Liquid Phase Methanol Research Articles

Preparation, Characterization, and Acidity Evaluation of Perfluorosulfonic Acid-Functionalized Silica Catalysts

Three different hybrid organic/inorganic solid acid catalysts were prepared by grafting perfluorosulfonic acid onto amorphous silica gel by covalently anchoring β-sultone onto the hydroxyl groups on the silica surface. The anchored sulfonic groups have been characterized by thermal analysis, infrared spectroscopy, and photoelectron spectroscopy (XPS). Particularly, the XPS technique has proven to be an extremely powerful tool to determine the nature and chemical state of sulfur and carbon, as well as the surface density of the acid groups. The hybrid organic/inorganic systems functionalized with sulfonic acid groups were tested in the esterification reaction of acetic acid with methanol in liquid phase. Activity results obtained at 333 K and using an initial molar ratio AcOOH:MeOH = 1:1 revealed that the acid-functionalized, nonsilylated catalyst reaches acetic acid conversion of ∼50%, which contrasts with the much lower level (∼30%) reached by a commercial Nafion silica composite sample. Treatment of the catalysts in methanol at 333 K under stirring for 48 h emphasized that only the acid-functionalized and silylated sample retains some of the sulfonic groups.

Effect of Temperature, Pressure and Volume of Reacting Phase on Photocatalytic CO2 Reduction on Suspended Nanocrystalline TiO2

The effect of temperature, pressure and volume of reactant solution on the photocatalytic reduction of CO2at suspended TiO2was studied in an annular batch photoreactor. Reaction products in the liquid phase (methanol, formaldehyde) and in the gas phase (methane, ethane, carbon monoxide, molecular oxygen and hydrogen) were analysed by gas chromatography. The photocatalytic reduction of CO2was not sensitive significantly to small temperature variations within 10 K. The CO2pressure at carbonation of the solution influenced the selectivity of the CO2conversion to methane and methanol, while the dihydrogen yield was higher by two orders of magnitude and independent of the pressure. The dependence of the product yields on the volume of the liquid phase confirmed the fact that the requirement for perfect mixing was difficult to fulfil for the annular configuration of the reactor.

Study of the Characteristics of Methanol Synthesis in a Recirculation Slurry Reactor – A Novel Three‐Phase Synthesis Reactor

AbstractA process feasibility analysis on the liquid phase methanol synthesis (LPMeOHTM) process was performed in a recirculation slurry reactor (RSR). In the three‐phase RSR system, a fine catalyst is slurried in the paraffin and this catalyst slurry is continuously recirculated through the nozzle from the slurry sector to the entrained sector by a pump. The syngas is fed concurrently with the downward flow of slurry to form the methanol product. A laboratory scale mini‐pilot plant version of a recirculation slurry reactor system was successfully designed and built to carry out process engineering research, and in addition, an identical cold model was built to measure the mass transfer coefficient in the recirculation slurry reactor. The effects of operating conditions, including temperature, pressure, gas flow rate and catalyst slurry recirculation flow rate on the productivity of methanol were studied. This experimental data helps the scale‐up and commercialization of the methanol synthesis process in recirculation slurry reactors.

2-23 低温液相メタノール合成触媒システムの開発((6)メタノール・DME,Session 2 天然ガス・メタンハイドレート等,研究発表(口頭発表))

2-23 低温液相メタノール合成触媒システムの開発((6)メタノール・DME,Session 2 天然ガス・メタンハイドレート等,研究発表(口頭発表))

The characteristics of liquid-phase methanol synthesis in an impinging stream reactor

A laboratory scale mini-pilot plant is successfully designed and built to carry out research in the liquid-phase methanol synthesis process in a impinging stream reactor, the reactor has good heat transfer and mass transfer performance because the catalyst slurry is atomized into fine drop when it goes through the pressure-flow nozzles, the mass transfer between gas phase and liquid-phase is promoted. Sustained operating conditions of temperatures approximately at 230 °C, space velocity at 10,000 h −1, high slurry recirculation flow rate and two or four opposed nozzles represent a major extension of the operating range for this type of reactor. A high slurry recirculation flow rate is benefit to the inter-phase mass transfer because the inter-phase disturbance is enhanced, and the catalyst slurry after atomized impacts each other when the opposed nozzles are used, this promotes the inter-phase interfusion and distribution so as to increase the gas–liquid mass transfer.

