Esterification Of Lauric Acid Research Articles

In situ impregnation of cobalt‐doped tungstophosphoric acid on MOF‐801 toward enhanced catalytic activity for esterification

Development of an energy‐efficient and economical route is necessary for society to synthesize green biofuels. Herein, cobalt‐doped tungstophosphoric acid (Co‐HPW) is in‐situ impregnated in the Zr‐based metal–organic framework (MOF‐801) forming composite of Co‐HPW/MOF‐801. The chemical composition, morphology, and acidic sites of the Co‐HPW/MOF‐801 composite were analyzed through x‐ray diffractometer (XRD), Fourier transform infrared (FTIR), scanning electron microscope (SEM), energy‐dispersive x‐ray spectroscopy (EDS), thermogravimetric analysis (TG), N2 physisorption, ammonia temperature‐programmed desorption (NH3‐TPD), pyridine‐adsorbed infrared spectra (Py‐FTIR), and x‐ray photoelectron spectroscopy (XPS). The catalytic performance of the as‐synthesized catalyst was explored to catalyze esterification of lauric acid (LA) with methanol. The outcomes revealed that the Co‐HPW/MOF‐801 nanocatalyst achieved a high conversion of 86.3% under the optimized reaction condition (catalyst amount of 0.15 g, temperature of 100°C, time of 4 h, and methanol/LA molar ratio of 20:1). The excellent catalytical performance is mainly due to the large BET surface area, exposure of more active centers from available pore structure, and simultaneous possession of high Lewis and Brønsted acidity. Furthermore, the kinetic study revealed that the reaction process was kinetically controlled and the activation energy was found to be 42.1 kJ/mol. The results suggest that the synthesized Co‐HPW/MOF‐801 nanocatalyst is an environmental greenness, low cost, and suitable for easy scale‐up for the production of biofuels.

Unlocking glycerol monolaurate potential: A comprehensive review of synthesis pathways, catalyst insights, and optimization strategies

Glycerol monolaurate (GML) is a versatile green chemical with wide industrial applicability, including in the food, pharmaceutical, and personal care product industries. This review provides a thorough analysis of the processes involved in GML production, along with the diverse applications of GML. And also, addresses various limitations and challenges associated with esterification of lauric acid with glycerol to produce GML through enzymatic, homogeneous, and heterogeneous catalytic pathways. Among these routes, heterogeneous catalytic routes exhibited superior catalytic activity, achieving over 90% selectivity with good stability. Furthermore, the review offers a constructive assessment of the process parameters associated with catalysts and reaction conditions that influence the GML yield and selectivity. Notably, wide pore and short pore length were found to be suitable for attaining higher selectivity in esterification of lauric acid. Techno-economic assessments suggest that the enzyme route is more environmentally sustainable. However, in practice, the heterogeneous catalytic route proves more suitable for industrial-scale production. Therefore, this review may provide crucial guidance for researchers and industries aiming to produce GML in an economic and eco- friendly manner.

Extending the computational and experimental analysis of lipase active site selectivity.

Molecular docking is an important computational analysis widely used to predict the interaction of enzymes with several starting materials for developing new valuable products from several starting materials, including oils and fats. In the present study, molecular docking was used as an efficient in silico screening tool to select biocatalysts with the highest catalytic performance in butyl esters production in a solvent-free system, an eco-friendly approach, via direct esterification of free fatty acids from Licuri oil with butanol. For such purpose, three commercial lipase preparations were used to perform molecular docking studies such as Burkholderia cepacia (BCL), Porcine pancreatic (PPL), and Candida rugosa (CRL). Concurrently, the results obtained in BCL and CRL are the most efficient in the esterification process due to their higher preference for catalyzing the esterification of lauric acid, the main fatty acid found in the licuri oil composition. Meanwhile, PPL was the least efficient because it preferentially interacts with minor fatty acids. Molecular docking with the experimental results indicated the better performance in the synthesis of esters was BCL. In conclusion, experimental results analysis shows higher enzymatic productivity in esterification reactions of 1294.83μmol/h.mg, while the CRL and PPL demonstrated the lowest performance (189.87μmol / h.mg and 23.96μmol / h.mg, respectively). Thus, molecular docking and experimental results indicate that BCL is a more efficient lipase to produce fatty acids and esters from licuri oil with a high content of lauric acid. In addition, this study also demonstrates the application of molecular docking as an important tool for lipase screening to achieve more sustainable production of butyl esters with a view synthesis of biolubricants.

