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The catalytic conversion of meta-cresol (3-methylphenol) was investigated over HBeta, Pt/SiO2, and Pt/HBeta catalysts at 400 °C and atmospheric pressure. The acid sites of zeolite HBeta catalyze methyl transfer reactions (isomerization and transalkylation), yielding cresol isomers (para- and ortho-cresol), dimethylphenol (xylenol) isomers, and phenol. Pt alone catalyzes hydrodeoxygenation and hydrogenation reactions, leading to toluene as the major product and methylcyclohexane as the minor product. Bifunctional Pt/HBeta catalyzes both methyl transfer reactions and hydrodeoxygenation reactions at the same time, producing toluene, benzene, and xylenes. The Pt/HBeta catalyst is about 10 times more active than the Pt/SiO2 catalyst toward hydrodeoxygenation, with a turnover frequency (on the basis of Pt only) 3 times higher, highlighting the significant role of acid sites in the metal-catalyzed hydrodeoxygenation reactions of phenolics. While Pt/HBeta and Pt/SiO2 exhibit similar rates of coke formation, the former has a higher stability than the latter under the same reaction conditions.

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Catalytic conversion of glycerol to gasoline-range alkyl-aromatics has been investigated on a series of zeolites (HZSM-5, HY, Mordenite, and HZSM-22) at 300-400 °C and atmospheric pressure or 2 MPa. Although propenal (acrolein) is the major primary glycerol dehydration product over all zeolites, the pore structure of the zeolite plays a significant role on the final product distribution.The major products over one-dimensional zeolites Mordenite and HZSM-22 are oxygenates (propenal, acetol, and heavy oxygenates) without aromatic formation. HZSM-22 is suitable for the production of acrolein with 86% yield at 100% glycerol conversion. However, it is found that glycerol can be converted to high yields of alkyl-aromatics, mainly C 8 -C 10 over three-dimensional HY and HZSM-5. A longer contact time, higher temperatures, and higher pressures favor the formation of aromatics, with a maximum yield of 60% over HZSM-5. A two-bed configuration with a deoxygenation/hydrogenation catalyst (Pd/ZnO) as the first bed and HZSM-5 as the second bed can further increase the alkyl-aromatic yield. The mono-functional oxygenates produced by the first bed were oligomerized and aromatized into gasoline-range alkyl-aromatics over the second bed.

The deoxygenation of methyl octanoate and methyl stearate over alumina-supported Pt was studied in both the vapor phase in a flow reactor and in the liquid phase in a semibatch reactor. The conversion of both methyl esters resulted in hydrocarbons with one carbon less than the fatty acid of the corresponding ester as the dominant products. In the vapor phase, acid and other oxygenates were observed in low concentrations, but they were not detected when the reaction was conducted in the liquid phase. Under He, condensation products (from esterification and ketonization) were observed. By contrast, under H 2 , mostly paraffins were obtained. These results show promise to directly produce standard diesel components from biodiesel.

The results of catalytic treatment of vapors exiting a g/min pyrolysis unit before product condensation to the liquid phase using a Ru/TiO2 catalyst for oak and switchgrass pyrolysis are reported. The pyrolysis is conducted at 500°C and the catalysis at 400°C at atmospheric pressure with a hydrogen partial pressure of 0.58 atm. It is found that the catalytic treatment provides significant conversion of light oxygenates to larger, less oxygenated, molecules and, simultaneously, bio‐oil phenolics are also converted to less oxygenated phenolics with methoxy methyl groups transferred to the ring. The activity of the catalyst gradually diminished with increasing biomass fed to the system. Untreated pyrolysis oil forms a single liquid phase with some tarry material, consistent with the literature, whereas the treated liquid product forms separate oil and aqueous phases, the latter of which is about 80% water. The oil from the treated vapors has a lower initial viscosity with only a small increase upon accelerated aging compared to the untreated product oil, which has a dramatic increase in viscosity after aging. This is indicative of poor oil stability for untreated oil that is further confirmed by large increases in molecular weight, while the treated oil has a small increase in molecular weight after accelerated aging. In an effort to understand compatibility with refinery streams, the solubility of the oils in tetralin was examined. The untreated oil was found to have very limited solubility in tetralin, whereas the treated oil phase was completely soluble except for a small aqueous phase that appeared. There are a number of challenges in developing a high yield process for pyrolysis based conversion of biomass to transportation fuels. The Ru/TiO2 catalyst used here shows promise for conducting multiple types of favorable reactions in the presence of the full spectrum of primary pyrolysis products that creates significant product stability under mild conditions. This could lead to higher liquid yields of stable, refinery compatible, product oil. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2275–2285, 2013