The Carbonate-Catalysed Transesterification of Sunflower Oil for Biodiesel Production: In Situ Monitoring and Density Functional Theory Calculations - data

Biodiesel has emerged as a promising alternative fuel to replace dwindling fossil-based resources, particularly in view of its added environmental merit of reducing additional air pollution. Its specific attraction stems from the similarity of its physical properties to fossil fuel-derived diesel. Although the production of biodiesel is a relatively straightforward process, reaction progress monitoring and product analysis require costly specialist equipment, such as gas chromatography and mass spectrometry. In this study, we investigate the use of pH in monitoring the progress of carbonate-catalysed transesterification reactions. Specifically, we focus on potassium and sodium carbonates and sunflower oil. Our results are consistent with the results obtained by other studies using different methods of monitoring. To test the generality of the method, pH measurements were also used to monitor the progress of the potassium carbonate transesterification reaction in the presence of added water, glycerol and gamma-valerolactone (GVL). The obtained results are as expected, with a limited amount of water increasing the transesterification rate; glycerol slowing the reaction slightly in accord with Le Chatellier’s principles, and GVL increasing the rate due to co-solvent effects. Atomic-level insights into the adsorption mechanism of methanol and water on the (001) surface Na₂CO₃ and K₂CO₃ catalysts is provided by first-principles DFT calculations, which explain the increase in transesterification reaction rate upon the addition of water.

The experimental and Density functional theory (DFT) theoretical simulation datasets are available in the .xlsx format (can be viewed either by MS Office or Libre Office) comprising 11 datasheets named after the Figure numbers in the published manuscript in the South African Journal of Chemistry. The experimental data is comprised of the conversion of sunflower oil to biodiesel using (Na₂CO₃ and K₂CO₃) as catalysts; effect of adding water to the pH the on catalysed reactions; pH time profile for catalysed reaction with different amounts of added glycerol. The DFT data is comprised of optimized structures for the bulk Na₂CO₃ and K₂CO₃ materials; surface structures; and lowest-energy adsorption structures of methanol and water. The CONTCAR files consist of lattice parameter and atomic positions and can be viewed either by VESTA program, MS Office or WordPad.

Research results based upon these data are published at http://dx.doi.org/10.17159/0379-4350/2021/v74a8