Modified methanol synthesis catalysts

Higher alcohol formation from synthesis gas is also known to occur over MoS2-based catalysts. The alcohol product distribution is quite different from the modified methanol synthesis catalysts and consists primarily of linear alcohols [114], In particular, the product distribution with Cs/Co/MoS2 catalysts has a maximum in the yield of ethanol [115], A modification of this synthesis in which higher alcohols formed from methanol and synthesis gas has been claimed by Quarderer et aL [116]. As K2C02-promoted CoS/MoS2 catalyst,... 

C and 13.7 MPa, yielded a produet with signifieant ethanol content, as shown by the data in Table 8. This process is similar to the higher alcohol synthesis over promoted Cu/Zn and Zn/Cr catalysts however, the rate of ethanol formation is significant greater with the MoS2-based catalysts than with the modified methanol synthesis catalysts. 

Cabrera, I.M. Granados, ML. Terreros, R Fier-ro, J.L.G. CO Hydrogenation over Pd-modified Methanol Synthesis Catalysts. Catal. Today. 1998,45,251-256. 

In our previous studies, CO2 was converted to methane[2] or methanol[3] at extraordinarily rapid conversion rates. However, rapid ethanol synthesis from CO2 has been much more difficult owing to both equilibrium limitation and retardation caused by H2O, which inevitably forms in the CO2 hydrogenation. In this study, to synthesize ethanol from CO2 with higher yield, a catalyst (Cu-Zn-Al-K mixed oxides) having a function of partial reduction of CO2 was combined with a Fe based F-T type catalyst which we had already developed[l]. Then Pd and Ga, which have promotion effect for Cu-Zn based methanol synthesis catalyst[3], were added to modify the catalyst, and the performance was examined. 

A modified form of eqn. 3, in which the time constants for catalyst deactivation were assumed to be independent of temperature, was used to analyze the deactivation of a different methanol-synthesis catalyst in a series of commercial, packed-bed reactors [ref. 8]. The values of a[T) shown in Fig. 5 are about an order of magnitude higher than those derived in ref. 8. 

Zn/AljOj catalysts, 31 249 -Zn/Cr Oj catalysts, 31 250 -ZnO/AljO, 31 276, 292-295 -ZnO binary catalyst, 31 257-287 activity patterns, 31 271-274 BET argon surface areas, 31 259 calcination, 31 261-262 catalytic testing, 31 272 chemisorption, 31 268-271 CO2 effects, selectivity, 31 284-285 color spectra, 31 259-261 component comparison, 31 258-259 methanol synthesis, 31 246-247 modifiers, weakening of adsorption energy, 31 283... 

In a new study of a series of binary Cu-ZnO catalysts a correlation was found between methanol synthesis activity and strain in the Cu metal phase.619 Structural defects of Cu resulting from ZnO dissolved in Cu, incomplete reduction, or epitaxial orientation to ZnO are believed to bring about strain, which modifies the Cu surface and, consequently, affects the catalytic activity. The higher amount of water formed in methanol synthesis from a C02-rich feed compared to a CO-rich feed brings about significant catalyst deactivation by inducing crystallization of both Cu and ZnO.620... 

A far less selective synthesis for alcohols in the Ci -C range has been developed by Sugiei and Freund from IFF. A modified methanol catalyst is used and besides linear afcoltols, branched alcohols such as isopropano) and isobuianol are also found 11511. 

Figure 2 shows X-ray diffraction patterns of the catalysts after the liquid-phase methanol synthesis. The crystallite size of the catalyst modified with the special silicone oil was lower than that of the original catalyst without modification. The crystallite size of the catalyst modified with the hydrophilic silica B was a little lower than that of the original catalyst. And also the formation of Zn2Si04 phase was detected in the catalysts modified with the special silicone oil and the hydrophilic silica B after the liquid-phase methanol synthesis. The catalyst modified with the hydrophilic silica B was more stable than the original catalyst without... 

In Japan, the conventional method of methanol synthesis has been modified by adopting a fluidized granular catalyst bed rather than a fixed bed which allows the possibility to enlarge the scale of the reactor, to reduce the power required, and to exchange the catalyst during operation [2]. 

Recent advances have shown zeolites are effective in catalysing the direct conversion of synthesis gas to motor fuels. The MTO (methanol-to-olefins) process converts MeOH to C2-C4 alkenes and is also catalysed by ZSM-5. The development of a gallium-modified ZSM-5 catalyst (Ga-ZSM-5) has provided an efficient catalyst for the production of aromatic compounds from mixtures of C3 and C4 alkanes (commonly labelled LPG). 

In addition, LagOg is a particularly attractive support because it affords high selectivity and specific activity in the methanol synthesis reaction. LagOg-modified palladium catalysts have been reported to be very active for the synthesis of methanol from (CO -I- Hg)... 

Zhang Y, Fei J, Yu Y, Zheng X (2006) Methanol synthesis from CO2 hydrogenation over Cu based catalyst supported on zirconia modified Y-AI2O3. Energy Convers Manag 47 3360-3367... 

The selective alkylation of toluene with methanol to produce -xylene as a predominant isomer can be achieved over shape-selective catalysts (99—101). With a modified ZSM-5 zeoHte catalyst, more than 99% -xylene in xylene isomers can be produced at 550°C. This -xylene concentration exceeds the equiHbrium concentration of 23% (99). The selective synthesis of -xylene using relatively low cost toluene is economically attractive however, this technology was not commercialized as of 1991. 

---