Supported CaO Catalysts Used in the Transesterification of Rapeseed Oil for the Purpose of Biodiesel Production

Abstract

Supported CaO/MgO catalysts were used as the catalyst of the transesterification of rapeseed oil with methanol. The supported catalyst showed a higher activity than pure CaO and was easily separated from the product mixture. The results of comparative experiments and catalyst characterization, such as XRD, CO2-TPD, BET, and AAS, showed that the activity of CaO catalysts is associated with their alkalinity. The preparation method of this catalyst was optimized, and furthermore, the reaction parameters were investigated. With the CaO/MgO catalyst so obtained, the conversion of rapeseed oil reached 92% at 64.5 °C. The supported basic catalyst was found to be easily contaminated by the gaseous poisons in air, such as O2, CO2, and H2O, and as a result, a thermal treatment was required before the reaction to activate the catalyst.

Biodiesel Production by Using Heterogeneous Catalysts

“…Besides, heterogeneous catalysts exhibit a less corrosive character and can be used in a fixed-bed reactor, leading to safer, cheaper and more environment-friendly operations and the number of separation steps is less than when using homogeneous catalysts. The heterogeneous catalysts do not leave neutralization salts in the glycerol, and are plausible to be retained in the reactor by filtration (Di Serio et al, 2008;Kaita et al, 2002;Kawashima et al, 2009;Kovacheva et al, 2001;MacLeod et al, 2008;Madje et al, 2004;Park et al, 2010;Suppes et al, 2004;Waghoo et al, 1999;Xie & Li, 2006;Yan et al, 2008). The most commonly studied heterogeneous basic catalysts are alkaline metals carbonates (Na 2 CO 3 , K 2 CO 3 ), alkaline earth metal carbonates (CaCO 3 ), alkaline earth metal oxides (CaO, MgO, SrO, BaO) and other oxides as ZnO (Dossin et al, 2006b;Encinar et al, 2005;Fukuda et al, 2001;Liu et al, 2007;López et al, 2005;Ma & Hanna, 1999;MacLeod et al, 2008;Verziu et al, 2008).…”

“…However, the use of BaO is not practical enough since it is soluble in methanol and also forms highly toxic compounds. Regarding SrO, this oxide possesses a strong tendency to react with CO 2 and water present in air to form strontium hydroxide and strontium carbonate, thus losing its catalytic ability (Yan et al, 2008). Among the abovementioned oxides, the CaO and MgO have been extensively studied in the transesterification reaction.…”

The Effect of Mesoporous H-ZSM-5 Crystallinity as a CaO Support on the Transesterification of Used Cooking Oil

“…Heterogeneous catalysts have been studied have a relatively high catalytic activity, but requires phase synthesis is complex and time-consuming. Thus, for further research to look for heterogeneous catalysts are an ideal, inexpensive, environmentally friendly in nature, and is effective for the transesterification reaction [4].…”

Activated carbon supported CaO for conversion of palm oil to biodiesel: Kinetic experiment

“…The type of alcohol and the fatty acid profile of the oil affect the properties of biodiesel product (Yan et al, 2007).…”

“…Basic zeolites, hydrotalcites and alkaline earth oxides are among the reported solid catalysts used for the transesterification reaction (Helwani et al, 2009 (Helwani et al, 2009). It has been reported elsewhere (Kouzu, 2012) that CaO supported by porous materials could be a potential solid catalyst f rom the economic and catalytic activity point of view (Yan et al, 2007;Tongpoothorn et al, 2011;Buasri et al., 2012).…”