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Background: Two of the excipients in intravenous formulations of amiodarone, polysorbate 80 and benzyl alcohol, have been shown to cause hypotension. A newer formulation of amiodarone, which contains cyclodextrin, is devoid of these excipients. Objective: To evaluate the change in mean arterial pressure when utilizing 2 intravenous amiodarone formulations. Methods: This was a retrospective cohort analysis conducted at an academic medical center. Patients received intravenous amiodarone containing either polysorbate 80/benzyl alcohol (control) or cyclodextrin (cyclodextrin). Patients received these formulations based on a standard institutional protocol of 1 mg/min for 6 hours, followed by 0.5 mg/min for at least 18 hours or until discontinued by the provider. All data were collected from the medical record and included changes in blood pressures, time to lowest systolic blood pressure, concurrent antihypertensive use, and number of patients requiring treatment for hypotension. Results: A total of 160 patients (120 control, 40 cyclodextrin) were included. There was a statistically significant difference in mean arterial pressure between the groups receiving the control formulation of amiodarone compared with the cyclodextrin formulation across the 24-hour maintenance phase infusion (P < 0.001). There was a significant difference between formulations with regard to the change in mean arterial pressure during the 0- to 6-hour and 12- to 18-hour time blocks. There was a statistically significant difference in the number of patients receiving fluid boluses for treatment of hypotension (P = 0.001). Conclusions: The excipients in the formulation of intravenous amiodarone may have a significant role in the hypotensive effects seen throughout the duration the maintenance phase infusion.

The focus of this thesis was on the synthesis, characterization and application of ceria nanocubes. This thesis is divided into two main sections; the first section investigates the electronic properties of ceria nanocubes, and the second explores their catalytic applications towards alcohol oxidation reactions. The first project of this thesis consisted of the X-ray characterization of hydrothermally synthesized ceria nanocubes of various sizes. For the first time, the electronic properties of such nanocubes were systematically studied using high resolution XPS and XANES. It was found that the concentration of Ce3+ present within the nanocubes was independent of the particle size, as well as the Ce precursor used during synthesis. Throughout the analysis of the Ce 3d and 4d XPS spectra, it was observed that the surface of the ceria nanocube samples was undergoing photoreduction/damage over time. This damage was attributed to the samples’ exposure to high intensity X-ray radiation. This was confirmed through examination of the Ce M4,5- and N4,5-edge XANES spectra. From these results, it was clear that the concentration of Ce3+ on the surface of the ceria nanocubes was independent of particle size. This fact may become important when investigating their potential catalytic activity. The second project of this thesis concentrated on the analysis of the catalytic activity of a variety of CeO2, Au and Au/CeO2 catalysts towards the oxidation of benzyl alcohol. The low temperature oxidation reactions were studied using 1H NMR spectroscopy. It was observed that Au NPs, Au/bulk CeO2, and Au/CeO2 nanocubes in water and K2CO3 were active catalysts for this oxidation reaction at 60°C in both air and O2 (g) atmospheres. Surprisingly, however, the Au/bulk CeO2 and Au/CeO2 nanocube catalysts showed very similar activities. It was also found that ceria nanocubes alone, and Au25(SR)18/bulk CeO2 showed no activity for this reaction under similar conditions. It was determined that below a substrate to catalyst ratio of ~ 1500:1, the Au/CeO2 catalysts, which showed the highest activities, were mass-transport limited with respect to the O2 in the system. The turnover frequencies of the supported catalysts were approximately double those of the unsupported NPs. Furthermore, these reactions have indicated that activating Au25(SR)18/CeO2 for catalysis is a non-trivial task, and more work needs to be done to understand the activation of such clusters.

The solvent-free (Cp*IrCl2)2 catalyzed N-alkylation of urea with benzyl alcohol has been studied. A variety of reaction conditions were studied and optimized to produce a high yield (82%) of N,N-dibenzylurea. A series of substituted benzyl alcohols were examined at the optimal reaction conditions. However, the preparation of substituted benzyl urea derivatives using conditions optimized for benzyl alcohol gave poor yields or intractable mixtures.

