Methanol conversion catalysts

Using two-stage series reactor system, gasoline fraction of hydrocarbons was also synthesized. [41] As a methanol conversion catalyst, MFI-type metallosihcate such as H-Fe-sdicate and H-Ga-sdicate were optimum for gasohn fraction synthesis. 

The reaction of MP and methanol was conducted using a conbined catalyst system consisting of a methanol conversion catalyst and an aldol-condensation catalyst. As the methanol conversion catalyst, a 1.0 g portion of Ag-MOH/Si02 (M = alkali metal, Ag/M/Si atomic ratio = 4/20/1000) was used. As the catalyst for the aldol-condensation, a 20 g portion of CsOH/Zr-SiOa (Cs/Zr/Si atomic ratio = 22/10/100) was used. A mixed gas of MP, methanol, oxygen, and nitrogen was passed at 360 °C. The feed rate of MP/methanol/oxygen/nitrogen was 50/75/10/250 mmol/h. The results areshown in Table 6. They are summarized as follows. 

The carboaylatioa of methanol to give formic acid is carried out ia the Hquid phase with the aid of a basic catalyst such as sodium methoxide. It is important to minimi2e the presence of water and carbon dioxide ia the startiag materials, as these cause deactivatioa of the catalyst. The reactioa is an equHibrium, and elevated pressures are necessary to give good conversions. Typical reaction conditions appear to be 80°C, 4.5 MPa (44 atm) pressure and 2.5% w/w of catalyst. Under these conditions the methanol conversion is around 30% (25). 

A Belgian patent (178) claims improved ethanol selectivity of over 62%, starting with methanol and synthesis gas and using a cobalt catalyst with a hahde promoter and a tertiary phosphine. At 195°C, and initial carbon monoxide pressure of 7.1 MPa (70 atm) and hydrogen pressure of 7.1 MPa, methanol conversions of 30% were indicated, but the selectivity for acetic acid and methyl acetate, usehil by-products from this reaction, was only 7%. Ruthenium and osmium catalysts (179,180) have also been employed for this reaction. The addition of a bicycHc trialkyl phosphine is claimed to increase methanol conversion from 24% to 89% (181). 

Detergent manufacturing Catalytic cracking and hydrocracking Xylene isomerization, benzene alkylation, catalytic cracking, catalyst dewaxing, and methanol conversion. 

In the above three processes, the catalysts are all composed of Cu-based methanol synthesis catalyst and methanol dehydration catalyst of AI2O3. The reactors used by JFE and APCI are slurry bubble column, while a circulating slurry bed reactor was used in the pilot plant in Chongqing. It can be foxmd from Table 1 that conversion of CO obtained in the circulating slurry bed reactor developed by Tsinghua University is obvious higher and the operation conditions are milder than the others. 

The results in Table 3 show that H-mordenite has a high selectivity and activity for dehydration of methanol to dimethylether. At 150°C, 1.66 mol/kg catal/hr or 95% of the methanol had been converted to dimethylether. This rate is consistent with that foimd by Bandiera and Naccache [10] for dehydration of methanol only over H-mordenite, 1.4 mol/kg catal/hr, when extrt lat to 150°C. At the same time, only 0.076 mol/kg catal/hr or 4% of the isobutanol present has been converted. In contrast, over the HZSM-5 zeolite, both methanol and isobutanol are converted. In fact, at 175 X, isobutanol conversion was higher than methanol conversion over HZSM-5. This presents a seemingly paradoxical case of shape selectivity. H-Mordenite, the zeolite with the larger channels, selectively dehydrates the smaller alcohol in the 1/1 methanol/ isobutanol mixture. HZSM-5, with smaller diameter pores, shows no such selectivity. In the absence of methanol, under the same conditions at 15(fC, isobutanol reacted over H-mordenite at the rate of 0.13 mol/kg catal/hr, higher than in the presence of methanol, but still far less than over H M-5 or other catalysts in this study. 

GP 4] [R 11] For methanol conversion over sputtered silver catalyst, variation in oxygen content from 10% to more than 90% of the gas mixtare results in a slight decrease of conversion from 75 to 70% and of selectivity from 91 to 89% (8.5 vol.-% methanol balance helium 510 °C 10 ms slightly > 1 atm) [72]. 

