Continuous Fixed-bed Reactor Research Articles

Continuous processing of JP-10 production: Hydroisomerization of endo-tetrahydrodicyclopentadiene to exo-tetrahydrodicyclopentadiene using a novel bimetal catalyst of Ba/Se supported on TiO2/SO4

High-energy-density liquid fuels can be utilized as an energetic supplement to conventional fuels and are essential for volume-limited aerospace vehicles to boost payload and flying range. JP-10 has attracted much attention because of its high density, flash point, high volumetric heat, and low freezing point. Here we report the hydroisomerization of endo-tetrahydrodicyclopentadiene to exo-tetrahydrodicyclopentadiene (the main component of JP-10) was investigated over the TiO2/SO4 supported Ba(10 %)/Se(5–20 %) catalysts. This work aims to examine changes in continuous processing settings to maximize exo-THDCPD production, selectivity, and conversion. It was discovered that the synthesized TiO2/SO4/Ba(10 %)/Se(5–20 %) heterogeneous catalysts were novel, more effective, affordable, environmentally friendly, and simple to produce. The catalyst’s physicochemical characteristics were examined using FT-IR, BET, XRD, HR-SEM, HR-TEM, TGA and NH3-TPD. The produced TiO2/SO4/Ba(10 %)/Se(5–20 %) nano-catalysts have good catalytic activity and a wide range of active Lewis and Brønsted acid sites. Evaluation of the isomerization of endo-THDCPD to exo-THDCPD was conducted in a high-pressure fixed-bed continuous reactor operating at 200 °C, 20 bar of pressure, and 4.0mol/h of H2 flow rate. According to the investigations, the synthesized catalyst with a 15 % Se load performs exceptionally well, exhibiting 100 % conversion, 98.5 % selectivity, and 98.5 % yield at an H2 flow rate of 10 ml/min. The isomerized product is used in Jet Propellant-10, a high-density fuel. Under ideal circumstances, exo-THDCPD with a high degree of purity (>98 wt%) was produced without the need for any sort of separation technique.

Performance analysis, statistical modeling, and multiple response optimization of a novel fixed-bed quartz reactor packed with Ba-Pt@γ-AL2O3 using response surface methodology

In the present study, a novel fixed-bed continuous reactor with a preheating chamber was designed to be utilized for the practical application of removal studies of dangerous pollutants, especially NOX removal by NOX Storage Reduction (NSR) catalysts on a laboratory scale. The reactor's design and operational parameters, including outer wall temperature (50–600 °C), volumetric flow rate (0.3–3 L/min), wall temperature time (0.16–10 min), and granule surface area inside the preheating chamber (0–270 cm2), were statistically modeled and optimized using Response Surface Methodology (RSM). For more logical and effective parameter optimization, the ratio of gas and catalyst temperatures and pressure drop to the reactor outer wall temperature (GT/ROWT, CT/ROWT, and PD/ROWT) were also included in the optimization process. Experimental results showed that gas temperature, catalyst temperature, and pressure drop ranged from 31 to 177 °C, 51–585 °C, and 7–153 Pa, respectively. Optimal conditions were determined to be an outer wall temperature of 230 °C, a volumetric flow rate of 3 L/min, a wall temperature time of 0.16 min, and a granule surface area of 67.3 cm2. The results demonstrated that outer wall temperature, flow rate, time, and surface area of granules have significant and interaction effects on the responses and should be considered when researchers assess the removal efficiency of thermal catalysts.

Fischer-tropsch synthesis: effect of temperature and iron-cobalt ratio in Fe-Co/meso-HZSM-5 catalyst on liquid product distribution

The Fischer-Tropsch synthesis converted hydrogen and carbon monoxide into linear hydrocarbons as liquid fuel. Iron and cobalt were used as polymerization catalyst, that impregnated on HZSM-5. The Fe-Co/HZSM-5 could be applied as bifunction catalyst which combined polymerizing synthesis gas and long chain hydrocarbon cracking for making biofuel. The objective of this study is observing the effect of temperature and composition of iron and cobalt combination, supported by HSZM-5 (Fe-Co/HZSM-5) catalyst on fuel product composition. The results obtained from this study would be used to find optimum condition for various iron and cobalt ratio in the catalyst. The mesoHZSM-5 was prepared from ammonium ZSM-5 over calcination, desilication, and dispersion. The mixed solution consisted of Co(NO3)2.6H2O and Fe(NO3)3.9H2O were used as precursor for incipient wetness impregnation on HZSM-5. The catalyst performance was observed in a continuous fixed bed reactor using Fe-Co/meso-HZSM-5 catalyst with synthesis gas at various composition iron and cobalt ratio (10–40 % wt. Fe in Co), various temperature (225–275 °C) at 20 bars. All catalysts were reduced in situ in the reactor. The 10Fe-90Co/mesoHZSM-5 catalyst was more suitable for FTS at 250 °C with alkane (20.49 %) as the main product and alcohol as the by-product (79.51 %). The others catalysts composition of 20–40 % Fe (by weight) in Fe-Co were more suitable for FTS at 225–250°C because under these conditions, alkanes as the main product were obtained in relatively higher compositions compared to other compounds. The mechanism of paraffins, olefins, aldehydes and alcohols formation in this FTS reaction followed the hydrogen assisted CO dissociation with CO-insertion mechanism

