The human protein kinase superfamily consists of over 500 members that individually control specific aspects of cell behavior and collectively control the complete range of cellular processes. That such a large group of proteins is able to uniquely diversify and establish individual identities while retaining common enzymatic function and significant sequence/structural conservation is remarkable. The means by which this is achieved is poorly understood, and we have begun to examine the issue by performing a comparative analysis of the catalytic domain of protein kinases. A novel approach for protein structural alignment has revealed a high degree of similarity found across the kinase superfamily, with variability confined largely to a single region thought to be involved in substrate binding. The similarity detected is not limited to amino acids, but includes a group of conserved water molecules that play important structural roles in stabilizing critical residues and the fold of the kinase domain. The development of a novel technique for identifying kinase substrates on a large scale directly from cell lysate has revealed that substrate specificity is not what discriminates the closely related p38α and β mitogen-activated protein kinases. Instead cellular localization appears to be their distinguishing characteristic, at least during myoblast differentiation. Together these results highlight the extent of conservation, as well as the minimal variability, that is found in the catalytic domain of all protein kinase superfamily members, and that while distantly related kinases may be distinguished by substrate specificity, closely related kinases are likely to be distinguished by other factors. Although these results focus on representative members of the kinase superfamily, they give insight as to how all protein kinases likely diversified and established unique non-redundant identities. In addition, the novel techniques developed and presented here for structural alignment and substrate discovery offer new tools for studying molecular biology and cell signaling.

The presence of micropollutants, particularly pesticides, in surface waters across Canada has been of concern not only for their environmental impact, but also for their potential effects on human health and recalcitrant nature to conventional water treatment methods. Although ozone has been mainly applied for disinfection of drinking water, oxidation of trace organics by ozonation has been considered potentially effective. In an effort to meet increasingly stringent drinking water regulations, different solid catalysts have been used to enhance the removal of water contaminants by ozonation. In spite of the increasing number of data demonstrating the effectiveness of heterogeneous catalytic ozonation, the influence of different factors on the efficiency of micropollutants oxidation is still unclear.<p> In the present work, application of three solid catalysts in ozonation of two model micropollutants in pure water was examined using a laboratory-scale reaction system over a range of operating conditions. The three catalysts investigated were activated carbon, alumina, and perfluorooctyl alumina, and the two model micropollutants were the pesticides atrazine and 2,4-dichlorophenoxyactic acid. The effects of solution pH, presence of a radical scavenger, pesticide adsorption on catalyst, and catalyst dose on micropollutant removal were investigated. Solution pH was found to significantly influence the catalyst ability to decompose ozone into free hydroxyl radicals. The effect of these free radicals was markedly inhibited by the radical scavenger resulting in a negative impact on pesticides degradation. In general, the removal rate of pesticides was found to increase with increasing doses of catalyst.<p> In the ozonation process in the presence of activated carbon, atrazine removal rates increased four and two times when using a catalyst dose of 0.5 g L-1 at pH 3 and 7, respectively, whereas observed reaction rates for 2,4-D increased over 5 times in the presence of 1 × 10-4 M tert-butyl alcohol at pH 3. In the ozonation system catalyzed by 8 g L-1 alumina, the observed reaction rate constant of atrazine removal notably improved at neutral pH by doubling the micropollutant removal rate. For the pesticide 2,4-D in the presence of 1 × 10-4 M tert-butyl alcohol at pH 5, the observed removal rate was over ten times higher than that for the non-catalytic ozonation process using also using a catalyst dose of 8 g L-1. Modification of alumina to produce perfluorooctyl alumina resulted in a material able to significantly adsorb atrazine, while not exhibiting affinity for adsorption of 2,4-D. In spite of its adsorptive properties, perfluorooctyl alumina was found to enhance neither molecular ozone reactions nor ozone decomposition into hydroxyl radicals. Thus, the observed removal rates for atrazine and 2,4-D by ozonation in the presence of perfluorooctyl alumina did not increase significantly.