Gao L, Huang H, Korzeniewski C. 2004. The efficiency of methanol conversion to CO2 on thin films of Pt and PtRu fuel cell catalysts. Electrochim Acta 49 1281-1287. 

Figure 2. The influence of both BAS (Bronsted acid sites) and LAS (Lewis acid sites) acidity (in pmol/g) on selectivities of methanol conversion products on Fe-Beta-300(a) as well as co-reaction products (b) of methanol with methyl iodide on Fe-Beta-300 as a function of catalyst temperature.

Figure 6.20 Quick EXAFS and XRD measurements recorded during the temperature programmed reduction of copper in a Cu/Zn0/Al203 methanol synthesis catalyst. The disappearance and appearance of peaks with increasing temperature in the series of EXAFS spectra corresponds to the conversion of oxidic to metallic copper. The intensity of the relatively sharp peak around 9040 eV, indicative of Cu metal, clearly illustrates the kinetics of the reduction process, as does the intensity of the (111) reflection of Cu metal in the XRD spectra (adapted from Clausen 44J).

Fig. 6 Methanol conversion and TOFs for product formation using SILP SiOi - [BMIM] [Rh(CO)2l2] - [BMIM]I catalyst in continuous, gas-phase methanol carbonylation (Reaction conditions T=180°C, P = 20bar, Fco = 50 ncm min" F quid (MeOHiMel = 75 25wt%) = 0.69 gh- ) [49]...

The effect of the Si/Al ratio of H-ZSM5 zeolite-based catalysts on surface acidity and on selectivity in the transformation of methanol into hydrocarbons has been studied using adsorption microcalorimetry of ammonia and tert-butylamine. The observed increase in light olefins selectivity and decrease in methanol conversion with increasing Si/Al ratio was explained by a decrease in total acidity [237]. 

The approach of this work is to measure product compositions and mass balances in much detail in a time resolved manner and to relate this to the controlling kinetic principles and elemental reactions of product formation and catalyst deactivation. Additionally the organic matter, which is entrapped in the zeolite or deposited on it, is determined. The investigation covers a wide temperature range (250 - 500 °C). Four kinetic regimes are discriminated autocatalysis, retardation, reanimation and deactivation. A comprehensive picture of methanol conversion on HZSM5 as a time on stream and temperature function is developed. This also explains consistently individual findings reported in literature [1 4]. 

Fig. 2 Autocatalysis and retardation during methanol conversion on HZSM5 (left) and HUSY (right) at different temperatures. Yield of hydrocarbons (yield of coke neglected) as a function of duration of the experiment (inlet Pruonu =2.5 bar, WHSV = 1 h ) Catalysts HSZM5 Si/Al = 26, obtained from DEGlTSSiii HUSY basic cracking catalyst Si/Al = 4.5, obtained from Engelhard.

With increasing reaction temperature the HUSY zeolite is seriously coked. The HZSM5 however, is reanimated. Fig. 5 shows the catalyst life time and the yield of coke as a function of reaction temperature. Catalyst life time (time during which 100 % methanol conversion is obtained) increases by more than 3 orders of magnitude from about 5 minutes at 270 °C to approximately 200 hours at 400 °C. The average coke yield, as obtained at the end of life time by means of combustion, declines from about 12 % at 280 °C to about 0.1 % at 375 °C. 

Fig. 5 Reanimation of HZSM5 for methanol conversion. Coke yield and catalyst life time as a function of reaction temperature. Pruonu 2.5 bar, WHSV = 1 h. ...

Fig. 6 Schematic drawing of ZSM5 catalyst bed deactivation. View of the fused silica reaction tube at about 40 % of catalyst life time. Black zone (I) of deactivated catalyst particles covered with coke ("methanol coke"). Small dark reaction zone (II) in which methanol conversion to 100 % occurs. Blue/grey zone (III) of active catalyst on which a small amount of "olefin coke" produced by the olefinic hydrocarbon product mixture has been deposited on the crystallite surfaces. The quartz particles before and behind the catalyst bed (zones 0) remain essentially white.

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