Catalytic bi-reforming of methane as a potential source of hydrogen rich syngas: Promotional effect of strontium on the catalytic performance of Ni/MgO-ZrO2

Bi-reforming of methane (BRM) has gained significant attention due to escalating environmental concerns. This study investigates the performance of a monometallic Ni/MgO-ZrO2 catalyst with varying strontium (Sr) content ranging from 0 to 10 wt% added to the 10 wt% nickel, utilized in BRM. The synthesis of the MgO-ZrO2 support employed the co-precipitation method, while both Ni and Sr metals were added via impregnation route. The physiochemical properties of the prepared catalysts were analyzed using various characterization techniques such as X-Ray Diffraction (XRD), N2-Physisorption Analysis, Temperature-Programmed Reduction (TPR), Temperature-Programmed Desorption (TPD), X-ray Photoelectron Spectroscopy (XPS), Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM). To assess catalytic performance, the catalyst was tested in a fixed-bed continuous reactor using a reactant mixture of CH4, H2O, and CO2 in a 3:2:1 ratio, respectively, at a temperature of 800 °C. The Ni-6%Sr/ZrO2-MgO catalyst provided optimal conversion rates for both CH4 and CO2 at 95.2% and 85.7% respectively, without significant deactivation observed even after 36 h of reaction. This excellent catalytic performance was attributed to several factors, including smaller metal particle size, improved metal dispersion, stabilization of the t-phase in zirconia and synergistic effects between the Ni and Sr particles. The spent catalyst characterization including XRD, FESEM and HRTEM revealed that the addition of Sr significantly reduced carbon deposition. It also demonstrated that stable and best performance of the Ni-Sr/MgO-ZrO2 catalyst is ascribed to the production of filamentous carbon with a crystalline nanotubular structure. Conversely, the rapid deactivation of the Ni/MgO-ZrO2 monometallic catalyst may be attributed to amorphous carbon.

Engineered Ru on HY zeolite catalyst for continuous and selective hydrodeoxygenation of lignin phenolics to cycloalkanes under moderate conditions

We report a continuous selective hydrodeoxygenation (HDO) process of guaiacol conversion to cycloalkanes under 180 °C/1 MPa, which results in improved HDO chemistry for lignin-based jet fuel production. The incipient wetness impregnation method was modified to prepare an HY zeolite-supported Ru catalyst with better metal dispersion and acid site uniformity, which overcomes the low conversion and selectivity of previous literature. The modified catalyst (Ru-HY-60-MI) was tested in a continuous fixed bed reactor, resulting in increased HDO conversion of guaiacol to cycloalkanes compared to the unmodified catalyst. Pressure, temperature, and weight hourly space velocity-dependent tests validate guaiacol HDO over Ru-HY-60-MI catalyzed ring hydrogenation of guaiacol to 2-methoxycyclohexanol, acid-catalyzed demethoxylation and dehydration to cyclohexene, and further hydrogenation of cyclohexene to cyclohexane. These experiments enable exploring a continuous HDO process, demonstrate effectiveness for other β-β and α-O-4 lignin representatives and real lignin bio-oil, and pave the way towards commercialization of lignin-based jet fuel.

