Studies in pyrolysis

In Part I of this thesis, the thermal breakdown (vapour phase: ca. 500) of the lactides obtained from laotic and a-hydroxylsobutyric acid is critically re-examined, with the assistance of some model compounds. The pyrolysis of the lactide of 1-hydroxycyclohexane-carboxylic acid is also studied. The predominating breakdown reaction of all three is a concerted double decarbonylation (yielding carbon monoxide and an aldehyde or ketone) together with minor competing reactions. Reasons are advanced for the failure of the lactides and acyl derivatives of A-hydroxy acids to show major alkyl-oxygen scission to the corresponding unsaturated acids. Reaction mechanisms are discussed. In Part II, the thermal degradation at 220 - 26