Methanol Conversion Research Articles

Ecologic and Economic Evaluation of Combined Methanol Synthesis from CO2 and Biotechnological Upgrading to Value Products. Part 1: Environmental Impact

AbstractThe conversion of waste biomass with green hydrogen into methanol and subsequent biotechnological conversion of this into valuable materials could be a promising value chain. Starting from biogenic CO2 and green H2, methanol is produced in a first process path. This is then split into two separate process paths: methanol is used (i) in a biotechnological process with genetically modified bacteria to produce crotonic acid and (ii) to produce biomass protein. To evaluate the ecologically and economic benefits of both biological processes to the conventional production routes, first life cycle assessment and techno‐economic assessment of biotechnological and chemical processes are accomplished. For this, a baseline scenario and several scenarios are calculated to investigate the influence of various parameters on environmental impact and economic efficiency. The results also identify the processes that are mainly responsible for costs and environmental impact, as well as the material, energy and waste flows, and process parameters that cause them. From this, measures and conditions for improving economic efficiency and environmental impact are derived.

Circular Catalytic Hydrogen/Methanol Plate Burner with Stackable Clover Channels Supporting Rapid Start-Up and Stable Operation for Highly Efficient Reformer System

This study proposes a platinum catalytic plate burner with a clover-shaped microchannel design to reduce the maximum temperature difference (ΔTmax) and improve long-term hydrogen production (HP) performance in an autothermal methanol steam reforming (ATMSR) microreactor. The burner integrates with a plate reformer within a cylindrical adiabatic container. By optimizing catalyst arrangement and incorporating a parallel clover-type microchannel design, thermal gradients inside the burner are minimized, enabling better operation conditions for the plate reformer. Three Pt catalyst gradients (50/50, 40/60, and 30/70) reduce ΔTmax from 48.2 °C and 38.3 °C to 25.8 °C. Additionally, the startup time to 250 °C is reduced from 35, 25, and 14 min, respectively. The integration of the plate burner and reformer with the 30/70 catalyst type shows a higher methanol conversion rate (98%), better hydrogen yield, and lower CO selectivity compared to the 50/50 type. Long-term testing for 30 h shows a low catalyst degradation rate, making it suitable for sustained operation.

Exploring the potential of perovskite LaBO3 (B = Co, Fe, Cu, Al) as an efficient and durable hydrogen production catalyst for methanol steam reforming: Experimental and DFT studies

In this study, LaBO3 (B = Co, Fe, Cu, Al) perovskite catalysts were introduced for Methanol Steam Reforming (MSR). Results showed that LaCoO3 displayed a 100 % methanol conversion efficiency and a notable hydrogen production rate of 7.86 mol/min/gcat, maintaining stability for more than 40 h at 600 °C. Theoretical computations indicate that the CH3O dehydrogenation to CH2O (a rate-determining process) occurs without methanol breaking down into methane and coke, thus ensuring its long-lasting stability. The fusion of experimental findings with theoretical forecasts underscores the prowess of LaCoO3 as a remarkable perovskite catalyst and its extensive possibilities in the realm of methanol hydrogen generation.

Electrochemical Oxidation of Methanol to Formate with High Yield and Conversion for Paired Electrosynthesis Processes

