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The synthesis, reactivity and magnetism of lanthanide organometallic and coordination complexesGrindell, Richard January 2017 (has links)
This project was focused on the synthesis and reactivity of rare-earth nbutyl complexes of the formula [CpMe2M(μ-nBu)]2 (where M = Y, Dy). Dysprosium was used as it has a large magnetic moment which is favourable for producing single molecule magnets (SMMs). Yttrium was used as a diamagnetic analogue to examine the reactivity of [CpMe2Y(μ- nBu)]2 in solution, and provide further characterisation of isolated complexes with NMR spectroscopy. Another goal of the project was to establish the reactivity of [CpMe2M(μ- nBu)]2 with respect to the commonly used alkylating reagent nbutyllithium (nBuLi). It was found that the nbutyl complexes are remarkably stable in solution and the solid state, allowing for the synthesis to be scaled up and for the nbutyl complexes to be used as starting materials. The reactivity of [CpMe2M(μ- nBu)]2 towards ferrocene was investigated. The product was a ferrocenyl-bridged dimer of the formula [CpMe2M(μ-(C5H4)FeCp)]2 resulting from a single deprotonation of ferrocene. The reactivity of [CpMe2M(μ- nBu)]2 towards N-heterocyclic carbenes (NHCs) was also investigated. No reaction occurred between [CpMe2Y(μ- nBu)]2 and 1,3-bis-(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr), a reaction did occur between [CpMe2Y(μ- nBu)]2 and 1,3-bis-(tert-butyl)imidazol-2-ylidene (ItBu) but no crystalline product could be obtained. [CpMe2M(μ- nBu)]2 reacts with 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes) to form a monomeric, benzyl tethered carbene complex [CpMe2M(IMesâ)]. An ortho-methyl group on one of the mesityl substituents is deprotonated generating an asymmetric functionalised carbene. A control experiment between CpMe3M (M = Dy, Y) and IMes resulted in the formation of the abnormal, rearranged carbene complexes [CpMe3M(aIMes)]. C6H6. Structural analysis revealed a very short C-H---Ï interaction between neighbouring molecules. The mechanism of carbene rearrangement was probed by 1H NMR spectroscopy (M = Y). Magnetic susceptibility measurements revealed that [CpMe2Dy(μ- nBu)]2, [CpMe2Dy(μ-(C5H4)FeCp)]2, [CpMe2Dy(IMesâ)] and [CpMe3Dy(aIMes)]. C6H6 are not SMMs. [CpMe2M(μ- nBu)]2 activates sulfur and selenium to form hexanuclear clusters of the formula [CpMe10M((E3)2E2] (M = Dy, Y; E = S, Se). [CpMe10M((S3)2S2] is an SMM with an energy barrier to magnetisation reversal, Ueff, of 73 cm-1. The analogous selenium cluster could be characterised by single crystal X-ray diffraction however separation from unreacted selenium proved difficult without using coordinating solvent. Extraction of [CpMe10Y((Se3)2Se2] with THF resulted in the crystallisation of the ion pair [CpMe2Y(THF)3][{CpMeY(Se2)}6Se] and [{CpMe2Y(THF)}(µ-Se2)]. A trimetallic dysprosium coordination complex containing a hexaazatrinapthalene (HAN) bridging ligand is reported. Magnetic measurements on [{(thd)3Dy}3HAN] (Dy3HAN) show that it is an SMM in zero field and two magnetic relaxation mechanisms are present. An optimised DC field of 1 kOe allowed for better resolution of the two relaxation processes and an energy barrier for each process could be extracted. The Ueff barriers are 42 and 52 cm-1. Ab initio theoretical analysis revealed the magnetic anisotropy axes are nearly collinear precluding the presence of a toroidal magnetic moment. The ground state of Dy3HAN was found to be frustrated.
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Performance Study on the Treatment of MTBE-Borne Waste Gas by Activated Sludge Aeration and Biotrickling Filtering ProcessesSu, Li-Chun 14 June 2005 (has links)
In this study, a laboratory-scale activated sludge reactor and a biotrickling filter were constructed to study the removal of methyl tert-butyl ether (MTBE) from air vented from contaminated sites.
The activated sludge tank (0.4 m¡Ñ0.4 m cross-sectional area, 3.0 m height, and 480 L total volume) was made by acrylic resin. A mixed liquor suspended solids (MLSS) concentration of 2000-3000 mg/L was maintained in the experimental mixed liquor and the sludge was acclimated for 30 days under selected conditions of a Food to Microorganism Ratio (F/M) of 0.3 g BOD/(g MLSS¡Dday) and an influent gas MTBE concentration (C0) of 180 mg/Am3 (@27oC). Results on performance tests show that an average MTBE removal efficiency of 93.6% was obtained with the operation conditions of C0 of 610 mg/Am3 (@27oC), volumetric aeration rate of 0.063 m3/m3¡Dmin, MLSS of 2600 mg/L, and submerged liquid depth of 1.0 m.
