Methanol Catalyst Research Articles

Production of Dimethyl Ether from Nitrogen-Containing Syngas

A series of experiments in conversion of nitrogen-rich (above 40 vol %) syngas to produce dimethyl ether (DME) was carried out in a flow-through pilot installation. Two commercial catalysts, specifically a DV-8-2 methanol catalyst and a γ-Al2O3 dehydration catalyst, were used as components of a bifunctional catalyst. The paper introduces the concept of reacting gas, the content of which in syngas corresponds to the sum of the content of hydrogen and carbon oxides. No methanol or DME was detected in the converted gas leaving the reactor, as these compounds condense in a water-cooled separator. The following performance values were achieved after more than 600 total running hours of the bifunctional catalyst: DME selectivity at least 66% and DME productivity up to 340 L kgcat–1 h–1. The study of single-stage DME synthesis from nitrogen-containing syngas has demonstrated the practicability for an industrial process technology using commercial components in a bifunctional catalyst.

Holey PdPb nanosheet array: An advanced catalyst for methanol electrooxidation

Holey PdPb nanosheet array is successfully synthesized using the CO confinement method. By tuning the ratio of Pd to Pb, the optimized holey Pd8Pb nanosheet array exhibits 4.8-fold higher peak current density and better stability toward methanol electrooxidation compared to the commercial Pd/C, holding great promise as an anode catalyst for direct methanol fuel cells.

Structure, Morphology and Catalytic Activity of PtRu/RGO Prepared by Different Processes

With the aim of developing an active catalyst for a direct methanol fuel cell and its preparation process, PtRu supported on reduced graphene oxide (RGO), PtRu/RGO, was prepared by three different processes using RGO with different sizes, i.e., large and small. The first process (A) involves the drying of RGO, the second one (B) does not involve the drying, and the third one (P) also does goes not involve the drying but goes through a polydopamine modification. (A) results in large agglomerates of RGO due to stacking and PtRu also formed agglomerates of nanoparticles on the outer surface of the RGO agglomerates. (B) resulted in a low Pt utilization due to the stacking of RGO. (P) improved its ECSA, Pt utilization and mass activity due to the modification that allows a homogeneous and small size PtRu deposition on the RGO. However, a problem with the modification that reduce the positive interaction between PtRu and RGO was also suggested. A smaller RGO was preferred in (P), but not in (A) and (B).

Environmentally Benign Synthesis of 4-Thiazolidinone Derivatives Using a Co/Al Hydrotalcite as Heterogeneous Catalyst

The present effort describes facile and environmentally benign synthesis of 4-thiazolidinone via oxidative cyclocondensation of benzyl alcohols, various substituted aromatic anilines and thioglycolic acid using a Co-Al hydrotalcite based heterogeneous catalyst (Co@HT) in methanol act as a solvent. We have synthesized three types of Co@HT with different molar ratio Co@HT-2 (1:1), Co@HT-3 (2:1), Co@HT-4 (3:1). Characterization of synthesized Co@HT catalyst using various analysis techniques such as FT-IR, powder XRD, SEM, XPS, EDS, DTG-TGA and N2 physical adsorption. Among the synthesized hydrotalcite, Co-HT-3 exhibit admirable catalytic activity towards oxidation of benzyl alcohol followed by cyclocondensation of respective aldehydes, anilines and thioglycolic acid into the corresponding 4-thiazolidinones in methanol at 60 οC using O2 as a oxidant. Furthermore, after end of the reaction, the catalyst is easily recovered and eco-friendly without any considerable loss in its catalytic efficiency.

