Mechanisms of Chemiluminescence

3-Acetyl-4,4-dimethyl-1,2-dioxetane (1) was prepared by the base-catalyzed rearrangement of 4-bromo-3-hydroxy-3,5,5-trimethyl-1,2-dioxolane. Thermal decomposition of this dissymmetric dioxetane to acetone and methylglyoxal proceeds with an activation energy of 26.0 (+OR-) 1 kcal/mol and a log A of 14.2. The enthalpy of activation and entropy of activation were determined to be 25.5 (+OR-) 1.0 kcal/mol and 4.0 (+OR-) 2 eu, respectively. The total yield of excited states produced in the thermal decomposition was determined to be (17 (+OR-) 3) %. Both excited state acetone and excited state methylglyoxal were detected. The excited state multiplicities and yields are: acetone triplet (0.45 (+OR-) 0.20)%, methylglyoxal singlet (1.6 (+OR-) 0.5)%, and methylglyoxal triplet (15 (+OR-) 3)%. No singlet excited state acetone was detected. It is suggested that the observed excited state yields and the low triplet to singlet excited state methylglyoxal ratio can best be rationalized in terms of the energetics of a stepwise bi-radical decomposition of the dioxetane.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Horn, Keith Alan

• Chemistry, Organic

Language dc:language

eng

Identifier

(UMI)AAI8017953

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/67221