Chlorination of Amino Acids: Reaction Pathways and Reaction Rates
Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chlo...
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| Format: | Journal Article |
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American Chemical Society
2017
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| Online Access: | http://purl.org/au-research/grants/arc/LP110100548 http://hdl.handle.net/20.500.11937/51516 |
| _version_ | 1848758718012850176 |
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| author | How, Zuo Tong Linge, Kathryn Busetti, Francesco Joll, Cynthia |
| author_facet | How, Zuo Tong Linge, Kathryn Busetti, Francesco Joll, Cynthia |
| author_sort | How, Zuo Tong |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected by-products. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modelling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4x104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9x102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0x10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3x10-4 s-1) and N-chloroisobutyraldimine (1.2x10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odour threshold concentration, resulting in aesthetic challenges and an unknown health risk. |
| first_indexed | 2025-11-14T09:48:26Z |
| format | Journal Article |
| id | curtin-20.500.11937-51516 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:48:26Z |
| publishDate | 2017 |
| publisher | American Chemical Society |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-515162018-03-16T03:10:08Z Chlorination of Amino Acids: Reaction Pathways and Reaction Rates How, Zuo Tong Linge, Kathryn Busetti, Francesco Joll, Cynthia Chlorination of amino acids can result in the formation of organic monochloramines or organic dichloramines, depending on the chlorine to amino acid ratio (Cl:AA). After formation, organic chloramines degrade into aldehydes, nitriles and N-chloraldimines. In this paper, the formation of organic chloramines from chlorination of lysine, tyrosine and valine were investigated. Chlorination of tyrosine and lysine demonstrated that the presence of a reactive secondary group can increase the Cl:AA ratio required for the formation of N,N-dichloramines, and potentially alter the reaction pathways between chlorine and amino acids, resulting in the formation of unexpected by-products. In a detailed investigation, we report rate constants for all reactions in the chlorination of valine, for the first time, using experimental results and modelling. At Cl:AA = 2.8, the chlorine was found to first react quickly with valine (5.4x104 M-1 s-1) to form N-monochlorovaline, with a slower subsequent reaction with N-monochlorovaline to form N,N-dichlorovaline (4.9x102 M-1 s-1), although some N-monochlorovaline degraded into isobutyraldehyde (1.0x10-4 s-1). The N,N-dichlorovaline then competitively degraded into isobutyronitrile (1.3x10-4 s-1) and N-chloroisobutyraldimine (1.2x10-4 s-1). In conventional drinking water disinfection, N-chloroisobutyraldimine can potentially be formed in concentrations higher than its odour threshold concentration, resulting in aesthetic challenges and an unknown health risk. 2017 Journal Article http://hdl.handle.net/20.500.11937/51516 10.1021/acs.est.6b04440 http://purl.org/au-research/grants/arc/LP110100548 http://purl.org/au-research/grants/arc/LP130100602 American Chemical Society fulltext |
| spellingShingle | How, Zuo Tong Linge, Kathryn Busetti, Francesco Joll, Cynthia Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title | Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title_full | Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title_fullStr | Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title_full_unstemmed | Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title_short | Chlorination of Amino Acids: Reaction Pathways and Reaction Rates |
| title_sort | chlorination of amino acids: reaction pathways and reaction rates |
| url | http://purl.org/au-research/grants/arc/LP110100548 http://purl.org/au-research/grants/arc/LP110100548 http://hdl.handle.net/20.500.11937/51516 |