Zirconium-based MOFs-loaded ionic liquid-catalyzed preparation of biodiesel from Jatropha oil

An environmentally acidic ionic liquid was prepared with 1-methyl-imidazole, 1,3-propyl sultone and H2SO4, and successfully loaded B acidic ionic liquid into three zirconium-based MOFs to synthesize the catalyst used to prepare biodiesel from Jatropha oil by impregnation method. The structure of the catalyst was characterized by XRD, SEM, FTIR and BET. Compare the activities of the three catalysts (through PSH/UiO-66, PSH/UiO-66NO2, PSH/UiO-66-NH2) experiments, the catalytic activity of PSH/UiO-66-NO2 was found to be the highest, and the conversion rates of Jatropha oil was 96.69%. The effect of methanol oil mole ratio, catalyst dosage, reaction temperature, and reaction time on the conversion of Jatropha oil to biodiesel was investigated, an orthogonal test determined the optimum reaction conditions of using PSH/UiO-66-NO2 catalyst. The optimal reaction conditions were obtained: reaction temperature was 343 K, catalyst dosage to oil was 4 wt%, methanol to oil ratio was 25:1, reaction time was 4 h, and the average conversion rates of Jatropha oil was 97.57%, the methyl ester rate was over 99.98%. The results showed that the four reaction factors had significant effects on the Jatropha oil conversion rates: reaction time > catalyst dosage > reaction temperature > methanol to oil ratio.

Construction of three-dimensional hierarchical Pt/TiO2@C nanowires with enhanced methanol oxidation properties

Three-dimensional (3D) hierarchical Pt/TiO2@C core-shell nanowire networks with high surface area have been constructed via wet chemical approaches. The 3D TiO2 nanowire framework was in situ synthesized within a porous titanium foam by hydrothermal method followed by carbon coating and self-assembled growth of ultrathin Pt nanowires. Structural characterization indicates that single crystalline ultrathin Pt nanowires of 3–5 nm in diameter were vertically distributed on the anatase TiO2 nanowires covered with a 2–4 nm thin carbon layer. The 3D hierarchical Pt/TiO2@C nanostructure demonstrates evidently higher catalytic activities towards methanol oxidation than the commercial Pt/C catalyst. The catalytic current density of the hierarchical catalyst is 1.6 times as high as that of the commercial Pt/C, and the oxidation onset potential (0.35 V vs. Ag/AgCl) is more negative than the commercial one (0.46 V vs. Ag/AgCl). Synergistic effect between the ultrathin Pt nanowires and the TiO2@C core-shell nanostructure accounts for the enhanced catalytic properties, which can be determined by X-ray photoelectron spectroscopy (XPS) investigation. The obtained hierarchical Pt/TiO2@C nanowire networks promise great potential in producing anode catalysts for direct methanol fuel cells applications.

Hydrogenative Cyclization of Levulinic Acid to γ-Valerolactone with Methanol and Ni-Fe Bimetallic Catalysts

A series of Ni-Fe/SBA-15 catalysts was prepared and tested for the catalytic hydrogenation of levulinic acid to γ-valerolactone, adopting methanol as the only hydrogen donor, and investigating the synergism between Fe and Ni, both supported on SBA-15, towards this reaction. The characterization of the synthesized catalysts was carried out by XRD (X-ray powder diffraction), TEM (transmission electron microscopy), H2-TPD (hydrogen temperature-programmed desorption), XPS (X-ray photoelectron spectroscopy), and in situ FT-IR (Fourier transform–infrared spectroscopy) techniques. H2-TPD and XPS results have shown that electron transfer occurs from Fe to Ni, which is helpful both for the activation of the C=O bond and for the dissociative activation of H2 molecules, also in agreement with the results of the in situ FT-IR spectroscopy. The effect of temperature and reaction time on γ-valerolactone production was also investigated, identifying the best reaction conditions at 200 °C and 180 min, allowing for the complete conversion of levulinic acid and the complete selectivity to γ-valerolactone. Moreover, methanol was identified as an efficient hydrogen donor, if used in combination with the Ni-Fe/SBA-15 catalyst. The obtained results are promising, especially if compared with those obtained with the traditional and more expensive molecular hydrogen and noble-based catalysts.

