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The methanol-to-gasoline (MTG) and methanol-to-olefins (MTO) process are 2 epochal technological discoveries in the synfuels arena, first introduced by Mobil Oil Corporation, some 50 years after the Fischer-Tropsch process. Apart from the technological breakthroughs, the MTG and MTO processes have also provided a rich tableau for scientific research and pursuits. In this report, we will first provide anecdotal information pertaining to the discovery and development of these 2 processes. We will then focus on how the MTO process has evolved into a stand-alone technology in its own right for the 2 value-added products, ethylene, and propylene.

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X‐ray absorption near‐edge structure (XANES) and extended X‐ray absorption fine structure (EXAFS) have been used to elucidate the structural features of a 2 % Rh–2.5 % Fe/TiO2 catalyst for syngas conversion to ethanol. The results from Rh K‐edge and Fe K‐edge spectroscopy on a fresh catalyst exposed to air indicated that both Rh and Fe were present as highly dispersed oxides on the titania, and that both adopted a +3 formal oxidation state. For the catalyst reduced in H2 at 573 K, the Rh K‐edge EXAFS revealed RhRh interactions (coordination number N=6.1, RhRh distance rRhRh=2.67 Å) and a second feature arising from either RhTi or RhO coordination. The metal particles contained on an average about 20 atoms, which is consistent with a particle size of 1 nm. A shift in the Rh K‐edge XANES by −2 eV indicated that the reduced Rh particles were electron rich compared to bulk Rh metal. Although Rh was reduced completely to the metal by H2, the iron oxide promoter was reduced primarily from FeIII to FeII oxide. The results from X‐ray absorption spectroscopy at both the Fe and Rh K‐edges were unchanged by exposure of the reduced catalyst to syngas (H2+CO) at 543 K. A structural model for this ethanol synthesis catalyst is proposed.

The development of a process for the synthesis of methyl methacrylate (MMA) from coal-derived syngas can alleviate the environmental hazards associated with the current commercial MMA technology, the acetone cyanohydrin (ACH) process. A three-step syngas-based process consisted of synthesis of a propionic acid, its condensation with formaldehyde, and esterification of resulting methacrylic acid (MAA) to form MMA. The first two steps, propionic acid synthesis and condensation, are discussed here. The low-temperature, low-pressure process for single-step hydrocarbonylation of ethylene to propionic acid is carried out using a homogeneous iodinepromoted Mo (CO) 6 catalyst at pressures (30-70 atm) and temperatures (150-200°C) lower than those reported for other catalysts. Mechanistic investigations suggest that catalysis is initiated by a rate-limiting CO dissociation from Mo(CO) 6 . This dissociation appears to be followed by an inner electron-transfer process of an I atom from EtI to the coordinately unsaturated Mo(CO) 5 . This homogeneous catalyst for propionate synthesis represents the first case of an efficient carbonylation process based on Cr group metals. The condensation of formaldehyde with propionic acid is carried out by acid-base bifunctional catalysts. As a result of screening over 80 catalytic materials, group V metals (V, Nb, and Ta) supported on an amorphous silica are found to be most effective. A 20% Nb/SiO 2 catalyst appears to be the most active and stable catalyst thus far. Preliminary relations among the reaction yield and catalyst properties indicate that a high surface area and a low overall surface acidity (<50 ) mol of NH 3 /g), with a high proportion of the acidity being weak (<350°C desorption of NH 3 ), are desirable. Long-term deactivation of V-Si-P, Nb-Si, and Ta-Si catalysts suggests that carbon deposition is the primary cause for activity decay, and the catalyst activity is partially restorable by oxidative regeneration.