Metal-Modified Zeolites for Hydrodeoxygenation of Lignin Derived Phenolics

Fuels from renewable sources can become a solution to several economic and environmental problems. Bio-oils obtained from pyrolysis of biomass cannot be used as fuels directly because of several reasons, including high oxygen content and low stability. The most common way to improve the quality of bio-oils is hydrodeoxygenation by removing oxygen from oxygen-containing bio-oil compounds. In kinetic studies model compounds, found in bio-oils are typically used. In the current work, hydroeugenol was applied, as it has hydroxyl, methoxy, and allyl groups, representative for bio-oils derived from lignin. Not only metal type can affect the reaction rate, conversion, and selectivity, but also the support nature. In particular, support acidity and the textural properties are the most important parameters that can influence the reaction. In this work, solventless hydrodeoxygenation of hydroeugenol and dihydroeugenol was investigated in batch and continuous reactors over different nickel-iron catalysts, prepared using a two-step impregnation method. The following catalysts were studied: mesoporous FeNi/H-MCM-۴۸ as well as microporous FeNi/H-Beta-۳۰۰, FeNi/H-Beta-۳۸, FeNi/H-Y-۵.۱, FeNi/USY-۳۰, as well as reference materials FeNi/Al۲O۳ and FeNi/SiO۲. The catalysts were characterized by SEM coupled with energy dispersive X-ray analysis, Mössbauer and X-ray absorption spectroscopy, hydrogen TPR, X-ray diffraction, TEM, nitrogen physisorption, and FTIR pyridine adsorption. A special emphasis was put on determination of the local environment of metals. In the presentation, the catalytic performance will be correlated with the material properties, aiding in revealing the reaction mechanism.

کلیدواژه ها:

Zeolites ، Hydrodeoxygenation ، Bio-oil ، Isoegenol