Mechanistische und kinetische Untersuchungen zur Ozonolyse von organischen Verbindungen in wässriger Lösung - Mechanistic and kinetic studies on the ozonolysis of organic compounds in aqueous solutions
The main focus of the dissertation is the reaction of ozone with vinyl compounds, nucleic acids, aliphatic and aromatic carbonic acids.
In product studies, material balance with respect to ozone consumption has been obtained. Rate constants of the reaction of ozonone with the investigated compounds and other kinetic studies were determined with conventional methods as well as with the Stopped-Flow method and with the competition technique. The Stopped-Flow apparatus can be used with optical and also with conductometric detection.
Especially, while the ozonolysis of vinyl compounds mixed anhydrides of the formic acid are build. Except HC(O)PO32-, the hydrolysis of the investigated anhydrides is faster than the decay. The kinetics of the hydrolysis are very different. Also, different hydroperoxides could be detected. Their pseudo-first-order kinetics with molybdate-activated iodide allows to characterise a given peroxide. The halftimes of the peroxides can differ up to seven orders of magnitude.
Besides this the ozonolysis of aliphatic unsaturated acids is described. The rate constant of this kind of acid is pH dependent. A particularity of the ozonolysis of fumaric and maleic acid is a marked isomerisation of these two acids occurs. This phenomenon is unknown in the ozone chemistry so fare. The yield of the isomerisation is pH dependent and increases with temperature.
From its high rate of reaction one has to assume that ozone reacts with the conjugated double bond rather than with the aromatic ring. This kinetic result could be confirmed with the result of the product analysis.
The ozonolysis of thymine and thymidine has been investigated by a product study complemented by kinetic studies using spectrophotometry, conductometry and stopped-flow with optical and conductometric detection. Material balance has been obtained.
Advisor:Prof. Dr. Alfred Golloch; Prof. Dr. Clemens von Sonntag
School:Universität Duisburg-Essen, Standort Essen
Source Type:Master's Thesis
Keywords:mpi für strahlenchemie
Date of Publication:10/09/2003