Iron(III) Complexes for Highly Efficient and Sustainable Ketalization of Glycerol: A Combined Experimental and Theoretical Study

Abstract

The growing production of biodiesel as a promising alternative and renewable fuel led as the main problem the dramatic increase of its by-product: glycerol. Different strategies for glycerol derivatization have been reported so far, some more efficient or sustainable than others. Herein, we report a very promising and eco-friendly transformation of glycerol in nontoxic solvents and chemicals (i.e., solketal, ketals), proposing three new families of Fe(III) compounds capable of catalysing glycerol acetalization with unpublished turn over frequencies (TOFs), and adhering most of the principles of green chemistry. The comparison between the activity of complexes of formula [FeCl 3 ( 1-R )] ( 1-R = substituted pyridinimine), [FeCl( 2-R , R′ )] ( 2-R , R′ = substituted O , O ′-deprotonated salens) and their corresponding simple salts reveals that the former are extremely convenient because they are able to promote solketal formation with excellent TOFs, up to 10 5 h –1 . Satisfactory performances were shown with respect to the entire range of substrates, with results being competitive to those reported in the literature so far. Moreover, the experimental activity was supported by an accurate and complete ab initio study, which disclosed the fundamental role of iron(III) as Lewis acid in promoting the catalytic activity. The unprecedented high activity and the low loading of the catalyst, combined with the great availability and the good eco-toxicological profile of iron, foster future applications of this catalytic process for the sustainable transformation of an abundant by-product in a variety of chemicals.

Catalytic Activity and Kinetic Modeling of Various Modules HZMS-5 and Treated MCM-41 Catalysts, for the Liquid-Phase Ketalization of Glycerol With Acetone

“…The activation energy using the liquid-phase ketalization of glycerol with acetone was also described in the literature (Esteban et al, 2015; Esposito et al, 2019). This current study found that an estimated E A , from the figure above is equal to 164.34 kJmol −1 and k 0 = 5.2678 * 10 28 (Con 1/2 .…”

Glycerol Oxidation over Supported Gold Catalysts: The Combined Effect of Au Particle Size and Basicity of Support

“…Glycerol, a highly functionalized molecule, was identified as one of the top twelve most important bio-based chemicals in the world by the US Department of Energy [1]. Glycerol has a wide range of applications, from the production of food additives to pharmaceuticals, cosmetics, personal care products and detergents, and it is also transformed into non-toxic solvents [2][3][4][5].…”

Emerging catalysis in biomass valorisation: simple Zn(II) catalysts for fatty acids esterification and transesterification

“…Homogeneous basic catalysis is the traditional industrial technology to obtain biodiesel and glycerol, (Scheme 4) also useful for several biobased product. [50] Its drawbacks are the difficult recovery of the catalyst, purification and disposal steps needed. Therefore, academic and industrial research focused on heterogeneous basic catalysts, mainly metal oxides.…”