Many particulate processes are preferably implemented in circulating fluidized beds (CFB) over traditional low-velocity fluidization to take advantage of the many benefits of circulating systems. Fluid catalytic cracking (FCC) is one of the most successfully applied processes in CFB technology, with more than 350 FCC units in operation worldwide. Despite its extensive use, an understanding of the complex behaviour of these units is incomplete.<p> A theoretical and experimental evaluation of the fluidization behaviour was conducted in the CFB riser, standpipe, and stripper. Initially, an extension of the existing CFB in the Fluidization Laboratory of Saskatchewan was designed. The experimental program conducted in this study included an examination of the solids flow behaviour in the riser, interstitial gas velocity in the downcomer, and stripping efficiency measurements. The hydrodynamic behaviour of the stripper was modeled using Multiphase Flow with Interphase eXchanges (MFIX) CFD code.<p> The solids flow behaviour in the bottom zone of a high-density riser was investigated by measuring the local upwards and downwards solids flux. Solids circulation rates between 125 and 243 kg/(m2⋅s) were evaluated at a constant riser superficial gas velocity of 5.3 m/s. The effect of the riser superficial gas velocity of the local upflow at the riser centerline was also conducted at a solids circulation rate of 187 kg/(m2⋅s). The results show that there is little variation in the local net solids flux at radial locations between 0.00 ¡Ü r/R ¡Ü 0.87. The results indicate that a sharp regime change from a typical parabolic solids flux profile to this more radially uniform solids flux profile occurs at a gas velocity between 4.8 and 4.9 m/s.<p> To quantify stripping efficiency, the underflow of an injected tracer into the standpipe must be known. Quantification of the underflow into the standpipe requires knowledge of two main variables: the interstitial gas velocity and the tracer gas concentration profiles in the standpipe. Stripping efficiency was determined for stripper solids circulation rates of 44, 60, and 74 kg/(m2⋅s) and gas velocities of 0.1, 0.2, and 0.3 m/s. For most conditions studied, the interstitial gas velocity profile was found to be flat for both fluidized and packed bed flow. The stripping efficiency was found to be sensitive to the operating conditions. The highest efficiency is attained at low solids circulation rates and high stripping gas velocities.<p> In the numeric study, stripper hydrodynamics were examined for similar operating conditions as those used in the experimental program. Due to an improved radial distribution of gas and decreasing bubble rise velocity, mass transfer is deemed most intense as bubbles crest above the baffles into the interspace between disc and donut baffles. Stripping efficiency is thought to improve with increasing gas velocity due to an increased bubbling frequency. Stripping efficiency is thought to decrease with increasing solids circulation rates due to a lower emulsion-cloud gas interchange coefficient and a decreased residence time of the emulsion in the stripper.

My thesis argues that a shift has taken place in white supremacist rhetoric post September 11, 2001. I focus on the pre-9/11 rhetoric of Jared Taylor, the post 9/11 rhetoric of Patrick Buchanan, and identify the attacks of September 11th as a catalytic event in the history of white supremacist rhetoric. Through careful rhetorical analysis, I identify the 9/11 shift as a shift in placement vis-à-vis the political mainstream.

The human protein kinase superfamily consists of over 500 members that individually control specific aspects of cell behavior and collectively control the complete range of cellular processes. That such a large group of proteins is able to uniquely diversify and establish individual identities while retaining common enzymatic function and significant sequence/structural conservation is remarkable. The means by which this is achieved is poorly understood, and we have begun to examine the issue by performing a comparative analysis of the catalytic domain of protein kinases. A novel approach for protein structural alignment has revealed a high degree of similarity found across the kinase superfamily, with variability confined largely to a single region thought to be involved in substrate binding. The similarity detected is not limited to amino acids, but includes a group of conserved water molecules that play important structural roles in stabilizing critical residues and the fold of the kinase domain. The development of a novel technique for identifying kinase substrates on a large scale directly from cell lysate has revealed that substrate specificity is not what discriminates the closely related p38α and β mitogen-activated protein kinases. Instead cellular localization appears to be their distinguishing characteristic, at least during myoblast differentiation. Together these results highlight the extent of conservation, as well as the minimal variability, that is found in the catalytic domain of all protein kinase superfamily members, and that while distantly related kinases may be distinguished by substrate specificity, closely related kinases are likely to be distinguished by other factors. Although these results focus on representative members of the kinase superfamily, they give insight as to how all protein kinases likely diversified and established unique non-redundant identities. In addition, the novel techniques developed and presented here for structural alignment and substrate discovery offer new tools for studying molecular biology and cell signaling.

