Two-Step Sequence of Acetalization and Hydrogenation for Synthesis of Diesel Fuel Additives from Furfural and Diols

Abstract

Acetalization of diols with furfural and subsequent hydrogenation of acetal products provided potential fuel additives that could be blended into commercial diesel. Glycerol could be an interesting polyol for acetalization with furfural due to its low cost, and it is produced as a byproduct in very large amount in the process of biodiesel production. In this work, glycerol acetalization with furfural has been selected as a model reaction. Acetalization reaction was performed under neat conditions (solventless) with 1:1 molar ratio of furfural and glycerol at room temperature over various acid catalysts, including homogeneous and heterogeneous acids. Among several catalysts, Zr-Mont, a heterogeneous solid acid having controlled acidity, gave as high as 78% isolated yield of acetal products. Interestingly, acetal products can be isolated in pure form by performing extraction using cyclohexane that enables selective extraction of product, and unreacted glycerol and furfural were left in aqueous phase, which can be recycled. Further, to make fuel components from isolated acetal product of glycerol and furfural, hydrogenation was performed over a series of supported noble-metal catalysts under low H2 pressure at room temperature. Among them, 5% Pd/C showed very high activity for ring hydrogenation that resulted in high yield of hydrogenation products. However, hydrogenated product contains free hydroxyl group that needs to be subsequently etherified or acetylated. Interestingly, etherified derivative was obtained in high yield compared to acetylated derivative. In addition, several other diols were treated with furfural and their products were subsequently hydrogenated over 5% Pd/C under very low H2 pressure. The properties of resulting compounds were investigated so as to find most suitable candidates as additives to commercial diesel.

Versatile Coordination Polymer Catalyst for Acid Reactions Involving Biobased Heterocyclic Chemicals

“…A rhenium-containing hectorite ReHectMw used in catalyst/Gly = 0.05 (entry 11 [101]) led to 23% total acetals yield at 40 • C/4 h, and 1 in a fifth of the catalyst/Gly ratio led to 37% total yield at 50 • C/0.5 h. Very good results were reported for Zr-Montmorillonite (entry 9 [106]), 12-tungstosilicic acid supported on MCM-48 (TSA-nMCM-48, entry 15 [113]) and a sulfonic acid functionalized organic polymer (An-POP-SO 3 H, entry 20 [84]), used in a catalyst/Gly ratio between 0.02 and 0.2, which led to 78-87% total acetals yield in the temperature range room temperature (rt)-40 • C and 0.5-4 h reaction time. Similar results (78-91% total yield) were reached for 1 with catalyst/Gly = 0.01-0.1, albeit at 90 • C/4 h (entries 5, 6).…”

“…Protonic lignosulfonate-based macro/mesoporous 80LS 20 PS 450 H + (synthesized in a multistep fashion involving freeze-dry, pyrolysis, ion exchange) was tested for the Fur/Gly reaction at 100 • C/1 h (entry 23 [103]), leading to similar results to 1 at 90 • C/4 h, in a higher catalyst:Gly ratio (entry 6), 93% and 91% total acetals yield, respectively. The performance of 1 seemed somewhat comparable/superior to the acid resins Amberlyst-15 (80% total yield at 70 • C/4 h, cyclohexane as co-solvent, entry 21 [77], compared to 81% for 1 at 70 • C/4 h without cosolvent, entry 4) and Amberlite-IR120 (56% total yield at rt/4 h, entry 22 [106], compared to 56% for 1 used in a sixth of the catalyst/Gly mass ratio at 50 • C/2 h, entry 1). Overall, the catalytic results for 1 in the Fur/Gly reaction seemed relatively good among the studied solid acid catalysts.…”

“…A literature survey for the Fur/Gly reaction to dioxane/dioxolane products indicated that crystalline coordination polymers/MOFs have not yet been investigated for this reaction. Table 3 compares the catalytic results for 1 (using 3.8 or 38 g cat L −1 , at 50-90 • C) to literature data for various other types of solid acid catalysts [31,32,77,78,81,84,86,101,103,106,[113][114][115]. When a work focused on the same type of catalyst modified in slightly different fashions, the best results reported in that work were chosen to be included in Table 3.…”

“…The reactions of Gly with aromatic aldehydes such as furfural (Fur) and benzaldehyde (Bza)-derived from lignocellulosic biomass (Fur) [104], pyrolysis of vegetable biomass (Fur and Bza) [105] or oil (Bza)-may give cyclic acetals (Scheme 1) as fuel additives [77,101,106] with antioxidant, non-toxic and renewable features [84]. Different types of acid catalysts were studied for the Bza/Gly reaction (organic acids [107], metal chlorides [108], ionic liquids [109], Keggin-tungstophosphoric acid-based [92], acid resins [77,79,110] and organic polymers [84], metal or mixed metal oxides [82,111], sulfated metal oxides [33], zeolites [19,79,82], functionalized silicas [93,102,112], mesoporous silicas or aluminosilicates [19,31,32,83,88,113] and silesquioxanes [80]), and for the Fur/Gly reaction (metal chlorides [114], resins [77,106] and organic polymer [84], metal or mixed metal oxides [78,81,99], mesoporous silicas or aluminosilicate (bulk and supported) catalysts [31,32,101,[113][114]…”

Batch and Continuous‐Flow Preparation of Biomass‐Derived Furfural Acetals over a TiO2 Nanoparticle‐Exfoliated Montmorillonite Composite Catalyst

“…Furthermore, acetals derived from furfural and polyols such as propylene glycol and glycerol are considered as potential biofuels and fuel precursors. [11] For the acetalization reactions of furfural and short-chain alcohols, it was usually required high reaction temperature (60-140°C) for pure Lewis acid catalysts, such as NiÀ Al LDH, [12] NiRh/ γ-Al 2 O 3 [13] and titanium suboxide Ti 2 O 3 , [14] whereas room temperature was enough for the Brønsted acid catalysts such as sulfonic cation exchange resin, H 2 SO 4 , HCl, p-toluenesulfonic acid, H 3 PW 12 O 40 , and H 3 PMo 12 O 40 , [10b,15] indicating Lewis acid and Brønsted acid are the two driving forces that can act independently to accelerate the acetalization reactions. Furthermore, it was revealed that the catalytic performance of the catalysts with both Brønsted acid (strong or weak) sites and hard Lewis acid sites was better than that of pure Brønsted acid catalysts.…”