Assessment of process variables on the use of macauba pulp oil as feedstock for the continuous production of ethyl esters under pressurized conditions

Abstract

-This study evaluated the potential of macauba pulp oil (MPO) as a feedstock for continuous ester production using ethanol under pressurized conditions. Experiments were performed in order to obtain data for the effect of process variables on ethyl ester (FAEE) and free fatty acid (FFA) conversion in a catalyst-free process. From the results, it appears that the MPO to ethanol mass ratio and the pressure were the variables with more favorable effect on the evaluated response variables. The addition of n-hexane caused an increase in the production of esters; however, this had a negative effect on FFA conversion. The addition of water was unfavorable for oil processing with high acidity. In this process, esterification and transesterification occur simultaneously, and the high FFA content in MPO provides high yields (85 wt% of esters; 93% FFA conversion) at low temperature, since the esterification reaction rate is higher than the transesterification. The decomposition of fatty acids was evaluated and levels <5% were observed under the evaluated experimental conditions.

Simultaneous extraction of the oil from the kernel and pulp of macauba fruit using a green solvent

“…These findings are in agreement with results reported by Colonelli et al. (2017), Lescano et al. (2015), Trentini et al.…”

“…Pulp oil is composed largely of unsaturated fatty acids, oleic being predominant, and palmitic acid was the main saturated fatty acid present. These findings are in agreement with results reported by Colonelli et al (2017), Lescano et al (2015), Trentini et al (2016), . The unsaturated fatty acids play an important role in lowering the risk of cardiovascular disease (Connor, 1999).…”

Catalyst-free production of fatty acid ethyl esters (FAEE) from macauba pulp oil

“…Several reports indicate that the oil extracted from the pulp of macauba presents a high content in free fatty acids (FFA), as observed by Dona et al, (2013) and Visioli et al, (2018), who reported 79.24 and 65.20% of free fatty acids (FFA) in macauba pulp oil, respectively. The oil is often obtained by pressing and filtration without the need for refining steps (Colonelli et al, 2017). Thus, the conventional method involving the use of homogeneous alkaline catalysts is not applicable for the transformation of this oil into biodiesel, since the presence of FFA neutralizes the catalyst and also produces soap emulsions, which hinders the separation of glycerol (Patil and Deng, 2009).…”

“…The amount of alcohol used in the process is higher than that of the stoichiometric oil-toalcohol molar ratio of 1:3, since an excess of alcohol will favor the formation of the esters, shifting the reaction toward the formation of products (Colonelli et al, 2017). This is because there is an increase in the miscibility and the area of contact between the substrates, which benefits the production of esters (Musa, 2016).…”

“…Some authors have reported that the use of an oil-toalcohol molar ratio of 1:40 (which equates to a mass ratio of ∼1:2) gives the highest ester yield (Silva et al, 2007;Trentini et al, 2018). However, other authors have found that the formation of esters was favored up to an oil-toalcohol molar ratio of 1:20 (mass ratio of ∼1:1) (Colonelli et al, 2017;Silva et al, 2010;Trentin et al, 2011).…”