Abstract: A brief overview of this PhD thesis, The emergence of nanotechnology has stimulated both fundamental and industrially relevant studies of the catalytic activity of noble metal nanoparticles. Palladium, ruthenium and gold are well known catalysts when used in nanoparticle- based systems. This body of work endeavoured to investigate the catalytic activity of these noble metal nanoparticles through three studies as a briefly overviewed below. Study 1: Palladium is a well-known catalyst, even in bulk phases, but its high cost had driven industry towards its use in nanoparticle- based systems well before nanotechnology had attracted the attention of the media. Palladium nanoparticles often show remarkable catalytic activity and selectivity, particularly for the hydrogenation of some unsaturated hydrocarbons, such as alkenes, alkynes and unsaturated carbonyl compounds. The nature of supports can affect the catalytic activity and selectivity of metal-support interaction. Natural polymeric supports, such as wool, can be suitable for new generation of composite materials incorporating nanosized metal nanoparticles and have the added advantage of being “environmentally friendly”. Catalytic hydrogenation of cyclohexene to cyclohexane by palladium nanoparticles immobilized on wool was demonstrated by using a Parr high pressure hydrogenation set-up. The efficiency of the process was explored over loading rates from 1.6% to 2.6% of palladium nanoparticles (by weight) with a variety of particle sizes. Optimization of the reaction conditions including, stirring rate, amounts of reactants, gas pressure and target temperature, led to series of catalytic activity tests carried out for 5 or 24 hours (each) at 400psi H2 and 40 oC using a stirring rate 750 rpm. Product mixtures were analysed using gas chromatography (GC-FID) to determine conversions. Samples S1 and S2 proved to be the most active catalysts because the average Pd particle size was around ~5 nm and the particles were more accessible for the reactant (i.e., Pd particles were on the surface of wool). However, under the catalytic testing conditions studied, wool (Pd/wool) did not show advantages over commercially used palladium nanoparticles on activated carbon (Pd/C). Study 2: Ruthenium fabricated as noble metal nanoparticles can be catalytically active for hydrogenation of organic compounds. However, a challenging issue for researchers is that Ru nanocatalysts can be spontaneously deactivated due to effects, such as sintering or leaching of active components, oxidation of noble metal nanoparticles, inactive metal or metal oxide deposition and impurities in solvents and reagents. Calcination of noble metal nanoparticles is one option for reactivation of Ru nanoparticles immobilized on SiO2 (Ru/SiO2) utilized as nanocatalysts in chemical reactions. In fact, the catalytic activity of noble metal nanoparticles is known to be proportional to the active part of the surface area. The effects of calcinations on catalytic activity of “shape- specific” 0.1 wt% Ru/SiO2 for hydrogenation of cyclohexene to cyclohexane were investigated. Optimization of calcinations by varying temperature and time proved to be effective on the activity of nanocatalysts retaining the Ru nanocatalysts shapes for the hydrogenation of cyclohexene. Product mixtures were analysed using gas chromatography (GC-FID) to determine conversions. The Ru catalysts showed the highest activity (100%) when they were activated by calcination following protocol No.1 in a furnace under the mildest reductive conditions studied (temperature = 200 oC for 1 hour, which was the shortest calcination time). HRTEM study showed only minor deformation of the Ru nanoparticles and minimal aggregation for this type of activation. Study 3: Supported gold nanoparticles have excited much interest owing to their unusual and somewhat unexpected catalytic activity particularly with the selective oxidation of organic compounds. Gold nanoparticles immobilized on Norit activated carbon (Au101/C) via colloidal deposition gave high selectivity of benzyl alcohol oxidation. The presence of a base (K2CO3) increased the catalytic activity of gold nanocatalysts (which was negligible in the absence of base) through dehydrogenation of the alcohol via deprotonation of a primary OH groups, and helped overcome the rate-limitation step of the oxidation process. The interaction between the gold species and the support