Carbon-based solid acid catalyst from de-oiled canola meal for biodiesel production

Towards carbon efficient biorefining: Multifunctional mesoporous solid acids obtained from biodiesel production wastes for biomass conversion

“…Further, the stronger weak acid peak in MACHT and JAC was in accord with their functionalized structures whereas the small peak at 310-370 • C in the non-sulfated materials (AC) was accounted by the presence of phosphates (Table 1). It is also worth pointing that NH 3 -acidities based on TPD were approximately ∼30% higher than the acid exchange capacities obtained by titration method, in good agreement with trends found in literature [14,34]. This overestimation can most likely be accounted for by desorption of SOx species along with NH 3 at temperatures 240-500 • C, due to removal of the sulfonic groups from catalyst surface; this, in turn, indicates the limitations of NH 3 -TPD method for acidity measurements of sulfonated carbon materials.…”

“…The single P2p peak at 133.5 ± 1 eV in the phosphoric acid activated carbons also suggested the existence of pentavalent tetracoordinated phosphate compounds (PO 4 or polyphosphates) in their structure (Table 2) [31]. Generally, the S2p photoelectron peak (163-168 eV) is of particular significance in the sulfonated materials and has been used to confirm the presence of SO 3 H groups [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Here, XPS surface analysis also revealed the effects of preparation method on catalyst surface structure.…”

“…But since the sulfonation step is carried out with large amounts of concentrated acids at a high temperature (150-250 • C), the process may not be reasonably called an eco-friendly. In addition, H 2 SO 4 is reported to be ineffective for sulfonating aromatized, ordered and rigid carbon materials such as graphite, activated carbons (AC) or carbons prepared by high temperature treatment [4,5,8,9,14,15]. Hence, by applying the conventional H 2 SO 4 sulfonation it is very difficult to sulfonate ACs, in other words to prepare catalysts simultaneously possessing high porosity (large pore size, pore volume, specific surface area) and SO 3 H density, vital features when considering catalytic applications in conversion of large biomass molecules.…”

“…Over the years, although a large number of manuscripts detailing preparation and applications of these sulfonic acid functionalized materials have been reported. The preparation has been seldom based on a method pioneered by Hara et al [4] involving sulfonation of an incompletely pyrolysed carbonaceous material obtained from sources such as: sucrose [7], glucose [4,8], starch [9], glycerol [10], biochar [11], wood [12], oil pitch [13], canola meal [14], corncob [15] and to name others. Similar, catalysts have also been prepared from more expensive carbon precursors such as phenolic resins [16], carbon foams [17] graphene [18] and OMCs [19,20].…”

Preparation and catalytic performance of a carbon-based solid acid catalyst with high specific surface area

“…Recently, much attention has been focused on carbon-based solid acid catalysts for their potential to replace traditional homogeneous acid catalysts [9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Michikazu Hara et al [9][10][11][12] first report a series of carbon-based solid acid catalysts, which can be readily obtained by incomplete carbonization and sulfonation of polycyclic aromatic hydrocarbons or carbohydrates.…”