CHED 1423 |
| The protonation of ethanol in sulfuric acid was studied using carbon-13 NMR spectroscopy. The pKBH+ was found to be -2.14 to -2.17 for the range of temperatures studied. The pKBH+ value decreases as temperature decreases. Over the temperature range of -20 ◦C to -5 ◦C, the protonation enthalpy of ethanol was found to be small and negative. This result indicates that as the temperature drops, ethanol is less easily protonated by sulfuric acid. In the atmosphere, gaseous ethanol is taken up by acidic sulfate particles. Since protonated ethanol is a precursor to reactions, if its concentration in atmospheric particles decreases as temperature decreases then this may reduce reaction rates. Ethanol dissolved in sulfate particles will be mostly molecular ethanol even at the highest acidities. Ethanol's behavior in the atmosphere is becoming more important due to the increasing use of ethanol as a fuel additive. |
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Undergraduate Research Poster Session: Physical Chemistry
2:00 PM-4:00 PM, Monday, March 26, 2007 Hyatt Regency Chicago -- Riverside Center, Poster
Division of Chemical Education |