eprintid: 7685 rev_number: 4 userid: 6 dir: disk0/00/00/76/85 datestamp: 2011-11-10 19:42:49 lastmod: 2016-11-15 13:42:45 status_changed: 2011-11-10 19:42:49 type: thesis_degree metadata_visibility: show contact_email: krt9@pitt.edu item_issues_count: 0 eprint_status: archive creators_name: Tilger, Kyle Richard creators_email: krt9@pitt.edu creators_id: KRT9 title: ION/MOLECULE REACTIONS STUDIED WITH THE FLOWING AFTERGLOW AND THEORETICAL METHODOLOGY ispublished: unpub divisions: sch_as_chemistry full_text_status: public keywords: gas phase ion chemistry abstract: Initial interest in ion/molecule chemistry was because of its importance in atmospheric chemistry, but researchers have moved to investigating other interests involving organic reaction mechanisms. The study of ion/molecule reactions has flourished with the invention of instruments, such as the flowing afterglow instrument, and the advances in computational chemistry. The hydronium ion has been utilized as a reagent ion in ion/molecule chemistry for the detection of volatile organic compounds (VOCs). A limitation to the utility of the hydronium ion is that it is susceptible to clustering reactions with water. The propensity to cluster can be eliminated by replacing the hydrogens on the hydronium ion with trimethylsilyl groups to form the tris-trimethylsilyloxonium ion, (TMS)3O+. This strategy takes advantage of the trimethylsilyl cation's proclivity to react as if it were a proton. Hexamethyldisiloxane was allowed to react with TMS+, (TMS)2Cl+, TMSOH2+, and TMSC6H6+ in an attempt to form (TMS)3O+. However, every attempt to create the novel (TMS)3O+ via a gas phase approach was unsuccessful. The available data suggests that the target ion may be formed, but is so reactive under the experimental conditions that it reacts away prior to detection. An investigation of the formation and reactions of the bis-trimethylsilylmethyloxonium ion ((TMS)2OCH3+) was conducted to gain further understanding of the chemistry of the formation and reactivity of oxonium ions. After successful formation of the bis-trimethylsilylmethyloxonium ion, six neutrals (water, dimethylsulfide, acetonitrile, ethyl acetate, triethylamine, and acetone) were allowed to react one at a time with it. Trimethylsilyl transfer was the primary reaction pathway, which bodes well for our goal of creating a novel reagent ion.The oxygen radical anion, O·-, has been studied by others with respect to atmospheric chemistry and has been utilized for chemical ionization reactions. To better understand its reactivity, a theoretical study of the reaction of the O·- with methanol has been analyzed. Reaction schemes and potential energy diagrams for observable products and for all possible products were created. The potential energy surface computed during this study suggests that at 298 K the expected product distribution is proton transfer. date: 2006-06-29 date_type: completed institution: University of Pittsburgh refereed: TRUE etdcommittee_type: committee_chair etdcommittee_type: committee_member etdcommittee_type: committee_member etdcommittee_name: Grabowski, Joseph etdcommittee_name: Jordan, Kenneth etdcommittee_name: Siska, Peter etdcommittee_email: joeg@pitt.edu etdcommittee_email: jordan@pitt.edu etdcommittee_email: pes@pitt.edu etdcommittee_id: JOEG etdcommittee_id: JORDAN etdcommittee_id: PES etd_defense_date: 2006-04-21 etd_approval_date: 2006-06-29 etd_submission_date: 2006-04-27 etd_access_restriction: immediate etd_patent_pending: FALSE assigned_doi: doi:10.5195/pitt.etd.2011.7685 thesis_type: thesis degree: MS committee: Joseph Grabowski (joeg@pitt.edu) - Committee Chair committee: Kenneth Jordan (jordan@pitt.edu) - Committee Member committee: Peter Siska (pes@pitt.edu) - Committee Member etdurn: etd-04272006-173428 other_id: http://etd.library.pitt.edu/ETD/available/etd-04272006-173428/ other_id: etd-04272006-173428 citation: Tilger, Kyle Richard (2006) ION/MOLECULE REACTIONS STUDIED WITH THE FLOWING AFTERGLOW AND THEORETICAL METHODOLOGY. Master's Thesis, University of Pittsburgh. (Unpublished) document_url: http://d-scholarship-dev.library.pitt.edu/7685/1/tilgerkr_etdPitt2006.pdf