title: Irradiation of ultrasound to 5-methylbenzotriazole in aqueous phase: Degradation kinetics and mechanisms.
abstract: Ultrasonic irradiation (640 kHz) leads to the effective degradation of 5-methyl-benzotriazole (5-MBT) in O2 saturated aqueous solution. Up to 97% of 5-MBT is eliminated within 2h of treatment. Upon extended treatment of 6h, UV absorbance of the n→π(∗) and π→π(∗) transitions associated with aromatic and conjugated systems are completely removed, indicating complete destruction of the aromatic system in 5-MBT. The decomposition of 5-MBT follows pseudo-first order kinetics and the observed decomposition rate dropped significantly in the presence of tertiary butyl alcohol. Detailed product studies were performed employing a negative mode ESI LC-MS. Twenty eight intermediate products were detected during ultrasonic mediated degradation of 5-MBT. Reaction pathways are proposed based on the structures of products assigned to observed 28 masses from LC-MS and commonly accepted degradation pathways observed by thermal and hydroxyl radical mediated pathways often associated with ultrasonic treatment.
authors.affiliation: Department of Chemistry, Auburn University at Montgomery, Montgomery, AL 36117, United States. Electronic address: dkim@aum.edu.
authors.forename: Duk K
authors.initials: DK
authors.lastname: Kim
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199, United States.
authors.forename: Yingxin
authors.initials: Y
authors.lastname: He
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199, United States.
authors.forename: Junho
authors.initials: J
authors.lastname: Jeon
authors.affiliation: Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199, United States.
authors.forename: Kevin E
authors.initials: KE
authors.lastname: O'Shea
keywords: 5-Methylbenzotriazole; Degradation kinetics and mechanisms; LC–MS analyses; Ultrasonic degradation