Synergy between heterogeneous catalysis and homogeneous radical reactions for pharmaceutical waste destruction: Perspective

Enormous quantities of pharmaceuticals are consumed by humans leading to a growing and continuous release of harmful components into the environment. Existing conventional water treatment plants are designed mainly for eliminating biodegradable organics and nutrients and cannot degrade pharmaceuticals and personal care products efficiently enough due to their chemical stability. Advanced oxidation processes using radicals generated from ozone can be efficiently combined with heterogeneous catalysis for treatment of wastewater containing pharmaceuticals and personal care products. From the technology viewpoint, elimination of pharmaceuticals from water by heterogeneously catalyzed ozonation should done in a continuous fixed bed reactor. The structured catalysts can be prepared by additive manufacturing using 3D-direct printing of supports/catalysts allowing a high degree of freedom in both the composition and design of the final catalytic material for a fixed bed heterogeneous-homogeneous reaction. Structured materials can exhibit non-periodic structure, such as for example semi-ordered structures, inspired by nature. For periodic and semi-periodic structures, heat and mass transfer should be investigated using computational fluid dynamics and flow imaging methods, guiding further design of novel architectures and subsequently allowing in combination with the materials development efficient control of activity and selectivity. The innovative catalytic reactor engineering should include experimental and numerical investigation of the stage wise injection of the oxidation agent, variation of the reactor cross-section size, changing the distance between the catalyst beds and introduction of the recycle loops.

Sorption-enhanced glycerol steam reforming over lithium cuprate-based bifunctional material for the production of high-purity hydrogen

We investigated the production of high-purity H2 through sorption-enhanced glycerol steam reforming (SEGSR) using lab-made bifunctional materials consisting of nickel, Al2O3, and Li2CuO2. Different bifunctional materials were prepared with 10 wt % Ni loading but varying wt % of Al2O3 and Li2CuO2, and their catalytic activity was evaluated in a continuous fixed-bed down-flow reactor. HM-50, which had an equal wt % of Al2O3 and Li2CuO2, showed the highest performance. The conversion of glycerol and the purity of H2 were examined with respect to temperature, feed flow rate, and steam-to-carbon molar ratio (S/C). At the optimum reaction conditions (temperature = 700 °C, feed flow rate = 0.5 ml/min, and S/C = 6), glycerol conversion and H2 purity were 100 % and 94 mol %, respectively. The adsorption capacity of HM-50 was found to be 3.9 mmol CO2 per gram. With a breakthrough time of 15 min, the substance was stable for 13 adsorption-desorption cycles. The material was regenerated by substituting the feed with a N2 and steam mixture heated to 700 °C for 30 min. A most likely reaction mechanism suggested that glycerol was catalytically converted to acetaldehyde, which was then quickly decomposed to CO and CH4. We are the first research team to investigate the use of Li2CuO2 in any steam reforming process.

Production of renewable mesitylene as jet-fuel additive: Reaction kinetics of acetone self-condensation over basic (TiO2) and acid (Al-MCM-41) catalysts

Sustainable production of jet fuel additives plays an essential role to decrease greenhouse gas emissions in the aviation industry. Acetone obtained from biomass fermentation is one of the platform molecules of the bio-refinery that can be used as raw material of newly developed sustainable processes. Mesitylene jet fuel additive can be obtained by acetone self-condensation reaction catalyzed by porous solids. In the present work, TiO2 and Al-MCM-41 have been chosen, respectively, as basic and acid catalysts, because of having some tolerance to deactivation. The reaction was studied in a continuous fixed-bed reactor operated in the gas phase at space velocities of 7900 mol/kg h for TiO2 and 5000 mol/kg h for Al-MCM-41. The influence of feed concentration (5–20% acetone and 0–5% mesityl oxide) and temperature (200–350 °C) was studied. First, the reaction scheme was assessed based on the product distribution. It was found that the acid catalyst Al-MCM-41 favors mesityl oxide decomposition to undesired isobutylene and acetic acid. Then, a mechanistic kinetic model of the different steps of the reaction scheme was developed and fitted the experimental results of each catalyst. This model constitutes a valuable tool for the scale-up of this process.

Performance of Mesoporous Ceria-Supported Pt Catalysts for Oxidative Degradation of Aqueous Solution of Toxic Phenol in a Continuous Fixed Bed Reactor: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, and Characterization

Performance of Mesoporous Ceria-Supported Pt Catalysts for Oxidative Degradation of Aqueous Solution of Toxic Phenol in a Continuous Fixed Bed Reactor: Optimization of Reaction Conditions, Kinetics, Catalyst Stability, and Characterization

Utilization of steel industry waste derived magnetic iron-oxide nanoparticles for reverse water gas shift reaction

