Related Experiment Video
Updated: Jun 19, 2026

A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products
Published on: October 4, 2019
Disinfection by-products from halogenation of aqueous solutions of terpenoids
Cynthia A Joll1, Michael J Alessandrino, Anna Heitz
1Curtin Water Quality Research Centre, Department of Applied Chemistry, Curtin University of Technology, GPO Box U1987, Perth WA 6845, Australia. C.Joll@curtin.edu.au
Abstract:
We report the formation of trihalomethanes and other disinfection by-products from four polyfunctional terpenoids during simulated chlorination of natural waters. Complex suites of products were identified by closed loop stripping analysis (CLSA)/gas chromatography-mass spectrometry (GC-MS) from halogenation of beta-carotene and retinol. beta-Ionone appeared to be a key intermediate in the halogenation of beta-carotene and retinol, reacting further under the reaction conditions to produce trans-beta-ionone-5,6-epoxide and beta-cyclocitral. Halogenation of the four terpenoids also produced trihalomethanes (THMs), most likely through haloform reaction on methyl ketone groups within many of the intermediates. Since halogenation of retinol produced a significant quantity of THMs at a slow reaction rate, retinol-based structures may possibly contribute to the slow reacting phase of THM formation in natural waters. Two polyhydroxyphenol model compounds were halogenated for comparison. The only products identified by CLSA/GC-MS from halogenation of 4',5,7-trihydroxyflavanone and ellagic acid were THMs. 4',5,7-Trihydroxyflavanone rapidly produced THMs, with an extremely high molar yield (94%) at pH 7. Terpenoids of the beta-ionone and retinol type should be considered to be significant THM precursors, while 4',5,7-trihydroxyflavanone has been shown to be an extremely significant THM precursor, potentially present within natural organic matter in water treatment processes and distribution systems.
Related Concept Videos
Formation of Halohydrin from Alkenes
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Reactions at the Benzylic Position: Halogenation
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
Microbial Bioremediation of Pesticides
Chemical Agents for Microbial Control
