Influence of various cosolvents on the calcium oxide-catalyzed ethanolysis of sunflower oil

Abstract

Ten organic solvents (triethanolamine, diethanolamine, ethylene glycol, methyl ethyl ketone, n-hexane, triethylamine, ethylene glycol dimethyl ether, glycerol, tetrahydrofuran and dioxane) were applied as cosolvents in the CaO-catalyzed ethanolysis of sunflower oil performed in a batch stirred reactor under the following reaction conditions: temperature 70 °C, ethanol-to-oil mole ratio 12:1, initial catalyst concentration 1.374 mol•L-1 and amount of cosolvent 20 % based on the oil amount. The main goals were to assess the effect of the used cosolvents on the synthesis of fatty acid ethyl esters (FAEE) and to select the most efficient one with respect to the final FAEE content, reaction duration and safety profile. In the absence of any cosolvent, the reaction was rather slow, providing a FAEE content of only 89.7±1.7 % after 4 h. Of the tested cosolvents, diethanolamine, triethanolamine and ethylene glycol significantly accelerated the ethanolysis reaction, whereby the last two provided a final FAEE content of 93.1±2.1 and 94.1±1.5 %, respectively, within 0.5 h. However, because of its safety profile, triethanolamine was selected as the best cosolvent for the ethanolysis of sunflower oil catalyzed by calcined CaO.

Application of Tubular Reactor Technologies for the Acceleration of Biodiesel Production

“…However, ethanolysis is reputed for its higher cost, energy consumption, lower transesterification reactivity, higher viscosity, formation of an azeotrope with water, and formation of more stable emulsions than methanolysis. Moreover, from the ecological point of view, FAEEs emit less exhaust gas and possess a higher biodegradability in water [ 30 , 31 ].…”

The influence of fatty acid composition on the kinetics of the vegetable oil methanolysis reaction

“…The TAG conversion degree is calculated by the following equation: As can be concluded from Figure 5, there is a good agreement between the model and the experiment, which is confirmed by the low value of the mean relative deviation percentage (MRPD) (±3.1% for 79 data). The reliability of the used kinetic model was also evaluated based on the values of the coefficient of determination (R 2 ) for the linear dependences shown in Figure 3 and 10(2) (2021) [24][25][26][27][28][29][30][31] the MRPD between the calculated and experimental values of TAG conversion degree for each oil type (Table 2). In addition, the model was verified for OAO and SAO that were not included in the analysis of dependence of the reaction rate constant on UFA content.…”

“…The various waste materials have been used as calcium oxide sources, such as eggshells of different poultry species [16,17], mollusk shells [18,19] , and agricultural biomass [20][21][22][23]. Some researchers have also dealt with increasing the activity of calcium oxide in the production of biodiesel, by adding organic [24] and eutectic solvents [25] as cosolvents.…”

Triethanolamine as an efficient cosolvent for biodiesel production by CaO-catalyzed sunflower oil ethanolysis: An optimization study

“…TEOA alone did not show catalytic activity as the FAEE content after 6 h in the absence of CaO was practically neglectable (0.5 %). The positive action of TEOA was related to the visually noticed reduction of the viscosity of the reaction mixture due to the improved mutual miscibility of the reactants in the initial stage of the reaction, thus reducing the mass transfer resistance and increasing both the reaction rate and FAEE yield [24]. Also, hydrophilic TEOA mixed well with ethanol and was able to penetrate faster into the pores of CaO, which resulted in easier diffusion passage of the oil and ethanol to the active sites of the catalyst, resulting in a higher reaction rate [9].…”