Development of bio-inspired supports based on Ca–SiO2 and their use in hydrodeoxygenation of palmitic acid

Abstract

Novel supports were developed for biomass conversion. A series of Ca–SiO2 materials were synthesized with a bio-inspired methodology. We used CaCO3 and CaSO4 for the modification of high surface area SiO2 to introduce basic and acid sites into the support. These two calcium sources were impregnated into the SiO2 in the presence of l-Alanine or l-Glycine. Both amino acids are able to bind calcium and those were used as a bio-inspiration procedure for changing the surface properties of SiO2. A series of MoO3 catalysts were prepared on the different supports and those were tested in the hydrodeoxygenation (HDO) of palmitic acid (PA). We found the formation of crystalline phases at the support surface due to the Ca addition. CaCO3 crystalline structure disappeared after the preparation of the catalysts because a new compound is formed, CaMoO4, while CaSO4 is not able to form any new compound with MoO3. Surface basicity and acidity were characterized by FT-IR using CO2 or pyridine adsorbed on the materials, respectively. We found that acidity plays a major role in the HDO of PA. Highly active MoO3-based catalysts were obtained by using SiO2–CaSO4 or SiO2–CaCO3 supports combined with amino acids.