Catalytic Conversion of Chloromethane to Olefins and Aromatics Over Zeolite Catalysts

We report the tunable conversion of chloromethane to olefins and aromatics using different metal-promoted zeolites as catalysts. Despite SAPO-34 was industrially used as catalysts for methanol to olefins reaction (MTO), the SAPO-34 based zeolites exhibited low activity and short lifetime when using chloromethane as the feed. Higher chloromethane conversion and longer catalyst lifetime were found on H-ZSM-5. The activity and product distribution can be improved by optimizing the reaction temperature and space velocity. Impregnating the H-ZSM-5 zeolite with 1 wt% and 5 wt% metal oxide as promoters significantly enhanced the conversion efficiency and altered the product distribution. The highest aromatics selectivity (38%) was obtained on the H-ZSM-5 zeolite promoted by 5 wt% Ni, whereas on 5 wt% Mg and 5 wt% Mn promoted H-ZSM-5, the aromatics selectivity is merely 5%. Therefore, different modified H-ZSM-5 could be used to convert chloromethane to either aromatics or olefin-heavy products. It was found that the aromatics yield is strongly correlated to the acidity of the H-ZSM-5 zeolite.

Effect of reaction conditions on the lifetime of SAPO-34 catalysts in methanol to olefins process – A review

There is a rising demand for light olefins production to meet the increase in human population, burgeoning transportation network and rapid pace of industrialization. Methanol-to-olefins (MTO) conversion process is the most preferentially-selected route to synthesize olefins even though obtaining the high selectivity remains a challenge to this day. Methanol is industrially-produced via two-steps catalytic routes, viz. gasification of coal to syngas followed by syngas conversion. Due to the abundance of methanol, conversion of methanol to light olefins (ethylene and propylene) or polyolefins (polypropylene and high-density polyethylene) is most desired. Although, natural gas or syngas routes are well established and implemented at industrial level but still direct or indirect transformation of methanol to petrochemicals gained core interest. Significantly, the use of molecular sieves as a catalyst support or directly as a catalyst has been an area of active commercial developments for the past two decades. The engineered molecular sieves possess specialized topographical structure that can efficiently reduce the rate of coke deposition, enhance mass transport and improve the catalytic performance, viz. lifetime and olefins selectivity for methanol to olefins reaction. In this regard, the SAPOs molecular sieves are highly selective for the synthesis of ethylene and propylene. Among them, SAPO-34 molecular sieves exhibit the best performance for the MTO process. The current review highlights the importance of SAPO-34 supported catalysts in terms of lower chain hydrocarbon (C2–C4) selectivity, lower paraffinic and aromatic by-products ratio, catalyst stability, and renderability. In addition, the conditions causing the SAPO-34 catalysts deactivation such as coking, crystal size, water content, pressure metal incorporation, acid site strength, and influence of process conditions on triglyceride-based feeds are also thoroughly reviewed.

Development of copper oxide nanostructures modified indium tin oxide electrode for electrochemical catalytically oxidation of methanol

The design of metal oxide nanomaterials as electrochemical catalysts has received attracted extensive attention. Here, we reported on a simple synthesis of copper oxide nano-electrocatalyst modified indium tin oxide (ITO) based on the hydrothermal method. Then the modified electrode was applied as an effective electrochemical catalyst in direct methanol fuel cell applications. The cyclic voltammetry technique was used to monitor the efficiency of this electrode towards the methanol oxidation and hydrogen evolution reactions. Our results showed that uses of the CuO nano-electrocatalyst modified ITO has a strong electrochemical catalyst toward methanol electrochemical oxidation in acidic and alkaline media within the concentration range from 0.5 mol L−1 to 5 × 10−8 mol L−1. The durability of the developed electrode was investigated that showed long-time stability and the electrode reserve about 96.4% of its efficiency after 100 cycles.

Liquid fuel synthesis from Leonotis nepetifolia seeds through in-situ transesterification method

ABSTRACT In the present research work, biodiesel is produced by in-situ technique using directly the dried seeds of Leonotis nepetifolia. Herein, methanol plays a dual role, as solvent for extraction of oil from the seeds of Leonotis nepetifolia and as a reactant in the process of alcoholysis in presence of KOH catalyst. The influence of seed to methanol molar ratio, reaction time, temperature and catalyst loading is investigated. The result showed that the maximum yield of about 96% is obtained with 1: 393 molar ratios of seed oil to methanol at 60°C, using 3.0% (w/w) KOH catalyst for 100 min. Biodiesel parameters are experimentally evaluated and calculated by using various mathematical models. The experimentally determined and empirically calculated fuel properties of Leonotis nepetifolia methyl esters are found comparable with the existing biodiesels and petro-diesel and satisfy the ASTM and EN limits. This study reveals that the FAMEs produced by the nonedible seeds of Leonotis nepetifolia using in-situ method of transesterification can be used as an alternative to diesel fuel.

