File Download

There are no files associated with this item.

  Links for fulltext
     (May Require Subscription)
Supplementary

Article: Water-catalyzed O-H insertion/HI elimination reactions of isodihalomethanes (CH 2X-I, where X = Cl, Br, I) with water and the dehalogenation of dihalomethanes in water-solvated environments

TitleWater-catalyzed O-H insertion/HI elimination reactions of isodihalomethanes (CH 2X-I, where X = Cl, Br, I) with water and the dehalogenation of dihalomethanes in water-solvated environments
Authors
Issue Date2005
PublisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/jpca
Citation
Journal Of Physical Chemistry A, 2005, v. 109 n. 6, p. 981-998 How to Cite?
AbstractA combined experimental and theoretical investigation of the ultraviolet photolysis of CH 2XI (where X = Cl, Br, I) dihalomethanes in water is presented. Ultraviolet photolysis of low concentrations of CH 2XI (where X = Cl, Br, I) in water appears to lead to almost complete conversion into CH 2(OH) 2 and HX and HI products. Picosecond time-resolved resonance Raman (ps-TR 3) spectroscopy experiments revealed that noticeable amounts of CH 2X-I isodihalomethane intermediates were formed within several picoseconds after photolysis of the CH 2XI parent compound in mixed aqueous solutions. The ps-TR 3 experiments in mixed aqueous solutions revealed that the decay of the CH 2X-I isodihalomethane intermediates become significantly shorter as the water concentration increases, indicating that the CH 2X-I intermediates may be reacting with water. Ab initio calculations found that the CH 2X-I intermediates are able to react relatively easily with water via a water-catalyzed O-H insertion/HI elimination reaction to produce CH 2X(OH) and HI products, with the barrier for these reactions increasing as X changes from Cl to Br to I. The ab initio calculations also found that the CH 2X(OH) product can undergo a water-catalyzed HX elimination reaction to make H 2C=O and HX products, with the barrier to reaction decreasing as X changes from Cl to Br to I. The preceding two water-catalyzed reactions produce the HI and HX leaving groups observed experimentally, and the H 2C=O product further reacts with water to make the other CH 2(OH) 2 product observed in the photochemistry experiments. This suggests that that the CH 2X-I intermediates react with water to form the CH 2(OH) 2 and HI and HX products observed in the photochemistry experiments. Ultraviolet photolysis of CH 2XI (where X = Cl, Br, I) at low concentrations in water-solvated environments appears to lead to efficient dehalogenation and release of two strong acid leaving groups. We very briefly discuss the potential influence of this photochemistry in water on the decomposition of polyhalomethanes and halomethanols in aqueous environments.
Persistent Identifierhttp://hdl.handle.net/10722/167894
ISSN
2015 Impact Factor: 2.883
2015 SCImago Journal Rankings: 1.231
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLin, Xen_US
dc.contributor.authorGuan, Xen_US
dc.contributor.authorKwok, WMen_US
dc.contributor.authorZhao, Cen_US
dc.contributor.authorDu, Yen_US
dc.contributor.authorLi, YLen_US
dc.contributor.authorPhillips, DLen_US
dc.date.accessioned2012-10-08T03:12:38Z-
dc.date.available2012-10-08T03:12:38Z-
dc.date.issued2005en_US
dc.identifier.citationJournal Of Physical Chemistry A, 2005, v. 109 n. 6, p. 981-998en_US
dc.identifier.issn1089-5639en_US
dc.identifier.urihttp://hdl.handle.net/10722/167894-
dc.description.abstractA combined experimental and theoretical investigation of the ultraviolet photolysis of CH 2XI (where X = Cl, Br, I) dihalomethanes in water is presented. Ultraviolet photolysis of low concentrations of CH 2XI (where X = Cl, Br, I) in water appears to lead to almost complete conversion into CH 2(OH) 2 and HX and HI products. Picosecond time-resolved resonance Raman (ps-TR 3) spectroscopy experiments revealed that noticeable amounts of CH 2X-I isodihalomethane intermediates were formed within several picoseconds after photolysis of the CH 2XI parent compound in mixed aqueous solutions. The ps-TR 3 experiments in mixed aqueous solutions revealed that the decay of the CH 2X-I isodihalomethane intermediates become significantly shorter as the water concentration increases, indicating that the CH 2X-I intermediates may be reacting with water. Ab initio calculations found that the CH 2X-I intermediates are able to react relatively easily with water via a water-catalyzed O-H insertion/HI elimination reaction to produce CH 2X(OH) and HI products, with the barrier for these reactions increasing as X changes from Cl to Br to I. The ab initio calculations also found that the CH 2X(OH) product can undergo a water-catalyzed HX elimination reaction to make H 2C=O and HX products, with the barrier to reaction decreasing as X changes from Cl to Br to I. The preceding two water-catalyzed reactions produce the HI and HX leaving groups observed experimentally, and the H 2C=O product further reacts with water to make the other CH 2(OH) 2 product observed in the photochemistry experiments. This suggests that that the CH 2X-I intermediates react with water to form the CH 2(OH) 2 and HI and HX products observed in the photochemistry experiments. Ultraviolet photolysis of CH 2XI (where X = Cl, Br, I) at low concentrations in water-solvated environments appears to lead to efficient dehalogenation and release of two strong acid leaving groups. We very briefly discuss the potential influence of this photochemistry in water on the decomposition of polyhalomethanes and halomethanols in aqueous environments.en_US
dc.languageengen_US
dc.publisherAmerican Chemical Society. The Journal's web site is located at http://pubs.acs.org/jpcaen_US
dc.relation.ispartofJournal of Physical Chemistry Aen_US
dc.titleWater-catalyzed O-H insertion/HI elimination reactions of isodihalomethanes (CH 2X-I, where X = Cl, Br, I) with water and the dehalogenation of dihalomethanes in water-solvated environmentsen_US
dc.typeArticleen_US
dc.identifier.emailPhillips, DL:phillips@hku.hken_US
dc.identifier.authorityPhillips, DL=rp00770en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1021/jp0450843en_US
dc.identifier.pmid16833405-
dc.identifier.scopuseid_2-s2.0-14544287683en_US
dc.identifier.hkuros99137-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-14544287683&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume109en_US
dc.identifier.issue6en_US
dc.identifier.spage981en_US
dc.identifier.epage998en_US
dc.identifier.isiWOS:000226955800007-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridLin, X=35205535200en_US
dc.identifier.scopusauthoridGuan, X=8313149700en_US
dc.identifier.scopusauthoridKwok, WM=7103129332en_US
dc.identifier.scopusauthoridZhao, C=7403563836en_US
dc.identifier.scopusauthoridDu, Y=35310175500en_US
dc.identifier.scopusauthoridLi, YL=27168456500en_US
dc.identifier.scopusauthoridPhillips, DL=7404519365en_US

Export via OAI-PMH Interface in XML Formats


OR


Export to Other Non-XML Formats