is a functionally diverse large group of proteins sharing a jelly roll β-barrel fold. An enzymatic member 3-hydroxyanthranilate-3,4-dioxygenase (HAO) and a non-enzymatic member pirin, which is a human nuclear metalloprotein of unknown function present in all human tissues, were selected for structural and functional studies in this dissertation work. HAO is an important enzyme for tryptophan catabolism and for 2-nitrobenzoic acid biodegradation. In this work, seven catalytic intermediate were captured in HAO single crystals, enabling for the first time a nearly complete structural snapshot viewing of the entire molecular oxygen activation and insertion mechanism in an iron- and O2-depedent enzyme. The rapid catalytic turnover rate was found achieved in large part by protein dynamics that facilitates O2 binding to the catalytic iron, which is bound to the enzyme by a facile 2-His-1-carboxylate ligand motif. An iron storage and chaperon mechanism was also discovered in the bacterial source of this enzyme, which led to a proposed novel biological function of a mononuclear iron-sulfur center. Although human pirin protein shares the same structural fold with HAO, its iron ion is coordinated by a 3-His-1-carboxylate ligand motif. Pirin belongs to a subset of proteins whose members are playing regulatory functions in the superfamily. In this work, pirin is shown to act as a redox sensor for the NF-κB transcription factor, a critical mediator of intracellular signaling that has been linked to cellular responses to pro-inflammatory signals which controls the expression of a vast array of genes involved in immune and stress responses.

The direct catalytic hydrogenation of nitrile butadiene rubber (NBR) in latex form was studied as a model system for the development of a new latex hydrogenation process for the modification of unsaturated diene-based polymers. NBR is a synthetic rubber of copolymerized acrylonitrile and butadiene produced in latex form by emulsion polymerization. The catalytic hydrogenation of NBR is an important post-polymerization process resulting in a more stable and tougher derivative, hydrogenated NBR (HNBR), which has been widely used in the automotive and oil drilling industry. The present commercial process involves a number of cumbersome steps to obtain solid NBR from the latex and subsequent dissolution of the solid NBR in a large amount of organic solvent followed by solvent recovery after coagulation of the hydrogenated NBR. Since NBR is produced in latex form, it is very desirable to directly hydrogenate NBR in the latex form which will significantly simplify the hydrogenation process and facilitate subsequent applications. As an economical and environmentally benign alternative to the commercial processes based on the hydrogenation of NBR in organic solution, this direct latex hydrogenation process is of special interest to industry. The objective of this project is to develop an efficient catalytic system in order to realize the direct catalytic hydrogenation of NBR in latex form. OsHCl(CO)(O2)(PCy3)2 was initially used as the catalyst to investigate the possibility of hydrogenation of NBR in latex form and to understand the major factors which affect the hydrogenation operation. It was found that an organic solvent which is capable of dissolving or swelling the NBR was needed in a very small amount for the latex hydrogenation using the Os catalyst, and gel occurred in such a catalytic system during hydrogenation. Wilkinson’s catalyst, RhCl(PPh3)3, was then used for the latex hydrogenation in the presence of a small amount of solvent successfully without gel formation. Further investigation found that Wilkinson’s catalyst has a high activity for NBR latex hydrogenation without the use of any organic solvent. The influences of various operation conditions on hydrogenation rate, such as catalyst and polymer concentrations, latex system composition, agitation, reaction temperature and hydrogen pressure, have been investigated. It was found that the addition of triphenylphosphine (TPP) has a critical effect for the hydrogenation of NBR latex, and the hydrogenation rate was mainly controlled by the amount of catalyst which diffused into the polymer particles. In the presence of TPP, NBR latex can be hydrogenated to more than 95% degree of hydrogenation after about 30 hours at 160oC using Wilkinson’s catalyst with a catalyst to NBR rubber ratio of 1 wt%, without the addition of any organic solvent. The apparent activation energy for such NBR latex hydrogenation over the temperature range of 152oC to 170oC was found to be 57.0 kJ/mol. In the present study, it was also found that there are some impurities within the NBR latex which are detrimental to the hydrogenation reaction and are suspected to be water-soluble surfactant molecules. Deliberately designed solution hydrogenation experiments were conducted to study the impurity issue, and proper latex treatment methods have been found to purify the latex before hydrogenation. To improve the hydrogenation rate and to optimize the latex hydrogenation system, water soluble RhCl(TPPMS)3 catalyst (TPPMS: monosulphonated-triphenylphosphine) was used for the latex hydrogenation of NBR. The latex hydrogenation using the water soluble catalyst with TPP can achieve more than 90% degree of hydrogenation within 20 hours at 160oC. Further experiments using RhCl3 with TPP proved that the water soluble RhCl3 can be directly used as a catalyst precursor to generate the catalytic species in situ for the latex hydrogenation, and a stable NBR latex with 96% degree of hydrogenation can be produced without any gel problem within 19 hours of reaction at 160oC. The catalyst mass transport processes for these Rh based catalysts in the latex system were investigated in order to further optimize the solvent-free latex hydrogenation process. While maintaining the emulsified state of the original latex, the direct catalytic hydrogenation of NBR latex can be carried out efficiently without any cross-linking problem to more than 92% degree of hydrogenation within 8 hours at 160oC. As a result of this research project, new latex hydrogenation technologies were successfully developed to fulfill all major requirements for a solvent-free polymer latex hydrogenation route, which is a significant milestone for the improvement of this polymer modification technology. The finding of TPP’s role as the “catalyst mass transfer promoter” is a breakthrough for the research field related to the hydrogenation of unsaturated diene-based polymers in latex form.