Anthropogenic climate change driven by greenhouse gas emissions from fossil-based processes highlights the importance for alternative synthesis pathways for platform chemicals. Electrochemical CO2 reduction and hydrogen evolution offer sustainable options for platform chemical synthesis. However, pairing of the reduction reactions is often done with the oxygen evolution reaction (OER) at the anode, which consumes a major share of the total energy demand without contributing to value creation. In contrast, the partial methanol oxidation reaction (MOR) is an energy-efficient alternative to OER, yielding formate as a valuable product.While MOR is often studied in terms of high Faraday efficiencies, little attention is paid to conversion and yield regarding paired processes. In this work, we investigate the oxidation of methanol to formate and examine the influence of different reaction parameters including current density, temperature, flow rate, and electrolyte to increase the yield and conversion towards industrially relevant levels.Hierarchically structured CuO foam electrodes (5x5cm²) were employed as the MOR anode. To this end, electrochemically deposited dendrites on a fine-pored copper foam were subsequently oxidized to provide a large surface area for the MOR. The electrode was positioned within an electrochemical cell to ensure continuous flow through the foam, thereby utilizing the high electrode surface area. A defined electrolyte volume was recirculated through the cell and product analysis was conducted via Fourier Transformation Infrared Spectroscopy (FTIR) for calculation of methanol conversion and Faradaic efficiency (FE) to formate.Increasing the current density from 50 to 200 mA/cm² led to a decrease in the initial FE and final conversion from 92% to 76% and 88% to 85%, respectively. Conversely, elevating temperature from 25 °C to 55 °C increased FE from 83% to 93% and conversion from 74% to 83%. A raise of the electrolyte flow rate from 25 to 100 mL/min showed no impact on FE and conversion. Change in electrolyte composition revealed a negative correlation between KOH concentration and FE, decreasing from 91% to 64% with a rise from 1 M to 4 M KOH. Conversely, increasing MeOH concentration from 0.5 M to 2 M enhanced FE from 71% to 92%.Finally, MOR was paired with alkaline hydrogen evolution reaction (HER) using two different membrane types, either a bipolar membrane (BPM) or an anion exchange membrane (AEM). Operating at optimized conditions resulting from the previous investigations (100 mA/cm², 55 °C, 50 mL/min, 2 M KOH, and 1 M MeOH), both setups achieved over 90% methanol conversion before the FE dropped to zero. The BPM approach exhibited slightly higher initial FE (over 95%) compared to the AEM approach (over 86%), with respective yields of 70% and 68% at anodic potentials of 1.49 V and 1.33 V.This study provides valuable insights into the influence of reaction conditions on methanol oxidation to formate regarding industrially relevant conversions. Furthermore, the study successfully demonstrates two concepts of pairing HER as the value-adding cathode reaction with MOR as an additional value-adding anode reaction for future applications.

Sustainable Electrochemical Synthesis of Dry Formaldehyde from Anhydrous Methanol

Facing climate change, we switch our energy sources from fossil fuels to renewable electricity. This often requires the electrification of industrial processes that have so far been thermally driven. One of these large-scale processes is the methanol oxidation to formaldehyde with a yearly production of ca 45 MT worldwide. Formaldehyde is a versatile C1 building block that is used, for example, in the syntheses of polymers, resins and complex organic molecules. Conventionally, it is obtained by methanol oxidation with air to formaldehyde and water.[1] Attempts to electrify this process have been mainly studied in aqueous electrolytes, where a reasonable formaldehyde production was proven on the lab scale, but these reactions still struggle with the subsequent oxidation to CO or CO2 due to the presence of water.[2] Furthermore, for many products, formaldehyde is required in its dry form, such that energy intensive drying processes are needed subsequently.[3] The first promising results for the electrochemical conversion of anhydrous methanol to formaldehyde on platinum electrodes were obtained in the 1960s. Faraday efficiencies of up to 75% were reported at low current densities (~3 mA cm-2) for batch systems under ice-bath cooling.[4] In this work, we report the successful oxidation of anhydrous methanol to formaldehyde and hydrogen.[5] We not only verify the initial reports, now with modern reference electrodes and reliable measurement procedures, but also make the next step in the scaling of the process. Based on the reported setup, we changed to a non-aqueous reference electrode and worked at room temperature. Chronoamperometries over 2 hours yielded Faraday efficiencies of up to 78% at current densities of up to 10 mA cm-2, which already surpassed the reported results. To scale the reaction up, we switched from an H-cell to a flow reactor with a surface area of 12 cm2 and applied current densities of up to 100 mA cm-2, i.e. a total of 1.2 A. This scaled-up system performed even better and reached Faraday efficiencies of up to 91% (Figure 1) and formaldehyde concentrations of up to 7.5 g L-1 in 30 minutes. Studying the impact of various reaction parameters, like current density, flow rate and electrolyte concentration, we furthermore reveal a fascinating potential dependent reactivity for the oxidation of anhydrous methanol. Our experiments indicate a vastly different behavior for the two mechanisms regarding mass transport and electrolyte viscosity and basicity. Our results proof that the electrochemical synthesis of formaldehyde is selective and able to produce significant amounts of formaldehyde. The whole synthesis can be carried out anhydrously, which avoids energy intensive water removal for the industrial synthesis of resins, glues and polymers, and further recycles H2 from methanol as the cathode product. The robust behavior at elevated current densities is vital for further scale up and shows potential for industrial application.

