Biodiesel wastes: An abundant and promising source for the preparation of acidic catalysts for utilization in etherification reaction

Abstract

Environmentally friendly sulfonated black carbon (BC) catalysts were prepared from biodiesel waste, glycerol. These black carbons (BCs) contain a high amount of acidic groups, mainly sulfonated and oxygenated groups. Furthermore, these catalysts show a high catalytic activity in the glycerol etherification reaction with tertbutyl alcohol, the activity being larger for the sample prepared with a higher glycerol:sulfuric acid ratio (1:3). The yield for mono-tert-butyl glycerol (MTBG), ditert-butyl glycerol (DTBG) and tri-tert-butyl-glycerol (TTBG) were very similar to those obtained using a commercial resin, Amberlyst-15. Furthermore, experimental results show that the carbon with the lowest acidic surface group content, BC prepared in minor glycerol:sulfuric acid ratio (10:1), can be chemically treated after carbonization to achieve an improved catalytic activity. The activity of all BCs is high and very similar, about 50% and 20% for the MTBG and DTBG + TTBG, respectively.

An Overview of the Production of Oxygenated Fuel Additives by Glycerol Etherification, Either with Isobutene or tert-Butyl Alcohol, over Heterogeneous Catalysts

“…Furthermore, the active groups of the acid black carbons exhibited a high stability, allowing them to be used in consecutive reactions. Gonçalves et al [72] also studied the preparation of carbons by hydrothermal treatment of glycerol, that was obtained in the biodiesel production, and sulfuric acid. The best catalytic activity was obtained on the carbon prepared with a glycerol:sulfuric acid ratio of 1:3, attaining yields to the high ethers around 20%, similar to those obtained over the commercial Amberlyst-15.…”

Green acid catalyst obtained from industrial wastes for glycerol etherification

“…The BC materials were prepared by the partial carbonization of the wastes, adapting the procedure described in previous works of our research group [21,22]. The waste coffee grounds used to produce the black carbon were obtained from dried solid residue produced after preparation of the coffee beverage and the PET powder waste was generated during the grinding of the PET bottles for recycling in the PET industry.…”

Optimization of microwave-assisted etherification of glycerol to polyglycerols by sodium carbonate as catalyst

“…Valuable chemicals obtained from glycerol include glyceraldehyde, dihydroxyacetone, hydroxyl pyruvic acid glycolic acid, and glyceric acid [7], 1,3-propanediol [8], polyglycerol esters [9,10], and oxygenated acetals and ketals [11][12][13]. Glycerol by-product from biodiesel production can be a source for the preparation of acidic catalysts for utilization in etherification reactions producing oxygenated additives for fuels [14]. Oxygenated components such as polyglycerols and polyglycerol ethers derived from etherification process are efficient chemical platforms [15].…”