Catalytic Conversion Of Methanol Research Articles

Hierarchical chabazites synthesized by combining primary and secondary structure-directing agents

Modifying the physical and chemical properties of zeolites by altering the synthesis parameters or using post-synthesis treatments may offer additional properties other than those that make them widely used materials. Remarkably, the chabazite SSZ-13 zeolite possesses a small pore opening that provides access to a large cavity, making the structure suitable for converting methanol to products. Herein, we altered the porosity of SSZ-13 by adding various amounts (2, 4, and 8% in relation to the molar silica content) of dimethyloctadecyl[3-(trimethoxysilyl)propyl] ammonium (DMOAP) into the reaction mixture. The introduction of DMOAP enabled the formation of the pure chabazite structure without affecting the incorporation of aluminum atoms into the zeolite framework. At the same time, its incorporation led to changes in porosity, increasing the external surface area and creating mesopores without affecting the formation of micropores. Concerning the catalytic conversion of methanol into products at low temperatures (210 °C), the additional porosity decreased the methanol to dimethyl ether conversion, indicating that the confinement effect plays an essential role in stabilizing the reaction intermediates. However, at higher temperatures (400 °C), the mesopores played an essential role in the methanol to olefins reaction by increasing the catalyst lifetime and the conversion over time due to improved accessibility of methanol to reaction intermediates confined in the micropores.

Catalytic Conversion of Methanol and Straight-Run Gasoline over Granulated Catalysts with Different Concentrations of H-Form ZSM-5 Zeolite

Catalytic Conversion of Methanol and Straight-Run Gasoline over Granulated Catalysts with Different Concentrations of H-Form ZSM-5 Zeolite

Advances in Methanol Production and Utilization, with Particular Emphasis toward Hydrogen Generation via Membrane Reactor Technology.

Methanol is currently considered one of the most useful chemical products and is a promising building block for obtaining more complex chemical compounds, such as acetic acid, methyl tertiary butyl ether, dimethyl ether, methylamine, etc. Methanol is the simplest alcohol, appearing as a colorless liquid and with a distinctive smell, and can be produced by converting CO2 and H2, with the further benefit of significantly reducing CO2 emissions in the atmosphere. Indeed, methanol synthesis currently represents the second largest source of hydrogen consumption after ammonia production. Furthermore, a wide range of literature is focused on methanol utilization as a convenient energy carrier for hydrogen production via steam and autothermal reforming, partial oxidation, methanol decomposition, or methanol–water electrolysis reactions. Last but not least, methanol supply for direct methanol fuel cells is a well-established technology for power production. The aim of this work is to propose an overview on the commonly used feedstocks (natural gas, CO2, or char/biomass) and methanol production processes (from BASF—Badische Anilin und Soda Fabrik, to ICI—Imperial Chemical Industries process), as well as on membrane reactor technology utilization for generating high grade hydrogen from the catalytic conversion of methanol, reviewing the most updated state of the art in this field.

Monitoring the methanol conversion process in H-ZSM-5 using synchrotron X-ray powder diffraction-mass spectrometry

Using synchrotron X-ray powder diffraction-mass spectrometry in combination with theoretical calculations, we probed the structural changes of adsorbed methanol species in H-ZSM-5 for the first time during catalytic conversion of methanol. Preliminary experimental and computational findings suggested that associative mechanism was the dominant reaction pathway in the early stage of the reaction at 200 °C. Also, we observed a minor contribution from dissociative mechanism of the adsorbed methoxy intermediate species, CH3-Oz (where Oz is a framework oxygen atom), at Brønsted acid sites. It led to methoxy accumulation during the late stage of the reaction, which was postulated to be the initial step that produced ‘hydrocarbon pool’ and ‘coke’ through the formation of CC bonds.

Hydrogen Transfer versus Methylation: On the Genesis of Aromatics Formation in the Methanol-To-Hydrocarbons Reaction over H-ZSM-5

The catalytic conversion of methanol (MeOH) and dimethyl ether (DME) into fuels and chemicals over zeolites (MTH process) is industrially emerging as an alternative route to conventional oil-derived processes. After 40 years of research, a detailed mechanistic understanding of the intricate reaction network is still not fully accomplished. The overall reaction is described as two competitive catalytic cycles, dominated by alkenes and arenes, which are methylated and cracked or dealkylated to form effluent products. Herein, we present the reaction of isobutene with methanol and DME as an efficient tool for measuring the relative formation rates of alkenes and arenes, and we provide detailed mechanistic insight into the hydrogen-transfer reaction. We provide experimental and theoretical evidence that manifest a strong competition of methylation and hydrogen transfer of isobutene by methanol, while methylation is substantially favored by DME. Experiments performed at higher conversion facilitate projection o...

