The butyne, HC≡CCF(CF₃)₂, can be prepared via the dehydro-halogenation of ICH=CHCF(CF₃)₂, the olefin is produced by the ultraviolet irradiation of mixtures of (CF₃)₂CFI and acetylene. Group IV perfluoroalkynyl derivatives (CH₃)[subscript n]M(C≡CR[subscript f])[subscript 4-n] (n = 0 ↦ 3; M = Si, Ge, Sn; R[subscript f] = CF₃> C₂F₅, CF(CF₃)₂) can be prepared by the reaction of XMg C≡CR[subscript f] (X = Br, I) with the appropriate group IV organohalide. Some, but not all, of the combinations of n, M, and R[subscript f] are described. The reaction of CH₃Si[symbol omitted]₃ with IMgC≡CCF₃ produces (CH₃)₂Si(C≡CCF₃)₂. Difluorocarbene from (CH₃)₃SnCF₃ at 150° adds to the C≡C bond of HC≡CR[subscript f] (R[subscript f] = CF₃, C₂F₅, CF(CF₃)₂) and some of the (CH₃)[subscript n]M(C≡CR[subscript f])[subscript 4-n] derivatives to give the corresponding cyclopropenes, [formula omitted] and [formula omitted] respectively. The spectral properties of the group IV perfluoroalkynyl and cyclopropenyl derivatives exhibit several novel trends. The difluorocarbene species from (CH₃)₃SnCF₃ is electrophilic and is in a singlet state in gas phase addition reactions to unsaturated bonds. The carbene adds stereospecifically to both cis- and to trans-butene-2 to give the corresponding isomeric cyclopropanes. The carbene also inserts into the Sn-H bond of (CH₃)₃SnH. The ultraviolet irradiation of mixtures of (CF₃)₂CFI and (CH₃)₃SnSn(CH₃) produces (CH₃) ₃SnCF(CF₃) ₂. A similar reaction involving (CH₃)₃SnSn(CH₃)₃ and CF₂=CFI produces (CH₃)₃SnCF=CF₂. None of the derivatives, (CH₃)₃SnR[subscript f] (R[subscript f] = C₂F₅, CF(CF₃)₂, CF=CF₂) , produces a carbene upon pyrolysis. Bis(trifluoromethyl)diazomethane reacts with HC≡CCF₃ and with CF₃C≡CCF₃ at ca. 150° to give a mixture of the corresponding isopyrazole, [formula omitted], and cyclopropene, [formula omitted]. Similar reactions of the diazo compound with (CH₃)₃MC≡CCF₃ (M = Ge, Sn) produce [formula omitted] derivatives. The reaction of bis(trifluoromethyl)diazirine and (CH₃)₃GeC=CCF₃ also produces the cyclopropene. The diazo compound inserts C(CF₃)₂ into the M-H bonds of (CH₃)₃SnH and (CH₃)₂AsH and produces (CH₃ )₂AsCF(CF₃) ₂H and (CH₃)₂AsCF=CF₂ upon reaction with (CH₃)₂AsAs(CH₃)₂. The diazo compound fails to react however, with either (CH₃)₃MH (M = Si, Ge), (CH₃)₃GeBr, or (CH₃)₃ GeGe(CH₃ )₃. The Mössbauer spectra of the compounds (CH₃)₃SnR[subscript f] reveal that the quadrupole splitting in the Sn nucleus increases in the order R[subscript f] = CFH₂ < CF₂H < CF₃ ≲ CH(CF₃)₂ < C₂F₅ < CF(CF₃)₂ which indicates the order of increasing electronegativity of the R[subscript f] groups. The order of electronegativity, CF₃ < C₂F₃ < CF(CF₃)₂, is also supported by n.m.r. studies of the compounds HC≡CR[subscript f] and [formula omitted]. As an Appendix the stereochemistry of the olefins produced by the ultraviolet irradiation of mixtures of R[subscript f]I (R[subscript f] = CF₃, C₂F₅, CF(CF₃)₂) and acetylene is described. Predominantly trans addition takes place. / Science, Faculty of / Chemistry, Department of / Graduate

Call number: LD2668 .T4 1960 C66

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Chemistry. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / Ph.D.

