I. J. Smith, B. Tighe
1981
Citations
0
Influential Citations
22
Citations
Journal
Macromolecular Chemistry and Physics
Abstract
5-Phenyl-1,3-dioxolan-2,4-dione (the anhydrocarboxylate derivative of mandelic acid) has been shown to undergo polymerisation in the presence of tertiary organic bases such as pyridine in a reaction that has somewhat unusual characteristics. Thus, although the reaction in nitrobenzene shows first-order kinetic dependence on both monomer and pyridine over a reasonable concentration range, the pyridine is not consumed and does not appear to control the molecular weight of the resultant polymer. The most important factor in controlling molecular weight is the presence of adventitious moisture which enters into the polymerisation process producing poly-α-esters that are hydroxyl/carboxyl terminated. The rate of polymerisation increases progressively as pyridine is replaced by 2-methylpyridine and 2,6-dimethylpyridine but decreases dramatically when 2-methoxypyridine is used, indicating the importance of the basicity of the attacking species. The results are interpreted in terms of the interaction of the basic nitrogen and the C-4 ring carbonyl leading to the formation of a transient charge transfer complex which subsequently decomposes to form pyridine, carbon dioxide and the α-lactone. The chain growth process involves the interaction of the α-lactone with any nucleophiles present which control the molecular weight and nature of the end groups.