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|Title:||Part One: Ozonolysis of Diphenylvinylene Carbonate. Synthesis and Thermolysis of Dibenzoyl Monoperoxycarbonate. Part Two: Singlet Oxygen: The Lifetime of Singlet Oxygen in Solution and Its Reaction With Ene-Type Olefins|
|Author(s):||Hurst, John Robert|
|Department / Program:||Chemistry|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||The reaction of ozone and diphenylvinylene carbonate is found to give dibenzoyl monoperoxycarbonate in good yield. A mechanism for the formation of this peroxide is proposed and is consistent with the Criegee mechanism for ozonolysis of most olefins. The thermolysis of dibenzoyl monoperoxycarbonate in benzene is also reported. The products of that thermolysis are very similar to the products of benzoyl peroxide thermolysis, but the rate of decay is significantly faster. The activation parameters for the decay of dibenzoyl monoperoxycarbonate were found to be consistent with the simultaneous cleavage of two bonds in the initial step.
By using a germanium photodiode detector, the emission of singlet oxygen at 1270 nm was monitored and the lifetimes of singlet oxygen in several solvents were determined. A mechanism for solvent quenching of singlet oxygen is proposed which accounts for the large solvent and solvent deuterium isotope effects on the lifetime of singlet oxygen. The relative radiative rates were also investigated and were found to be increased by aromatic solvents relative to non-aromatic solvents.
The singlet oxygen quenching rate constants for several ene-type olefins were determined and were found to depend on the structure of the olefin. This quenching is entropy dominated, and the overall rate depends on the presence of absence of hydrogen atoms on cis substituents, such that the olefins with the hydrogen containing substituents are found to quench singlet oxygen faster.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1983.
|Date Available in IDEALS:||2014-12-15|