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Reactions of Drinking Water Contaminants with Aqueous Chlorine and Monochloramine
Published in Rhoda G.M. Wang, Water Contamination and Health, 2020
Frank E. Scully, William N. White, Robert S. Boethling
Ketones and aldehydes are halogenated at the a-carbon atoms on reaction with aqueous chlorine. The halogenation of methyl ketones results in the elimination of a trihalomethane molecule in a reaction referred to as the haloform reaction. This reaction has been thought to be partially responsible for the formation of chloroform on chlorination of natural humic substances during water treatment processes. The a-halogenation of ketones and aldehydes is acid or base catalyzed (16-21) and involves initial slow enolization of the ketone. For example, the mechanism for the base-catalyzed reaction of acetone is as follows:
Reactions With Disinfectants
Published in Richard A. Larson, Eric J. Weber, Reaction Mechanisms in Environmental Organic Chemistry, 2018
Richard A. Larson, Eric J. Weber
The classical organic reaction for the synthesis of THMs, the so-called “haloform reaction,” is actually a series of reactions of enolizable compounds whose rate is usually determined by the rate of enolization of a precursor molecule. It is outlined in Figure 5.5.
Local structure and orientational ordering in liquid bromoform
Published in Molecular Physics, 2019
Jacob J. Shephard, John S. O. Evans, Christoph G. Salzmann
Trihalomethanes (CHX3) are important in a wide range of environmental settings and industrial applications.[1] To emphasise the chemical similarities with formic acid, they are often called haloforms and can be prepared using the well-known haloform reaction.[2] Fluoroform (CHF3) is a non-ozone depleting greenhouse gas that is used in refrigeration.[3] Both chloroform (CHCl3) and bromoform (CHBr3) are solvents with high densities and are often used for extraction processes. Famous examples include the extraction of morphine from poppies [4] and atropine from thorn apple leaves [5]. Iodoform (CHI3) is solid at room temperature and used as a disinfectant whose distinctive smell is often associated with hospitals. The crystal structure of CHI3 displays disorder with respect to the either parallel or antiparallel alignments of the molecular dipole moments in line with the nonpolar 6/m point-group symmetry of P63/m [6]. Similar types of disorder are also observed for the high-temperature/low-pressure phases of CHBr3 and CHCl3 [7].