Gas-Phase Reactions and Rearrangements of Alkyl Esters with H3O+, NO+, and O2+: A Selected Ion Flow Tube Study

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• 作者：Gregory J. Francis ; Daniel B. Milligan ; Murray J. McEwan
• 刊名：Journal of Physical Chemistry A
• 出版年：2007
• 出版时间：October 4, 2007
• 年：2007
• 卷：111
• 期：39
• 页码：9670 - 9679
• 全文大小：181K
• 年卷期：v.111,no.39(October 4, 2007)
• ISSN：1520-5215

文摘

Selected ion flow tube mass spectrometry (SIFT-MS) has been employed to study the ion-molecule reactionsof 17 alkyl esters reacting with the common SIFT-MS reagent ions, H₃O⁺, H₃O⁺·nH₂O (n = 1, 2, 3), NO⁺,and O₂⁺. The majority of reactions were observed to proceed at or near collision rate, with the exception ofH₃O⁺·3H₂O, which was found to be slow for 8 of 17 alkyl esters. Unexpected product ions in the form of theparent carboxylic acid cation were observed to arise from the H₃O⁺ and NO⁺ reactions of some alkyl esters.The observed reactions have been probed by the ab initio CBS-4M and G2(MP2,SVP) methods. The postulatedreaction pathway involves a 1,5 H atom migration from a -carbon onto the carbonyl oxygen.