Measurement and correlation of vapor–liquid equilibria for methanol + methyl laurate and methanol + methyl myristate systems near critical temperature of methanol

A flow-type method was adopted to measure the vapor–liquid equilibria for methanol + methyl laurate and methanol + methyl myristate systems at 493–543 K, near the critical temperature of methanol ( T c = 512.64 K), and 2.16–8.49 MPa. The effect of temperature and fatty acid methyl esters to the phase behavior was discussed. The mole fractions of methanol in liquid phase are almost the same for both systems. In vapor phase, the mole fractions of methanol are very close to unity at all temperatures. The present vapor–liquid equilibrium data were correlated by PRASOG. A binary parameter was introduced to the combining rule of size parameter. The binary parameters of methanol + fatty acid methyl ester systems were determined by fitting the present experimental data. The correlated results are in good agreement with the experimental data. The vapor–liquid equilibria for methanol + methyl laurate + glycerol and methanol + methyl myristate + glycerol ternary systems were also predicted using the methanol + fatty acid methyl ester binary parameters. The mole fractions of methanol in vapor phase are around unity even if glycerol is included in the systems.

2-14.低温液相メタノール合成触媒システムの開発((4)メタノール・DEM等,Session 2 天然ガス・メタンハイドレート等)

2-14.低温液相メタノール合成触媒システムの開発((4)メタノール・DEM等,Session 2 天然ガス・メタンハイドレート等)

Remarkable support effect for liquid phase methanol reforming with water over supported Pt–Ru catalysts

Support effect for the catalytic activity of liquid phase reforming of methanol with water was investigated over various supported Pt–Ru bimetallic catalysts. The SiO 2, TiO 2, Al 2O 3, MgO, CeO 2 and ZrO 2 were used as support materials by conventional impregnation method. Basic oxide supports improved the selectivity to CO 2, whereas acidic supports suppressed the catalytic activity and selectivity. The Pt–Ru/TiO 2 catalyst exhibited highest activity and selectivity for CO 2, which were improved by higher temperature reduction. The improved activity and selectivity were attributable to the occurrence of SMSI state and Pt–Ru alloy, respectively. The reforming reaction over Pt–Ru/TiO 2 catalyst proceeded through partially dehydrogenated HCOOCH 3 and HCOOH intermediate with the similar mechanism as that over SiO 2 supported Pt–Ru catalyst.

Marked Effect of Various Supports and Additives Upon Liquid Phase Methanol Reforming with Water over Supported Group 8–10 Metal Catalysts

The support effects (SiO2, TiO2, Al2O3, MgO, CeO2 and ZrO2) as well as addition effect of group 6b and 7b elements were studied over various supported group 8–10 metal catalysts. Basic oxide support improved the selectivity to CO2 and acidic support suppressed the catalytic activity and selectivity. Among the investigated catalysts Pt–Mo/TiO2 was the most active catalysts, whereas Ir–Re/SiO2 was the most selective catalysts for H2 and CO2 formation. The mechanism of the liquid phase methanol reforming reaction over silica supported Pt–Ru catalyst was studied by kinetic investigations. The rate of H2 formation over Pt–Ru/SiO2 catalysts was more than 20 times faster than that over Pt/SiO2 catalysts with high selectivity for CO2 (72.3%), indicating a marked addition effect of Ru. In the case of HCHO–H2O reaction over Pt–Ru/SiO2, the H2 formation rate was five times larger than that in the CH3OH–H2O reaction but selectivity to CO2 was only 4%. On the contrary, in the HCOOCH3–H2O and HCOOH–H2O reactions, both high activity and selectivity were observed over Pt–Ru/SiO2. These results clearly indicate that the CO2 formation does not proceed via HCHO decomposition and following water gas shift reaction.