The direct catalytic hydrogenation of nitrile butadiene rubber (NBR) in latex form was studied as a model system for the development of a new latex hydrogenation process for the modification of unsaturated diene-based polymers. NBR is a synthetic rubber of copolymerized acrylonitrile and butadiene produced in latex form by emulsion polymerization. The catalytic hydrogenation of NBR is an important post-polymerization process resulting in a more stable and tougher derivative, hydrogenated NBR (HNBR), which has been widely used in the automotive and oil drilling industry. The present commercial process involves a number of cumbersome steps to obtain solid NBR from the latex and subsequent dissolution of the solid NBR in a large amount of organic solvent followed by solvent recovery after coagulation of the hydrogenated NBR. Since NBR is produced in latex form, it is very desirable to directly hydrogenate NBR in the latex form which will significantly simplify the hydrogenation process and facilitate subsequent applications. As an economical and environmentally benign alternative to the commercial processes based on the hydrogenation of NBR in organic solution, this direct latex hydrogenation process is of special interest to industry. The objective of this project is to develop an efficient catalytic system in order to realize the direct catalytic hydrogenation of NBR in latex form. OsHCl(CO)(O2)(PCy3)2 was initially used as the catalyst to investigate the possibility of hydrogenation of NBR in latex form and to understand the major factors which affect the hydrogenation operation. It was found that an organic solvent which is capable of dissolving or swelling the NBR was needed in a very small amount for the latex hydrogenation using the Os catalyst, and gel occurred in such a catalytic system during hydrogenation. Wilkinson’s catalyst, RhCl(PPh3)3, was then used for the latex hydrogenation in the presence of a small amount of solvent successfully without gel formation. Further investigation found that Wilkinson’s catalyst has a high activity for NBR latex hydrogenation without the use of any organic solvent. The influences of various operation conditions on hydrogenation rate, such as catalyst and polymer concentrations, latex system composition, agitation, reaction temperature and hydrogen pressure, have been investigated. It was found that the addition of triphenylphosphine (TPP) has a critical effect for the hydrogenation of NBR latex, and the hydrogenation rate was mainly controlled by the amount of catalyst which diffused into the polymer particles. In the presence of TPP, NBR latex can be hydrogenated to more than 95% degree of hydrogenation after about 30 hours at 160oC using Wilkinson’s catalyst with a catalyst to NBR rubber ratio of 1 wt%, without the addition of any organic solvent. The apparent activation energy for such NBR latex hydrogenation over the temperature range of 152oC to 170oC was found to be 57.0 kJ/mol. In the present study, it was also found that there are some impurities within the NBR latex which are detrimental to the hydrogenation reaction and are suspected to be water-soluble surfactant molecules. Deliberately designed solution hydrogenation experiments were conducted to study the impurity issue, and proper latex treatment methods have been found to purify the latex before hydrogenation. To improve the hydrogenation rate and to optimize the latex hydrogenation system, water soluble RhCl(TPPMS)3 catalyst (TPPMS: monosulphonated-triphenylphosphine) was used for the latex hydrogenation of NBR. The latex hydrogenation using the water soluble catalyst with TPP can achieve more than 90% degree of hydrogenation within 20 hours at 160oC. Further experiments using RhCl3 with TPP proved that the water soluble RhCl3 can be directly used as a catalyst precursor to generate the catalytic species in situ for the latex hydrogenation, and a stable NBR latex with 96% degree of hydrogenation can be produced without any gel problem within 19 hours of reaction at 160oC. The catalyst mass transport processes for these Rh based catalysts in the latex system were investigated in order to further optimize the solvent-free latex hydrogenation process. While maintaining the emulsified state of the original latex, the direct catalytic hydrogenation of NBR latex can be carried out efficiently without any cross-linking problem to more than 92% degree of hydrogenation within 8 hours at 160oC. As a result of this research project, new latex hydrogenation technologies were successfully developed to fulfill all major requirements for a solvent-free polymer latex hydrogenation route, which is a significant milestone for the improvement of this polymer modification technology. The finding of TPP’s role as the “catalyst mass transfer promoter” is a breakthrough for the research field related to the hydrogenation of unsaturated diene-based polymers in latex form.

