(532q) Production and Evaluation of Esterification Catalysts Based on Starch-Derived Mesoporous Carbons (Starbons®) Using Colombian Starches As Feedstock
AIChE Annual Meeting
2022
2022 Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 16, 2022 - 3:30pm to 5:00pm
Fatty acid esters are mainly produced via fisher esterification of free fatty acids (FFAs) using homogeneous catalysts (e.g. sulfuric acid). However, these catalysts can promote dehydration, oxidation, and product darkening. Alternatively, heterogeneous catalysts are able to avoid such problems, but most commercial ones are better suited for the conversion of small molecules. In this regard, mesoporous structures can be used to enhance the accessibility of larger molecules to the active sites, improving reaction yields. Among different alternatives, mesoporous biobased carbons are suitable materials, as they can be activated to be used as catalysts in esterification reactions.
In this regard, this work focuses on the production of acid catalysts for esterification of FFAs. The materials were based upon starch-derived mesoporous carbons (Starbons®) using Colombian starches as feedstock. Starbon® catalyst was produced by carbonizing cassava starch at 450°C and functionalizing it with sulfuric acid. The obtained material exhibited a surface area around 600 m2/g, with an average pore width between 8 nm and 10 nm, a mesoporous fraction of approximately 80%, and an exchange capacity of 1.64 Eq. H+/kg. The cassava Starbon® catalyst (CS450-SO3H) was tested in the batch esterification of stearic acid with isopropyl alcohol, and compared with a set of commercial homogeneous (H2SO4, p-toluene sulfonic acid, methane sulfonic acid) and heterogeneous (Amberlyst 15, Amberlyst 35, Amberlyst 70, Lewatit K2629, and commercial Starbon®) catalysts. The comparison was done under the same loading of acid equivalents in the reactive media. Despite CS450-SO3H exhibited lower yields in comparison with the homogeneous catalysts, it can be reused without significant loss of activity. Regarding the heterogeneous catalysts, CS450-SO3H enabled to obtain higher conversion with respect to the ion exchange resins, but lower than the commercial Starbon®. Further studies are required to improve surface characteristics of the cassava-based catalysts in order to improve their catalytic activity.
In this regard, this work focuses on the production of acid catalysts for esterification of FFAs. The materials were based upon starch-derived mesoporous carbons (Starbons®) using Colombian starches as feedstock. Starbon® catalyst was produced by carbonizing cassava starch at 450°C and functionalizing it with sulfuric acid. The obtained material exhibited a surface area around 600 m2/g, with an average pore width between 8 nm and 10 nm, a mesoporous fraction of approximately 80%, and an exchange capacity of 1.64 Eq. H+/kg. The cassava Starbon® catalyst (CS450-SO3H) was tested in the batch esterification of stearic acid with isopropyl alcohol, and compared with a set of commercial homogeneous (H2SO4, p-toluene sulfonic acid, methane sulfonic acid) and heterogeneous (Amberlyst 15, Amberlyst 35, Amberlyst 70, Lewatit K2629, and commercial Starbon®) catalysts. The comparison was done under the same loading of acid equivalents in the reactive media. Despite CS450-SO3H exhibited lower yields in comparison with the homogeneous catalysts, it can be reused without significant loss of activity. Regarding the heterogeneous catalysts, CS450-SO3H enabled to obtain higher conversion with respect to the ion exchange resins, but lower than the commercial Starbon®. Further studies are required to improve surface characteristics of the cassava-based catalysts in order to improve their catalytic activity.