Fluorocarbons (FCs) and their derivatives (FCDs) are heavily relied on due to their wide range of uses (e.g. solvents, surfactants, refrigerants, and pharmaceuticals). Currently, FCs and FCDs are produced on an industrial scale via energy-intensive processes, using hazardous materials. Hence, new catalytic chemical technologies are required to provide cleaner and greener synthetic routes to partially fluorinated materials. The exploration of fundamental organofluorometallic chemistry of base metals, such as nickel, has potential to advance the development of novel catalytic processes towards this end. It has been established previously that zero-valent nickel complexes have the ability to efficiently catalyze the hydrodimerization of polyfluoroalkenes. The reactivity of the intermediate polyfluoronickelacycles was found to be influenced by modifications in the ligand sphere. Furthermore, an increase in oxidation state of the central metal atom was proposed as an additional strategy to increase the reactivity of the M-RF bond. In this thesis, through variation of the ligand environment and oxidation state of nickel, we have further developed the chemistry of high-valent polyfluoronickelacycles. Synthesis and characterization (NMR, EPR, UV/Vis, IR spectroscopy and electrochemistry) of new trivalent polyfluoronickelacycles are described as well as attempts to generate the corresponding tetravalent cations. Attempts to induce nucleophilic insertion of acetonitrile into the Ni-RF bond were also investigated herein. Challenges were encountered with the isolation of the tetravalent cations due to decomposition to the corresponding divalent nickelacycle.

Fluorocarbons (FCs) and their derivatives (FCDs) are heavily relied on due to their wide range of uses (e.g. solvents, surfactants, refrigerants, and pharmaceuticals). Currently, FCs and FCDs are produced on an industrial scale via energy-intensive processes, using hazardous materials. Hence, new catalytic chemical technologies are required to provide cleaner and greener synthetic routes to partially fluorinated materials. The exploration of fundamental organofluorometallic chemistry of base metals, such as nickel, has potential to advance the development of novel catalytic processes towards this end. It has been established previously that zero-valent nickel complexes have the ability to efficiently catalyze the hydrodimerization of polyfluoroalkenes. The reactivity of the intermediate polyfluoronickelacycles was found to be influenced by modifications in the ligand sphere. Furthermore, an increase in oxidation state of the central metal atom was proposed as an additional strategy to increase the reactivity of the M-RF bond. In this thesis, through variation of the ligand environment and oxidation state of nickel, we have further developed the chemistry of high-valent polyfluoronickelacycles. Synthesis and characterization (NMR, EPR, UV/Vis, IR spectroscopy and electrochemistry) of new trivalent polyfluoronickelacycles are described as well as attempts to generate the corresponding tetravalent cations. Attempts to induce nucleophilic insertion of acetonitrile into the Ni-RF bond were also investigated herein. Challenges were encountered with the isolation of the tetravalent cations due to decomposition to the corresponding divalent nickelacycle.

Thesis (DTech (Chemical Engineering))--Cape Peninsula University of Technology, 2009. / Includes bibliographical references. Also available online.

Fluorocarbons (FCs) and their derivatives (FCDs) are heavily relied on due to their wide range of uses (e.g. solvents, surfactants, refrigerants, and pharmaceuticals). Currently, FCs and FCDs are produced on an industrial scale via energy-intensive processes, using hazardous materials. Hence, new catalytic chemical technologies are required to provide cleaner and greener synthetic routes to partially fluorinated materials. The exploration of fundamental organofluorometallic chemistry of base metals, such as nickel, has potential to advance the development of novel catalytic processes towards this end. It has been established previously that zero-valent nickel complexes have the ability to efficiently catalyze the hydrodimerization of polyfluoroalkenes. The reactivity of the intermediate polyfluoronickelacycles was found to be influenced by modifications in the ligand sphere. Furthermore, an increase in oxidation state of the central metal atom was proposed as an additional strategy to increase the reactivity of the M-RF bond. In this thesis, through variation of the ligand environment and oxidation state of nickel, we have further developed the chemistry of high-valent polyfluoronickelacycles. Synthesis and characterization (NMR, EPR, UV/Vis, IR spectroscopy and electrochemistry) of new trivalent polyfluoronickelacycles are described as well as attempts to generate the corresponding tetravalent cations. Attempts to induce nucleophilic insertion of acetonitrile into the Ni-RF bond were also investigated herein. Challenges were encountered with the isolation of the tetravalent cations due to decomposition to the corresponding divalent nickelacycle.

Thesis (M.Sc.)--City University of Hong Kong, 2004. / At head of title: City University of Hong Kong, Department of Physics and Materials Science, Master of Science in materials engineering & nanotechnology dissertation. Title from title screen (viewed on Sept. 1, 2006) Includes bibliographical references.