Hydrothermal synthesis of nanosized ZSM-22 and their use in the catalytic conversion of methanol

ZSM-22 zeolite with different crystal lengths was prepared using a modified hydrothermal method. Rotation speed, Si/Al molar ratio and co-solvent have important effects on the crystal size of ZSM-22. The nanosized zeolite samples were characterized by X-ray diffraction, X-ray fluorescence, nitrogen adsorption, scanning electron microscopy, temperature-programmed desorption of ammonia and solid state nuclear magnetic resonance. The catalytic performance of nanosized ZSM-22 was tested using the conversion of methanol. Compared to conventional ZSM-22, the nanosized ZSM-22 zeolite exhibited superior selectivity to ethylene and aromatics and lower selectivity to propylene. Stability against deactivation was clearly shown by the nanosized ZSM-22 zeolite. A higher external surface area and smaller particle size make this nanosized ZSM-22 zeolite attractive for catalytic applications.

Comparative study on the catalytic conversion of methanol and propanal over Ga/ZSM-5

Comparative study on catalytic conversion of methanol and propanal over Ga/ZSM-5 is reported in this paper. A series of Ga/ZSM-5 catalysts were obtained by post modification of ZSM-5 in a mixture of Ga(NO3)3 and NH4HF2. The obtained zeolite samples were subjected to detailed characterization and catalytic evaluation in methanol and propanal conversion reactions. It was found that the post-modification step by Ga(NO3)3 and NH4HF2 had effects both on structure and acidity: (1) decreasing both acid concentration and strength as indicated by NH3-TPD, FT-IR analysis and elemental analysis, (2) selective removing the defective zone of ZSM-5 zeolite, and (3) depositing Ga species on zeolite. The catalyst lifetime in methanol conversion reaction was dramatically improved after post-modification; the longest catalyst lifetime of Ga/ZSM-5-1 observed was 14days. On the contrast, the catalyst lifetime in propanal conversion was kept constantly at 8h over all zeolite samples. The different effects of zeolite after post-modification in methanol and propanal conversion are due to the reactivity difference between methanol and propanal.

Mechanistic study of methanol oxidation by RuIV–oxo complexes

The catalytic conversion of methanol to formaldehyde by three kinds of non-porphyrin Ru complexes, Ru IV O ( TPA ) (TPA = tris(2-pyridylmethyl)amine) (1a), Ru IV O (6- COO - TPA ) (6-COO-TPA = 2-(6-carboxyl-pyridyl)methyl-bis(2-pyridylmethyl)amine) (1b), and Ru IV O ( N4Py ) (N4Py = N,N-bis(2-pyridyl-methyl)-N-bis(2-pyridyl)methylamine) (1c), is discussed by using density functional theory (DFT) calculations. There are two possible reaction pathways for the oxidation of methanol to formaldehyde with respect to the first hydrogen abstraction from the methyl group (path 1) and the hydroxyl group (path 2). Path 1 and path 2 involve the hydroxymethyl radical (• CH 2 OH ) and the methoxyl radical ( CH 3 O •), respectively, as an intermediate. DFT calculations demonstrate that the two pathways are energetically comparable in the reactions by the three Ru IV –oxo complexes. The reactions with 1a and 1c are initiated by the C – H bond dissociation with activation barriers of 22.2 and 21.4 kcal/mol, respectively, while the reaction with 1b is initiated by the O – H bond dissociation with an activation barrier of 18.1 kcal/mol. However, the calculations showed that the rate-determining step is the H -atom abstraction from the CH 3 group of methanol in all the pathways. These results are in good agreement with kinetic analysis of the reactions by the Ru IV –oxo complexes, being useful for considering the mechanism of methanol oxidation.

Use Alloy Quasicrystalline Al62, 2cu25, 3fe12, 5 for Steam Reforming of Methanol

This study shows the good performance of quasicrystal Al62,2Cu25,3Fe12,5 as catalyst in catalytic reactions. The metal catalyst without being leached with acid or base with the stoichiometric composition of dry Al62,2Cu25,3Fe12,5 among the reactions shown to be a partial oxidation occurred , which formation of the products was methanol, methanal + methanoic acid, water and dimethyl ether. For this research used experimental techniques as X-Ray Diffraction-XRD to follow the evolution of the alloy phase, the Scanning Electron Microscopy-SEM allowing the study of surface microstructure, and Transmission Electron Microscopy-TEM studies the morphology of internal phase, and defects quasicrystalline nuclei; tests for the catalytic conversion of methanol and selectivity and products formed from this material used as catalyst. The activity and stability of catalyst quasicrystal for steam reforming of methanol showed sufficient performance compared to other catalysts. The Fe and Cu species highly dispersed in the homogeneous layer quasicrystal catalyst increases the catalytic activity and suppresses the aggregation of Cu particles. We propose that the quasicrystal can be a good catalyst to be used in catalytic steam reforming, with high catalytic activity and excellent thermal stability.