was investigated by measuring change in catalytic activity with different activation methods (i.e., washing with a solvent at elevated temperature, and/or followed by calcinations). A mixture of benzyl alcohol as a reactant, methanol as a solvent, K2CO3 as a base and oxygen gas was studied by the activated gold nanocatalysts using a mini reactor set-up. The efficiency of the process was explored by varying the amounts of benzyl alcohol and the base, target temperature, metal loading of the gold catalysts rate and the solvent, between 3 and 24 hours at 73 psi O2 and a stirring rate (750 rpm). The samples of the reaction mixture were centrifuged and analysed by highperformance liquid chromatography (HPLC) to determine conversions. The effect of size on the catalytic activity was studied for different types of gold particles (Au101, Aunaked and Aucitrate) and clusters (Au8 and Au9) immobilized on powder Norit activated carbon. The highest activity of benzyl alcohol oxidation was observed for activated 1.0 wt% Au101/C catalysts (washed with toluene and followed by calcination under vacuum at 100 oC for 3 h) for ~3.5 nm gold particles. Additionally, the support effect was studied for gold particles immobilized on different types of carbons, such as Norit activated carbon (powder, granular and powdered) and mesoporous carbons (CMK-3, CMK-8 and NCCR-41), granular modified carbon (–SH and –SO3H groups) and Vulcan carbon. The highest activity was observed by activated 1.0 wt% Au101/C8 catalysts (washed with toluene and followed by calcination under vacuum at 100 oC for 3 h). Activated 1% Au101/C41 (washed with toluene followed by calcination under vacuum at 100 oC for 3 hours) with 2.6 ± 0.1 nm gold particle size showed the highest selectivity towards methyl benzoate as a main product (S%: 88%) after 3 hours reaction time. However, activated 1% Au101/C (calcination in O2 -H2 at 100 oC for 3 hours) with 6.6 ± 0.3 nm gold particle size exhibited the highest selectivity towards benzoic acid as a main product (S: 86%) after 24 hours reaction time.Therefore, particle size and type of carbon support can be considered as playing crucial roles in defining the catalytic activity of gold nanocatalysts which were used for benzyl alcohol oxidation.

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<p>The mass transfer of ethanol and toluene from air stream to liquid phase, and bioremediation of contaminated air streams containing either ethanol or toluene have been investigated using a stirred tank bioreactor. This investigation was conducted in six phases: </p> 1) mass transfer experiments involving the transport of toluene and ethanol from contaminated air streams into the liquid phase,</p> 2) study of air stripping effects of ethanol and toluene out of the liquid phase,</p> 3) batch growth experiments to determine growth kinetic models and model parameters,</p> 4) bioremediation of ethanol or toluene as the sole substrate to determine the capacity of Pseudomonas putida (P. putida) (ATCC 23973) growth on these substrates,</p> 5) toluene removal from contaminated air streams using ethanol and benzyl alcohol as co-substrates, and</p> 6) modelling the above studies using metabolic pathways to better understand the bioremediation process.</p> <p>Preliminary oxygen mass transfer studies showed that the presence of ethanol in the liquid phase enhances the overall oxygen mass transfer coefficients. Increasing the ethanol concentration from 0 to 8 g/L caused the oxygen mass transfer coefficients to increase from 0.015 to 0.049 s-1, and from 0.017 to 0.076 s-1, for impeller speeds of 450 and 600 rpm, respectively. Mass transfer studies using ethanol vapor in the air stream demonstrated complete absorption into the aqueous phase of the bioreactor at all operating conditions investigated (air flowrates up to 2.0 L/min and inlet concentrations up to 95.0 mg/L) and therefore mass transfer coefficients for ethanol absorption could not be determined. On the other hand, toluene mass transfer coefficients could be measured and were found to be 8.3x10-4, 8.8x10-4 and 1.0x10-3 s-1 at agitation speeds of 300, 450 and 600 rpm, respectively. The ethanol air stripping parameters (b values) were determined (at initial ethanol liquid concentration of 8.6 g/L) to be 0.002 and 0.007 h-1 for air flow rates of 0.4 L/min (0.3 vvm) and 1.4 L/min (1 vvm), respectively. The toluene air stripping rates, at initial liquid toluene concentration of 440 mg/L, were found to be 1.9, 5.3, 10.4, and 12.6 h-1 for air flow rates of 0.4, 0.9, 1.4, 2.1 L/min, respectively, which is much higher than those of ethanol at the same air flow rates and stirring speed of 450 rpm. It was also observed that benzyl alcohol was not stripped to any detectable level at any of the operating conditions used in this study.