Quinaldinic acid, decarboxylation

However, the zwitterion mechanism appears attractive for picolinic and related acids. The volumes of activation for decarboxylation of picolinic are large and positive. This is consistent with release of solvent in going to the transition state as is indicated in reaction (4) of the zwitterion mechanism. The rate data for the decarboxylation of quinaldinic acids fits attractively into the zwitterion mechanism. The ratio of rate coefficients for the decarboxylation of zwitteron ion (I) to that of quinaldinic acid (II) shows a minimum value of 57 in quinoline solvent at 145.8 The anion of quinaldinic acid shows no detectable decomposition in... 

Several polynuclear aromatic hydrocarbons may be synthesized by procedures involving decarboxylation. The dry distillation of 3-phe-nanthrylacetic acid and powdered soda lime furnishes the best method of synthesis of 3-methylphenanthrene (84%). Heating aryl carboxylic acids with copper powder or copper oxide in quinoline or quinaldine is also an effective method of decarboxylation. ... 

Dyson P, PLl Hammick. Experiments on the mechanism of decarboxylation. Part I. Decomposition of quinaldinic and rioquinaldinic acids in the presence of compounds containing carbonyl groups.Chem Soc. 1937 1724—1725. 

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