The Development of APCI Mass Spectrometry Based Systems for Quantitative Real-Time Monitoring of Process-Scale Homogenous and Heterogeneous Reactions

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.