Chromium–tungsten heterogeneous catalyst for esterification of palm fatty acid distillate to fatty acid methyl ester

Bentonites Modified with Phosphomolybdic Heteropolyacid (HPMo) for Biowaste to Biofuel Production

“…With the additional increase in reaction time there is no significant increase in DDPO conversion. Comparatively, these results significantly improved as compared to results from, Wimonrat [15], Khayoon [42], Wan, Lim and Hameed [68] and Wan and Hameed [69], for which similar conversions could only be achieved after 3–5 h reaction employing similar supported heteropolyacid catalysts in esterification reactions.…”

“…Considering other catalyst studies which report washing with tert-Butyl alcohol and very high reaction times [14], leaching of heteropolyacid [5] and significant loss of activity [20], optimum catalysts prepared in this work show advantages including minumum leaching of active HPMo species, good recyclability with moderate loss of activity and simple regeneration in the absence of high temperature calcination (as reported by [21,68,69]).…”

“…12-tungstophosphoric acid supported on metakaolin (25% HPW/MK700) [9] exhibited considerably high conversions at a high temperature (200 °C) despite the minor molar ratio of reactants. Comparatively, CrWO 2 and CrWTiO 2 catalysts required a temperature of 170 °C and a reaction time of 3 h to obtain high conversions (>80%), even though a small molar ratio of reagents is used [68,69], while a catalyst made of the kaolin residue functionalized with –SO 3 H groups) achieved excellent catalytic efficiency (98% conversion) [49] under similar reaction conditions to those employed in this work. Therefore, the present catalysts showed high DDPO conversions under comparatively more benign reaction conditions to most catalysts listed in Table 4.…”

The Functionality of Ion Exchange Resins for Esterification, Transesterification and Hydrogenation Reactions

“…This behaviour was ascribed to improved reactants mixing which enhanced mass transfer rates and movement of reactants . However, when the reactant ratio was increased from 6 : 1 to 12 : 1, the free fatty acid conversion dropped to about 17% which was as a result of surface reaction and mass transfer rates effects . Therefore, it is worthy to note that large reactants ratio (methanol) does not necessarily translate to more conversion, especially when the active sites are insufficient .…”

“…[53] However, when the reactant ratio was increased from 6 : 1 to 12 : 1, the free fatty acid conversion dropped to about 17% which was as a result of surface reaction and mass transfer rates effects. [54] Therefore, it is worthy to note that large reactants ratio (methanol) does not necessarily translate to more conversion, especially when the active sites are insufficient. [16,55] In a different type of esterification study, Tejero et al [4] prepared butyl levulinate from the esterification reaction between levulinic acid and 1-butanol (BuOH) over ionic resins.…”