Versatile Coordination Polymer Catalyst for Acid Reactions Involving Biobased Heterocyclic Chemicals

Abstract

The chemical valorization/repurposing of biomass-derived chemicals contributes to a biobased economy. Furfural (Fur) is a recognized platform chemical produced from renewable lignocellulosic biomass, and furfuryl alcohol (FA) is its most important application. The aromatic aldehydes Fur and benzaldehyde (Bza) are commonly found in the slate of compounds produced via biomass pyrolysis. On the other hand, glycerol (Gly) is a by-product of the industrial production of biodiesel, derived from fatty acid components of biomass. This work focuses on acid catalyzed routes of Fur, Bza, Gly and FA, using a versatile crystalline lamellar coordination polymer catalyst, namely [Gd(H4nmp)(H2O)2]Cl·2H2O (1) [H6nmp=nitrilotris(methylenephosphonic acid)] synthesized via an ecofriendly, relatively fast, mild microwave-assisted approach (in water, 70 °C/40 min). This is the first among crystalline coordination polymers or metal-organic framework type materials studied for the Fur/Gly and Bza/Gly reactions, giving heterobicyclic products of the type dioxolane and dioxane, and was also effective for the FA/ethanol reaction. 1 was stable and promoted the target catalytic reactions, selectively leading to heterobicyclic dioxane and dioxolane type products in the Fur/Gly and Bza/Gly reactions (up to 91% and 95% total yields respectively, at 90 °C/4 h), and, on the other hand, 2-(ethoxymethyl)furan and ethyl levulinate from heterocyclic FA.

Acetalization of Glycerol with Citral over Heteropolyacids Immobilized on KIT-6

“…Great selectivity to 5R acetal was obtained after the fifth utilization of PW4-K-6 (Table 3). The glycerol acetalization with citral may be triggered by interactions between the oxygen atom of the carbonyl group of citral (aldehyde) and Brönsted acid sites, according to the mechanistic proposal given in Figure 13 [18,41]. Specifically, the formation of a hemiacetal in the reaction of the citral with glycerol may be followed by the elimination of an H 2 O molecule and formation of a carbocation [41], which, in turn, suffers an attack involving the inner or terminal hydroxyl group of the glycerol molecule, finally giving the cyclic acetals 1,3-dioxolane and 1,3-dioxane, respectively.…”

“…Glycerol acetalization with aldehydes and ketones yield acetal compounds, which can be employed in different industries. Acetal compounds obtained from glycerol acetalization are useful fuel additives, fragrances, cosmetics, and pharmaceuticals products [12][13][14][15][16][17][18][19][20][21][22][23].…”

Preparation and Characterization of a Coordination Polymer Based on Iron (III)-Cyamelurate as a Superior Catalyst for Heterogeneous Fenton-Like Processes

“…All reports on compounds based on cyamelurates suggested good chemical stability in aqueous media, supporting their use in different catalytic processes under this condition. There have been many works that reported that CPs can be superior heterogeneous catalysts by different reactions. − In this way, this work evaluated for the first time the use of a CP based on the tris- s -triazine derivative, iron­(III) cyamelurate, as a potential catalyst to boost the heterogeneous Fenton-like reaction.…”