Kinetics of African pear seed oil (APO) methanolysis catalyzed by phosphoric acid-activated kaolin clay

Abstract

Kinetics and mechanism of heterogeneous transesterification reaction of African pear seed oil (APO) catalyzed by phosphoric acid-activated kaolin clay to produce biodiesel were investigated. Heterogeneous catalyst synthesized by activating clay with phosphoric acid was used to examine the effect of time, temperature, methanol/oil molar ratio, catalyst concentration and agitation speed on the production of biodiesel. The kinetics was studied using two elementary reaction mechanisms: Eley-Rideal (ER) and Langmuir-Hinshelwood-Hougen-Watson (LHHW). The results obtained showed that the clay belongs to kaolinite group and acid-activated clay catalyst, AAC was able to convert APO to standard biodiesel with the variation of catalyst concentration, temperature methanol, speed and reaction time having significant effect in the production. About 78-80% biodiesel production was obtained with 10:1 methanol/oil molar ratio, 3 wt% AAC catalyst concentration, time 3 h, speed 300 rpm and at 60 °C temperature. The kinetics result revealed that the LHHW is the most reliable representation of the experimental data using acid-activated clay catalyst with surface reaction between adsorbed triglyceride and adsorbed methanol as rate determining step (RDS). The activation energy for the forward reaction was determined to be 10.08 kJ/ mol. Hence, the production of biodiesel from non edible oil APO with cheap and available heterogeneous catalyst (AAC) is achievable.

Heterogeneous Catalysis of African Pear Seed Oil and Modelling of Some Thermo-Physical Properties of its Biodiesel

“…The yield of oil obtained is 52%. This is very close to 53.1% obtained by Onukwuli and Ude (2018) when they used n-hexane to extract oil from African pear seed. It is greater than the ones reported for some nonedible seed oil like 36.86% yield reported by Okonkwo and Mukhtar (2013) , 47% seed oil of almond (Ogunsuyi and Daramola 2013) and 16% seed oil of tigernut (Ofoefule et al 2013).…”

“…It is a solid acid catalyst which exhibits both Lewis and Bronsted acid behaviour in their natural and ionexchanged form (Ude and Onukwuli 2019a;Clark 2004). It can catalyse transesterification in thermally activated form (Ude and Onukwuli 2019b), acid activated form (Onukwuli and Ude 2018) and alkaline activated form (Ude and Onukwuli 2019a). It is pertinent to predict some vital thermo-physical properties of biodiesel produced using activated clay in order to widen its application in biodiesel technology.…”

Evaluation of engine performance and emission of African pear seed oil (APO) biodiesel and its prediction via multi‐input‐multi‐output artificial neural network (ANN) and sensitivity analysis

“…The procedure used by Onukwuli and Ude 33 was adopted in the APO extraction with little modification. The seed oil was extracted by solvent extraction; 150 g of the crushed kernel with a particle size of 850 μm was mixed with petroleum ether in a solvent / solute ratio of 2.0 mL g −1 .…”

“…Biodiesel was produced using the method employed by Onukwuli and Ude 33 . The seed oil (100 g) was poured into a three‐neck round‐bottom flask, attached to a condenser and stirrer in a water bath.…”

Heterogeneously Catalyzed Methanolysis of Gmelina Seed Oil to Biodiesel

“…The production of biodiesel for this study was carried out by adopting the method of Onukwuli and Ude [21]. A 500-mL three-neck round-bottom flask fitted with condenser and stirrer placed in a water bath was filled with 100 g of GSO.…”