Assessing the Potential for the Reactions of Epoxides with Amines on Secondary Organic Aerosol Particles

Title:
Assessing the Potential for the Reactions of Epoxides with Amines on Secondary Organic Aerosol Particles
Authors:
Stropoli, Santino J.; Elrod, Matthew J.
Abstract:
Nuclear magnetic resonance techniques were used to study the kinetics and products of the reaction of a variety of epoxides with various amines under varying pH conditions. In agreement with a previous finding, the amine epoxide reactions were found to be water-catalyzed and not directly dependent on the pH of the reaction environment. At pH values higher than the plc of the particular amine, the amine epoxide reactions were extremely efficient, outcompeting hydrolysis reactions even for conditions where water was the solvent and the amine was a relatively low-concentration solute. This finding was rationalized by measurements that showed that the relative nucleophilic strength of amines relative to water was on the order of 1000, while the nucleophilic strength of protonated amines (which are predominant when pH < pK(a) was negligible. The epoxide carbon substitution environment was found to have a large effect on the measured rate constants (more substituted epoxides had slower rate constants), while the amine carbon substitution environment had a much more limited effect. While the amine epoxide rate constants are large enough such that amine epoxide reactions may be kinetically feasible for isoprene-derived epoxides and high amine secondary organic aerosol (SOA) concentrations, most atmospheric amines are expected to be present in protonated form on the largely acidic SOA found in the atmosphere and thus are expected to be largely unreactive toward epoxides.
Citation:
Stopoli, S.J., and M.J. Elrod. 2015. "Assessing the Potential for the Reactions of Epoxides with Amines on Secondary Organic Aerosol Particles." Journal of Physical Chemistry A 119(40): 10181-10189.
Publisher:
American Chemical Society
DATE ISSUED:
2015-10-08
Department:
Chemistry and Biochemistry
Type:
Article
PUBLISHED VERSION:
10.1021/acs.jpca.5b07852
Additional Links:
http://pubs.acs.org/doi/10.1021/acs.jpca.5b07852
PERMANENT LINK:
http://hdl.handle.net/11282/593464

Full metadata record

DC FieldValue Language
dc.contributor.authorStropoli, Santino J.en
dc.contributor.authorElrod, Matthew J.en
dc.date.accessioned2016-01-14T19:52:29Zen
dc.date.available2016-01-14T19:52:29Zen
dc.date.issued2015-10-08en
dc.identifier.citationStopoli, S.J., and M.J. Elrod. 2015. "Assessing the Potential for the Reactions of Epoxides with Amines on Secondary Organic Aerosol Particles." Journal of Physical Chemistry A 119(40): 10181-10189.en
dc.identifier.issn1089-5639en
dc.identifier.urihttp://hdl.handle.net/11282/593464en
dc.description.abstractNuclear magnetic resonance techniques were used to study the kinetics and products of the reaction of a variety of epoxides with various amines under varying pH conditions. In agreement with a previous finding, the amine epoxide reactions were found to be water-catalyzed and not directly dependent on the pH of the reaction environment. At pH values higher than the plc of the particular amine, the amine epoxide reactions were extremely efficient, outcompeting hydrolysis reactions even for conditions where water was the solvent and the amine was a relatively low-concentration solute. This finding was rationalized by measurements that showed that the relative nucleophilic strength of amines relative to water was on the order of 1000, while the nucleophilic strength of protonated amines (which are predominant when pH < pK(a) was negligible. The epoxide carbon substitution environment was found to have a large effect on the measured rate constants (more substituted epoxides had slower rate constants), while the amine carbon substitution environment had a much more limited effect. While the amine epoxide rate constants are large enough such that amine epoxide reactions may be kinetically feasible for isoprene-derived epoxides and high amine secondary organic aerosol (SOA) concentrations, most atmospheric amines are expected to be present in protonated form on the largely acidic SOA found in the atmosphere and thus are expected to be largely unreactive toward epoxides.en
dc.language.isoen_USen
dc.publisherAmerican Chemical Societyen
dc.identifier.doi10.1021/acs.jpca.5b07852en
dc.relation.urlhttp://pubs.acs.org/doi/10.1021/acs.jpca.5b07852en
dc.subject.departmentChemistry and Biochemistryen_US
dc.titleAssessing the Potential for the Reactions of Epoxides with Amines on Secondary Organic Aerosol Particlesen_US
dc.typeArticleen
dc.identifier.journalJournal of Physical Chemistry Aen
dc.identifier.volume119en_US
dc.identifier.issue40en_US
dc.identifier.startpage10181en_US
dc.rightsArchived with thanks to The Journal of Physical Chemistry Aen
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