The improvements associated with developing newer pathways for the catalytic reduction of carbon dioxide (CO2) into valuable products have grown a lot in recent times. Herein, we investigated the possibility of using waste red-colored iron oxide dust (IOD) as a low-cost available precursor for synthesizing magnetic black-colored iron oxide nanoparticles (Fe3O4-NP). The as-synthesized Fe3O4-NP has been used to thermo-catalytically reduce CO2 to carbon monoxide (CO) using the well-known process of reverse water gas shift reactions (RWGS) with a > 97 % selectivity with ∼ 22 % CO2 conversion. The catalytic activity of Fe3O4-NP for converting CO2 into CO has been analyzed in a laboratory-scale continuous fixed bed reactor, where Fe3O4-NP showed better results than IOD. The electrochemical studies have also supported the improved RWGS activity of Fe3O4. Additionally, the catalytic activity of synthesized nanoparticles for RWGS has been compared with two commercially available samples of Fe3O4 named CS1 and CS2, where the synthesized Fe3O4-NP showed better results, which advocates the suitability of the reported procedure related to the utilization of iron-based industrial waste.

High Acidity and Low Carbon-Coke Formation Affinity of Co-Ni/ZSM-5 Catalyst for Renewable Liquid Fuels Production through Simultaneous Cracking-Deoxygenation of Palm Oil

This study investigates the effect of chemically doped Co and Ni metals on ZSM-5 catalyst with respect to the catalysts’ characteristics and performance for palm oil cracking. Some characterization methods have been conducted to identify the physicochemical properties of the synthesized catalysts, including X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), N2-physisorption, NH3- and CO2-probed Temperature Programmed Desorption (NH3-TPD and CO2-TPD) methods. The deposited carbon-coke on the spent catalysts is analysed using simultaneous thermal gravimetric – differential scanning calorimetry (TG-DTG-DSC) analysis. The performance of catalysts was evaluated on palm oil cracking process in a continuous fixed-bed catalytic reactor at 450 °C. To determine the liquid product composition functional group and components, we used Attenuated Total Reflectance Fourier-transform Infrared Spectroscopy (ATR-FTIR) and batch distillation methods, respectively. We found that the Co metal chemically-doped on Ni/SM-5 catalyst, resulting the increase in the catalysts acidity and the decrease in catalysts basicity. The conversion of palm oil increases as the increase of the ratio of catalysts’ acidity to basicity. The highest triglyceride conversion (76.5%) was obtained on the 3Co-Ni/ZSM-5 with the yield of gasoline, kerosene, and diesel of 2.61%, 4.38%, and 61.75%, respectively. It was also found that the chemically doping Co metal on Ni/ZSM-5 catalyst decreased carbon-coke formation due to the low catalysts’ basicity. Overall, it is proven that the combination of Co and Ni, which chemically doped, on ZSM-5 catalyst has a good activity in palm oil conversion with low carbon-coke formation affinity and high acidity of catalyst.

Kinetics of the catalytic oxidation of toluene over Mn,Cu co-doped Fe2O3: Ex situ XANES and EXAFS studies to investigate mechanism

In this study, the catalytic mechanism of Mn,Cu-Fe2O3 catalyst was directly determined through reaction kinetics coupled with surface characterization. The impact of operating conditions on the catalytic performance of Mn,Cu-Fe2O3 nanocomposite for toluene oxidation in a continuous fixed-bed reactor was investigated. It was found that Mn,Cu-Fe2O3 catalyst gave the best catalytic performance in toluene removal when the initial concentrations of toluene and oxygen were at 165 ppmv and 10% at a flow rate of 200 mL min−1, respectively. Subsequently, Power-law, Mars-van Krevelen, and Langmuir-Hinshelwood models were developed to describe the kinetics of the total toluene oxidation for both toluene- and oxygen-dependent mixtures in a range of temperatures. According to the results, the basic Power-law model could not properly represent the kinetics of toluene oxidation over the catalyst. Meanwhile, the Mars-van Krevelen model allows for determining the kinetic mechanism under the variation of C7H8 concentration. The Langmuir-Hinshelwood model is attainable to express the kinetics of the oxygen-involved reaction mechanism. Moreover, the change in the structure of Mn,Cu-Fe2O3 catalyst after the catalytic reaction was characterized by X-ray Absorption Near-edge Structure (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) measurements to confirm the catalytic mechanism determined through reaction kinetics. The achieved results suggest the possibility of using various models to justify the correlation between model-simulated and experimental data for VOCs oxidation in a continuous-flow catalytic reactor.

