Transesterification reaction of triglycerides in the presence of Ag-doped H3PW12O40

Advancements in solid acid catalysts for ecofriendly and economically viable synthesis of biodiesel

“…H 3 PW 12 O 40 displays a Keggin structure that is comprised of an oxygen tetrahedral‐coordinated heteroatom (PO 4 ) surrounded by 12 edge‐shared oxygen octahedraly‐coordinated addenda atoms (WO 6 ) 42. Although in general, heteropolyacids work as homogeneous catalysts, they can be transformed to solid acid catalysts by combining them with monovalent cations such as NH 4 + , K + , Cs + , and Ag + 43. The Keggin heteropolyacid as H 3 PW 12 O 40 is soluble in methanol and ethanol, while the ammonium salt is insoluble in alcohol.…”

“…The catalyst when reused after washing with n‐hexane, drying, and calcination at 300 o C for 4 h resulted in 70% conversion. Silver has been doped over heteropoly acid to form Ag x H 3‐x PW 12 O 40 , with Ag content varying from 0.5 to 3 by Zieba et al 43 The FTIR analysis indicated no change in structure of Keggin anions of the heteropoly acid when the protons were replaced by the silver cations. With silver content x > 1, only one phase of silver salt with good crystallinity was observed.…”

Cs-substituted H3PW12O40on Palygorskite Clay for Esterification of Oleic Acid with Ethanol

“…Bulk HPW hexahydrate has a cubic structure (Zieba et al, 2010) and is characterized by the corresponding reflections in the XRD patterns ( Figure 2). The patterns of bulk CsHPW exhibited the characteristic lines of the cubic HPW structure, although somewhat different: the reflections of CsHPW were broader and shifted toward higher angles, which was in agreement with the smaller cubic lattice constants obtained for these compounds (Okuhara et al, 2000;Volkova et al, 2002;Dias et al, 2004).…”

Preparation and characterization of magnetic CsH 2 PW 12 O 40 /Fe–SiO 2 nanocatalysts for biodiesel production

“…Reaction was studied for triacetin, a model triglyceride and for vegetable oil, castor oil [14]. Butacaine sulfate and 12-tungstophosphoric acid (HPW) was supported over conventional mesoporous silica and MCM-41.…”