of fluorinated compounds. However, the first is mainly limited to C(sp2)–F bonds which partially are activated by an adjacent heteroatom, and the latter is limited to simple C(sp3)–F bonds due to particularly strong Lewis acid character. LÄS MER