Utilization of agricultural waste (rice husk) in synthesis of TS-1 zeolite as a support for NiMo nanocatalyst employed in hydrodesulfurization of heavy oil

Agricultural waste, rice husk (RH) was treated to obtain rice husk ash (RHA) and utilized as silica precursor in hydrothermal synthesis of TS-1 zeolite. Results of characterization analyses, XRD, FTIR, FESEM and N2 adsorption-desorption, confirmed that TS-1 zeolite was properly synthesized from RHA. Synthesis of TS-1 was also carried out with TEOS for comparison of textural properties. Prepared TS-1 zeolite with RHA was used as support for HDS catalyst preparation. Molybdenum active phase and nickel promoter were loaded via three different methods, impregnation, precipitation and solution combustion, to obtain NiMo/TS-1 hydrodesulfurization catalyst. EDX dot-mapping and H2-TPR analyses indicated on better preparation of NiMo/TS-1 catalyst by solution combustion method, in terms of distribution and amount of successfully loaded metal over the support surface. Hydrodesulfurization (HDS) activity of synthesized samples was examined in hydrodesulfurization of heavy oil feed, carried out in a continuous fixed bed reactor apparatus. Performance test revealed that NiMo/TS-1 catalyst synthesized by solution combustion method eliminated 63.5 % of the feed sulfur content (4000 ppm); a superior hydrodesulfurziation activity, compared to the samples prepared via impregnation and precipitation methods with 40.8 % and 50.2 % sulfur removal, respectively. Amount of sulfur present in the feed and treated product was determined with GC-MS analysis.

The Role of Ion Exchange Resins for Solving Biorefinery Catalytic Processes Challenges

Different possible applications of ion exchange resins in the framework of biorefinery catalytic applications are discussed in this article. Three case studies were selected for this approach, connected to three main routes for biomass upgrading: syngas upgrading to high-value chemicals, biomass hydrolysate upgrading, and direct upgrading of oily fraction. The tailored acidic properties of these materials, as well as their stability in the presence of water, have made them promising catalysts for applications such as obtaining biodiesel from activated sludge wastes in batch reactors and obtaining polyoxymethylene methyl ether from syngas (via formaldehyde and methylal, and working in a continuous fixed bed reactor). However, the acidity of these materials may still be too low for acid-catalyzed aldol condensation reactions in the aqueous phase.

Production of dimethyl carbonate by gas-phase oxidative carbonylation of methanol over Cu/Y zeolite: Mechanism and kinetics

Dimethyl carbonate (DMC) has become into an appealing fuel additive for reducing the formation of pollutants during combustion and, together with the post-combustion treatment, allowing to fulfill the most stringent environmental regulations. Although the production of this chemical is still an open issue, the oxidative carbonylation of methanol catalyzed by solids and with reactants and products in the gas phase has been proposed to replace the homogeneous commercial process (CuCl in aqueous phase). In this work, we propose the use of a Cu/Y zeolite (prepared by solid-state ion exchange with copper (I) chloride) as alternative catalyst for this purpose, optimizing the reaction conditions and proposing a rigorous kinetic model for this reaction. For accomplishing this aim, gas phase reaction was performed in a continuous fixed-bed reactor. Temperature (100–200 °C) played a critical role in product distribution, DMC being the main product at 120 °C. The influence of different reactant (CH3OH/CO/O2) concentrations on reaction rate and product distribution was determined at 120 °C. The experimental data have been successfully fitted to a kinetic model, derived from the mechanism of the reaction.

Tuning CO2 Hydrogenation Selectivity through Reaction-Driven Restructuring on Cu-Ni Bimetal Catalysts.

Tuning the selectivity of CO2 hydrogenation is of significant scientific interest, especially using nickel-based catalysts. Fundamental insights into CO2 hydrogenation on Ni-based catalysts demonstrate that CO is a primary intermediate, and product selectivity is strongly dependent on the oxidation state of Ni. Therefore, modifying the electronic structure of the nickel surface is a compelling strategy for tuning product selectivity. Herein, we synthesized well dispersed Cu-Ni bimetallic nanoparticles (NPs) using a simple hydrothermal method for CO selective CO2 hydrogenation. A detailed study on the monometallic (Ni and Cu) and bimetallic (CuxNi1-x) catalysts supported on γ-Al2O3 was performed to increase CO selectivity while maintaining the high reaction rate. The Cu0.5Ni0.5/γ-Al2O3 catalyst shows a high CO2 conversion and more CO product selectivity than its monometallic counterparts. The surface electronic and geometric structure of Cu0.5Ni0.5 bimetallic NPs was studied using ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and in situ diffuse reflectance infrared Fourier-transform spectroscopy under reaction conditions. The Cu core atoms migrate toward the surface, resulting in the restructuring of the Cu@Ni core-shell structure to a Cu-Ni alloy during the reaction and functioning as the active site by enhancing CO desorption. A systematic correlation is obtained between catalytic activity from a continuous fixed-bed flow reactor and the surface electronic structural details derived from AP-XPS results, establishing the structure-activity relationship. This investigation contributes to providing a strategy for controlling CO2 hydrogenation selectivity by modifying the surface structure of bimetallic NP catalysts.

