Transesterification of rapeseed oil with ethanol over heterogeneous heteropolyacids

Deactivation of solid catalysts in liquid media: the case of leaching of active sites in biomass conversion reactions

“…64 In other acidic catalysts, like 30 supported heteropolyacids, leaching of active phase has been found to occur under reaction conditions. 65 Lixiviation leading to catalyst deactivation has also been detected when basic catalysts have been employed in the transesterification reaction. Alkali and alkali-earth oxides, like 35 CaO, or hydrotalcites, present leaching problems under biodiesel synthesis conditions.…”

“…Finally, it has to be noted that in some contexts, the leaching of expensive metals from used catalysts is a standard procedure in 65 metal recovery processes, which enables the recycling of the metal from waste catalysts and represents a necessary step to minimize environmental impacts.…”

“…The catalyst stability and deactivation in gas-solid catalytic reactions have been extensively studied and established in the past years. Numerous reviews, proceedings and investigations address the mechanisms of catalyst deactivation when gas reactants are used and the possibilities of regeneration or 65 prevention of the deactivation. 24,25 .…”

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

“…In order to avoid some of the neutralization and purification equipments, the use of a heterogeneous catalyst appears to be a good brand new alternative. In this case, solid acid resins and basic solid resins could be used obtaining good results (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. The advantages of using this catalyst appears in the final products obtained, more pure Biodiesel and glycerin;: and also, in the process itself, which required less equipment and ergo a lower investment.…”

“…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 …”