Sulfonic Acid-Functionalized Solid Acid Catalyst in Esterification and Transesterification Reactions

Application of Box-Behnken Design in Production of Monoglyceride with Esterification of Glycerol and Oleic Acid

Monoglyceride MG has a wide function in the food industry, in particular as a natural emulsifier, pharmaceuticals, cosmetics, antioxidant, and antibacterial. Therefore, the production of polyol ester from esterification of acid (OA) and glycerol was investigated. The process optimization was performed using a Box-Behnken design, examining the effects of temperature, molar ratio, and catalyst amount. For predicting the optimal point, a second-order polynomial model was fitted to correlate the relationship between independent variables and response (% MG). The effects of temperature (100, 150, and 200 °C); catalyst amount (4, 10, and 16% w/w); and glycerol/oleic acid ratio (1:1, 1:2, and 1:3) were investigated and found to deeply affect the reaction outcome. At the optimal reaction conditions: 200 °C, 0.2% w/w KSF, and a glycerol/oleic acid ratio (3:1), more than 71.8% monoglycerides with selectivity of 80% were obtained. Confirmation experiments were performed to demonstrate the effectiveness of this approach, and the characterization of monoglycerides was performed using high-performance liquid chromatography (HPLC).

Interesterification of Glyceryl Trioctanoate Catalyzed by Sulfonic Silica-Based Materials: Insight into the Role of Catalysts on the Reaction Mechanism

In the present work, the acid-catalyzed interesterification of glyceryl trioctanoate (GTO) with ethyl acetate was investigated as a model reaction for the one-step production of biofuel and its additives. The activity of heterogeneous acid catalysts, such as silica-based propyl-sulfonic ones, was evaluated. Propyl-sulfonic groups were grafted on both amorphous and mesoporous silica oxide (SBA-15, KIT-6) using different functionalization processes and characterized by N₂ adsorpion-desorption isotherm (BET), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, and potentiometric titration. During the optimization of the reaction conditions with the most active catalyst (Am-Pr-SO₃H), it was shown that the addition of ethanol allowed a total conversion of GTO together with 89% and 56% yield of ethyl octanoate and triacetin, respectively. The catalytic performance is strictly correlated to the catalyst features, in terms of both the acid capacity and the porous structure. Moreover, the catalytic performance is also affected by a synergistic mechanism between silanols and Pr-SO₃H groups towards the 'silanolysis' of ethyl acetate. The overall results show that the presence of ethanol, the reaction time, and the amount of catalyst shifts the reaction towards the formation of the biofuel mixture composed by ethyl octanoate and triacetin.

Sulfonated Mesoporous Silica-Carbon Composite Derived from a Silicate-Polyethylene Glycol Gel and Its Application as Solid Acid Catalysts

Solid acid catalyst is a promising alternative to the counterpart homogeneous acid for esterification reaction from the viewpoint of reusability and environmental concerns. This work aims to develop sulfonated mesoporous silica-carbon composite as solid acid catalyst for the esterification. The catalyst was synthesized from sodium silicate as the silica precursor and polyethylene glycol (PEG) as both carbon precursor and template via a sol-gel route in an aqueous system. Then, it was carbonized to produce mesoporous silica-carbon composite. Using the proposed method, the surface area of the silica-carbon composite could reach as high as 1074.21 m2/g. Although the surface area decreased to 614.02 m²/g when it was functionalized with sulfonate groups, the composite had a high ionic capacity of 5.3 mEq/g and exhibited high catalytic activity for esterification reaction of acetic acid with ethanol. At a reaction temperature of 80 °C, the acetic acid conversion reached 76.55% in 4 h. In addition, the catalyst had good reusability, which can be comparable with the commercial catalyst Foltrol F-007. It appears that the sulfonated silica-carbon composite prepared from sodium silicate using PEG as the carbon source a promising candidate as catalyst for esterification and the related area. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Biodiesel Production Using Solid Acid Catalysts Based on Metal Oxides

The development of solid acid catalysts, especially based on metal oxides and different magnetic nanoparticles, gained much awareness recently as a result of the development of different nano-based materials. Solid acid catalysts based on metal oxides are promising for the (trans)esterification reactions of different oils and waste materials for biodiesel production. This review gives a brief overview of recent developments in various solid acid catalysts based on different metal oxides, such as zirconia, zinc, titanium, iron, tungsten, and magnetic materials, where the catalysts are optimized for various reaction parameters, such as the amount of catalyst, molar ratio of oil to alcohol, reaction time, and temperature. Furthermore, yields and conversions for biodiesel production are compared. Such metal-oxide-based solid acid catalysts provide more sustainable, green, and easy-separation synthesis routes with high catalytic activity and reusability than traditionally used catalysts.

Single-pot template-free synthesis of a glycerol-derived C–Si–Zr mesoporous composite catalyst for fuel additive production

The C–Si–Zr material synthesized from bio-derived waste glycerol, ZrO(NO₃)₂ and TEOS exhibits excellent catalytic activity for tri-acetin production from low-value glycerol.

Widely used catalysts in biodiesel production: a review

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative renewable source of energy. In this context, biodiesel has attracted attention worldwide as an eco-friendly alternative to fossil fuel for being renewable, non-toxic, biodegradable, and carbon-neutral. Although the homogeneous catalyst has its own merits, much attention is currently paid toward the chemical synthesis of heterogeneous catalysts for biodiesel production as it can be tuned as per specific requirement and easily recovered, thus enhancing reusability. Recently, biomass-derived heterogeneous catalysts have risen to the forefront of biodiesel productions because of their sustainable, economical and eco-friendly nature. Furthermore, nano and bifunctional catalysts have emerged as a powerful catalyst largely due to their high surface area, and potential to convert free fatty acids and triglycerides to biodiesel, respectively. This review highlights the latest synthesis routes of various types of catalysts (including acidic, basic, bifunctional and nanocatalysts) derived from different chemicals, as well as biomass. In addition, the impacts of different methods of preparation of catalysts on the yield of biodiesel are also discussed in details.

An ever-increasing energy demand and environmental problems associated with exhaustible fossil fuels have led to the search for an alternative energy. In this context, biodiesel has attracted attention worldwide as an alternative to fossil fuel.

Multicomponent synthesis of new curcumin-based pyrano[2,3-d]pyrimidine derivatives using a nano-magnetic solid acid catalyst

An novel nano-magnetic solid acid catalyst was used for the efficient synthesis of new curcumin-based pyrano[2,3-d]pyrimidine derivatives via a multicomponent reaction under mild conditions.