Reactivity of ethanol over hydroxyapatite-based Ca-enriched catalysts with various carbonate contents†
The Guerbet reaction of ethanol to produce heavier products was performed over a series of extensively characterized carbonate-containing hydroxyapatites (HAPs) with different Ca/P ratios and thus different densities, strengths and natures of acid and basic sites. These properties were correlated with the reactivity of the solids and an optimal ratio between the amount of acid and basic sites was evidenced (ca. 5). The best performance was accordingly obtained over the Hap-CO3 catalyst, which gave a yield of 30% of heavier alcohols at 40% ethanol conversion.