Use of NaNO3/SiAl as Heterogeneous Catalyst for Fatty Acid Methyl Ester Production from Rapeseed Oil

Abstract

The use of heterogeneous catalysts to produce fatty acid methyl esters (FAME) through transesterification with methanol might contribute to both green chemistry and a circular economy, as the process can be simplified, not requiring additional stages to recover the catalyst once the reaction takes place. For this purpose, different catalysts are used, including a wide range of possibilities. In this research the use of NaNO3/SiAl as a heterogeneous catalyst for FAME production through transesterification of rapeseed oil with methanol is considered. A thorough characterization of the catalyst (including XDR and XPS analysis, SEM microscopy, lixiviation and reusability tests, among others), specific optimization of transesterification by using the final catalyst (considering catalyst amount, stirring rate, methanol/oil ratio, and temperature), and quality determination of the final biodiesel (following the UNE-EN 14214 standard) were carried out. In conclusion, 20 mmolNa·gsupport−1 (that is, NaNO3/SiAl 20/1) offered the best results, with a high activity (exceeding 99% w/w of FAMEs) without requiring higher impregnation amounts. The best chemical conditions for this heterogeneous catalyst were 5% w/w catalyst, 700 rpm, 9:1 methanol/oil ratio, and 65 °C, obtaining Ea = 73.3 kJ·mol−1 and a high-quality biodiesel, similar to those obtained through homogeneous catalysis. Consequently, this catalyst could be a suitable precursor for FAME production.

Catalytic Transformation of Triglycerides to Biodiesel with SiO2-SO3H and Quaternary Ammonium Salts in Toluene or DMSO

“…The rate of reaction is higher when homogeneous base catalysts are used, but the cost of the process is high because of the need to separate the catalysts from the reaction media after product formation. In another study, Encinar et al [ 6 ] studied the use of NaNO 3 /SiAl as a heterogeneous catalyst for FAME production through transesterification of rapeseed oil with methanol. The highest yields of biodiesel containing 99% FAME were obtained with 5% w / w catalyst, with stirring at 700 rpm, with a 9:1 methanol/oil ratio at 65 °C.…”

Kinetic Study of Ultrasound-Intensified Biodiesel Production Using Anion Exchange Resin as a Heterogeneous Catalyst

“…The pseudohomogenous model was the one that better adjusted the experimental results because of the small catalyst particle sizes and hence the absence of mass transfer limitations. Encinar et al 33 studied the production of free acid methyl ester (FAME) with NaNO 3 / SiAl as a heterogeneous catalyst using rapeseed and applying the LH and ER models. The ER model properly predicted the transesterification kinetics studied in this case.…”

Transesterification reaction of tristearin (TS) & glycerol mono stearate (GMS) over surface basified PAN fibrous solid catalyst

“…Nonetheless, our heterogenous basified PANF solid catalyst showed a very high catalytic activity after 9th recycles and for four cycles after regeneration as compared to other works. [40][41][42][43]…”