Hepatoprotective effect of cyanidin-3-O-glucoside–lauric acid ester against H2O2-induced oxidative damage in LO2 cells

Hepatoprotective effect of cyanidin-3-O-glucoside–lauric acid ester against H2O2-induced oxidative damage in LO2 cells

Catalytic activity in methyl esterification reactions and characterization of the superacid HNbMoO6 treated with different inorganic acids

The superacid HNbMoO6 was synthesized from the treatment of the precursor LiNbMoO6 with different acids (HNO3, H2SO4, or H3PO4) in the concentrations of 2, 4, and 6 mol L−1. The solids obtained were characterized to elucidate their composition, acidity, and properties. The materials presented similar diffraction patterns and spectra regardless of the acid type and concentration used. The microscopy analysis showed that at lower concentrations of acid, lower crystal agglomeration was observed. The results of the energy-dispersive X-ray spectroscopy indicated that HNbMoO6 synthesized with H2SO4 6 mol L−1 had the highest Nb5+/Mo6+ ratio (1.95), besides the highest surface area among the synthesized solids (8.53 m2 g−1), and highest Lewis acidity (1.5 mmol of n-butylamine). All solids were efficient in the methyl esterification of lauric acid and did not undergo structural changes after the reactions. The best result was obtained with HNbMoO6 treated with H2SO4 6 mol L−1, with a high conversion rate of 81.79% in methyl laurate, an expressive catalytic gain of 36.82 p.p in contrast to the thermal conversion.

Organic-Exchanged Silicotungstic Acid Compounds as Efficient and Environmental-Friendly Catalysts for Synthesis of Glycerol Monolaurate

A series of organic-exchanged silicotungstic acid catalysts were synthesized by changing the variety and amount of organic compounds. The structure, thermal stability and acidic properties of the catalysts were characterized by FT-IR, XRD, TGA and 31P-MAS NMR. The catalytic performances of the catalysts were investigated on the selective esterification of lauric acid with glycerol to glycerol monolaurate. Among the various catalysts, [QuH]1H3SiW12O40 with molar ratio of quinoline to silicotungstic acid of 1:1 showed excellent activity and reusability due to strong Brand#248;nsted acidity and “pseudo-liquid” catalytic modes. The optimal conditions optimized by response surface methodology were as follows: the molar ratio of glycerol to lauric acid was 5.3:1, the amount of catalyst was 4.8 wt%, the reaction temperature was 424 K, and the reaction time was 1.5 h. Under these conditions, the average yield of glycerol monolaurate was 79.7%, which was basically consistent with the values predicted by the mathematical model. Moreover, the kinetic data of this reaction were fitted to a second-order kinetic model and the apparent activation energy Ea was 52.35 kJ / mol

Lipase-Entrapped Colloidosomes with Tunable Positioning at the Oil-Water Interface for Pickering Emulsion-Enhanced Biocatalysis.

Pickering interfacial biocatalysis (PIB) paves the way for efficient enzymatic catalysis in the biphasic system. However, the Pickering interfacial biocatalysts located on the oil-water interface still face the inevitable deactivation when one of the phases contains the reactant that inactivates the enzyme. Herein, the positioning of lipase-entrapped colloidosomes (LECs) at the emulsion interface is rationally designed by physically tuning the wettability, which allows LECs to protrude into the selected phase to protect the lipase away from the damage of the reactant. As a proof of concept, LECs with different positioning at the interface are used as Pickering interfacial biocatalysts to produce biodiesel by esterification of lauric acid and methanol. Impressively, the LECs that protrude into the oil phase possess an optimal catalytic performance to protect more lipases away from the damage of the reactant of short-chain alcohol, which shows an 8.18-fold enhancement in specific activity relative to the free lipase, reach a biodiesel yield of 80.37% after 8 h, and retain the 96.44% of relative activity after 10 cycles. This study provides a novel and robust platform for Pickering emulsion-enhanced biocatalysis.

Investigating the high‐shear mixed catalytic esterification of lauric acid with methanol using central composite design

Investigating the high‐shear mixed catalytic esterification of lauric acid with methanol using central composite design

Antimicrobial activity of cyanidin-3-O-glucoside–lauric acid ester against Staphylococcus aureus and Escherichia coli

Enzymatic acylation of anthocyanin with fatty acid improves its lipophilic solubility and application potential. Nevertheless, evaluation of functional properties of product is premise for application. This study investigated the antimicrobial potential and the underlying mechanisms of an acylated anthocyanin, namely, cyanidin-3-O-glucoside–lauric acid ester (C3G-LA), to provide guidelines for its application. C3G-LA exhibited outstanding antibacterial activity against Staphylococcus aureus [minimum inhibitory concentration (MIC) = 0.3125 mg/mL] and modest activity against Escherichia coli (MIC = 5 mg/mL). Moreover, C3G-LA manifested bactericide ability against S. aureus at 0.625 mg/mL. Decreases in membrane integrity (by 96% and 92% at MIC in S. aureus and E. coli, respectively), intracellular ATP concentration (by 96% and 92%) and intracellular pH (by 11% and 9%) and changes in cellular morphology altogether indicated the dysfunction of cell membrane under C3G-LA treatment. These findings demonstrated that C3G-LA could be adopted as an alternative food preservative against foodborne pathogens.