</p> <p>The growth of <i>P. putida</i> using toluene as sole substrate was carried out at several operating conditions by varying the dilution rates (D) from 0.01 to 0.1 h-1, the toluene air inlet concentration from 4.5 to 23.0 mg/L and air flow rates of 0.25 to 0.37 L/min (resulting in inlet toluene loadings from 70 to 386 mg/L-h). Steady state operation could not be achieved with toluene as the sole substrate. Ethanol and benzyl alcohol were therefore used as co-substrates for the toluene removal process. In order to understand the kinetics of P. putida growing on ethanol or benzyl alcohol, batch growth experiments were carried out at different initial substrate concentrations. The specific growth rates determined from the batch runs showed that ethanol had no inhibition effect on the growth of P. putida. The growth on ethanol followed the Monod equation with the maximum growth rate of 0.56 h-1 and yield of 0.59. The results from the batch growth experiments on benzyl alcohol showed that benzyl alcohol inhibits the growth of P. putida when the initial concentration of benzyl alcohol in the growth media is increased. The maximum growth rate was 0.42 h-1 in the inhibition model and the yield value was 0.45. </p><p>By operating the bioreactor in continuous mode using a pure strain of <i>P. putida</i>, it was possible to continuously convert ethanol into biomass without any losses to the gas phase or accumulation in the bioreactor at inlet ethanol concentrations of 15.9 and 19.5 mg/L. With ethanol as a co-substrate, toluene was efficiently captured in the bioreactor and readily degraded by the same strain of P. putida. A toluene removal efficiency of 89% was achieved with an ethanol inlet concentration of 15.9 mg/L and a toluene inlet concentration of 4.5 mg/L. With the introduction of benzyl alcohol as co-substrate at a feed rate of 0.12 g/h, the toluene removal efficiency reached 97% at toluene inlet concentrations up to 5.7 mg/L. All the experimental results at steady state were obtained when the bioreactor operated in a continuous mode at a dilution rate of 0.1 h-1, an air flowrate of 0.4 L/min, an agitation speed of 450 rpm and a reactor temperature of 25.0oC. The results of this study indicate that the well-mixed bioreactor is a suitable technology for the removal of VOCs with both high and low water solubility from polluted air streams. The results were achieved at higher inlet pollutant concentrations compared to existing biofilter treatments.</p><p>A metabolic model has been developed to simulate the bioremediation of ethanol, benzyl alcohol and toluene. For continuous steady state operations, ethanol as a sole substrate required less maintenance for biomass growth (0.010 C-mol/C-mol-h) than bioremediations in the presence of toluene, as seen with the ethanol/toluene mixture (0.027 C-mol/C-mol-h), and the benzyl alcohol/toluene mixture (0.069 C-mol/C-mol-h).</p>

<p>The mass transfer of ethanol and toluene from air stream to liquid phase, and bioremediation of contaminated air streams containing either ethanol or toluene have been investigated using a stirred tank bioreactor. This investigation was conducted in six phases: </p> 1) mass transfer experiments involving the transport of toluene and ethanol from contaminated air streams into the liquid phase,</p> 2) study of air stripping effects of ethanol and toluene out of the liquid phase,</p> 3) batch growth experiments to determine growth kinetic models and model parameters,</p> 4) bioremediation of ethanol or toluene as the sole substrate to determine the capacity of Pseudomonas putida (P. putida) (ATCC 23973) growth on these substrates,</p> 5) toluene removal from contaminated air streams using ethanol and benzyl alcohol as co-substrates, and</p> 6) modelling the above studies using metabolic pathways to better understand the bioremediation process.