Liquid phase methanol and dimethyl ether synthesis from syngas

The Liquid Phase Methanol Synthesis (LPMeOHTM) process has been investigated in our laboratories since 1982The reaction chemistry of liquid phase methanol synthesis over commercial Cu/ZnO/Al2O3 catalysts, established for diverse feed gas conditions including H2-rich, CO-rich, CO2-rich, and CO-free environments, is predominantly based on the CO2 hydrogenation reaction and the forward water-gas shift reactionImportant aspects of the liquid phase methanol synthesis investigated in this in-depth study include global kinetic rate expressions, external mass transfer mechanisms and rates, correlation for the overall gas-to-liquid mass transfer rate coefficient, computation of the multicomponent phase equilibrium and prediction of the ultimate and isolated chemical equilibrium compositions, thermal stability analysis of the liquid phase methanol synthesis reactor, investigation of pore diffusion in the methanol catalyst, and elucidation of catalyst deactivation/regenerationThese studies were conducted in a mechanically agitated slurry reactor as well as in a liquid entrained reactorA novel liquid phase process for co-production of dimethyl ether (DME) and methanol has also been developedThe process is based on dual-catalytic synthesis in a single reactor stage, where the methanol synthesis and water gas shift reactions takes place over Cu/ZnO/Al2O3 catalysts and the in-situ methanol dehydration reaction takes place over γ-Al2O3 catalystCo-production of DME and methanol can increase the single-stage reactor productivity by as much as 80%. By varying the mass ratios of methanol synthesis catalyst to methanol dehydration catalyst, it is possible to co-produce DME and methanol in any fixed proportion, from 5% DME to 95% DMEAlso, dual catalysts exhibit higher activity, and more importantly these activities are sustained for a longer catalyst on-stream life by alleviating catalyst deactivation.

In Situ ATR-IR Spectroscopic and Reaction Kinetics Studies of Water−Gas Shift and Methanol Reforming on Pt/Al2O3 Catalysts in Vapor and Liquid Phases

Reaction kinetics measurements of the water-gas shift reaction were carried out at 373 K on Pt/Al2O3 in vapor phase to investigate the effects of CO, H2, and H2O partial pressures. Results of in situ ATR-IR studies conducted in vapor phase under similar conditions suggest that the Pt surface coverage by adsorbed CO is high (approximately 90% of the saturation coverage), leading to a negligible effect of the CO pressures on the rate of reaction. The negative reaction order with respect to the H2 pressure is caused by the increased coverage of adsorbed H atoms, and the fractional positive order with respect to the water pressure is consistent with non-equilibrated H2O dissociation on Pt. Results of in situ ATR-IR studies carried out at 373 K show that the presence of liquid water leads to a slight decrease in the Pt surface coverage by adsorbed CO (approximately 80% of the saturation coverage) when the CO partial pressure is the same as in the vapor-phase studies. The rate of the WGS reaction in the presence of liquid water is comparable to the rate under complete vaporization conditions when other factors (such as CO partial pressure) are held constant. Reaction kinetics measurements of methanol reforming were carried out at 423 K over a total pressure range of 1.36-5.84 bar. In situ ATR-IR studies were conducted at 423 K to determine the Pt surface coverage by adsorbed CO in completely vaporized methanol feeds and in aqueous methanol solutions. The decomposition of methanol is found to be slower during the reforming of methanol in liquid phase than in vapor phase, which leads to a lower rate of hydrogen production in liquid phase (0.08 min(-1) at 4.88 bar) than in vapor phase (0.23 min(-1) at 4.46 bar). The lower reaction order with respect to methanol concentration observed for vapor-phase versus liquid-phase methanol reforming (0.2 versus 0.8, respectively) is due to the higher extent of CO poisoning on Pt for reforming in vapor phase than in liquid phase, based on the higher coverage by adsorbed CO observed in completely vaporized methanol feeds (55-60% of the saturation coverage) than in aqueous methanol feed solutions (29-40% of the saturation coverage).

Catalytic activity of various supported Ir–Re catalysts for liquid phase methanol reforming with water

The catalytic activity of various supported Ir–Re catalysts was investigated for the liquid phase reforming reaction of methanol. Although Ir/SiO 2 exhibited poor activity for the hydrogen production but the addition of Re enhanced the activity more than one order of magnitude, and reached to the comparable value of Pt–Ru/SiO 2. The TOF of H 2 formation over Ir–Re/SiO 2 catalysts increased with the increase of Re/Ir ratio, accompanied with the increase of the particle sizes of Ir–Re composites. From the investigation of support effect, it was disclosed that CeO 2 and ZrO 2 enhanced catalytic activity of Ir–Re catalysts significantly.

Novel Anion Exchange Resin-based Catalyst for Liquid-phase Methanol Synthesis at 373–393 K

Abstract A thermo-stable anion exchange resin–Raney Cu system was found as the most effective solid catalyst for low-temperature liquid-phase methanol synthesis at 373 to 393 K under 5.0 MPa of syngas (2H2/CO). With the catalyst (20 mL of the resin and 2.0 g of Cu) suspended in methanol solution 72% of CO was converted to methanol (70%) and methyl formate (HCOOCH3) (30%) in 4 h.