Template‐Free ZSM‐5 Synthesis Using Bio‐Sourced Waste Materials

AbstractHydrochars synthesized from lignocellulosic waste (rice husk and exhausted black wattle bark) through hydrothermal carbonization were used as pore‐forming agents in template‐free ZSM‐5 zeolites. The influence of the amount of hydrochar added to the zeolite synthesis and the nature of the hydrochar on the zeolite features and catalytic performance were evaluated. It was observed that the hydrochar had little influence on the textural properties and Si/Al ratio of the zeolites. However, the hydrochar was able to enhance the number of Brønsted acid sites in the zeolite and led to different ZSM‐5 crystal morphologies (french‐fries and twinned crystals). The latter zeolites exhibited a higher cracking activity of n‐hexane, favoring the formation of light olefins, due to the presence of Brønsted sites and suitable shape selectivity. In contrast, they exhibited a lower conversion of methanol into hydrocarbons (MTH), favoring the formation of dimethylether due to rapid deactivation. The hydrochars acted therefore, in the synthesis of template‐free ZSM‐5 zeolite, as a mean to both raise the acidity and control the aggregation of zeolite crystals.

Highly Efficient and Selective Synthesis of Renewable Isoprene Over Mo-Fe-O and MgO/Mg(OH)2 Composite Catalysts.

Synthesis of renewable isoprene continues to attract significant interest, yet catalysts still need improvement for industrial applications. We report herein an efficient and novel Prins tandem approach for highly selective production of isoprene from bio-based methanol and isobutene over Mo-Fe-O and MgO/Mg(OH)2 acid-base bifunctional catalysts. Hydration decreases the number of strong basic sites O2- ions and increases OH groups over MgO, thus improving the isoprene selectivity. Basic OH on Mg(OH)2 promotes the Prins condensation of formaldehyde and isobutene, while acidic OH promotes dehydration of isoprenol to isoprene. Suitable contents and proportions of basic and acidic OH groups over Mg(OH)2 increase isoprene selectivity and methanol conversion to 90 and 92 % on the Mo-Fe-O+Mg(OH)2 composite catalysts, respectively. It exhibits good recycling stability, with isoprene selectivity remaining 90 % after five successive regenerations. DFT calculations reveal OH groups formed after hydration reduce the energy barrier of the H transfer step, thereby promoting the overall reaction.

Constructing hollow bivalve nanocomposite ZSM-5 with inverse Al zoned distribution to strengthen the stepwise conversion of methanol to aromatics

ZSM-5 catalyzed methanol aromatization was one of the alternative routes for petroleum aromatics production, but its performance was limited to the unreasonable acid distribution and pore structure of ZSM-5. Herein, a series of dual-ZSM-5 nanocomposite catalysts with inverse Al zoned distribution have been constructed by seed growth-desiliconization-recrystallization strategy. It was found that the solid ZSM-5 with decreased Al gradient distribution promoted the conversion of light hydrocarbons intermediates, which obtained high aromatic selectivity of 23.7 % even at a low acid density. However, the diffusion of aromatics generated in interior area was inhibited by external shell and tended to be deep alkylated and transform into coke precursors, resulting in poor catalytic lifetime of 37 h. Desiliconization and recrystallization in Na+-containing alkali liquor over a composite ZSM-5 with conventional Al zoned distribution could realize the reversal of Al zoned distribution. Not only that, a huge internal cavity and a large amount of interlayer cavity were generated, which promoted the diffusion of olefin intermediates and aromatic products. Because of this, the catalytic lifetime of hollow bivalve ZSM-5 catalyst signally improved to 58 h. Based on this, directly stacking the high Si/Al ratio ZSM-5 crystals on low high Si/Al ratio core could signally improve anti-coking performance due to the abundant surface accumulation mesoporous, and the lifetime further prolonged to 99 h with the aromatic selectivity of 24.0 %. This work could provide a reference for the design of ZSM-5 catalyst with special composite structure and Al zoned distribution for stepwise aromatization of methanol with high stability.

