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Enhanced Acidity of Acetic and Pyruvic Acids on the Surface of Water

Eugene, Alexis J. and Pillar, Elizabeth A. and Colussi, Agustín J. and Guzmán, Marcelo I. (2018) Enhanced Acidity of Acetic and Pyruvic Acids on the Surface of Water. Langmuir, 34 (31). pp. 9307-9313. ISSN 0743-7463. doi:10.1021/acs.langmuir.8b01606.

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Understanding the acid–base behavior of carboxylic acids on aqueous interfaces is a fundamental issue in nature. Surface processes involving carboxylic acids such as acetic and pyruvic acids play roles in (1) the transport of nutrients through cell membranes, (2) the cycling of metabolites relevant to the origin of life, and (3) the photooxidative processing of biogenic and anthropogenic emissions in aerosols and atmospheric waters. Here, we report that 50% of gaseous acetic acid and pyruvic acid molecules transfer a proton to the surface of water at pH 2.8 and 1.8 units lower than their respective acidity constants pK_a = 4.6 and 2.4 in bulk water. These findings provide key insights into the relative Bronsted acidities of common carboxylic acids versus interfacial water. In addition, the work estimates the reactive uptake coefficient of gaseous pyruvic acid by water to be γ_(PA) = 0.06. This work is useful to interpret the interfacial behavior of pyruvic acid under low water activity conditions, typically found in haze aerosols, clouds, and fog waters.

Item Type:Article
Related URLs:
URLURL TypeDescription Information
Colussi, Agustín J.0000-0002-3400-4101
Guzmán, Marcelo I.0000-0002-6730-7766
Additional Information:© 2018 American Chemical Society. ACS AuthorChoice - This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes. Received: May 14, 2018; Revised: June 25, 2018; Published: July 5, 2018. M.I.G. thanks research funding from the National Science foundation under NSF CAREER award CHE-1255290. A.J.E. acknowledges the support by the NASA Earth and Space Science Fellowship (NESSF) Program. A.J.C. acknowledges funding from the National Science Foundation under grant AGS-1744353. The authors declare no competing financial interest.
Funding AgencyGrant Number
NASA Earth and Space Science FellowshipUNSPECIFIED
Issue or Number:31
Record Number:CaltechAUTHORS:20180706-134535054
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Official Citation:Enhanced Acidity of Acetic and Pyruvic Acids on the Surface of Water Alexis J. Eugene, Elizabeth A. Pillar, Agustín J. Colussi, and Marcelo I. Guzman Langmuir 2018 34 (31), 9307-9313 DOI: 10.1021/acs.langmuir.8b01606
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:87605
Deposited By: Tony Diaz
Deposited On:06 Jul 2018 20:56
Last Modified:15 Nov 2021 20:49

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