Glycerol conversion towards valuable fuel blending compounds with the assistance of SO3H-functionalized carbon xerogels and spheres

Abstract

The SO3H-functionalized carbon xerogels and carbon spheres were obtained via modification of the initial materials with sulfuric acid or in situ generated diazonium salt (4‑benzenediazonium sulfonate). The catalytic activity of the prepared samples was evaluated in glycerol acetylation leading to valuable fuel blending compounds. The process was conducted at 80 °C, at a glycerol/acetic acid molar ratio of 1:6. The catalysts tested in the reaction were characterized by texture and elemental analysis, potentiometric titration, FTIR measurement, and also using SEM. The catalytic data obtained demonstrate that oxygenated fuel additives can be produced with a combined selectivity of 75% to diacetin and triacetin (DA and TA, respectively), and a selectivity of 25% to monoacetin (MA), with the glycerol conversion of about 97%. These results are comparable to those obtained for a commercial ion exchange resin (Amberlyst 15), indicating a great potential of modified carbons in the glycerol esterification process and other acid-catalyzed reactions.