SO3H@carbon powder derived from waste orange peel: An efficient, nano-sized greener catalyst for the synthesis of dihydropyrano[2,3-c]pyrazole derivatives

Optimization and Characterization of Mesoporous Sulfonated Carbon Catalyst and Its Application in Modeling and Optimization of Acetin Production

“…The S2p spectrum ( Figure 5 c) is deconvoluted into two peaks, S2p 3/2 and S2p 1/2, at 169.0 eV and 170.1 eV, respectively, which were assigned to sulfur in the SO 3 H groups, indicating successful sulfonation. The above functional groups were assigned in line with similar sulfonated carbon materials reported in the literature [ 37 , 42 , 43 , 44 ]. The observation of these functional groups and the data from FTIR confirmed the presence of a variety of acidic -SO 3 H, -COOH, and -OH groups.…”

“…This was further confirmed by the pore size distribution ( Figure 6 b) centered between 30 and 50 Å [ 41 , 45 ]. The surface area and pore volume of the catalyst reduced after sulfonation optimization from 484 to 217 m 2 /g and from 0.327 to 0.164 cm 3 /g, respectively ( Table 2 ), suggesting blockage of some pores arising from successful sulfonation process [ 22 , 43 ]. The increase in pore size of the catalyst may permit easy diffusion of the products out of the pores, which may be a contributing factor in the excellent performance of the catalyst in acetylation [ 34 ].…”

“…The catalyst exhibited two major weight losses, as observed in Figure 7 . The first weight loss, which was 6.4%, occurred below 100 °C and was attributed to the loss of moisture or water molecules, while the second weight loss of 10.1% occurred between 250 and 300 °C, attributable to the decomposition of –SO 3 H groups [ 43 , 46 ]. This observation indicates the high stability of the sulfonated catalyst and could be used at a temperature below 250 °C.…”

Tungstic acid (H4WO5) immobilized on magnetic‐based zirconium amino acid metal–organic framework: An efficient heterogeneous Brønsted acid catalyst for l‐(4‐phenyl)‐2,4‐dihydropyrano[2,3c]pyrazole derivatives preparation

“…[ 8 ] Generally, MCR avoids the setbacks such as time‐consuming reaction, low yields, toxicity of the chemicals and solvents, dynamic reaction conditions and tedious workup. [ 7 ] Recently, to improve the efficiency of pyranopyrazoles and its derivatives production, several catalysts such as SO 3 H@carbon powder, [ 8 ] MIL‐53 (Fe) metal–organic frameworks (MOFs), [ 9 ] iron‐doped calcium oxalates, [ 10 ] poly (ethylene imine)‐modified magnetic hallo site nanotubes, [ 11 ] and nano‐Al 2 O 3 /BF 3 /Fe 3 O 4 [ 12 ] have been developed. All of these catalysts suffer from several drawbacks: difficult separation from the reaction medium, high costs, low surface area, middle electronic and thermal stability, and the use of toxic organic solvents.…”

Glycolysis of Poly(Ethylene Terephthalate) Using Biomass-Waste Derived Recyclable Heterogeneous Catalyst

“…Though orange peel (OP) contains some important by-products and was traditionally used to obtain essential oils and flavouring compounds [ 39 ], such a level of consumption generates a huge amount of orange peel waste, which eventually ends up in landfills [ 53 ]. More recently, efforts have been made to utilize OP waste either as a carbon activated for catalyst support [ 54 ], as a heterogeneous catalyst for chemical transformations [ 55 , 56 ] and for the production of low-cost biodiesel [ 57 , 58 ]. However, to our knowledge, there is no report of biomass waste-derived heterogeneous catalyst for the depolymerization of PET waste.…”