COx hydrogenation to methanol and other hydrocarbons under mild conditions with Mo3S4@ZSM-5

The hydrogenation of CO2 or CO to single organic product has received widespread attentions. Here we show a highly efficient and selective catalyst, Mo3S4@ions-ZSM-5, with molybdenum sulfide clusters ([Mo3S4]n+) confined in zeolitic cages of ZSM-5 molecular sieve for the reactions. Using continuous fixed bed reactor, for CO2 hydrogenation to methanol, the catalyst Mo3S4@NaZSM-5 shows methanol selectivity larger than 98% at 10.2% of carbon dioxide conversion at 180 °C and maintains the catalytic performance without any degeneration during continuous reaction of 1000 h. For CO hydrogenation, the catalyst Mo3S4@HZSM-5 exhibits a selectivity to C2 and C3 hydrocarbons stably larger than 98% in organics at 260 °C. The structure of the catalysts and the mechanism of COx hydrogenation over the catalysts are fully characterized experimentally and theorectically. Based on the results, we envision that the Mo3S4@ions-ZSM-5 catalysts display the importance of active clusters surrounded by permeable materials as mesocatalysts for discovery of new reactions.

Efficient Cu-based catalysts for the selective demethoxylation of guaiacols

Lignin is an attractive feedstock for low molecular weight biobased phenols using depolymerization strategies such as reductive catalytic fractionation or fast pyrolysis. Such strategies often yield a product mixture enriched in lignin-derived monomers with methoxy substituents. Selective catalytic hydrodeoxygenation (HDO) is an effective methodology to demethoxylate these monomers into valuable alkylated phenols. Here, we report the use of non-precious Cu based catalysts supported on SiO2, ZrO2, TiO2 (various forms), MoO3-ZrO2, and MoO3-TiO2 in a continuous fixed-bed reactor at elevated temperature and pressure (300–360 °C, 10 bar) for the selective demethoxylation of guaiacol. Among the various catalysts, Cu/TiO2-P25 was found to be an effective and highly stable catalyst (100 h on stream) with a selectivity of 87% to demethoxylated compounds like phenol and cresols at a guaiacol conversion of 98%. A correlation was found between the oxygen storage capacity of the support (TiO2-P25, TiO2-A HSA, TiO2-R, and MoO3-TiO2) and guaiacol conversion, indicating that this property plays a role in the catalytic cycle. Besides, the demethoxylation of 4-n-propylguaiacol and a realistic guaiacol-rich feed isolated from a representative pyrolysis oil was successfully demonstrated. 87% of the guaiacols present in the feed were converted to demethoxylated phenols with a selectivity of 81%.

ALKYLATION OF PHENOL WITH METHANOL BY USING ZEOLITE CATALYSTS

Alkylation of phenol with methanol using beta zeolite, H-beta zeolite, MCM-22, and H-MCM-22 was studied on a continuous fixed bed reactor. The obtained products were anisole, o-cresol, p-cresol, and 2,4-xylenol. The effect of various parameters such as mole ratio of reactants (phenol:methanol), temperature, and time on stream were studied to attain the highest phenol conversion and the selectivity of the individual products. The maximum conversion of phenol was exhibited by H-MCM-22 with moderate anisole selectivity of 21%. The best selectivity of anisole (63%) was obtained by H-beta zeolite with 50% conversion of phenol. Selectivity of anisole decreases with increase in temperature which suggests that at high temperature C-methylation is favored over O-methylation. In addition, selectivity of anisole increases with the increase of the phenol to methanol feed ratio. The time on stream shows an increase in selectivity of anisole, p-cresol, and o-cresol with a decrease in 2,4-xylenol selectivity.

Wilkinson-type catalysts in ionic liquids for hydrogenation of small alkenes: understanding and improving catalyst stability

We apply supported ionic liquid phase (SILP) catalysts to hydrogenate small 1-alkenes in a continuous fixed-bed reactor. We rationalize the origin of catalyst decomposition via IR spectroscopy and adapt the catalyst design for improved stability.