Identifying the nature of the active sites in methanol synthesis over Cu/ZnO/Al2O3 catalysts

The heterogeneously catalysed reaction of hydrogen with carbon monoxide and carbon dioxide (syngas) to methanol is nearly 100 years old, and the standard methanol catalyst Cu/ZnO/Al2O3 has been applied for more than 50 years. Still, the nature of the Zn species on the metallic Cu0 particles (interface sites) is heavily debated. Here, we show that these Zn species are not metallic, but have a positively charged nature under industrial methanol synthesis conditions. Our kinetic results are based on a self-built high-pressure pulse unit, which allows us to inject selective reversible poisons into the syngas feed passing through a fixed-bed reactor containing an industrial Cu/ZnO/Al2O3 catalyst under high-pressure conditions. This method allows us to perform surface-sensitive operando investigations as a function of the reaction conditions, demonstrating that the rate of methanol formation is only decreased in CO2-containing syngas mixtures when pulsing NH3 or methylamines as basic probe molecules.

Effect of Sb-Doped SnO2 Nanostructures on Electrocatalytic Performance of a Pt Catalyst for Methanol Oxidation Reaction

In this study, antimony-doped tin oxide (ATO) support materials for a Pt anode catalyst in direct methanol fuel cells were prepared and electrochemically evaluated. When the heating temperature was increased from 300 to 400 °C, the ATO samples exhibited a slightly decreased specific surface area and increased electrical conductivity. In particular, the ATO sample heated at 350 °C in an air atmosphere showed improved electrical conductivity (1.3 S cm−1) with an optimum specific surface area of ~34 m2 g−1. The supported Pt catalysts were synthesized using a polyol process with as-prepared and heated ATO samples and Vulcan XC-72R as supports (denoted as Pt/ATO, Pt/ATO-350, and Pt/C, respectively). In the methanol oxidation reaction (MOR), compared to Pt/C and Pt/ATO, Pt/ATO-350 exhibited the best electrocatalytic activity and stability for MOR, which could be attributed to Pt nanoparticles on the relatively stable oxide support with high electrical conductivity and interaction between the Pt catalyst and the heated ATO support.

Povidone‐Phosphotungstic Acid Hybrid: An Efficient and Environmentally Benign Catalyst for the Synthesis of Quinazolinone Derivatives

AbstractIn this research, a novel strategy for synthesis of quinazolinones has been formulated via one pot condensation of aromatic aldehydes, isatoic anhydride, and aniline by employing prepared povidone‐phosphotungstic acid (PVP‐PWA) hybrid as a novel solid acid heterogenous catalyst in methanol at 80 °C. The synthesized PVP‐PWA is confirmed by FTIR, XRD and studied for TGA, BET plots. The reaction is optimized for different solvents and loading of catalyst. The yields of all quinazolinone derivatives are observed in the range of 78–86%. All the synthesized quinazolinones are investigated by spectral data. The use of ecologically benign catalyst, good atom economy, environmental affordability, and easy work up makes this protocol sustainable.

Optimization of Biodiesel Production from Neem Oil using KOH Supported with Activated Carbon

Fossil fuel reduction and environmental degradations are the two crises that the world threatened by generally and UAE specifically. Biodiesel is a fuel produced through a chemical reaction of animal fat or vegetable oil with alcohol, and consider a potential alternative of diesel engines. However, this reaction needs a catalyst to complete successfully. The current article contains transesterification of neem oil with KOH catalyst supported with activated carbon (KOH/AC). This study included experimental work by applying KOH/AC as an effective catalyst for transesterification of local neem oil. The response surface methodology (RSM) software tool was used in this study to determine the optimal conditions of reaction time, amount of catalyst and ratio of methanol to oil in order to obtain the highest percentage of biodiesel product. The optimal settings obtained were 60 min reaction time, a ratio of oil to methanol 1:6 and 1 wt% of catalyst, which lead to the highest yield of biodiesel (100 wt%). The specific features of biodiesel were checked and compared to ASTM standards.

