Showing papers on "Methanol published in 2012"
TL;DR: This Review presents several commercial MTH projects that have recently been realized, and also fundamental research into the synthesis of microporous materials for the targeted variation of selectivity and lifetime of the catalysts.
Abstract: Liquid hydrocarbon fuels play an essential part in the global energy chain, owing to their high energy density and easy transportability. Olefins play a similar role in the production of consumer goods. In a post-oil society, fuel and olefin production will rely on alternative carbon sources, such as biomass, coal, natural gas, and CO(2). The methanol-to-hydrocarbons (MTH) process is a key step in such routes, and can be tuned into production of gasoline-rich (methanol to gasoline; MTG) or olefin-rich (methanol to olefins; MTO) product mixtures by proper choice of catalyst and reaction conditions. This Review presents several commercial MTH projects that have recently been realized, and also fundamental research into the synthesis of microporous materials for the targeted variation of selectivity and lifetime of the catalysts.
1,379 citations
TL;DR: In this article, the authors proposed the use of carbon dioxide as a feedstock for the carboxylation of four types of reactive substrates: epoxides, alcohols, nitrogen and hydrogen.
525 citations
TL;DR: Iron copper zeolite (Fe-Cu-ZSM-5) with aqueous hydrogen peroxide is active for the selective oxidation of methane to methanol giving meethanol selectivity and 10 % conversion in a closed catalytic cycle (see scheme).
Abstract: Iron copper zeolite (Fe-Cu-ZSM-5) with aqueous hydrogen peroxide is active for the selective oxidation of methane to methanol. Iron is involved in the activation of the carbon–hydrogen bond, while copper allows methanol to form as the major product. The catalyst is stable, re-usable and activates methane giving >90 % methanol selectivity and 10 % conversion in a closed catalytic cycle (see scheme).
478 citations
449 citations
TL;DR: Snail shell is a novel source for the production of heterogeneous base catalyst that can be successfully utilized for synthesis of biodiesel of high purity and the fuel properties of the biodiesel were found to be within the specifications.
346 citations
TL;DR: In this paper, several copper based catalysts were prepared, characterized and evaluated for the hydrogenation of levulinic acid and its methyl ester in methanol and water respectively.
310 citations
TL;DR: Two birds with one stone: the simultaneous production of two important bulk chemicals from CO(2) and ethylene oxide has been achieved under mild conditions by the highly efficient homogeneous catalytic hydrogenation of ethylene carbonate in the presence of a (PNP-Ru(II) catalyst.
Abstract: Two birds with one stone: the simultaneous production of two important bulk chemicals, methanol and ethylene glycol, from CO(2) and ethylene oxide has been achieved under mild conditions by the highly efficient homogeneous catalytic hydrogenation of ethylene carbonate in the presence of a (PNP)Ru(II) catalyst.
304 citations
TL;DR: The aim is to design a system that could supplant commercial processes and postulate that there could be three distinct classes of catalyst/oxidant/solvent systems, based on the continuum base- or acid-modulated (BAM) catalysis.
Abstract: In an effort to augment or displace petroleum as a source of liquid fuels and chemicals, researchers are seeking lower cost technologies that convert natural gas (largely methane) to products such as methanol. Current methane to methanol technologies based on highly optimized, indirect, high-temperature chemistry (>800 °C) are prohibitively expensive. A new generation of catalysts is needed to rapidly convert methane and O2 (ideally as air) directly to methanol (or other liquid hydrocarbons) at lower temperatures (∼250 °C) and with high selectivity.Our approach is based on the reaction between CH bonds of hydrocarbons (RH) and transition metal complexes, LnM–X, to generate activated LnM–R intermediates while avoiding the formation of free radicals or carbocations. We have focused on the incorporation of this reaction into catalytic cycles by integrating the activation of the CH bond with the functionalization of LnM–R to generate the desired product and regenerate the LnM–X complex. To avoid free-radical ...
290 citations
TL;DR: In this article, the authors describe and critically analyze the literature dealing with the use of supported gold catalysts in the catalytic deep oxidation of volatile organic compounds (VOCs).
Abstract: This review intends to describe and critically analyze the growing literature dealing with the use of supported gold catalysts in the catalytic deep oxidation of volatile organic compounds (VOC). Among the wide family of VOC, attention has been given to the oxidation of saturated (methane, ethane, propane, isobutane, n-hexane) and unsaturated (acetylene, ethylene, propene) aliphatic compounds, aromatic hydrocarbons (benzene, toluene, xylenes, naphthalene), alcohols (methanol, ethanol, n- and iso-propanol), aldehydes (formaldehyde), ketones (acetone), esters (ethylacetate). Moreover, the oxidation of chlorinated VOC (dichloromethane, o-dichlorobenzene, o-chlorobenzene), as well as of nitrogen- (trimethylamine) and sulphur-containing (dimethyldisulfide) compounds has been addressed. The reaction mechanism and the influence of different factors, such as the nature and the properties of the support, the Au particle size and shape, the electronic state of gold, the preparation method and the pretreatment conditions of catalysts, the nature and the concentration of the organic molecule, are discussed in detail.