An evaluation of synthesis gas contaminants as methanol synthesis catalyst poisons

The liquid phase methanol (LPMEOH™) process has successfully produced methanol from coal-derived synthesis gas on an industrial scale. This process uses a standard copper, zinc oxide, and alumina catalyst suspended in an inert mineral oil in a slurry bubble column reactor. A series of common synthesis gas contaminants were evaluated to determine their effect on catalyst activity. The following representative species were found to adversely affect the rate of methanol synthesis: phosphine (PH 3), carbonyl sulfide (COS), carbon disulfide (CS 2), thiophene (C 4H 4S), methyl thiocyanate (CH 3SCN), methyl chloride (CH 3Cl), and methyl fluoride (CH 3F). The nitrogen-containing contaminants hydrogen cyanide (HCN), acetonitrile (CH 3CN), and methylamine (CH 3NH 2) had no effect on catalyst activity. The surprising inactivity of HCN is likely attributable to its hydrogenation under methanol synthesis conditions. An approximate order of decreasing catalyst poison potency was obtained: C 4H 4S≅AsH 3>CH 3Cl>CH 3SCN>CS 2>COS>PH 3>CH 3F. Based on catalyst surface area and molar effectiveness for each poison, catalyst poisoning cannot be attributed solely to a loss of copper surface area. Although this study involved the liquid phase process, the results should be applicable to methanol synthesis by a gas phase, fixed bed process. A rationalization of contaminant/catalyst reactivity is presented.

Liquid-phase methanol carbonylation catalyzed over tin promoted nickel–aluminium layered double hydroxide

A nickel–aluminum layered double hydroxide (LDH), of which structure is similar to that of hydrotalcite, has been synthesized. Liquid-phase carbonylation of methanol to methyl acetate is catalyzed over the LDH in presence of methyl iodide at 473 K. Dimethyl ether is also formed in the reaction, but formation of acetic acid is undetectable. Nickel ions in the LDH can be replaced with tin ions, and the presence of tin significantly promotes the activity of the LDH. Formation of methyl formate depends on the pressure of carbon monoxide in the reaction, suggesting that insertion of carbon monoxide to methyl iodide is a key step of the carbonylation and dimethyl ether reacts with the intermediate to form methyl formate.

The role of arsine in the deactivation of methanol synthesis catalysts

The liquid phase methanol (LPMEOH™) process is successfully producing methanol from coal-derived synthesis gas on an industrial scale. This process uses a standard copper, zinc oxide, and alumina catalyst suspended in an inert mineral oil in a slurry bubble column reactor. An arsenic-containing species, most reasonably arsine, was found in the feed to the LPMEOH™ commercial demonstration facility located at Eastman Chemical Company’s chemicals-from-coal complex in Kingsport, TN. Laboratory testing showed that arsine is, in fact, a powerful methanol synthesis catalyst poison. At levels as low as 150 ppbv, arsine results in a rapid deactivation of the catalyst. Removal of arsine results in a deactivation rate consistent with a clean synthesis gas feed; that is, arsine poisoning stops when it is removed from the feed. We infer that arsine reacts irreversibly with the catalyst under the methanol synthesis conditions. X-ray absorption spectroscopy (XAS) of arsenic-containing used catalyst indicated the presence of zero-valent arsenic in an intermetallic surface phase that is structurally related to Domeykite (Cu 3As). Experimental evidence, thermodynamics, and literature relating to other metal–arsine chemistry were consistent with dissociative adsorption of arsine on the copper surface to form gaseous H 2 and Cu 3As. To deal with arsine poisoning, we have developed adsorption technology that can remove arsine to levels low enough that catalyst performance is unaffected.