Thesis submitted in fulfilment of the requirements for the degree DOCTOR TECHNOLOGIAE: ENGINEERING: CHEMICAL In the FACULTY OF ENGINEERING At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2009 / The white rot fungus, Phanerochaete chrysosporium strain BKMF-1767 (ATCC 24725), produces the extracellular enzymes, Lignin peroxidase (LiP) and Manganese peroxidase (MnP), that constitute the major route for lignin degradation by this organism. LiP and MnP have also been shown to play a major role in aromatic pollutant degradation. Due to the need for continuous production of LiP and MnP, a fixed-film bioreactor, classified as a membrane gradostat reactor (MGR), was developed. The implementation of batch-reactor operational parameters to the MGR system was found to be ineffective, thus creating the need for further research to improve the operational aspects of the MGR system to optimise its capabilities for continuous and industrial-scale operations. The research undertaken in this study, provides information that can be used to classify the dissolved oxygen (DO) transport kinetics into immobilised fixed-films of P. chrysosporium. Operational limitations of the MGR relating to environmental stresses in the bioreactor during operation and to biofilm deterioration, including limitations of DO mass transport, oxidative stress, trace element accumulation and polysaccharide storage in the fungal biomass, were evaluated in single capillary MGR systems (SCMGRs). These conditions were identified as existing in the continuous MGR systems. From DO profiles, the oxygen consumption and flux into the biofilms, including the distribution of DO, was determined to be dependent on the immobilised biofilm’s age. Younger biofilms showed higher DO distribution than older biofilms even when aeration was directed to the extracapillary space (ECS) of the reactor against the biofilm’s surface. An increase in anaerobic zone thickness was observed to be increasing with an increase in biofilm thickness. Although, DO kinetic parameters were comparable with those obtained in submerged mycelia pellets, higher oxygen consumption values were observed in biofilms grown in the SCMGRs. The limitations of MGR were identified as: 1) poor DO distribution in immobilised biofilms because of b-glucan production and storage in the immobilised biomass, resulting in ethanol production; 2) the peroxidation of lipids of the biofilms, which in turn will affect the long-term performance of the biomass caused by oxygenation and 3) trace element ion accumulation enhanced by b-glucan production. Furthermore, trace element ion accumulation was higher in the MGRs than in batch cultures using the same nutrient medium. The development of a perfluorocarbon (PFC) emulsion for the MGRs to counteract these limitations was investigated. The compatibility of the emulsion with oxygen-carrying capacity was shown with an improvement in biomass generation, LiP/MnP production and overall consumption of primary substrates, mainly glucose and ammonium tartrate, in batch cultures. The emulsions investigated were based on the addition of oxygen carriers: Perfluorooctyl bromide (PFOB), Bis-(Perfluorobutyl) ethene (PFBE) and Perfluoropropylamine (PFPA), using Pluronic F 68 (PF 68) as the surfactant. Concentrations of 10 to 30% (w/v) PFC and 8.5% (w/v) PF 68 were tested successfully in batch cultures. The emulsions containing 10% (w/v) PFCs resulted in improved biomass performance as opposed to emulsions with higher PFC oil concentrations. An emulsion containing 10% (w/v) PFOB was used to evaluate its efficacy in the SCMGRs, as the biomass yield and overall enzyme production were superior to PFPA and PFBE-based emulsions with similar oil concentrations. After successfully applying PFOB and PF 68 to the SCMGRs, the following results were obtained: 1) reduced ethanol production; 2) reduced trace element accumulation; 3) lower b-glucan production and 4) improved DO-penetration ratio in immobilised biofilms.

Fluorocarbons (FCs) and their derivatives (FCDs) are heavily relied on due to their wide range of uses (e.g. solvents, surfactants, refrigerants, and pharmaceuticals). Currently, FCs and FCDs are produced on an industrial scale via energy-intensive processes, using hazardous materials. Hence, new catalytic chemical technologies are required to provide cleaner and greener synthetic routes to partially fluorinated materials. The exploration of fundamental organofluorometallic chemistry of base metals, such as nickel, has potential to advance the development of novel catalytic processes towards this end. It has been established previously that zero-valent nickel complexes have the ability to efficiently catalyze the hydrodimerization of polyfluoroalkenes. The reactivity of the intermediate polyfluoronickelacycles was found to be influenced by modifications in the ligand sphere. Furthermore, an increase in oxidation state of the central metal atom was proposed as an additional strategy to increase the reactivity of the M-RF bond. In this thesis, through variation of the ligand environment and oxidation state of nickel, we have further developed the chemistry of high-valent polyfluoronickelacycles. Synthesis and characterization (NMR, EPR, UV/Vis, IR spectroscopy and electrochemistry) of new trivalent polyfluoronickelacycles are described as well as attempts to generate the corresponding tetravalent cations. Attempts to induce nucleophilic insertion of acetonitrile into the Ni-RF bond were also investigated herein. Challenges were encountered with the isolation of the tetravalent cations due to decomposition to the corresponding divalent nickelacycle.