Isobutanol process development

Experiments were carried out using isotopically labelled methanol (97% 0) and ethanol (98% purchased from MSD Isotopes. Anhydrous isobutanol was purchased from Aldrich Chemical Co., Inc. and contained the natural abimdances of orygen isotopes, i.e. 99.8% and 0.2% O. Nafion-H was obtained fi om C. G. Processing, Inc. and Amberlyst resins were provided by Rohm and Haas. The 2SM-5 zeolite was provided by Mobil Research Development Corp. H-Mordenite, montmorillonite K-10, and silica-alumina 980 were obtained firom Norton, Aldrich, and Davison, respectively. y-AIumina was prepared from Catapal-B fi om Vista. 

The low-temperature selective catalytic reduction of NO over an active carbon-supported catalyst was studied in order to develop catalysts that are active at temperatures around 150 X as part of a low-temperature process for NO control in flue gases from coal-fired power plants. Reductants studied include acetone, isopropanol, isobutanol, ethyl ether, ethanol, propene, and methanol. Acetone is the most active reductant for the selective reduction of NO over the 5%Cu-2%Ag/C catalyst tested. At 150 C, 35% NO conversion was obtained in the presence of 4% O2 and 8% H2O at 3,000 h space velocity after 5 h on stream. There is some decrease in NO and hydrocarbon conversion with time on stream. It is believed that the oxidation of acetone minimizes the oxidation of carbon in the presence of O2 and promotes the selective reduction of NO. 

All of the above-mentioned examples for fermentative isobutanol production were performed in simple flasks or bottles. However, the development of feasible production processes is challenging since not only common upscale problems arise, but also the cytotoxicity of higher alcohols is a striking problem for the transfer into the industrial scale. 

In analogy to the process with C. glutamicum Iso7, a two-phase fermentation process was developed with PDHC-deficient B. subtilis n-,05 yielding 74 mM isobutanol (5.5 g/L). In this case, the yield obtained [0.47 mole per mole (0.19 g/g) Li et al 2012b] was about the same (or even slightly higher) when compared to that observed in flask batch fermentations (Table 12.4). 

Bntamax A fermentation process for making isobutanol, for use as a diesel fuel, from sugar. The process depends on a novel yeast that has been genetically engineered to maximize the production of butanols. Developed by Butamax Advanced Biofuels, a joint venture of BP and DuPont. A demonstration plant was being built in Hull, United Kingdom, in 2012. 

Although MTBE synthesis from methanol and isobutylene is a well-established commercial process, shortfalls in olefin feedstock have led to studies aimed at alternative routes to MTBE. The direct coupling of methanol and 2-methyl-1-propanol to yield methyl isobutyl ether (MIBE) has been demonstrated over resin catalysts [141,142]. Over aNafion H resin at 157°C, Nunan et aL [141] reported hi selectivity for MIBE from methanol and 2-methyl-1-propanol (42 mol% of product mix). Air Products and Chemicals have also reported the synthesis of ethers from methanol-isobutanol, the latter produced from synthesis gas (CO/ C02/H2) over Cs/Cu/ZnO catalysts [143]. In this case, the reaction occurs in a slurry reactor and the feedstock is synthesis gas. Laboratory studies of MTBE synthesis via the oxidative coupling of methane have also been reported [144]. However, yields of these process are very low and require more development before they can be considered alternatives to current commercial technolo . ... 

Abstract Biorefineries focus on fermentative production of butanol, isobutanol and isobutene. This paper encompasses the entire development process, such as strain and substrate selection and optimisation, fermentation modes and purification techniques. Special attention is dedicated to various natural or synthetic metabolic pathways for obtaining these compounds. 

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