ChemInform Abstract: ADVANCES IN FISCHER‐TROPSCH CHEMISTRY

Recent Advances in Direct Synthesis of Value‐Added Aromatic Chemicals from Syngas by Cascade Reactions over Bifunctional Catalysts

“…While transmission electron microscopy (TEM) image of the impregnated Fe/HZSM‐5 in an aqueous solution showed the well dispersed Fe nanoparticles on the HZSM‐5 surfaces (Figure b),[55b] the decreases of Brönsted acid sites on the AI catalyst owing to the migration of metal ions by proton‐exchanges on the HZSM‐5 were not able to convert the formed olefin intermediates (≈32 vol%) to aromatic monomers on the Fe nanocrystallites. [55a] Other researchers have also revealed similar phenomena of the possible migration of alkali cations (K or Na) by proton‐exchanges on the HZSM‐5 surfaces . It is also worthy to mention that the Co‐based catalyst prepared by incipient wetness impregnation method was found to have reducible Co 3 O 4 crystallites on the external surface of the ZSM‐5, whereas nonreducible Co 2+ species exist on the inside surfaces of the ZSM‐5.…”

“…The first report of the production of aromatics from syngas was published in 1979 by combining the traditional FTS or methanol synthesis catalyst with solid‐acid zeolites as the hybridized composite catalysts . The researchers, Mobil Oil Corporation, observed two important features that after incorporation of the HZSM‐5 with transitions metals such as Fe, Zr, and Zn–Cr, they break the limitations of the Anderson–Schulz–Flory (ASF) distribution from CO hydrogenation to hydrocarbons, which greatly increased the aromatic selectivity by reducing olefins selectivity along with suppressing oxygenates as well as by effectively shifting hydrocarbon distribution toward gasoline‐range aromatics (C 6 C 10 ) .…”

The influence of ZSM-5 zeolite composition and crystal size on the in situ conversion of Fischer–Tropsch products over hybrid catalysts

“…One interesting approach to overcome both product selectivity and quality limitations in conventional FTS processes is the use of hybrid (or composite) catalysts in a single bed combining a typical Fischer-Tropsch catalyst and an acidic co-catalyst, such as ZSM-5 zeolite [3][4][5]. The addition of the ZSM-5 zeolite component promoted the production of aromatics and branched paraffins by secondary reactions of the primary a-olefins formed on the FT catalyst component over the zeolite acid sites.…”

The addition of HZSM-5 to the Fischer–Tropsch process for improved gasoline production

“…The range of FT catalysts include those based on iron [6][7][8][9], iron/manganese [10,11], cobalt [12,13], cobalt/manganese [14,15] and even iron/cobalt [16]. The use of different zeolites (mordenite, erionite, ZSM-11, ZSM-12, L, omega and beta) in combination with a Fischer-Tropsch catalyst has been investigated [17], while other researchers tested HZSM-5 [6,16], gallium-substituted HZSM-5 [14,15] and HY [10].…”