</p> <p>Preliminary oxygen mass transfer studies showed that the presence of ethanol in the liquid phase enhances the overall oxygen mass transfer coefficients. Increasing the ethanol concentration from 0 to 8 g/L caused the oxygen mass transfer coefficients to increase from 0.015 to 0.049 s-1, and from 0.017 to 0.076 s-1, for impeller speeds of 450 and 600 rpm, respectively. Mass transfer studies using ethanol vapor in the air stream demonstrated complete absorption into the aqueous phase of the bioreactor at all operating conditions investigated (air flowrates up to 2.0 L/min and inlet concentrations up to 95.0 mg/L) and therefore mass transfer coefficients for ethanol absorption could not be determined. On the other hand, toluene mass transfer coefficients could be measured and were found to be 8.3x10-4, 8.8x10-4 and 1.0x10-3 s-1 at agitation speeds of 300, 450 and 600 rpm, respectively. The ethanol air stripping parameters (b values) were determined (at initial ethanol liquid concentration of 8.6 g/L) to be 0.002 and 0.007 h-1 for air flow rates of 0.4 L/min (0.3 vvm) and 1.4 L/min (1 vvm), respectively. The toluene air stripping rates, at initial liquid toluene concentration of 440 mg/L, were found to be 1.9, 5.3, 10.4, and 12.6 h-1 for air flow rates of 0.4, 0.9, 1.4, 2.1 L/min, respectively, which is much higher than those of ethanol at the same air flow rates and stirring speed of 450 rpm. It was also observed that benzyl alcohol was not stripped to any detectable level at any of the operating conditions used in this study.</p> <p>The growth of <i>P. putida</i> using toluene as sole substrate was carried out at several operating conditions by varying the dilution rates (D) from 0.01 to 0.1 h-1, the toluene air inlet concentration from 4.5 to 23.0 mg/L and air flow rates of 0.25 to 0.37 L/min (resulting in inlet toluene loadings from 70 to 386 mg/L-h). Steady state operation could not be achieved with toluene as the sole substrate. Ethanol and benzyl alcohol were therefore used as co-substrates for the toluene removal process. In order to understand the kinetics of P. putida growing on ethanol or benzyl alcohol, batch growth experiments were carried out at different initial substrate concentrations. The specific growth rates determined from the batch runs showed that ethanol had no inhibition effect on the growth of P. putida. The growth on ethanol followed the Monod equation with the maximum growth rate of 0.56 h-1 and yield of 0.59. The results from the batch growth experiments on benzyl alcohol showed that benzyl alcohol inhibits the growth of P. putida when the initial concentration of benzyl alcohol in the growth media is increased. The maximum growth rate was 0.42 h-1 in the inhibition model and the yield value was 0.45. </p><p>By operating the bioreactor in continuous mode using a pure strain of <i>P. putida</i>, it was possible to continuously convert ethanol into biomass without any losses to the gas phase or accumulation in the bioreactor at inlet ethanol concentrations of 15.9 and 19.5 mg/L. With ethanol as a co-substrate, toluene was efficiently captured in the bioreactor and readily degraded by the same strain of P. putida. A toluene removal efficiency of 89% was achieved with an ethanol inlet concentration of 15.9 mg/L and a toluene inlet concentration of 4.5 mg/L. With the introduction of benzyl alcohol as co-substrate at a feed rate of 0.12 g/h, the toluene removal efficiency reached 97% at toluene inlet concentrations up to 5.7 mg/L. All the experimental results at steady state were obtained when the bioreactor operated in a continuous mode at a dilution rate of 0.1 h-1, an air flowrate of 0.4 L/min, an agitation speed of 450 rpm and a reactor temperature of 25.0oC. The results of this study indicate that the well-mixed bioreactor is a suitable technology for the removal of VOCs with both high and low water solubility from polluted air streams. The results were achieved at higher inlet pollutant concentrations compared to existing biofilter treatments.</p><p>A metabolic model has been developed to simulate the bioremediation of ethanol, benzyl alcohol and toluene. For continuous steady state operations, ethanol as a sole substrate required less maintenance for biomass growth (0.010 C-mol/C-mol-h) than bioremediations in the presence of toluene, as seen with the ethanol/toluene mixture (0.027 C-mol/C-mol-h), and the benzyl alcohol/toluene mixture (0.069 C-mol/C-mol-h).</p>

Thesis (Ph.D. in Pharmaceutical Sciences) -- University of Colorado Denver, 2007. / Typescript. Includes bibliographical references (leaves 133-143). Online version available via ProQuest Digital Dissertations.