Hydrodeoxygenation of Levulinic Acid Dimers on a Zirconia-Supported Ruthenium Catalyst

Abstract

The hydrodeoxygenation (HDO) of levulinic acid (LA) aldol condensation product dimers was studied between 250 and 300 °C and 50 bar H2 in a batch reactor with Ru catalyst supported on mesoporous zirconia. During the reaction, the unsaturated dimers, which contained ketone groups and double bonds, were hydrogenated to saturated dimers. A greater degree of deoxygenation was achieved at higher temperatures, and oxygen was removed as water and CO2. Oxygen removal was evidenced by elemental analysis and infrared spectroscopy, in which the C=O peak decreased with increasing temperature. A drawback of high reaction temperature (300 °C) was a minor degree of oligomerization. The formation of aromatics was also observed at the higher temperatures. Aside from the saturated dimers, volatile products were obtained at all temperatures, including ketones, acids, and esters. This study demonstrates for the first time the potential of LA dimers as a sustainable route from lignocellulosic biomass to biofuels and biocomponents.

Recent Advances in the Value Addition of Biomass‐Derived Levulinic Acid: A Review Focusing on its Chemical Reactivity Patterns

“…A 10 mol % loading of the SiO 2 ‐SO 3 H catalyst afforded a 56 % yield of the dimerized product when the reaction was performed at 130 °C for 6 h. The catalyst was successfully recycled without catastrophic loss of activity [213] . The aldol condensation product of LA was subjected to the HDO process at 250–300 °C and 50 bar H 2 pressure in a batch reactor setting using a Ru catalyst supported on mesoporous zirconia [214] . A greater degree of deoxygenation was achieved at higher temperatures, where the oxygen atoms were expelled in the form of H 2 O and CO 2 .…”

Insights into the Influence of Feed Impurities on Catalytic Performance in the Solvent-Free Dimerization of Renewable Levulinic Acid

“…The influence of LA impurities on the stability and performance of the catalysts has been described in the literature mainly for the hydrogenation of bio-derived LA to ɣ-valerolactone [18,[21][22][23][24][25]. However, although several catalytic systems have been reported for the self-condensation of LA into bio-jet fuel precursors [11,[14][15][16][26][27][28][29], all the studies used pure LA as feedstock employing reaction conditions that may not be suitable for using in a process operating with contaminated LA streams derived from a real lignocellulosic biorefinery.…”

Bifunctional Pt–Re Catalysts in Hydrodeoxygenation of Isoeugenol as a Model Compound for Renewable Jet Fuel Production

“…11,12 Studies on HDO catalysts were initially performed with sulfided NiMo and CoMo supported on Al 2 O 3 and SiO 2 used for hydrodesulfurization (HDS) due to obvious similarities between HDO and HDS. 13 Recently, attention has shifted to nonsulfided monometallic and bimetallic catalysts on a variety of supports, such as different types of carbon (activated carbon, 14 carbon black, 15 Vulcan carbon), 16 Sibunit, 17 metal oxides (TiO 2 , 18 ZrO 2 , 19 CeO 2 ), 2020 and nanostructured materials (carbon nanotubes, 21 SBA-15, 22 and MCM-41). 23 The most studied metals for HDO include Ni, Mo, Co, Pt, Ru, and Pd.…”