Physical Properties of Aconitic Acid

Aconitic acid, a white crystalline solid, exists as either the trans-or the cts-form with the fraws-aconitic acid being the more stable form41 while the cts-acid is the stronger acid. The fnms-aconitic acid exhibits a decomposition point rather than a true melting point. The values reported in the literature vary over a range from 185° to 208° and the observed decomposition point is a function not only of the purity of the acid but also of the temperature of the melting point bath when the sample is introduced and of the rate of heating.34-42 

The fmns-aconitic acid is easily soluble in water and the solubility increases as the temperature rises. The acid is quite soluble in methanol, ethanol, aqueous ethanol, dioxane, slightly soluble in diethyl ether and can be recrystallized from water, ether or concentrated hydrochloric acid. 

The physical properties of aconitic acid are listed in Table I. 

Molecular Heat of Combustion 481.3 kcal. (constant volume)8 476.3 kcal. (constant volume)88 475.4 kcal. (constant pressure)88 — 

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