An Oxalic-Acid-Treated Zno/Cuo/Hzsm-5 Catalyst With High Resistance To Coke Formation For The Conversion Of Methanol To Hydrocarbons

The deactivation behavior has been studied over HZSM-5, CuO/HZSM-5, CuO/ZnO/HZSM-5, and oxalic acid treated ZnO/CuO/HZSM-5 catalyst for the catalytic conversion of methanol to gasoline range hydrocarbons. The coke is formed over the catalyst with different time on stream and operating temperatures ranging from 635 K to 698 K. Coke was preferentially formed on strong acidic sites, in the pore channels, and/or on the external surface of the catalysts. The coke catalyst was characterized by BET surface area analysis, temperature-programmed desorption, and temperature-programmed oxidation.

Biomass and Natural Gas to Liquid Transportation Fuels: Process Synthesis, Global Optimization, and Topology Analysis

An optimization-based process synthesis framework is proposed for the thermochemical conversion of biomass and natural gas to liquid fuels (BGTL). Hydrocarbons are produced from synthesis gas either directly via Fischer–Tropsch synthesis or indirectly via catalytic conversion of methanol over ZSM-5. Different conversion technologies are investigated to examine their economic effects on BGTL refineries that produce gasoline, diesel, and kerosene. The process synthesis framework includes simultaneous heat, power, and water integration and utilizes a rigorous deterministic global optimization strategy to mathematically guarantee the minimal cost of the BGTL refineries. The refineries have at least 50% less life-cycle CO2 emissions than a standard petroleum-based refinery. Forty-eight case studies are presented to determine the effect of refinery capacity, liquid fuel composition, and biomass feedstock on the overall cost, topological design, material/energy balances, and life-cycle greenhouse gas emissions. Results suggest that these systems can be economically competitive with petroleum-based processes while achieving the 50% emissions reduction.

Novel Natural Gas to Liquids Processes: Process Synthesis and Global Optimization Strategies

An optimization‐based process synthesis framework is proposed for the conversion of natural gas to liquid transportation fuels. Natural gas conversion technologies including steam reforming, autothermal reforming, partial oxidation to methanol, and oxidative coupling to olefins are compared to determine the most economic processing pathway. Hydrocarbons are produced from Fischer–Tropsch (FT) conversion of syngas, ZSM‐5 catalytic conversion of methanol, or direct natural gas conversion. Multiple FT units with different temperatures, catalyst types, and hydrocarbon effluent compositions are investigated. Gasoline, diesel, and kerosene are generated through upgrading units involving carbon‐number fractionation or ZSM‐5 catalytic conversion. A powerful deterministic global optimization method is introduced to solve the mixed‐integer nonlinear optimization model that includes simultaneous heat, power, and water integration. Twenty‐four case studies are analyzed to determine the effect of refinery capacity, liquid fuel composition, and natural gas conversion technology on the overall system cost, the process material/energy balances, and the life cycle greenhouse gas emissions. © 2013 American Institute of Chemical Engineers AIChE J, 59: 505–531, 2013

Biomass to liquid transportation fuels (BTL) systems: process synthesis and global optimization framework

An optimization-based process synthesis framework is proposed for the thermochemical conversion of biomass to liquid fuels (BTL). Gasification of biomass is used to generate synthesis gas which can be converted to raw hydrocarbons either directly using Fischer–Tropsch synthesis or indirectly using catalytic conversion of methanol over ZSM-5. Multiple technologies are considered for generation of the raw hydrocarbons including (i) six types of Fischer–Tropsch units with different temperatures, catalyst types, and hydrocarbon effluent compositions, (ii) methanol conversion using methanol-to-gasoline, and (iii) methanol conversion using methanol-to-olefins. The hydrocarbons are upgraded into the final liquid fuel products (i.e., gasoline, diesel, and kerosene) using one or more technologies including ZSM-5 catalytic conversion, oligomerization, hydrocracking, isomerization, alkylation, and hydrotreating. A simultaneous heat, power, and water integration is included within the process synthesis framework to directly examine the costs associated with utility production and wastewater treatment with a particular topological design. A rigorous global optimization branch-and-bound strategy is implemented to mathematically guarantee the development of a BTL refinery that is economically and environmentally superior to all competing designs. Twenty-four case studies are investigated to determine the effect of refinery capacity, liquid fuel composition, and biomass feedstock on the overall system cost, the BTL refinery topological design, the process material/energy balances, and the lifecycle greenhouse gas emissions.

