Sökning: "organic carbon"

Visar resultat 6 - 10 av 769 avhandlingar innehållade orden organic carbon.

1. 6. New Reactions with Allyl- and Allenylboron Reagents : Transition-Metal-Catalyzed and Transition-Metal-Free Carbon-Carbon Bond Formation Processes

   Författare :Dong Wang; Kálmán J. Szabó; Jianbo Wang; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon-carbon bond formation; cross-coupling; organoboron compound; allylboron reagent; allylation; transition metal; metal carbene; allenylboron reagent; transition metal free; diazo compound; tosylhydrazone; quinone; organisk kemi; Organic Chemistry;

   Sammanfattning : Organoboron compounds have been widely used in carbon-carbon bond formation reactions in organic synthesis and catalysis. This thesis is focused on cross-coupling reactions of allyl-, allenylboronic acids and their ester derivatives via transition metal catalysis or transition-metal-free processes. LÄS MER

3. 7. Carbon Dioxide in Inland Waters : Drivers and Mechanisms Across Spatial and Temporal Scales

   Författare :Anna Cecilia Nydahl; Gesa A. Weyhenmeyer; Marguerite Xenopoulos; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; carbon dioxide; dissolved organic carbon; inland water; lake; stream; groundwater; mesocosm; carbonate system; carbon; Biology with specialization in Limnology; Biologi med inriktning mot limnologi;

   Sammanfattning : Inland waters are an essential component of the global carbon cycle as they are very active sites for carbon transformation processes. Much of this carbon is transformed into the greenhouse gas carbon dioxide (CO2) and emitted into the atmosphere. LÄS MER

4. 8. Photoinitiated Radical Carbonylation Using [11C]Carbon Monoxide : 11C-Labelling of Aliphatic Carboxylic Acids, Esters, and Amides

   Författare :Oleksiy Itsenko; Bengt Långström; Tor Kihlberg; Chryssostomos Chatgilialoglu; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Organic chemistry; 11C-labelling; radicals; carbonylation; carbon monoxide; solvent effects; sensitizers; sulfoxides; WAY-100635; PET; Organisk kemi; Organic chemistry; Organisk kemi;

   Sammanfattning : One-step photoinitiated free radical carbonylation was employed for the rapid (5–7 min) labelling of aliphatic carboxylic acids, esters, and amides with a short-lived positron emitter 11C (t½ = 20.3 min) at the carbonyl position. The labelled compounds were synthesized from alkyl iodides (0.05–0. LÄS MER

5. 9. Analysis of tracer molecules from organic aerosols - Application of liquid phase microextraction to aerosol analysis

   Författare :Murtaza Hyder; Centrum för analys och syntes; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Liquid membrane extraction; Secondary organic aerosols; Enrichment; Tracers; Hollow fiber liquid phase microextraction; Biomass burning; Organic carbon;

   Sammanfattning : Airborne particulate matter is well known because of its adverse impacts on human health and its role in climate processes. In order to understand completely the role of aerosols in atmosphere, their chemical composition is of basic importance. LÄS MER

7. 10. Permafrost carbon in a changing Arctic : On periglacial landscape dynamics, organic matter characteristics, and the stability of a globally significant carbon pool

   Författare :Niels Weiss; Peter Kuhry; Duane Froese; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Permafrost; Carbon; Climate; Arctic; Soil; Organic Matter; Cryosphere; Geomorphology; Physical Geography; naturgeografi;

   Sammanfattning : Organic matter (OM) in arctic permafrost ground contains about twice as much carbon (C) as is currently present in the atmosphere. Climate change is particularly strong in the Arctic, and could cause a considerable part of the OM in permafrost to thaw out, decompose, and be released as greenhouse gases; further enhancing global warming. LÄS MER