Highly active, stable, and recyclable magnetic nano-size solid acid catalysts: efficient esterification of free fatty acid in grease to produce biodiesel

Effect of Fe/Fe2O3 loading on the catalytic activity of sulfonated single-walled carbon nanohorns for the esterification of palmitic acid

“…23 The presence of the iron/iron-oxide core shell nanoparticles enhanced the catalytic activity on ring opening of epoxidized soybean oils and the recovery of the catalysts by magnetic force. 17,24,25 It has also been reported that iron-oxide nanoparticles can adsorb FFA from vegetable oil, which can promote the adsorption of FFA on the catalyst surface. 24 Thus, solid acid catalysts hybridized with iron oxide nanoparticles should achieve a high performance and act as ideal solid catalysts for the esterification of FFA.…”

“…17 Ideally, a solid acid catalyst should have the characteristics of interconnected pores with a large surface area, 18 a high concentration of strong acid sites, and a hydrophobic surface to prevent deactivation by water. 19 Various types of solid acid catalysts such as ion exchange resins, 20 sulphate oxide, 21 mixed oxides and derivatives 22 and carbon-based acid solid catalysts 15,16,23 have been studied.…”

Impacts of Calcination Temperature on Preparation of a Solid Acid Catalyst by Sulfonation of Single-Walled Carbon Nanohorns Dispersed with Iron Nanoparticles

“…Many studies have been reported about developments in novel solid acid catalysts with high acidity (de Angelis et al, 2004), stability, recyclability, and the low cost (Niu et al, 2012;Zillillah et al, 2012) for potential reactions. Additionally, some novel magnetic solid acid catalysts have been developed.…”

“…Additionally, some novel magnetic solid acid catalysts have been developed. Their magnetic property can play a key role to economically recover the catalysts from reaction mixtures (Gill et al, 2007;Kara and Erdem, 2011;Pourjavadi et al, 2012;Tan et al, 2012;Zillillah et al, 2012). For instance, Pourjavadi et al (2012) reported the synthesis of heterogeneous acid catalyst in which ferrimagnetic, Fe 3 O 4 , nanoparticles were coated with multiple layers of polyimidazolium functionalized with sulfonic acid by an ionexchange method.…”

“…It should be noted that nano-size magnetic solid materials containing acid groups on their surfaces are considered to be prime candidate for magnetic solid acid catalysts because such materials can have large active surface area without suffering from the limitations of mass transfer and acid loading amount which can be seen in porous and largesize materials (Zillillah et al, 2012). Among the nano-size materials, single-walled carbon nanohorns (SWCNHs) are promising candidates because of their suitable pore size (Murata et al, 2001), high surface area (Hashimoto et al, 2011), chemical resistance, and thermal stability for use as solid acid material.…”