Mixed metal oxides from sucrose and cornstarch templated hydrotalcite-like LDHs as catalysts for ethyl biodiesel synthesis

Abstract

Sucrose and cornstarch were used as organic templates in the synthesis of hydrotalcite-like layered double hydroxides (LDHs) prepared by the coprecipitation with partial replacement of Mg by Zn, and Al by Fe. Non-template materials were taken as references. All LDHs were used as precursors of mixed metal oxides (MMOs) by calcination and applied as catalysts for ethyl biodiesel synthesis via transesterification reactions of soybean oil and ethanol. The LDHs were characterized by XRD, TG, FTIR-ATR and the respective MMOs by SEM, BET, basicity and acidity. Crystallographic data from templated LDHs showed lower crystallinity compared to the reference homologous materials, and it was observed that cornstarch decreases the average surface areas (from 173 to 94 m 2 g −1) and the size of the crystallites (from 147 to 92 Å). FTIR spectra indicated carbohydrates were occluded inside the crystals. While this did not influence the number of acidic sites on the MMOs, it enhances the alkaline sites. Under the catalytic conditions of this experiment, cornstarch templated MMOs reach an average ethyl biodiesel conversion of 70% whereas those prepared with sucrose 45%, and the homologous reference materials only 36%. These results demonstrated the great potential of using carbohydrates as biotemplates in the preparation of heterogeneous catalysts for transesterification reactions.

Synthesis of Nanocrystalline Mg-Al Hydrotalcites in the Presence of Starch—the Effect on Structure and Composition

“…In contrast, the use of sacrificial soft biotemplates, i.e., deformable systems based on organic molecules or supramolecules, remains, as yet, a virtually unexplored area, with only a couple of recent works addressing this issue [20,21], despite the known ability of Ht to form nanocomposites with soft biopolymers [22]. There is no doubt, however, that this methodology will soon gain on importance, since soft biotemplating procedures proved fruitful in the syntheses of nanostructured metal oxides [23][24][25][26].…”

Parametric optimization of biodiesel synthesis from Capparis spinosa oil using NaOH/NaX as nanoheterogeneous catalyst by response surface methodology

“…Biodiesel is a long-chain mono-alkyl fatty acid methyl ester (FAME) derived from edible or non-edible vegetable oils and animal fats through transesterification and esterification reactions (Quah et al 2019). Triglyceride oils as a feedstock for biodiesel production change from country to country (Coelho et al 2017). Most of the vegetable oils and animal fats are considered a resource for human food, but the use of edible oils is not reasonable (Hoseini et al 2019).…”

“…In another approach, using acid catalysts like H 2 SO 4 for biodiesel production causes corrosion in the reactor and needs washing steps to neutralize products and remove the produced effluent (Kaur et al 2018). Therefore, it is necessary to find a heterogeneous catalyst with the properties of large surface area, low cost, easy separation from the reaction mixture, recoverable, and able to be used several times (Coelho et al 2017;Quah et al 2019).…”

Synthesis, Structural and Magnetic Properties of Manganese Substituted Magnesium Chromite.

“…Res. 5(6), 759-765 760 obtain improved powder characteristics, more homogeneity and narrow particle size distribution, thereby influencing the structural and magnetic properties of spinel Mg 1-x 3 ] were used to prepare system compositions.Metal nitrates and citric acid were dissolved in minimum quantity of deionized water with 1:1 molar ratio for all compositions. The pH of the solution was adjusted to 9.5 using ammonia solution.…”

“…The interest in these oxides emerges from their versatile applicability in telecommunication, power transformers, audio and video and many other applications involving electrical signals. Oxides spinel have been extensively studied by several workers [1][2][3] in order to elucidates the relationship between structure, bonding and magnetic properties because of technological potential of these materials. The benefit found in the oxides due to their structural and chemical variations on a nano scale, which are important for developing optimal magnetic properties [4][5][6].…”