Alternative carbon based acid catalyst for selective esterification of glycerol to acetylglycerols

Graphite oxide activated zeolite NaY: applications in alcohol dehydration

“…Sulfonated pyrolyzed carbon sources such as olive stone, sucrose and starch have also been utilized as SACs for the dehydration of ethanol, the esterification of glycerol, and the hydration of 2,3-dimethyl-2-butene, respectively. 11,12,14 These sulfonated carbon materials maintain a high level of acidity even in the presence of water which offers advantages over traditional inorganic oxides such as zeolites, whose acidity can be compromised under aqueous conditions. 11 Unfortunately, the pyrolysis step required to prepare these sulfonated catalysts utilizes temperatures that commonly exceed 400 1C.…”

“…1,2 The composition and structure of SACs is diverse and includes alumina and modified alumina, 3,4 modified zirconia, 5 reactive clays, 6 sulfonated polymer resins, [7][8][9] carbon-based materials, [10][11][12][13][14][15] and zeolites. [16][17][18][19] Zeolites, which are high-surface area aluminosilicates with a well-defined structure, are among the most widely used SACs largely because they are employed in the petroleum industry as fluid cracking catalysts.…”

Biobased catalyst in biorefinery processes: sulphonated hydrothermal carbon for glycerol esterification

“…25 The use of sulphonated carbons in glycerol esterification has been recently described. 26,27 Sulphonated pyrolised (400°C) sucrose provided excellent glycerol conversion and a maximum of 50% selectivity towards TAG at 180°C. 26 Sulphonated activated carbon led to mixtures of 38% MAG, 28% DAG and 34% TAG at 120-135°C with glycerol conversions over 90%.…”

“…26,27 Sulphonated pyrolised (400°C) sucrose provided excellent glycerol conversion and a maximum of 50% selectivity towards TAG at 180°C. 26 Sulphonated activated carbon led to mixtures of 38% MAG, 28% DAG and 34% TAG at 120-135°C with glycerol conversions over 90%. 27 Carbons prepared under mild conditions, such as hydrothermal carbon (HTC), are very attractive materials from a sustainability point of view.…”

Zr-modified hierarchical mordenite as heterogeneous catalyst for glycerol esterification

“…A major drawback to using homogeneous catalysts is that they lead to serious technical and environmental problems. Therefore, employing heterogeneous acid catalysts can contribute to overcome these drawbacks [1,11,[13][14][15][16]. Due to their stronger Brönsted acidity than conventional solid acids like mixed oxides and zeolites, Keggin type heteropolyacids (HPAs) can be employed instead of classical homogeneous acids [17][18][19][20][21][22][23][24][25][26][27][28][29].…”