Date of Award
Doctor of Philosophy
John E. Bartmess
Jon P. Camden, Robert N. Compton, Stephen J. Paddison
The dissertation presents solutions to monitor industrial chemical processes quantitatively in real time by mass spectrometry. Chapter 1 presents the background of atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Chapters 2-6 present methods developed based on flow injection analysis coupled to atmospheric pressure chemical ionization mass spectrometry (FIA/APCI-MS) for quantitative real-time monitoring of homogeneous and heterogeneous reactions conducted at molar concentrations.
Chapter 2 introduces auto-sampling FIA/APCI-MS with the ability to overcome potential sample overloading when molar concentration samples were analyzed without sample pretreatment procedures. A homogenous Michael-addition reaction between phenethylamine and acrylonitrile was conducted at room temperature and monitored quantitatively in real time at 1.63 M (molar) level. In chapter 3, auto-sampling FIA/APCI-MS was adapted for the quantitative real-time monitoring of a transesterification reaction, methanolysis of glycerol trioctanoate, which proceeded as a homogenous liquid system and a heterogeneous bi-phasic liquid-liquid system at an alcohol-to-oil molar ratio of 30:1 and 6:1, respectively. Simultaneous quantification of major compounds including two intermediates was achieved using calibrations based on the analysis of simulated reaction mixtures of standards and validated by parallel off-line reaction monitoring with HPLC/APCI-MS.
Chapter 4 introduces slurry FIA/APCI-MS with the ability to overcome potential instrumental clogging and sample overloading in quantitative real-time monitoring of a heterogeneous solid-liquid system, i.e. a batch slurry reaction. Slurry samples up to 30% (w/w) were successfully quantified. Chapter 5 describes an alternative slurry FIA/APCI-MS setup to accommodate a different mass spectrometer, aiming to prepare the slurry FIA/APCI-MS method to be used in quantitative real-time monitoring of a model batch slurry reaction at DuPont Crop Protection where a similar mass spectrometer was to be used. In Chapter 6, slurry FIA/APCI-MS was adapted for the quantitative real-time monitoring of a heterogeneous-catalyzed Pechmann condensation reaction using 50 g/L silica supported perchloric acid as catalyst.
Chapter 7 presents a study on the differentiation of underivatized monosaccharides from their stereoisomers using APCI quadrupole time-of-flight mass spectrometry (QTOF-MS). Identities of ions were assigned after accurate mass measurement by QTOF-MS. Distinctive fragmentation patterns were used to distinguish isomers of hexoses, methyl D-glucopyranosides, hexosamins and N-acetylhexosamines.
Chapter 8 presents the conclusion.
Zhu, Zhenqian, "The Development of APCI Mass Spectrometry Based Systems for Quantitative Real-Time Monitoring of Process-Scale Homogenous and Heterogeneous Reactions. " PhD diss., University of Tennessee, 2014.