286 citations
TL;DR: In this paper, the active sites and structure-activity relationships for methanol synthesis from a stoichiometric mixture of CO2 and H2 were investigated for a series of coprecipitated Cu-based catalysts with temperature-programmed reduction (TPR), X-ray diffraction (XRD), transmission electron microscopy (TEM), Xray photoelectron spectroscopy (XPS), and N2O decomposition.
Abstract: Active sites and structure–activity relationships for methanol synthesis from a stoichiometric mixture of CO2 and H2 were investigated for a series of coprecipitated Cu-based catalysts with temperature-programmed reduction (TPR), X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and N2O decomposition. Experiments in a reaction chamber attached to an XPS instrument show that metallic Cu exists on the surface of both reduced and spent catalysts and there is no evidence of monovalent Cu+ species. This finding provides reassurance regarding the active oxidation state of Cu in methanol synthesis catalysts because it is observed with 6 compositions possessing different metal oxide additives, Cu particle sizes, and varying degrees of ZnO crystallinity. Smaller Cu particles demonstrate larger turnover frequencies (TOF) for methanol formation, confirming the structure sensitivity of this reaction. No correlation between TOF and lattice strain in Cu crystallite...
284 citations
TL;DR: In this paper, the Bilik reaction was used to epimerize glucose to mannose by a Lewis acid-mediated intramolecular carbon shift mechanism known as Bilik Reaction.
Abstract: Here, we show that framework tin sites in pure silica zeolite Beta (Sn-Beta) can isomerize glucose to fructose by a Lewis acid-mediated intramolecular hydride shift in aqueous solvent, but not in methanol solvent. Mechanistic studies using isotopically labeled (2H, 13C) glucose reactants show that in methanol, Sn-Beta instead epimerizes glucose to mannose by a Lewis acid-mediated intramolecular carbon shift mechanism known as the Bilik reaction. We also provide evidence that extraframework tin sites located within the hydrophobic channels of zeolite Beta can isomerize glucose to fructose in both water and methanol solvent, but through a base-catalyzed proton-transfer mechanism. SnO2 particles located at external zeolite crystal surfaces or supported on amorphous silica catalyze isomerization in methanol but not in water, suggesting that contact with bulk water inhibits isomerization at SnO2 surfaces. 119Sn MAS NMR spectroscopy was used to unambiguously identify framework Sn sites, which give resonances fo...
TL;DR: In this article, solid acid carbon supported catalysts were generated from biomass by pyrolysis to generate a soft to hard carbon backbone (i.e., biochar) for addition of acidic functional groups.
TL;DR: A ruthenium catalyst for the reduction of esters by hydrogenation has been developed as mentioned in this paper, which shows good catalytic activity for the hydrogenation of (R)-1,2-propanediol in methanol.
TL;DR: In this paper, density functional theory (DFT) calculations and Kinetic Monte Carlo (KMC) simulations were employed to investigate the methanol synthesis reaction from CO2 hydrogenation (CO2 + 3H2 → CH3OH + H2O) on metal-doped Cu(111) surfaces.
Abstract: Density functional theory (DFT) calculations and Kinetic Monte Carlo (KMC) simulations were employed to investigate the methanol synthesis reaction from CO2 hydrogenation (CO2 + 3H2 → CH3OH + H2O) on metal-doped Cu(111) surfaces. Both the formate pathway and the reverse water-gas shift (RWGS) reaction followed by a CO hydrogenation pathway (RWGS + CO-Hydro) were considered in the study. Our calculations showed that the overall methanol yield increased in the sequence: Au/Cu(111) < Cu(111) < Pd/Cu(111) < Rh/Cu(111) < Pt/Cu(111) < Ni/Cu(111). On Au/Cu(111) and Cu(111), the formate pathway dominates the methanol production. Doping Au does not help the methanol synthesis on Cu(111). Pd, Rh, Pt, and Ni are able to promote the methanol production on Cu(111), where the conversion via the RWGS + CO-Hydro pathway is much faster than that via the formate pathway. Further kinetic analysis revealed that the methanol yield on Cu(111) was controlled by three factors: the dioxomethylene hydrogenation barrier, the CO bin...
TL;DR: In this paper, the authors measured and correlated the solubilities of (Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid in different pure solvents and binary mixtures of water + (ethanol, methanol, or glycol).