Revealing Active Sites and Reaction Pathways in Direct Oxidation of Methane over Fe-Containing CHA Zeolites Affected by the Al Arrangement.

Fe-containing zeolites are effective catalysts in converting the greenhouse gases CH4 and N2O into valuable chemicals. However, the activities of Fe-containing zeolites in methane conversion and N2O decomposition are frequently conflated, and the activities of different Fe species are still controversial. Herein, Fe-containing aluminosilicate CHA zeolites with Fe species at different spatial distances affected by the arrangement of framework Al atoms were synthesized in a one-pot manner in the presence or absence of Na. The arrangement of framework Al atoms was identified by 27Al and 29Si MAS NMR spectra and thermogravimetry-differential thermal analysis (TG-DTA) curves. Ultraviolet (UV)-vis, X-ray absorption spectroscopy (XAS), and NO adsorption fourier transform infrared spectroscopy (FTIR) spectra were adopted to analyze Fe speciation. The higher proportion of Fe species in the 6 MR of Fe-CHA zeolites in the presence of Na was confirmed by the NO adsorption FTIR spectrum. The activities of proximal and distant Fe sites in reactions including direct oxidation of methane to methanol, methanol to hydrocarbon, and N2O decomposition were compared at different temperatures to provide the corresponding active sites and reaction pathways. The distant, isolated Fe and isolated proton were more active in the direct oxidation of methane to methanol and tandem conversion of methanol to hydrocarbon reactions than the proximal, isolated Fe and paired protons, respectively. Additionally, proximal, isolated Fe sites afforded higher activity in N2O decomposition. These findings guide the design of highly active catalysts in methane oxidation, methanol to hydrocarbon, and N2O decomposition reactions, addressing energy and environmental concerns.

Optimized Carbon Coupling for Enhanced Ethylene Production via a Unique Single-Atom-Substrate Synergy Mechanism within Photocatalytic Processes.

The utilization of solar-driven technologies for the direct conversion of methanol (CH3OH) into two or multi-carbon compounds through controlled carbon-carbon (C-C) coupling is an appealing yet challenging objective. In this study, we successfully demonstrate the photocatalytic CH3OH coupling to ethylene (C2H4), a valuable chemical raw material, by employing a carbon nitride-based catalyst. Specifically, we modify the layered polymer carbon nitride (PCN) photocatalyst through the incorporation of Au single atoms (Au1/PCN) using a chemical-scissors method. The synergistic effect between the PCN substrate and the Au single atoms reduces the potential barrier associated with C-C coupling, thereby enhancing the efficiency of CH3OH reforming to C2H4. This investigation not only reveals a novel pathway for C2H4 production via CH3OH reforming but also provides fresh insights into the possibilities of C-C coupling.

Combination of Hollow Capsule Structure and Zn Uniform Load for the Conversion of Methanol to Aromatics over Zn/ZSM-5 Zeolites.