Dispersed niobia catalysts were prepared via a non-aqueous synthesis route. The effects of the type of oxide support, the support thermal pre-treatment, the calcination temperature and the niobia loading on the activity and selectivity for mesityl oxide (MO) synthesis at 160C were investigated in an autoclave reactor. The morphological and chemical properties of the catalysts were characterized via EDXRF, XRD, BET and Raman spectroscopy. The strength and nature of the acid sites were elucidated via in situ DRIFT spectra of the adsorption of pyridine as well as the temperature programmed desorption of NH3 interacting with the surface oxide phase. All four catalyst parameters had significant effects on the catalytic properties. Significantly, the nature of the acidity was clearly linked to the catalyst activity and particularly the catalyst stability. Catalysts exhibiting predominantly Lewis acidity invariably deactivated despite good initial activity, with the final acetone conversion dependent on the catalyst formulation. In contrast, catalysts exhibiting Bronsted acidity showed no evidence of catalyst deactivation after 8 hours of reaction. A plausible mechanism which explains these observations is proposed. Catalysts exhibiting Lewis acidity were more active when the supports were first activated at elevated temperature, likely due to a stronger support-surface oxide interaction as a consequence of increased surface coordinative unsaturation of the support. SiO¬2 supported catalysts exhibiting Bronsted acidity were more active if the supports were initially activated at 100C. Evidently, the hydroxyl groups on the oxide support contribute to the generation of Bronsted acidity. Different oxide supports gave rise to distinct acidic and catalytic properties in the niobia overlayer. The most striking example of this was the direct comparison of niobia dispersed onto two kinds of silica supports following the same preparative method. Unique and very strong acid sites were observed in niobia dispersed onto a commercial SiO¬2 catalyst carrier that were not observed in niobia dispersed onto fumed SiO¬2. For SiO2 catalysts, the activity increased linearly with niobia loading regardless of calcination temperature. In contrast, Al2O3 catalysts exhibited an initial increase in activity for MO synthesis with niobia loading followed by a decrease in activity after reaching a maximum activity below 1/3 monolayer coverage. The effect was more pronounced for catalysts exhibiting Bronsted acidity. It is proposed that adlineation sites are primarily responsible for catalytic activity in Nb2O5/-Al2O3 catalysts exhibiting Bronsted acidity. Niobia catalysts were developed using commercially available catalyst carriers as supports. The macrokinetics of MO and MIBK syntheses were investigated in a benchtop fixed bed flow reactor. The catalysts showed excellent activity for MO and MIBK syntheses at 160°C, typically 0.9 to 1.3 [g/hr*gcat]. However, the MIBK selectivity was constrained from 82 to 85% due to the coproduction of 2-propanol and diisobutyl ketone. The productivity for MO synthesis was found to be strongly dependent on the space velocity suggesting product inhibition. The intrinsic kinetics of the one-step synthesis of MIBK over a 15.2 wt% Pd/Nb2O5/SiO2 catalyst was investigated in an autoclave reactor. A kinetic model was developed and is reported. The one step synthesis of MIBK was investigated at the pilot plant scale via catalytic distillation (CD). An important finding was that while operating at 100% reflux, the accumulation of water in the reactive section resulted in the suppression of the DAA dehydration reaction. The in situ removal of water from the reactive section via an overhead distillate stream operating at 83 to 97% reflux directly resulted in an increase in MIBK productivity and hydrogen uptake efficiency by factors of about 20 yielding a moisture free reboiler product stream with as high as 53 wt% MIBK. The process was found to be controlled by the external mass transfer of hydrogen. Interestingly, the results suggest that the catalyst wetting efficiency affects the transport of hydrogen to the active sites as evidenced by the dependence of MO conversion on the reflux flow rate. The condition of minimum reflux flow rate and maximum hydrogen flow rate resulted in 97% MO conversion and 90 wt% MIBK selectivity.