Liquid phase methanol reforming with water over silica supported Pt–Ru catalysts

The mechanism of the liquid phase methanol reforming reaction over silica supported Pt–Ru catalyst was investigated by kinetic studies, employing a pyrex glass reactor with reflux condensers connected to a closed gas circulation system under ambient pressure. The rate of H 2 formation over Pt–Ru/SiO 2 catalysts was more than 20 times faster than that over Pt/SiO 2 catalysts with high selectivity for CO 2 (72.3%), indicating a marked addition effect of Ru. In the case of HCHO–H 2O reaction over Pt–Ru/SiO 2, the H 2 formation rate was five times larger than that in the CH 3OH–H 2O reaction but selectivity to CO 2 was only 4%. On the contrary, in the HCOOCH 3–H 2O and HCOOH–H 2O reactions, both high activity and selectivity were observed over Pt–Ru/SiO 2. These results clearly indicate that the CO 2 formation does not proceed via HCHO decomposition and following water gas shift reaction. We propose the following pathway for liquid phase methanol reforming reaction over Pt–Ru/SiO 2; a partly dehydrogenated methanol (CH 2OH ∗) is the initial reaction intermediate, from which H 2 and CO 2 are formed through HCOOCH 3 and HCOOH as the successive reaction intermediates.

Acid-Functionalized Amorphous Silica by Chemical Grafting−Quantitative Oxidation of Thiol Groups

This work describes the synthesis and structural features of functionalized amorphous silica with sulfonic acid groups. The approach followed involved the condensation of (3-mercaptopropyl)trimethoxysilane or (3-mercaptopropyl)methyldimethoxysilane and/or phenyltrimethoxysilane on the hydroxyl groups of the silica substrate followed by oxidation with hydrogen peroxide. This oxidation reaction was effective, although some lixiviation of sulfur occurred, and the amount of S released depended on the hydrophobicity of the surface and the temperature of the treatment. The extent of oxidation of the thiol precursor, determined by photoelectron spectroscopy (XPS), was moderate at ambient temperature and much more effective at 333 K. The XPS technique proved to be extremely useful not only to discriminate between the −SH and −SO3H, whose chemical shifts differ by 5 eV, but also to quantify the proportion of these species and hence the conditions that make the oxidation process quantitative. The solid samples prepared according to this grafting−oxidation methodology exhibited strong acid sites, as revealed by their performance in the esterification reaction of acetic acid by methanol in liquid phase. Activity data indicated that the reaction is accelerated in the presence of the sulfonic acid-functionalized silica catalyst, being higher than that of the reference Nafion silica composite. Finally, this grafting procedure and the methodologies to quantify and test these acid-functionalized silica materials can be applied to other substrates.

化学反応を伴う熱交換過程に関する基礎的研究

A liquid-phase methanol synthesis and decomposition process was proposed to recover wasted or unused discharged heat from industrial sources for the thermal energy demands of residential and commercial areas by chemical reactions. This paper summarized five fundamental researches and their results of the development of liquid phase reactor (heat exchanger accompanying chemical reaction), which are important to the methanol system. The five researches are as follows. (1) To evaluate the effect of transport process in the whole reaction process, the transport process of carbon monoxide (CO) and hydrogen (H2) gases in liquid phase methanol and methyl formate were studied. The fundamental data of transport process, such as solubility and diffusion coefficient, were obtained. (2) Solution and diffusion processes of single CO bubbles in liquid phase methanol were theoretically and experimentally studied under various pressures and temperatures. (3) The chemical reaction rate of methanol synthesis by hydrogenolysis of methyl formate was measured using a plate-type of Raney copper catalyst. The effect of thickness of Raney copper catalyst on the liquid-phase chemical reaction rate were investigated by varying the development time of the catalyst. (4) Investigation results of the catalyst such as surface area, pore radius, lattice size, and photographs of scanning electron microscope (SEM) were also obtained. (5) Furthermore, the liquid film distillation column accompanying chemical reaction was analyzed numerically to clarify the effect of gas flow velocity and liquid thickness on the catalytic reaction process.

Geometry optimization of molecules in solution: Joint use of the mean field approximation and the free-energy gradient method

The average solvent electrostatic potential/molecular dynamics (ASEP/MD) and the free-energy gradient methods are applied together with the multidimensional geometry optimization of molecules in solution. The systems studied were formamide in aqueous solution and water and methanol in liquid phase. The solute molecules were described through ab initio quantum mechanics methods (density dunctional theory or Møller–Plesset second order perturbation theory) while the solvent structure was obtained from Molecular Dynamics calculations. The method is very efficient; the increase in computation time is minimal with respect to previous ASEP/MD versions that worked at a fixed geometry. Despite the use of the mean field approximation in the calculation of the solvent reaction potential the agreement with previous theoretical calculations was satisfactory. Large changes were observed in the solute charge distribution induced by the solvent, and the solute polarization was accompanied by an increase in the solvent structure around the solute.