As an important nonoil route for acquiring aromatics, the highly efficient conversion of methanol to aromatics over Zn/ZSM-5 zeolites remains an ongoing challenge. In this work, we developed a uniform loading approach of zinc and further combined it with a hollow capsule structure to design the high-performance Zn/ZSM-5 catalyst. The electrostatic assembly among EDTA3-, n-butylamine+ and negative silica-alumina gel gave rise to an "Inorganic-Organic Hybrid Sphere" in form of Na(l+m+n+3x)-(y+z)·{[(SiO)4Al-]l/(SiO-)m(n-butylamine+)y(EDTA3-)x(n-butylamine+)z(SiO-)n, which further transformed into mesoporous aluminosilicates sphere (MASS) through calcination. The characteristic of abundant mesopore guaranteed MASS fantastic ability to evenly incorporate Zn ingredient inside, and the resultant Zn/MASS further served as a "hard template" for the direct synthesis of Hollow Zn/ZSM-5 capsules, rather than after impregnation. When tested in the methanol-to-aromatics (MTA) process, the direct synthesis method not only facilitated the homogeneous dispersion of the Zn ingredient, but also benefited for the generation of more (ZnOH)+ sites and strengthened their synergism with zeolite acid for the superior aromatics selectivity (50.63%). Meanwhile, the hollow capsule structure increased the contact time of MTA intermediate products with the Zn/ZSM-5 shell, and it increased the coke-admitting capacity and suppressed the coke rate, which maintained quite an excellent stability (131 h). Therefore, the above combination of hollow capsule structure and uniform load of Zn ingredient brings forward a wide prospect to develop zeolite materials with excellent properties in catalysis.

Can Metal Promotion of SAPO-34 Genuinely Improve Its Catalytic Performance in Methanol Conversion to Light Olefins Reaction?

To genuinely assess the effect of secondary metal promotion on improving the SAPO-34 catalytic performance in MTO reaction, a broad spectrum of metals from different groups of the periodic table (alkali and alkaline earth metals, transition metals, rare earth metals, and basic metals) were investigated. Metals were added through a direct incorporation route with Me/Al2O3 molar ratio of 0.05. Some metals seamlessly incorporated into the SAPO-34 framework and replaced the Si and Al atoms, while others partially merged or even failed to be combined with SAPO and emerged as amorphous phases. Although, in some cases, the surface area of the metal-promoted samples increased due to enhanced nucleation rate and smaller particle formation, the majority of the promoted samples suffered from a severe loss in crystallinity that resulted in inferior catalytic performance. It was also illustrated that hydrogen co-feeding with methanol (H2/MeOH molar ratio of 1.5) at ambient pressure could extend the catalyst lifetime by 27 % due to hydrogenation and cracking of the coke species and improve the light olefins selectivity.

Oxidative Steam Reforming of Methanol over Cu-Based Catalysts

Several Cu and Ni-based catalysts were synthetized over Ce-based supports, either pure or mixed with different amounts of alumina (1:2 and 1:3 mol/mol). Different metal loadings (10–40 wt%) and preparation methods (wet impregnation, co-precipitation, and flame-spray pyrolysis—FSP) were compared for the oxidative steam reforming of methanol. Characterization of the catalysts has been performed, e.g., through XRD, BET, XPS, TPR, SEM, and EDX analyses. All the catalysts have been tested in a bench-scale continuous setup. The hydrogen yield and methanol conversion obtained have been correlated with the operating conditions, metal content, crystallinity of the catalyst particles, total surface area, and with the interaction of the metal with the support. A Cu loading of 20% wt/wt was optimal, while the presence of alumina was not beneficial, decreasing catalyst activity at low temperatures compared with catalysts supported on pure CeO2. Ni-based catalysts were a possible alternative, but the activity towards the methanation reaction at relatively high temperatures decreased inevitably the hydrogen yield. Durability and deactivation tests showed that the best-performing catalyst, 20% wt. Cu/CeO2 prepared through coprecipitation was stable for a long period of time. Full methanol conversion was achieved at 280 °C, and the highest yield of H2 was ca. 80% at 340 °C, higher than the literature data.

Ambient Air-Synthesized CsPbBr3 Nanocrystals Coupled with TiO2 Film as an Efficient Hybrid Photoanode for Photoelectrochemical Methanol-to-Formaldehyde Conversion.

