Glycerol conversion into value-added products in presence of a green recyclable catalyst: Acid black carbon obtained from coffee ground wastes

Black carbon from coffee grounds (BCC) was treated with sulfuric acid (BCC-S) or fuming sulfuric acid (BCC-SF) and utilized as catalysts in glycerol etherification reactions. The BCC-SF showed a high amount of sulfur groups, about 8%. However, the treated BCC-S showed the lowest amount of sulfur groups, about 3%. Furthermore, these catalysts show high catalytic activity in the glycerol etherification with tert-butyl alcohol (TBA), the activity being higher for the BCC-SF. The yields for mono-tert-butyl glycerol (MTBG), di-tert-butyl glycerol (DTBG) and tri-tert-butyl-glycerol (TTBG) were very similar to those obtained using a commercial resin, Amberlyst-15. The yields for BCC-SF were about 40 and 20% for the MTBG and DTBG + TTBG, respectively. Furthermore, the acid black carbons showed high stability of the active groups and can be reused in consecutive reactions. (C) 2015 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.