Adjusting acidity and porosity of Al‐SBA‐15 catalyst for methanol to dimethyl ether reaction

AbstractThe present study aims to conduct a systematic assessment of Al‐SBA‐15 as the aluminum‐substituted mesoporous catalyst for raw methanol dehydration to dimethyl ether (MTD). The catalysts are synthesized by varying the pretreatment variables (pH of the preparation and Si/Al ratio), the posttreatment variable (steaming time), and by the addition of aluminophosphate as the binder. The experimental design and the analysis of the results, especially the relation of characterization results and reactor performance, are performed by the optimal response surface method in Design‐Expert software. The prepared micro‐mesoporous catalyst exhibits an excellent activity, stability, and DME selectivity; therefore, it can be introduced as an efficient catalyst for raw methanol dehydration.

Effects of Desilication in NaOH/Piperidine Medium and Phosphorus Modification on the Catalytic Activity of HZSM-5 Catalyst in Methanol to Propylene Conversion.

Propylene is one of the main petrochemical building blocks applied as a feedstock for various chemical and polymer intermediates. The methanol-to-propylene (MTP) processes are reliable options for propylene production from non-petroleum resources. The highsilica ZSM-5 zeolite is found to be a reliable candidate for the methanol to propylene catalysis. In this study, the mesoporosity was first introduced into a high silica ZSM-5 zeolite via an alkaline treatment by NaOH solution with piperidine to decrease the diffusion limitation, and then the structure of zeolite was stabilized by phosphorus modification to improve the acidic properties and to enhance the catalyst stability. High-silica H-ZSM-5 catalysts (Si/Al = 200) were successfully prepared through microwave-assisted hydrothermal technique in the presence of tetrapropyl ammonium hydroxide (TPAOH) structure-directing agent. The mesoporosity was efficiently introduced into the ZSM-5 crystals via desilication derived from alkaline NaOH/piperidine solution. Then, the acidity of the desilicated ZSM-5 samples was improved using phosphorus modification. The catalysts were subjected to XRD, ICP-OES, FE-SEM, BET, TGA, FT-IR and NH3-TPD analysis. The catalytic performance of the prepared catalysts in the methanol to propylene (MTP) reaction was examined in a fixed-bed reactor at 475 °C, atmospheric pressure and methanol WHSV of 0.9 h-1. The results showed that the alkaline treatment in NaOH/piperidine solution created uniform mesoporosity with no severe damage in the crystal structure. Similarly, phosphorus modification developed the acidic features and led to the optimal catalytic efficiency in terms of the maximum propylene selectivity (49.16%) and P/E ratio (5.97) as well as the catalyst lifetime. The results showed an excellent catalytic activity in terms of 99.21% methanol conversion, good propylene selectivity up to 49.16%, a high ratio of P/E of 5.97 and a low selectivity to C5 + hydrocarbons of 11.57% for ZS-D-PI-P sample.

Characteristics analysis of julifora biodiesel derived from different production methods