Due to its exceptional optoelectronic properties in the visible spectrum, cesium lead bromide (CsPbBr3) perovskite has attracted considerable attention in solar-driven organic transformations via photoelectrochemical (PEC) cells. However, the performance of the devices is adversely affected by electron-hole recombination occurring between a transparent conductive substrate, such as fluorine-doped tin dioxide (FTO), and a perovskite layer. Herein, to mitigate this issue, a compact layer of titanium dioxide (TiO2) was employed as both an electron transport layer and a hole blocking layer to diminish charge recombination while facilitating electron transfer in such perovskite material. At the oxidation peak potential of 0.70 V vs Ag/AgNO3, a hybrid photoanode of CsPbBr3/TiO2/FTO exhibited a significant increase in photocurrent density, from 15 to 41 μA/cm2, compared to a configuration without a TiO2 layer. Furthermore, the introduction of methanol as a hole scavenger in the PEC system using the hybrid photoanode facilitated the separation of electron-hole pairs, which led to an enhanced photocurrent density of 60 μA/cm2 and promoted the production of formaldehyde. High-performance liquid chromatography (HPLC) confirmed the generation of formaldehyde at a concentration of 26.69 μM with a Faradaic efficiency of 92% under an applied potential of 0.50 V vs Ag/AgNO3 for 60 min of PEC reaction. In addition to the enhanced PEC performance achieved from this hybrid photoanode, CsPbBr3 nanocrystals (NCs) in this work were synthesized by the modified one-pot method under ambient air, where highly uniform and high-purity NCs were obtained. This work signifies the groundbreaking exploration of CsPbBr3 NCs with TiO2 as a photoelectrode material in the organic-based PEC cells, which efficiently improved the interfacial charge transfer within the photoanode for the conversion of methanol to formaldehyde, marking a significant advancement in the field.

Constructing Hierarchical Zeolites with Highly Complete Framework via Controlled Desilication

AbstractDesilication in alkaline medium has been widely used in construction of hierarchical zeolites for industrially relevant catalytic processes. The built of hierarchy in zeolites, especially with low aluminum stability or high Si/Al ratio, often suffers from uncontrolled destruction of zeolitic framework, accompanied by a significant loss of microporous domains and intrinsic acidity after desilication. Here, we report a novel and simple methodology for preparation of hierarchical zeolites with highly complete framework and minimum sacrifice of microporosity and acidity. The pre‐impregnated amines in zeolite micropores act as inner pore‐directing agents (iPDAs), largely protecting the zeolitic framework and moderating the silicon extraction during the alkaline treatment. The resulting hierarchical zeolites exhibit high crystallinity, tunable hierarchy, stable framework, and well‐preserved acidity, endowing them with significantly improved mass transport properties and enhanced activities in catalytic conversion of methanol or furfural.

Constructing Hierarchical Zeolites with Highly Complete Framework via Controlled Desilication.

Desilication in alkaline medium has been widely used in construction of hierarchical zeolites for industrially relevant catalytic processes. The built of hierarchy in zeolites, especially with low aluminum stability or high Si/Al ratio, often suffers from uncontrolled destruction of zeolitic framework, accompanied by a significant loss of microporous domains and intrinsic acidity after desilication. Here, we report a novel and simple methodology for preparation of hierarchical zeolites with highly complete framework and minimum sacrifice of microporosity and acidity. The pre-impregnated amines in zeolite micropores act as inner pore-directing agents (iPDAs), largely protecting the zeolitic framework and moderating the silicon extraction during the alkaline treatment. The resulting hierarchical zeolites exhibit high crystallinity, tunable hierarchy, stable framework, and well-preserved acidity, endowing them with significantly improved mass transport properties and enhanced activities in catalytic conversion of methanol or furfural.

