Complex Catalysis Reaction Studied By Multi-Photon Ionization

This dissertation is composed of two parts. The first part is "Spectral and massanalyzed detection of heterogeneous catalysis in real-time and the application incombinatorial catalysis"; the second part is "Mass analyzed threshold ionizationspectroscopy of p-, m-aminophenol".Screening of catalyst library in heterogeneous catalysis is the bottleneck ofcombinatorial chemistry, and up to date, there haven't been a technology that canbe mostly used for high throughput screening heterogeneous catalysis in real-time.Resonance Enhanced Multi-Photon Ionization (REMPI) and Time-of-Flight MassSpectroscopy (TOF-MS), mostly used for the research of chemical reactiondynamics, was introduced into investigation of heterogeneous catalysis and adetection system with high sensitivity and selectivity was developed, respectively.The important reaction of nature gas chemistry, dehydro-aromatization ofmethane to benzene over Mo/HZSM-5 in the absence of oxygen was observed byTOF-MS in connection with REMPI. Firstly, a single channel reaction andevaluation system was established and the spectra of catalyzed production benzenewere recorded to show the formation of benzene in the catalysis reactions. Thecatalytic performance of Mo-based catalysts supported on various zeolites has beenstudied, and it is found that the features of zeolite structure are associated with theformation of benzene on induction period. Following the single channel reaction, amulti-channel reactor and its detection and data acquisition system is designed. Theexpensive laser detection is replaced by cheap UV absorption for effectiveapplication. UV absorption method is simple and feasible to operate.The second part of this dissertation is extend to the first part. High resolutionmass analyzed threshold ionization spectroscopy in connection with two-colorresonant two-photon excitation scheme is applied to study excited state andcationic state of p-and m-aminophenol, which are the basic molecules of animportant amino acid tyrosine. The adiabatic ionization energy (IE) ofp-aminophenol is measured to be 58822 ±5 cm-1, the cis-and trans-rotamers ofm-aminophenol are 61460±5 cm-1 and 61734±5 cm-1, respectively. The activecation vibrations related to the in-plane ring motions are also recorded. Thesubstitution effect and the different orientation of the OH on the IE and cationvibration frequency are studied. Ab initio calculation and density function theory ofquantum chemistry also support our experimental new data.