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Physicochemical Properties of Terebic Acid, MBTCA, Diaterpenylic Acid Acetate, and Pinanediol as Relevant α‑Pinene Oxidation Products
journal contribution
posted on 2020-04-01, 00:13 authored by Agata Kołodziejczyk, Patryk Pyrcz, Kacper Błaziak, Aneta Pobudkowska, Kumar Sarang, Rafał SzmigielskiThe physicochemical properties and
the synthesis of four α-pinene
oxidation products, terebic acid, 3-methyl-1,2,3-butanetricarboxylic
acid (MBTCA), diaterpenylic acid acetate (DTAA), and pinanediol, are
presented in this study. The physicochemical properties encompass
thermal properties, solubility in water, and dissociation constant
(pKa) for the investigated compounds.
It was found that terebic acid exhibits a relatively high melting
temperature of 449.29 K, whereas pinanediol revealed a low melting
temperature of 329.26 K. The solubility in water was determined with
the dynamic method and the experimental results were correlated using
three different mathematical models: Wilson, NRTL, and UNIQUAC equations.
The results of the correlation indicate that the Wilson equation appears
to work the best for terebic acid and pinanediol. The calculated standard
deviation was for 3.79 for terebic acid and 1.25 for pinanediol. In
contrast, UNIQUAC was the best mathematical model for DTAA and MBTCA.
The calculated standard deviation was 0.57 for DTAA and 2.21 for MBTCA.
The measured water solubility increased in the following order: pinanediol
> DTAA ≥ MBTCA > terebic acid, which affects their multiphase
aging chemistry in the atmosphere. Moreover, acidity constants (pKa) at 298, 303, and 308 K were determined for
DTAA with the Bates–Schwarzenbach spectrophotometric method.
The pKa values obtained at 298, 303, and
308 K were found to be 3.76, 3.85, and 3.88, respectively.