Modified Niobium Oxyhydroxide Catalyst: An Acetalization Reaction to Produce Bio‐additives for Sustainable Use of Waste Glycerol

Abstract

We report the synthesis and characterization of new niobium oxyhydroxide catalysts from ammonium niobium oxalate (NH4[NbO(C2O4)2(H2O)](H2O)n) or niobium chloride (NbCl5) precursors. The materials have been modified by incorporating a surfactant, specifically cetyltrimethylammonium bromide, on the catalyst surface to impart partial hydrophobicity to the catalyst. The change in the precursor during the synthesis changes properties associated with the morphology, texture and number of acid sites. These properties provide increased contact at the interface between the hydrophilic and hydrophobic regions to improve the catalytic properties, particularly in biphasic reactions. Acetalization reactions were tested using three different glycerols: commercial glycerol p.a., a crude residual originating from biodiesel production and the same material after desalination. The results show 65 and 60 % conversion for the acetalization under mild reactions conditions.

Glycerol Acetylation over Organic-Inorganic Sulfonic or Phosphonic Silica Catalysts

“…Moreover, it can be utilized as a smart building block for the production of different fine chemicals. In the last years, several chemical reactions (dehydration, etherification, oxidation, acetalyzation) were considered in order to transform glycerol into value‐added chemicals ,,. Esterification and, in particular, acetylation reactions of glycerol is, nowadays, constantly studied because it is a useful approach to obtain mono‐(MAG), di‐(DAG) and tri‐(TAG) acetins (see Scheme ) .…”

Green acid catalyst obtained from industrial wastes for glycerol etherification

“…The reactions concerning glycerol valorization are of great industrial interest. According to Souza et al in 2014, many possibilities for the use of residual glycerin have been investigated, especially employing catalytic processes [9]. Catalytic conversion reactions of glycerol, which is a highly reactive molecule, favor obtaining chemical products with high added value.…”

Niobium Oxyhydroxide‐Polyoxometalate Composite as an Efficient Proton‐Conducting Solid Electrolyte

“…The combination of distinct building blocks into hybrids with the hierarchical structure can usually inherit full advantages of each component or augment their function . In this study, we first report a simple hydrolysis sol‐gel method to in‐situ impregnate crystalline polyoxometalates into amorphous niobium oxyhydroxide forming novel proton‐conducting composite materials.…”