Abstract: Article commenting on an article titled, "Measurement and correlation of solubilities of (Z)-2-(2-aminothiazol-4-yl)-2-methoxyiminoacetic acid in different pure solvents and binary mixtures of water + (ethanol, methanol, or glycol)," published in March 2011.
TL;DR: A multifunctional catalyst capable of achieving rapid release of hydrogen by protolytic cleavage of silanes with either water or methanol and hydrosilylation of aldehydes, ketones, and carbon dioxide, thereby providing a means for utilizing carbon dioxide as a C(1) feedstock for the synthesis of useful chemicals.
Abstract: [Tris(2-pyridylthio)methyl]zinc hydride, [κ3-Tptm]ZnH, is a multifunctional catalyst that is capable of achieving (i) rapid release of hydrogen by protolytic cleavage of silanes with either water or methanol and (ii) hydrosilylation of aldehydes, ketones, and carbon dioxide. For example, [κ3-Tptm]ZnH catalyzes the release of 3 equivalents of H2 by methanolysis of phenylsilane, with a turnover number of 105 and a turnover frequency surpassing 106 h–1 for the first 2 equivalents. Furthermore, [κ3-Tptm]ZnH also catalyzes the formation of triethoxysilyl formate by hydrosilylation of carbon dioxide with triethoxysilane. Triethoxysilyl formate may be converted into ethyl formate and N,N-dimethylformamide, thereby providing a means for utilizing carbon dioxide as a C1 feedstock for the synthesis of useful chemicals.
TL;DR: In this paper, the effects of temperature and weight hourly space velocity (WHSV) on the product carbon yields and selectivities of catalytic fast pyrolysis (CFP) of pure pine wood and methanol were investigated.
TL;DR: In addition to the complementarity and flexibility of the cage receptor, a combination of factors have been found to contribute to the observed anion selectivity, including the anions' charge, size, hydration, basicity, and hydrogen-bond acceptor abilities.
Abstract: We present an extensive study of a novel class of de novo designed tetrahedral M4L6 (M = Ni, Zn) cage receptors, wherein internal decoration of the cage cavities with urea anion-binding groups, via functionalization of the organic components L, led to selective encapsulation of tetrahedral oxoanions EO4n– (E = S, Se, Cr, Mo, W, n = 2; E = P, n = 3) from aqueous solutions, based on shape, size, and charge recognition. External functionalization with tBu groups led to enhanced solubility of the cages in aqueous methanol solutions, thereby allowing for their thorough characterization by multinuclear (1H, 13C, 77Se) and diffusion NMR spectroscopies. Additional experimental characterization by electrospray ionization mass spectrometry, UV–vis spectroscopy, and single-crystal X-ray diffraction, as well as theoretical calculations, led to a detailed understanding of the cage structures, self-assembly, and anion encapsulation. We found that the cage self-assembly is templated by EO4n– oxoanions (n ≥ 2), and upon ...
TL;DR: In this article, active biodiesel production catalysts were derived from waste eggshells by simple calcination in air and the physicochemical properties of the activated catalysts are characterized by XRD, N 2 sorption, CO 2 -TPD, TGA-DTG, XRF, and SEM, while the catalytic activity was tested in producing biodiesel via transesterification on palm oil with methanol under microwave conditions.
TL;DR: The immobilized lipase worked well when using wet microalgal biomass as the oil substrate and tolerated a high methanol to oil molar ratio when using the M-II approach, and can be repeatedly used for six cycles (or 288 h) without significant loss of its original activity.
TL;DR: Sodium dodecylbenzene sulfonate (SDBS) adsorbed graphene oxide (GO) has been used as a filler to modify sulfonated poly(ether ether ketone) (SPEEK) as mentioned in this paper.
Abstract: Sodium dodecylbenzene sulfonate (SDBS) adsorbed graphene oxide (GO) has been used as a filler to modify sulfonated poly(ether ether ketone) (SPEEK). The incorporation of SDBS-GO greatly increases the ion-exchange capacity (IEC), water uptake, and proton conductivity, while it reduces the methanol permeability through the SPEEK membranes. With well controlled contents of SDBS-GO, the composite membranes exhibit higher IEC, water uptake, and proton conductivity and lower methanol permeability than Nafion® 112, making them attractive as proton exchange membranes (PEMs). These superior characteristics make the composite membranes with optimized SDBS-GO contents exhibit superior performance in direct methanol fuel cells (DMFCs) compared to the plain SPEEK or Nafion® 112 membranes.
TL;DR: This multi-step reaction opens the possibility for methane to methanol conversion in a closed catalytic cyclic reaction system.
TL;DR: In this article, magnetic chitosan microspheres were prepared by the chemical co-precipitation approach using glutaraldehyde as cross-linking reagent for lipase immobilization.
