A large spill of 4-methylcyclohexanemethanol (MCHM) forced closure of tap water for nearly 300,000 residents in West Virginia in 2014. Typical water treatment methods, including activated carbon and bioremediation, are not effective for remediation of MCHM. With this in mind, we studied the ultrasonically induced degradation as a potential water treatment for the semi-volatile, MCHM. Ultrasonic irradiation of MCHM in aqueous media at 670 KHz leads to its rapid pseudo-first order degradation. Ultrasonic initiated degradation processes can be the result of both hydroxyl radical and pyrolytic processes that occur at or near the site of cavitation and the gas-liquid interface. To model the degradation process at the gas-liquid interface as a heterogeneous reaction surface the Langmuir-Hinshelwood (L-H) and Freundlich models were employed. The Freundlich model which takes into account non-uniform distribution of MCHM at the interface (reactive zone) showed an excellent correlation to the experimental data with R2 &gt; 0.99. The results of the modeling are rationalized as solute-solute clustering behavior, a supercritical fluid (SCF) phenomenon occurring at the interface. The primary reaction products are (4-methylcyclohexenyl) methanol and 4-methylcyclohexanone, shown in Scheme.1. Computational methods using density functional B3YPL/6-311G** calculations with Gaussian 09 provided insight of the hydroxyl radical and pyrolytic degradation pathways for the isomeric and conformational forms of MCHM. Our studies indicate that heterogeneous kinetic models and computational methods can be important tools for the fundamental understanding and effective modeling of ultrasonically mediated degradation of semi-volatile compounds.

Kinetic, product, and computational studies of the ultrasonically induced degradation of 4-methylcyclohexanemethanol (MCHM)

253rd National Meeting (2017)

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