Selective catalytic hydrogenation of biomass derived furans to secondary alcohols using Pt/polyoxometalate catalysts under mild reaction conditions

Abstract

Promising bifunctional catalyst systems composed of platinum and polyoxometalates (POMs) were applied successfully for the selective catalytic hydrogenation of 2,5‐dimethylfuran (DMF) to 2‐hexanol under mild conditions. Pt(acac)2 was found to be the most active Pt precursor for the ring opening of DMF, and the Keggin‐type POM K3[PW12O40] was identified as the most promoting acidic support for 2‐hexanol formation at 80 °C and 10 bar H2 pressure using n‐decane as a carrier liquid. It was revealed that modifications in the synthetic procedure of the Pt/K3[PW12O40] catalytic system allowed its catalytic performance to be enhanced. Thus, a higher yield of 2‐hexanol (72.5%) was achieved compared to that (49%) obtained using a commercial Pt/C catalyst with the same Pt loading. The Wells–Dawson‐type POM containing catalyst Pt/K6[α‐P2W18O62] was found to be selective for 2‐hexanon formation (56.4% yield) under identical reaction conditions. Furthermore, furan and 2‐methylfuran were also selectively hydrogenated to 1‐butanol (59.7% yield) and 1/2‐pentanol (44.3% yield), respectively, under the applied reaction conditions. Moreover, using analytical tools like N2‐physisorption, NH3‐TPD, inductively coupled plasma optical emission spectroscopy (ICP‐OES), CO chemisorption, and transmission electron microscopy (TEM), revealed that the higher total acid site density of the K3[PW12O40] enhances C=O hydrogenation and overcomes the rate‐limiting step of 2‐hexanone hydrogenation to 2‐hexanol. This demonstrates the high performance of the bi‐functional catalyst system Pt/K3[PW12O40] towards ring opening of various furans and the very high selectivity towards alcohol formation. This approach opens new interesting valorization pathways for several furanic compounds with respect to sustainable alcohol formation. © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.

Hydrodeoxygenation of Oxygenates Derived from Biomass Pyrolysis Using Titanium Dioxide-Supported Cobalt Catalysts

“…Based on the compositions found in the bio-oil before and after HDO at different temperatures, the reaction pathway is proposed in Figure 12. During the HDO process, cellulose derivatives in the bio-oil derived from pyrolysis of L. leucocephala trunk could be converted via several pathways, such as ring rearrangement of anhydrohexose to form furan ring compounds [76,77] or the ring scission of anhydrohexose or C-C cleavage after ring opening to produce C 2-4 products with carbon monoxide or methanol as by-products [78,79]. In the case of furan ring compounds derived from hemicellulose and rearranged from levoglucosan, they could be converted through hydrogenation and/or HDO to produce furan ring compounds having a higher degree of saturation or less oxygen atoms [79,80].…”

Selective Hydrogenolysis of 5‐Hydroxymethylfurfural to 2‐Hexanol over Au/ZrO2 Catalysts

“…Later on, Bell and co‐workers also pointed out the parallel formation of DMTHF, 2‐HON, and 2‐HOL during the liquid‐phase hydrogenation of DMF over Pt/C catalyst with a 2‐HOL yield of less than 10 % [20] . Moreover, Albert and co‐workers obtained a higher yield of 2‐HOL from DMF through Pt/polyoxometalate catalysts [25] . In fact, DMF always originates from the hydrodeoxygenation of HMF.…”

“…[23,24] The major route for 2-HOL synthesis involves the hydrogenolysis of 2,5-dimethylfuran (DMF) or hydrogenation of 2-HON by various heterogeneous or homogeneous catalysts. [25] Till now, studies on the preparation of 2-HOL have mainly used DMF as a substrate. For example, Gilkey et al employed DMF as a model compound to obtain insights into metalcatalyzed ring-opening by combining experiments and computational investigations.…”

“…[20] Moreover, Albert and co-workers obtained a higher yield of 2-HOL from DMF through Pt/polyoxometalate catalysts. [25] In fact, DMF always originates from the hydrodeoxygenation of HMF. To the best of our knowledge, few attempts have been made to directly convert HMF to monohydric alcohol products via ring-opening, although this one-step method seems to be more efficient and energy-saving.…”

“…Among them, 2‐HOL, as a multiuse platform molecule, can be directly converted or mixed with other alcohols to produce liquid transportation fuels, lubricants, or detergents [23,24] . The major route for 2‐HOL synthesis involves the hydrogenolysis of 2,5‐dimethylfuran (DMF) or hydrogenation of 2‐HON by various heterogeneous or homogeneous catalysts [25] …”