Solid acid catalyzed biodiesel production by simultaneous esterification and transesterification

Abstract

12-Tungstophosphoric acid (TPA) impregnated on four different supports such as hydrous zirconia, silica, alumina and activated carbon was evaluated as solid acid catalysts for the biodiesel production from low quality canola oil containing upto 20 wt% free fatty acids. The hydrous zirconia supported TPA was found to be the most promising catalyst exhibiting the highest ester yield (y77%). The FTIR, XRD and nitrogen adsorption analysis revealed that the Lewis acid sites generated by the strong interaction of TPA and surface hydroxyl groups of zirconia are responsible for their higher activity. Further, the optimization of reaction parameters was carried out with the most active catalysts i.e. TPA supported hydrous zirconia and it was found that at 200 uC, 1 : 9 oil to alcohol molar ratio and 3 wt% catalysts loading a maximum ester yield of 90 wt% could be obtained. The catalysts were recycled and reused with negligible loss in activity.

An Alternative Eco-Friendly Avenue for Castor Oil Biodiesel: Use of Solid Supported Acidic Salt Catalyst

“…A 40:1 alcohol to oil ratio at 70 0 C (external) temperature and 5 wt% catalysts loading gave a maximum yield of CastMe up to 95%. The textural properties (Kulkarni et al, 2006) of the catalyst were summarized in Table 3. The surface area of microporous silica of 60-100 mesh particle size has 300m 2 /g and pore volume 1.15cm 2 /g and its average pore diameter is 150 A 0 .…”

“…The same reaction when carried out in a similar fashion supporting KHSO 4 on alumina surface, the reaction gives very poor or no yield at all. It may be due to too narrow micropores of alumina which cannot accommodate KHSO 4 molecule to disperse uniformly to enhance catalytic activity (Kulkarni et al, 2006) although its surface area is higher (260m 2 /g). Even though alumina is an interesting support it is assumed that the surface basicity could bring about decomposition of KHSO 4 .…”

“…have the potentials to replace base catalysts since they do not show measurable susceptibility to free fatty acid (FFA) and can catalyse esterification and transesterification simultaneously (Kulkarni et al, 2006). However, separation problem, requirement of high temperature, high molar ratio of oil and alcohol, serious environmental and corrosion related problem make their use non practical for biodiesel production.…”

“…There have appeared in the literature several solid supported acid catalysts such as heteropolyacid, having Keggin structure viz-12-tungsto-phosphoric acid impregnated on various solid supports like hydrous zirconia (Kulkarni et al 2006), silica, alumina, and activated carbonate using as solid acid catalyst for biodiesel preparation from different feedstock with achievement of more than 77% yield of biodiesel. Zeolites (Lotero E et al, 2005, Wang et al,2009) with large pore size have been used with success with fatty acid esterification www.intechopen.com but at higher temperature.…”

A Comparison Between Raw Material and Technologies for a Sustainable Biodiesel Production Industry

“…The soap produced will also be a problem for the downstreaming separation of the biodiesel and the glycerol. The saponification reaction could be seen in Figure 2 (Marchetti et al, 2007, Srivastava & Prasad, 2000, Ma & Hanna, 1999, Fukuda et al, 2001, Knothe et al, 2005, Marchetti, 2010 In order to avoid this problem, the technological solutions put forward were: the use of homogeneous acidic catalysts such as sulfuric acid (Knothe et al, 2005, Marchetti, 2010, Schuchardt et al, 1998, Noureddini & Zhu, 1997, Freedman et al, 1984, Zheng et al, 2006, Canakci & Van Gerpen, 2003a, 2003b, solid catalysts such as zeolites, solid resins (basic as well as acid) (Bournay et al, 2005, Di Serio et al, 2005, Soriano et al, 2009, Hamad et al, 2008, Suppes et al, 2004, Kulkarni et al, 2006, López et al, 2008, enzymatic technologies (Bajaj et al, 2010, Ranganathan et al, 2008, Antczak et al, 2009, Rodrigues et al, 2008, Dalla Rosa et al, 2008, Matassoli et al, 2008, supercritical alcohols (Demirbaş, 2002, 2003, Hawash et al, 2009, Gui et al, 2008, Kasim et al 2009), membrane reactors (Dubé et al 2007, Baroutian et al, 2011, Zhu et al, 2010, Cheng et al, 2010, monolithic reactors …”