The objective of the present work is to compare the biodiesel derived from different methods from a single feed stock and analyse the fuel properties and suitability of an alternative to diesel using locally available vegetable oils. Feedstocks such as animal fats and vegetable oils play a vital role in biodiesel production. The demand for biodiesel production from non-edible oil is growing steadily as there are restrictions on the conversion of edible oils into fuels. Hence, researchers are looking for promising newer sources of non-edible oil which can sustain biodiesel production and use. These attributes have contributed to growing interest on biodiesel production from Prosopis juliflora. This study focuses on a promising newer source of non-edible oil which can sustain biodiesel growth. Prosopis juliflora appears to be an attractive alternate biodiesel feedstock in the near future. Yields more oil per hectare (The average oil yield: 5000 L/ha) compared to other plants. There is no competition for the cultivatable land, as these plants grow on seashores. The fuel properties such as oxidation stability, viscosity, acid value, peroxide value, and thermal stability have been found out for methyl ester of julifora, ethyl ester of julifora and julifora pyrolysis oil as per ASTM standards. The julifora oilis having higher viscosity, density, flash point and lower calorific value. The julifora seed oil is changed into methyl and ethyl ester by using transesterification process with KOH as a catalyst and methanol and ethanol as a solvent. The effect of biodiesel extraction process variables such as oil to methanol ratio, catalyst concentration and reaction time for both the stages are also examined. Methanol or ethanol content are found to be the major influencing process parameter along with the quantity of catalyst addition and reaction time. The methanolysis transesterification showed optimum molar ratio of 3:1 and catalyst concentration of 0.5 wt% at 65 for 90 min with a yield of 93.5%. The ethanolysis transesterification showed maximum yield for ethyl ester of julifora oil is about 87.5% when the oil to ethanol ratio at 3.62 v/v, KOH ratio at 1.35 w/v and at the reaction time of 120 min. The pyrolysis ofjulifora seed is carried out in a semi-batch reactor and 49% bio-oil yield is obtained at 525 °C and 20/min heating rate. Comparison of three biodiesel are made for all the fuel properties and it is found that JOME is the best among three The GC–MS study showed that higher ester content present in the julifora oil and the properties are within the ASTM standards when compared to that of diesel, which makes to use as a fuel in diesel engine.

Cu−Zn Alloy Formation as Unfavored State for Efficient Methanol Catalysts

AbstractThe active sites of Cu/ZnO‐based catalysts, commercially applied for the hydrogenation of CO2 or CO2‐rich synthesis gas, are still subject of current debates. Generally, the discussion is focused on the nature of the interfacial contact between Cu and ZnO, particularly whether it is rather of oxidic (Cu−ZnO) or alloying (Cu−Zn) character. We report on kinetic investigations on a Cu/ZnO : Al high performance catalyst activated at different temperatures. Incrementally increasing temperature under reductive conditions leads also to increased CuZn‐alloy formation, analyzed by in‐situ X‐ray diffraction, in‐situ X‐ray absorption spectroscopy and high resolution transmission electron microscopy. The combination of the catalytic data and the complementary characterization techniques provide valuable insights on the relevant reaction sites for CH3OH formation. Our results highlight the complexity of the interfacial contact with evidence for Cu−ZnO reaction sites and clarify the negative impact of CuZn alloy formation on the nature of the active site.

First Order Kinetics of Biodiesel Synthesis Using Used Frying Oil through Transesterification Reaction

This research aims to study the first-order kinetics of biodiesel production from used frying oil (UFO) through transesterification with methanol. Used frying oil was collected from fried peddlers around the campus of the University of Lampung. Technical grade methanol and NaOH catalyst were purchased from a local chemical supplier. The experiment was carried out with 100 ml of UFO at various combinations of oil to methanol molar ratio (1:4, 1:5, and 1:6), reaction temperatures(30 to 55oC, the ramping temperature of 5o C), and reaction time of 0.25 to 10 minutes. First-order kinetic was employed using 126 data pairs (87.5%). The acquired kinetic model was validated using 18 data sets (12.5%) observed at a reaction time of eight min. Results show that biodiesel yield was increased with reaction time, its molar ratio, and temperature. The maximum return of 78.44% was achieved at 55oC and molar ratio of 1:6. The kinetic analysis obtains the reaction rate constant (k) in the range of 0.045 to 0.130. The value of k increases with the reaction temperature and molar ratio. The analysis also reveals the average activation energy (Ea) of the UFO transesterification reaction with methanol and NaOH catalyst to be 21.59 kJ/mol. First-order kinetic is suitable to predict biodiesel yield from UFO because of low %RMSE (3.39%) and high R2 (0.8454