Phenolic compounds obtained from alkyl oleates as additives to improve the oxidative stability of methyl rapeseed biodiesel

Abstract

Phenolic antioxidants have limited solubility in biodiesel, so this research developed new antioxidants by addition of hydroquinone and catechol on unsaturated fatty acid esters, which improved significantly the oxidative stability of rapeseed biodiesel. This new compound class is more soluble in biodiesel than hydroquinone and catechol, in same molar concentrations. The aging of biodiesel was studied using Metrohm model 743 Rancimat and PetroOxy devices and it was possible to observe an improvement on oxidation stability in both testing using these new antioxidants. Especially the additives 2MB3 and 4MB3 improved the induction period (IP) of rapeseed methyl ester (RME‐B100), from 4 to 63 and 65 h, respectively, with 30 mmol/kg of additives, while hydroquinone in comparison improves the stability to 25 h in the same molar concentration. This new class of antioxidants is promising to enhance oxidative stability of biodiesel, showing the capability of such additives to be commercialized for this purpose. Practical applications: Biodiesel is obtained by different raw materials, so the composition is different according to the source. The biodiesel with higher amounts of unsaturated fatty acids is more susceptible to oxidation than those with higher saturation. To solve problems caused by oxidative deterioration of biodiesel, this research aimed to synthesize a new class of antioxidants as an alternative for preventing and minimize oxidative damage of biofuels. Rapeseed biodiesel without any addition of additive was out of specification according to EN 14214, which regulates oxidative stability greater or equal to 8 h. The additives herein obtained improved significantly the oxidation stability for rapeseed biodiesel by more than 100%.

Application of an electronic nose for determination of pre‐pressing treatment of rapeseed based on the analysis of volatile compounds contained in pressed oil

“…Rapeseed cultivation represents 10% of global oilseed production (Gancarz et al ., 2017b). In view of exploration of alternative energy sources, rapeseed oil not only is an edible product, but is also used in the production of diesel oil (biodiesel) (Rękas et al ., ; Nakayama et al ., ; Muniz‐Wypych et al ., ; Rahim et al ., ). At present, edible oil in Poland, other EU countries and Canada is produced exclusively from double‐refined rapeseed.…”

Influence of Changes in the Level of Volatile Compounds Emitted during Rapeseed Quality Degradation on the Reaction of MOS Type Sensor-Array

“…Rapeseed crops account for 10% of global oilseed production. In the era of the search for alternative energy sources, rapeseed oil is not only edible, but is also used for biodiesel production [19,20]. During the investigations, volatile compounds forming in the process of seed spoilage were identified using GC-MS, and changes in the content of ergosterol, i.e., an indicator of the presence of fungal biomass in stored materials, were determined.…”

Solubility and Antioxidant Potential of a Pyrogallol Derivative for Biodiesel Additive

“…Unfortunately, there is no analysis report about the product’s solubility in oil solutions. Other important research of the coupling reaction between phenolic compound and alkyl molecules in order to increase their solubility and oxidative stability in biodiesel was reported in [19]; the reaction is called synthesis of alkyl phenol using methanesulfonic acid catalyst. This reaction used hydroquinone and catechol to represent phenolic compounds, while the FAME molecules were represented by methyl oleate and ethyl oleate.…”