Mesoporous MCM-41 molecular sieves as support materials for metal-complexes and enzymes

Silanation of the internal pore surface of the mesoporous molecular sieve MCM-41(40A) has yielded ethylenediamine (ED), diethylenetriamine (DET) and ethylenediaminetriacetic acid salt (EDT) functionalized sites. These grafted ligands were used for the preparation of cobalt(II) complexes covalently bound to the MCM-41 support. These materials were characterized by SEM, UV-Vis, FT-IR, ESR and cyclic voltammetry as well as elemental analysis. Preliminary studies suggest the formation of a reversible cobalt-oxygen adduct with MCM-41 grafted ED and DET complexes. The reactivity of the MCM-41 bound complexes were found to differ significantly from grafted amorphous silica.; Chapter Two. In the study on "Enzyme Immobilization in the Mesoporous Molecular Sieve MCM-41", a series of enzymes, including cytochrome c, papain and trypsin, were immobilized on a MCM-41 host. The physical adsorption in the hexagonal 40A phase of MCM-41 showed a clear dependence on enzyme size. The efficiency of papain and trypsin immobilization was pH dependent, while immobilization of cytochrome c was less susceptible to pH changes. Silanation of the mesopore openings after trypsin adsorption eliminated the leakage of enzyme into solution. The entrapped trypsin enzyme was active for the hydrolysis of N-{dollar}alpha{dollar}-benzoyl-DL-arginine-4-nitroanilide (BAPNA). Results for the inhibition of this reaction by poly-L-lysine of various molecular weights are reported. The stability of trypsin was enhanced by the physical entrapment in MCM-41.; Industrial Practicum. The Industrial Practicum report on "Statistical Optimization, On-Line Process Control and Analytical Support of the Cefoxitin Acid Hydrate Process" discussed the optimization of the transacylation step of the cefoxitin acid hydrate process through the use of a statistical design of experiments approach. A method enabling the accurate appraisal of trimethylsilyl(methyl)urethane charge for the tosyl diester transacylation was developed. On-line process analyzers installed for the monitoring of methylene chloride in waste streams were validated. The validity of factory clean-out procedures through the study of the degradation of sodium cefoxitin and tosyl dicyclohexylamine salts in basic solution and the non-volatile hydrocarbon residue analysis, was assessed.; Apprenticeship Practicum. The study on "Alkene Triplets as 1,2-Biradicals: a Kinetic Study of the Photoaddition of p-Acetylstyrene to Styrene" investigated the behavior of p-acetylstyrene (PAS) triplet through its photoaddition reaction to styrene. Direct irradiation of PAS in the presence of styrene yielded trans-1-(4-acetylphenyl)-2-phenylcyclobutane, an expected addition product. Formation of 1-(4-acetylphenyl)-1,2,3,4-tetrahydronaphthalene was also observed. The rate of addition of {dollar}sp3{dollar}PAS to styrene was determined by laser flash photolysis and by quantum yield measurements. The involvement of a weak exciplex between the perpendicular PAS triplet and styrene ground state is suggested, and the validity of the 1,2-biradical representation of alkene triplets is discussed.