Abstract: Biodiesel fuel, produced by transesterification of vegetable oils or animal fats with methanol, is a promising alternative diesel fuel due to the limited resources of fossil fuels and the environmental concerns. An environmentally benign process for the transesterification reaction using immobilized lipase has attracted considerable attention for biodiesel production. In the work, magnetic chitosan microspheres were prepared by the chemical co-precipitation approach using glutaraldehyde as cross-linking reagent for lipase immobilization. The immobilization of lipase onto the magnetic particles was confirmed by magnetic measurements, transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR) spectra. Using the immobilized lipase, the conversion of soybean oil to fatty acid methyl esters reached 87% under the optimized conditions of methanol/oil amount-of-substance ratio 4:1 with the three-step addition of methanol, reaction temperature 35 °C, and reaction duration 30 h. Moreover, the immobilized lipase could be used for four times without significant decrease of the activity.
TL;DR: In this article, the performance of catalysts comprising zeolite ZSM-5 impregnated with precious metals including Ag, Cu, Ni, Pd, Ir and Ru, have been tested for the methanol to hydrocarbons reaction in a continuous flow fixed bed reactor.
TL;DR: A series of polyethylene glycol (PEG)-functionalized basic ionic liquids (ILs) were developed for efficient CO2 conversion into organic carbonates under mild conditions as discussed by the authors.
TL;DR: In this article, a study has been carried out by using different techniques (TPO, FTIR, Raman, 13C NMR, GC/MS of the coke dissolved in CH2Cl2) on the nature of coke deposited on a HZSM-5 catalyst modified with Ni in the transformation of the crude bio-oil obtained by flash pyrolysis of lignocellulosic biomass (pine sawdust) into hydrocarbons.
TL;DR: In this article, the effect of chemical treatments to augment the sorption capability was evaluated and pretreatments of biosorbent were carried out with a range of organic and inorganic reagents.
TL;DR: In this paper, a comparative study of algal biomass conversion into biodiesel using supercritical methanol (SCM) and microwave-assisted transesterification methods was investigated.
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TL;DR: In the case of methanol catalysts, the active component of these catalysts is Cu metal with the ZnO simply being involved as the preferred supporting support as discussed by the authors.
Abstract: Methanol, like ammonia, is one of the key industrial chemicals produced by heterogeneous catalysis. As with the original ammonia catalyst (Fe/K/Al2O3), so with methanol, the original methanol synthesis catalyst, ZnO, was discovered by Alwin Mittasch. This was translated into an industrial process in which methanol was produced from CO/H2 at 400 °C and 200 atm. Again, as with the ammonia catalyst where the final catalyst which is currently used was achieved only after exhaustive screening of putative “promoters”, so with methanol, exhaustive screening of additives was undertaken to promote the activity of the ZnO. Early successful promoters were Al2O3 and Cr2O3 which enhanced the stability of the ZnO but not its activity. The addition of CuO was found to increase the activity of the ZnO but the catalyst so produced was short lived. Current methanol synthesis catalysts are fundamentally Cu/ZnO/Al2O3, having high CuO contents of ~60 % with ZnO ~ 30 % and Al2O3 ~ 10 %. Far from promoting the activity of the ZnO by incorporation of CuO, the active component of these Cu/ZnO/Al2O3 catalysts is Cu metal with the ZnO simply being involved as the preferred support. Other supports for the Cu metal, e.g. Al2O3, MgO, MnO, Cr2O3, ZrO2 and even SiO2 can also be used. In all of these catalysts the activity scales with the Cu metal area. The original feed has now changed from CO/H2 to CO/CO2/H2 (10:10:80), radiolabelling studies having provided the unlikely discovery that it is the CO2 molecule which is hydrogenated to methanol; the CO molecule acts as a reducing agent. The CO2 is transformed to methanol on the Cu through the intermediacy of an adsorbed formate species. These Cu/ZnO/Al2O3 catalysts now operate at ~230° and between 50 and 100 atm. This important step change in the activity of methanol synthesis has resulted in a significant reduction in the energy required to produce methanol. The “step change” however has been incremental. It has been obtained on the basis of fundamental knowledge provided by a combination of surface science techniques, e.g. LEED, scanning tunnelling microscope, TPD, temperature programmed reaction spectroscopy, combined with catalytic mechanistic studies, including radiolabelling studies and chemisorption studies including reactive chemisorption studies, e.g. N2O reactive frontal chromatography.
TL;DR: In this paper, a catalytic conversion of HMF to valuable chemicals was achieved over a Cu-doped porous metal oxide in supercritical methanol using simple synthetic procedures, using inexpensive and earth-abundant starting materials.