The biotrickling filter was made by combining two same type of acrylic resin columns (each 0.2 m inner diameter, 2.0 m height, and packed with 900 pieces of polypropylene Pall rings to a height of 1.35 m) in series for the test gas flow and in-parallel for the trickling liquid flow. Each test was operated for 8 hours to reach a steady state for a set of selected conditions (gas flow rate 0.050 m3/min and superficial gas velocity 0.027 m/s, trickling liquid flow rate 0.004 m3/min and pH: 6.8-7.2, and liquid/gas flow ratio: 80 L/m3). Results show that the MTBE removal efficiencies from the influent gas were 40%, 22% and 15%, respectively, with C0 of 50,100 and 230 mg/Am3 (@27oC).
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The effect of YDL100c deficiency on the growth of Saccharomyces cerevisiae in the presence of t-BOOHJUNG, CHAN 28 July 2006 (has links)
To study the role of YDL100c during the growth of Saccharomyces cerevisiae in the presence of oxidant, the wild type strain (WT) and YDL100c disrupted strain (KO) were grown at 30oC for 6 hr after adding 0.25 mM of tert-butyl hydroperoxide (t-BOOH). The cells of both strains were assayed for the expression of anti-oxidant system, trehalose accumulation, intracellular molecular oxidation level, membrane lipid peroxidation, and glutathione (GSH) content. The results show that growth of KO is slower than that of WT and the cause of growth delay is the cell death. The data also show that the molecular oxidation level is lower but the lipid peroxidation of membrane is higher in KO compared with WT in the presence of t-BOOH, indicating that ROS do cause the damage on membrane. Further, analysis of the expression of cellular defense-related genes show that expressions of GSH1, CTT1, TPS1, TSL1, and NTH1 in KO are lower than in WT, but expressions of SOD1, TRR1 and TRX1 have no difference, demonstrating that the deletion of YDL100c in S. cerevisiae affects the general and specific stress response when grown in the presence of t-BOOH. In general, the decrease in CTT1 expression is not consistent with the catalase activity assay, however, decreased expressions of GSH1 and genes involved in trehalose metabolism are consistent with the decreased GSH content and increased trehalose accumulation in KO compared with WT. Therefore, the cause of KO cell death in the presence of t-BOOH is most likely related to the decrease in cellular GSH level and trehalose accumulation.
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Coordination Chemistry of a 5-tert-Butyl-2-[(2,6-diisopropylphenyl)aldimino]- pyrrolate LigandYang, Chih-Wei 13 September 2002 (has links)
The Vilsmeier-Haack reaction of pyrrole with oxalyl chloride and N,N-dimethylformaldehyde followed by Friedel-Crafts alkylation with Me3CCl in the presence of AlCl3 afforded 5-tert-butylpyrrole-2- carbal- dehyde in high yields. Condensation reactions of 5-tert-butylpyrrole-2- carbaldehyde with 2,6-diisopropylaniline produced 5-tert-Butyl-2-2[(2,6- diisopropylphenyl)aldimino]pyrrole (HL). Protonolysis of MgnBu2 with HL yielded the bis(iminopyrrolate) complex MgL2 (1) as a colorless crystalline solid. In situ lithiation of HL followed by addition of one equivalent of ZrCl4 or AlCl3 led to the mono(iminopyrrolate) complexes ZrLCl4Li(OEt2)2 (2) and AlLCl2 (3) , respectively. Treatment of 3 with two equivalents of MeMgBr produced AlLMe2 (4). In addition to the spectroscopic data, all metal complexes were characterized by X-ray crystallography.
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Microbial degradation of the fuel oxygenate methyl tert-bytyl ether (MTBE)Youngster, Laura K. G., January 2009 (has links)
Thesis (Ph. D.)--Rutgers University, 2009. / "Graduate Program in Microbiology and Molecular Genetics." Includes bibliographical references (p. 112-131).