Dispersed niobia catalysts were prepared via a non-aqueous synthesis route. The effects of the type of oxide support, the support thermal pre-treatment, the calcination temperature and the niobia loading on the activity and selectivity for mesityl oxide (MO) synthesis at 160C were investigated in an autoclave reactor. The morphological and chemical properties of the catalysts were characterized via EDXRF, XRD, BET and Raman spectroscopy. The strength and nature of the acid sites were elucidated via in situ DRIFT spectra of the adsorption of pyridine as well as the temperature programmed desorption of NH3 interacting with the surface oxide phase. All four catalyst parameters had significant effects on the catalytic properties. Significantly, the nature of the acidity was clearly linked to the catalyst activity and particularly the catalyst stability. Catalysts exhibiting predominantly Lewis acidity invariably deactivated despite good initial activity, with the final acetone conversion dependent on the catalyst formulation. In contrast, catalysts exhibiting Bronsted acidity showed no evidence of catalyst deactivation after 8 hours of reaction. A plausible mechanism which explains these observations is proposed. Catalysts exhibiting Lewis acidity were more active when the supports were first activated at elevated temperature, likely due to a stronger support-surface oxide interaction as a consequence of increased surface coordinative unsaturation of the support. SiO¬2 supported catalysts exhibiting Bronsted acidity were more active if the supports were initially activated at 100C. Evidently, the hydroxyl groups on the oxide support contribute to the generation of Bronsted acidity. Different oxide supports gave rise to distinct acidic and catalytic properties in the niobia overlayer. The most striking example of this was the direct comparison of niobia dispersed onto two kinds of silica supports following the same preparative method. Unique and very strong acid sites were observed in niobia dispersed onto a commercial SiO¬2 catalyst carrier that were not observed in niobia dispersed onto fumed SiO¬2. For SiO2 catalysts, the activity increased linearly with niobia loading regardless of calcination temperature. In contrast, Al2O3 catalysts exhibited an initial increase in activity for MO synthesis with niobia loading followed by a decrease in activity after reaching a maximum activity below 1/3 monolayer coverage. The effect was more pronounced for catalysts exhibiting Bronsted acidity. It is proposed that adlineation sites are primarily responsible for catalytic activity in Nb2O5/-Al2O3 catalysts exhibiting Bronsted acidity. Niobia catalysts were developed using commercially available catalyst carriers as supports. The macrokinetics of MO and MIBK syntheses were investigated in a benchtop fixed bed flow reactor. The catalysts showed excellent activity for MO and MIBK syntheses at 160°C, typically 0.9 to 1.3 [g/hr*gcat]. However, the MIBK selectivity was constrained from 82 to 85% due to the coproduction of 2-propanol and diisobutyl ketone. The productivity for MO synthesis was found to be strongly dependent on the space velocity suggesting product inhibition. The intrinsic kinetics of the one-step synthesis of MIBK over a 15.2 wt% Pd/Nb2O5/SiO2 catalyst was investigated in an autoclave reactor. A kinetic model was developed and is reported. The one step synthesis of MIBK was investigated at the pilot plant scale via catalytic distillation (CD). An important finding was that while operating at 100% reflux, the accumulation of water in the reactive section resulted in the suppression of the DAA dehydration reaction. The in situ removal of water from the reactive section via an overhead distillate stream operating at 83 to 97% reflux directly resulted in an increase in MIBK productivity and hydrogen uptake efficiency by factors of about 20 yielding a moisture free reboiler product stream with as high as 53 wt% MIBK. The process was found to be controlled by the external mass transfer of hydrogen. Interestingly, the results suggest that the catalyst wetting efficiency affects the transport of hydrogen to the active sites as evidenced by the dependence of MO conversion on the reflux flow rate. The condition of minimum reflux flow rate and maximum hydrogen flow rate resulted in 97% MO conversion and 90 wt% MIBK selectivity.