Development and performance evaluation of a novel solar mid-and-low temperature receiver/reactor with packed metal foam

Solar-driven hydrogen production from methanol decomposition (MD) is an important method of storing solar energy as clean fuels and improving the solar energy utilization efficiency. Catalyst preparation is one of the key steps, but conventional Cu-ZnO-Al2O3 particle catalysts lead to uneven reactor temperature, reducing the efficient conversion of solar energy into fuels. To alleviate this challenge, a monolithic catalyst utilizing packed foamy copper as a carrier is developed with exceptional thermal and mass transfer properties. The experimental results validate its excellent performance in hydrogen production using MD. The absolute conversion increases by an average of 12.11 % at 250 °C and further by 14.43 % at 270 °C compared to the particle catalyst. Based on these findings, a novel solar reactor is proposed, and a multi-field coupling model is built. The comparative results verify the performance advantage of the developed solar thermochemical receiver/reactor with packed metal foam-based catalyst. It maintains high conversion rates and solar-to-fuel energy efficiency, while alleviating overheating problems caused by traditional particle catalysts. Under the design conditions, the new reactor significantly improves the absolute conversion of methanol and the energy efficiency of solar-to-fuel conversion by 4.57 % and 3.00 %, respectively, resulting in 92.64 % and 67.56 %. This study provides a theoretical basis and technical solution for more stable and efficient use of mid-and-low temperature solar energy.

Kinetic Characterization of Pt/Al2O3 Catalyst for Hydrogen Production via Methanol Aqueous-Phase Reforming

Compared to steam reforming, methanol aqueous-phase reforming (APR) converts methanol to hydrogen and carbon dioxide at lower temperatures, but also displays lower conversion rates. Herein, methanol APR is studied over the active Pt/Al2O3 catalyst under different operating conditions. Studies were conducted at different temperatures, pressures, methanol mass fractions, and residence times. APR performance was evaluated in terms of methanol conversion, hydrogen production rate, hydrogen selectivity, and by-product formation. The results revealed that an increase in operating pressure and methanol mass fraction had an adverse effect on the APR performance. Conversely, it was found that hydrogen selectivity was unaffected by the operating pressure and residence time for the methanol feed mass fraction of 5%. For the methanol feed mass fraction of 55%, hydrogen selectivity was improved by operating pressure and residence time. The alumina support phase change to boehmite as well as sintering and leaching of the catalytic particles were observed during catalyst stability experiments. Additionally, a comparison between methanol steam reforming (MSR) and APR was also performed.

Cobalt Tetracationic 3,4-Pyridinoporphyrazine for Direct CO2 to Methanol Conversion Escaping the CO Intermediate Pathway.

Molecular catalysts offer a unique opportunity to implement different chemical functionalities to steer the efficiency and selectivity for the CO2 reduction for instance. Metalloporphyrins and metallophthalocyanines are under high scrutiny since their most classic derivatives the tetraphenylporphyrin (TPP) and parent phthalocyanine (Pc), have been used as the molecular platform to install, hydrogen bonds donors, proton relays, cationic fragments, incorporation in MOFs and COFs, to enhance the catalytic power of these catalysts. Herein, we examine the electrocatalytic properties of the tetramethyl cobalt (II) tetrapyridinoporphyrazine (CoTmTPyPz) for the reduction of CO2 in heterogeneous medium when adsorbed on carbon nanotubes (CNT) at a carbon paper (CP) electrode. Unlike reported electrocatalysis with cobalt based phthalocyanine where CO was advocated as the two electron and two protons reduced intermediate on the way to the formation of methanol, we found here that CoTmTPyPz does not reduce CO to methanol. Henceforth, ruling out a mechanistic pathway where CO is a reaction intermediate.

Экономическая эффективность перспективного авиационного топлива

Promising aviation fuel methanol for aircraft of various purposes is considered: unmanned aircraft, transport and passenger aviation. An economic analysis of methanol fuel application has been carried out. It has been shown that methanol has undeniable advantages, such as the cost of production, infrastructure costs, and the efficiency of a methanol propulsion system. The losses during the use of methanol from its production to the conversion of methanol into aerodynamic force are considered. It has been revealed that in modern economic conditions methanol has a number of undeniable advantages. The conclusion is made about the economic efficiency of using methanol as an aviation fuel.