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Emulsion Polymerization Using Switchable SurfactantsFOWLER, CANDACE IRENE 26 September 2011 (has links)
The work presented herein focuses on expanding the use of CO2-triggered switchable surfactants in emulsion polymerization of hydrophobic and hydrophilic
monomers. Bicarbonate salts of the following compounds were employed as surfactants in the emulsion polymerization of styrene, methyl methacrylate (MMA) and/or butyl methacrylate (BMA): N’-hexadecyl-N,N-dimethylacetamidine (1a), N’-dodecyl N,N-dimethylacetamidine (2a) and N’-(4-decylphenyl)-N,N-dimethylacetamidine (3a). A systematic study of the effects of surfactant and initiator concentrations and solids
content on the resulting particle size and ζ-potential was carried out, showing that a wide range of particle sizes (40 – 470 nm) can be obtained. It was found that as the basicity of the surfactant decreased, the particle size generated from emulsion polymerization increased. Destabilization of these latexes did not require the addition of salts and was carried out using only non-acidic gases and heat. It was shown that solids content,
temperature, particle size and surfactant basicity greatly affect the rate of destabilization of latexes. The area occupied by N’-dodecyl-N,N-dimethylacetamidinium acetate on PMMA particles was determined to be 104 Å2. The monomer-D2O partition coefficient of 2a was determined to be 21 for styrene and 2.2 for MMA. The monomer-D2O partition coefficient of the bicarbonate salt of 2a was determined to be 1.2 for styrene and
0.85 for MMA. An initial assessment of the use of switchable surfactants in the generation of inverse emulsions was carried out. It was determined that butylated polyethyleneimine (BPEI) can successfully stabilize inverse emulsions of cyclohexane and aqueous 2-(dimethylamino)ethyl methacrylate. Upon CO2 introduction, this emulsion separates into two distinct phases. / Thesis (Master, Chemistry) -- Queen's University, 2011-09-26 11:10:14.053
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Catalytic chain transfer polymerisation in C02-expanded monomersZwolak, Grzegorz, Chemical Sciences & Engineering, Faculty of Engineering, UNSW January 2009 (has links)
Experimental data on the solubility of CO2 in methyl methacrylate (MMA) and butyl methacrylate (BMA) are reported at temperatures from 308 to 333 K and pressures in the range of 1 to 10 MPa. The corresponding measurements of the volumetric expansion of the liquid phase are also presented. The solubility data are correlated with the Peng-Robinson equation of state using two interaction parameters. Solubilities of CO2 as high as 80 mol% can be attained in both monomers in the range of pressure considered. A near-linear relationship is observed between pressure and liquid-phase composition. The Peng-Robinson equation of state provides a satisfactory correlation of the solubility data. The average absolute relative deviations with respect to the calculated values of pressure are less than 2%. For a given monomer, the expansion isotherms coincide when plotted as a function of the liquid - phase composition. Catalytic chain transfer (CCT) polymerisation of CO2-expanded MMA, BMA and styrene is then described. Experimental values of the chain transfer constant are determined at 323 K and 333 K and in the range of pressure from 0.1 to 6 MPa. A cobaloxime complex is used as the chain transfer catalyst. The effect of small quantities of polymer on the volumetric expansion of the corresponding monomer is considered. The chain transfer constants for the expanded monomers are significantly higher than those obtained in the bulk monomers. It is demonstrated that a linear relationship exists between the chain transfer rate coefficient and the inverse of liquid-phase viscosity. These results provide significant evidence that the rate-determining step in the CCT process is diffusion-controlled. Finally, molecular weight evolution in CCT polymerization of CO2-expanded MMA is reported. Experimental molecular weight and polydispersity index data are presented at 323 K in the range of conversion from 1 to 25%, and at pressures of 5 and 6 MPa. Both molecular weight and polydispersity increase with conversion at conditions below the homogeneous expansion limit. Predici simulations suggest that either irreversible catalyst deactivation or cobalt-carbon bond formation is the most likely mechanism for the increase in molecular weight with conversion.
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Toxic decisions a sociological study of the contamination of US water supplies by methyl tertiary butyl ether (MTBE) /Oliver, Christopher Scott. January 2008 (has links)
Thesis (Ph. D.)--Michigan State University. Dept. of Sociology, 2008. / Title from PDF t.p. (viewed on Apr. 16, 2009) Includes bibliographical references (p. 173-198). Also issued in print.
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Adsorption removal of tertiary butyl alcohol from wastewater by zeoliteButland, Tricia Dorothy. January 2008 (has links)
Thesis (M.S.)--Worcester Polytechnic Institute. / Keywords: zeolite adsorption, TBA, tert butyl alcohol, wastewater remediation. Includes bibliographical references (leaves 60-62 ).
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Auf dem Wege zu einem Disilin RSiSiR supersilylierte Silane, Silanide, Silylene, Disilene /Niedermayer, Wolfgang. Unknown Date (has links)
Universiẗat, Diss., 2000--München.
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