Nanostructured chromium–iron mixed oxides: Physicochemical properties and catalytic activity

Chromium–iron bulk mixed oxides were prepared by a sol–gel method using 2-propanol solutions of the nitrate salts of both metals, and propylene oxide as a gelation promoter. Composites with iron content of 10%, 50% and 90% were prepared and compared with the corresponding pure oxides, α-Fe 2O 3 and Cr 2O 3. The mixed oxides were characterized by XRD, TEM, FT-IR, and N 2 adsorption. The XRD analysis indicated the formation of solid solutions of the mixed oxides which exhibited significantly modified textural characteristics, as indicated by N 2 adsorption studies. The characteristics of the mixed oxides were dependent on the Cr/Fe ratio and the composite with 50% Fe, in particular, exhibited significantly higher specific surface areas and porosity than other composites and pure oxides. The catalytic conversion of methanol was studied at 225 °C. The catalytic activities exhibited by the mixed oxides were significantly higher than those of the pure oxides. The yields of the products, dimethyl ether (DME), methyl formate (MF), and CO 2 were dependent on the Cr/Fe ratio.

Novel consecutive 11C- and 12C-methanol adsorption technique for the catalytic active sites characterization of vanadium modified MCM-41

Abstract Novel consecutive 11C- and 12C-methanol adsorption technique was used for the characterization of various vanadium species, which was formed during the solid state modification of MCM-41 with vanadia. Formation of redox and Lewis acidic sites, with dehydrogenation and dehydration activity, was assumed. Their contribution in the catalytic conversion of methanol could be successfully regulated by the pretreatment of the samples in oxidative and reductive medium.

Conversion of methanol on silicoaluminophosphate-formation of hexamethylbenzene and olefins

The catalytic conversion of methanol over new generation molecular sieve silicoaluminophosphate of type 5 (SAPO-5) has been studied. The formation of gaseous, liquid and solid hydrocarbons have been observed

Catalytic Conversion of Methanol by Oxidative Dehydrogenation

This study investigates the effects of addition of oxygen on the oxidative dehydrogenation (ODH) of methanol when a fluorotetrasilicic mica ion-exchanged with palladium (Pd 2+-TSM) was used as the catalyst. The reaction proceeded at a very low temperature in the presence of oxygen, and HCOOCH 3 was obtained at high selectivity. By calculating the equilibrium conversion, it has been shown that substantial ODH took place for HCOOCH 3 production. Consequently, this reaction would make dehydrogenation the dominant reaction at equilibrium. Not all the H dissociated from CH 3OH was converted to H 2O by oxidation. It has been shown that the H 2O was not produced from oxidative dehydrogenation by the direct reaction of CH 3OH and O 2 when an attempt was made to carry out oxidative dehydrogenation using an isotope oxygen trace method in the gas phase. Therefore, when CH 3OH was converted to CO 2 and dehydrogenated to HCOOCH 3, the C-O bonds were not dissociated.

Surface nature of nanoparticle gold/iron oxide aerogel catalysts

The aerogel catalysts investigated are constituted by two chemically different nanoparticle systems consisting of the gold phase and the iron oxide support. High-resolution transmission electronic microscopy (HRTEM) showed an increased surface roughness for aerogel particles with higher gold loading. X-ray photoelectron spectroscopy (XPS) revealed increases in the surface coverage of hydroxyl groups and the Fe 2+/Fe 3+ ratio due to the addition of gold, and showed the transition of gold from oxidized to metallic states due to calcination. In the presence of gold species, the Fe 3+ satellite structure in XPS was not produced. The crystallinity of maghemite as the support was found quite stable with respect to gold addition and thermal treatment. The aerogels were evaluated for methanol oxidation carried out in an ambient flow reactor. The oxidation activity enhanced with decreasing catalyst pretreatment temperatures and with increasing gold loadings up to 5 wt%. A wide selectivity pattern formed between dimethyl ether and carbon dioxide products. The size of gold particles and the status of surface gold species played a crucial role in the catalytic conversion of methanol. The oxidized gold was more active than the metallic gold towards the total combustion to carbon dioxide. The surface nature has been proven to transform from strong Lewis acidic to high basic characters due to the formation of reactive hydroxyl groups near by the gold sites.

Production of Formaldehyde by Catalytic Conversion of Methanol

Production of Formaldehyde by Catalytic Conversion of Methanol

Effect of Catalytic Alcohol Conversion on the Mechanical Strength of Porous ZrO2 and ZrO2 + Y2O3 Materials

The surface and bulk properties of ZrO2 and ZrO2 + Y2O3 powder compacts are studied by x-ray diffraction, x-ray electron spectroscopy, electron spin resonance, and Raman scattering spectroscopy. Heat treatment in air at 450–800°C and catalytic conversion of methanol and ethanol on the surface of the compacts are found to have a significant effect on their mechanical strength. The results offer some insight into the nature of surface diffusion, which reduces the area of intergranular contacts, thereby raising the mechanical strength of the material, and provide indirect evidence that similar molecular mechanisms underlie the strengthening of metal and oxide powder compacts by heat treatment and catalytic reactions.