Temporal relationships of carbon cycling and ocean circulation in glacial boundaries.

Piotrowski, A. M. and Goldstein, S. L. and Hemming, S. R. and Fairbanks, R. G. (2005) Temporal relationships of carbon cycling and ocean circulation in glacial boundaries. Science, 307. pp. 1933-1938. DOI 10.1126/science.1104883

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Abstract

Rate coefficients for reactions of nitrate radicals (NO3) with (Z)-pent-2-ene, (E)-pent-2-ene, (Z)-hex-2-ene, (E)-hex-2-ene, (Z)-hex-3-ene, (E)-hex-3-ene and (E)-3-methylpent-2-ene were determined to be (6.55 0.78) 1013 cm3 molecule1 s1, (3.78 0.45) 1013 cm3 molecule1 s1, (5.30 0.73) 1013 cm3 molecule1 s1, (3.83 0.47) 1013 cm3 molecule1 s1, (4.37 0.49) 1013 cm3 molecule1 s1, (3.61 0.40) 1013 cm3 molecule1 s1 and (8.9 1.5) 1012 cm3 molecule1 s1, respectively. We performed kinetic experiments at room temperature and atmospheric pressure using a relative-rate technique with GC–FID analysis. The experimental results demonstrate a surprisingly large cis–trans (Z–E) effect, particularly in the case of the pent-2-enes, where the ratio of rate coefficients is ca. 1.7. Rate coefficients are discussed in terms of electronic and steric influences, and our results give some insight into the effects of chain length and position of the double bond on the reaction of NO3 with unsaturated hydrocarbons. Atmospheric lifetimes were calculated with respect to important oxidants in the troposphere for the alkenes studied, and NO3-initiated oxidation is found to be the dominant degradation route for (Z)-pent-2-ene, (Z)-hex-3-ene and (E)-3-methylpent-2-ene.

Item Type: Article
Uncontrolled Keywords: 2005 PUBL 2005 AREP IA47
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Science
Volume: 307
Page Range: pp. 1933-1938
Identification Number: 10.1126/science.1104883
Depositing User: Sarah Humbert
Date Deposited: 23 Aug 2010 13:08
Last Modified: 23 Jul 2013 09:59
URI: http://eprints.esc.cam.ac.uk/id/eprint/1779

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