Transesterification of Castor Oil: Effect of Catalyst and Co-Solvent

Abstract

Biodiesel is emerging as an alternative fuel with several advantages over the common petroleum based fuels. In its production, however, variables such as raw material, catalyst, and co-solvent are an issue worth exploring because of the impact they have on final biodiesel properties. Therefore, this work aims to establish the effect of the aforesaid variables on methyl ester content, viscosity, acidity, and water content of biodiesel produced from castor oil. In this context, the methanolysis of castor oil has been conducted at 60 °C in a batch reactor, and the effect of three alkaline catalysts (CH3ONa, NaOH, and KOH) and a co-solvent (hexane) has been established. It is concluded that sodium methoxide leads to considerably higher methyl ester content than the other essayed catalysts. Besides, when utilizing a co-solvent the methyl ester content increases up to a very close value (95.5%) to that established by the EN14214 norm (>96.5%). This has been ascribed to a significant improvement on oil−methanol contact.

Synthesis of biodiesel by In-situ transesterification of Karanja oil

“…That is, extraction and transesterification takes place simultaneously, the alcohol acts as an extraction solvent and an esterification reagent (Gerhard, 2005). Several authors (Han et al, 2005;Georgogianni et al, 2008: Pena et al, 2009 have discussed the problem of the mass transfer limitations in transesterification reactions due to low oil solubility in alcohol phase; this problem slows down the reaction resulting in low ester yield. "…”

Co-Solvent Transesterification of Bitter Almond Oil Into Biodiesel: Optimization of Variables and Characterization of Biodiesel

“…Many non-edible oils were used in the production of BD, such as Jatropha curcas seed oil, rubber seed oil and castor seed oil (Mohammed-Dabo et al 2012;Morshed et al 2011;Peña et al 2009;Berchmans et al 2013;Fadhil et al 2017a;Shambhu et al 2013). There are two types of almond; the first is the sweet almond, which is characterized by its white flowers, whereas the second is bitter almond, which flowers are pink.…”

“…As a result, the mass transfer between the two phases becomes a significant factor that affects the reaction rate. Thus, to enhance miscibility between the two phases, transesterification temperature is raised, but this is an energy-consumptive process (Encinar et al 2010;Mohammed-Dabo et al 2012;Peña et al 2009). Transesterification in the presence of a cosolvent was proposed as a new technique to increase the mixing efficiency and the mass transfer between alcohol and triglyceride (Encinar et al 2010;Mohammed-Dabo et al 2012;Peña et al 2009;Surya Abadi Ginting et al 2012).…”

“…Thus, to enhance miscibility between the two phases, transesterification temperature is raised, but this is an energy-consumptive process (Encinar et al 2010;Mohammed-Dabo et al 2012;Peña et al 2009). Transesterification in the presence of a cosolvent was proposed as a new technique to increase the mixing efficiency and the mass transfer between alcohol and triglyceride (Encinar et al 2010;Mohammed-Dabo et al 2012;Peña et al 2009;Surya Abadi Ginting et al 2012). The presence of co-solvent within the reaction medium increases the reaction rate by increasing the collision among the reactants molecules, resulting in better mass transfer and shorter reaction time.…”

“…The presence of co-solvent within the reaction medium increases the reaction rate by increasing the collision among the reactants molecules, resulting in better mass transfer and shorter reaction time. Many solvents, such as Tetrahydrofuran (THF), hexane, diethyl ether, acetone and acetonitrile were used as co-solvents on transesterification process (Mohammed-Dabo et al 2012;Encinar et al 2010;Peña et al 2009). It was reported that co-solvent utilized during transesterification reaction is preferable to have boiling point near that of employed alcohol so that it could be recycled with excess alcohol at the same time (Mohammed-Dabo et al 2012;Encinar et al 2010).…”