Self-assembly and cleaning and wettability of a polysaccharide-surfactant system formed from the cationic hydroxypropyltrimethyl ammonium chloride chitosan and nonionic sucrose lauric acid ester

Contact lens care solution was prepared via hydroxypropyltrimethyl ammonium chloride chitosan (HACC) and sucrose lauric acid ester (SML) via self-assembly in borate buffer solution (BBS). The elution efficiency of lipids, micellization, and wettability properties of HACC-SML in BBS was studied systematically using high-performance liquid chromatography (HPLC), dynamic light scattering (DLS), zeta potential, surface tension, and contact angles methodologies. The elution efficiency of the lipid increased from 46.98% to 65.68%, whereas DLS and zeta potential data varied with the addition of SML. These caused the shrinkage of micelles, and the system became stable, and further revealed that SML was a non-ionic biosurfactant with excellent performance. The result of surface tension at water-air and contact angles on silicone hydrogel lens at 25 °C showed that SML has outstanding adsorption capacity with an increased degree of wetting, ensuring the comfort and safety of wearing.

Hybrid Nanocomposites Formed by Lanthanide Nanoparticles in Zr-MOF for Local Temperature Measurements during Catalytic Reactions

Zr-metal organic frameworks (MOFs) are waterstable materials with high surface properties and chemical stabilities and are often employed for catalysis. They can also become hosts for various upconverting nanoparticles via selfassembly, which opens up possibilities to use such nanocomposite materials for combined catalysis-thermometry applications. In our work, we show that the NaGdF4:Er, Yb@UiO-66-NH2, NaGdF4:Tm,Yb@UiO-66-NH2, and NaYF4:Er,Yb@NaYF4@UiO-66-NH2 nanocomposite materials display excellent temperaturedependent luminescence properties. Additionally, these nanocomposite materials can perform as a stable and reusable catalyst for the esterification of lauric acid (biomass-derived free fatty acid) with methanol to obtain methyl laurate. The NaGdF4/NaYF4 nanoparticles incorporated in the MOF do not significantly decrease their catalytic performance. At the same time, photoluminescence measurements can be performed in a working catalytic environment and the temperature can be read out from the ratio of the H-2(11/2) and S-4(3/2) transition peaks of Er3+ or F-3(3) and H-3(4) transition peaks of Tm3+ from the nanocomposites. The correlation between temperature, luminescent intensities, and catalytic reactivity was studied and showed that all the three factors depend on each other, but do not interfere. To the best of our knowledge, the combination of catalysis and luminescence thermometry in a MOF hybrid material has not been reported to date. However, it opens a wide range of possibilities, keeping in mind the large and versatile number of MOFs as well as different thermometry systems that can be incorporated into inorganic nanoparticles.

Lipase-catalyzed two-step esterification for solvent-free production of mixed lauric acid esters with antibacterial and antioxidative activities

Mixed lauric acid esters (MLE) with antibacterial and antioxidative activities were produced through lipase-catalyzed two-step esterification in solvent-free system without purification. In the first reaction, erythorbyl laurate was synthesized for 72 h. Successive reaction for 6 h at molar ratio of 1.0 (lauric acid to glycerol) produced MLE containing erythorbyl laurate and glyceryl laurate with small amounts of residual substrates, by converting 99.52% of lauric acid. MLE addition (0.5–2.0%, w/w) to Tween 20-stabilized emulsions decreased droplet size, polydispersity index, and zeta-potential, possibly enhancing the emulsion stability. In the emulsions, MLE at 0.5 and 2.0% (w/w) caused 4.4–4.6 and 5.9–6.1 log reductions of Gram-positive (Staphylococcus aureus, Listeria monocytogenes) and Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa), respectively, within 12 h. Lipid hydroperoxide concentrations decreased to 50.8–98.3% in the presence of 0.5–2.0% (w/w) MLE. These findings support a novel approach without needing purification to produce multi-functional food additives for emulsion foods.

Selective synthesis of glyceryl monolaurate intensified by boric acid based deep eutectic solvent

Glyceryl monolaurate (GML), as one of widely used industrial chemicals, can be synthesized via Fischer esterification of lauric acid (LA) and glycerol (GL). In this work, we screened boric acid-based deep eutectic solvent (DES) formed from tetrapropylammonium bromide (TPAB) and boric acid to intensify the selective Fischer esterification through conductor-like screening model for realistic solvents (COSMO-RS) theory. The solid liquid equilibrium (SLE) phase behavior, hydrogen bond formation process, and thermal stability of the DES were characterized by differential scanning calorimetry (DSC), Fourier transform infrared spectrometry (FT-IR), and thermogravimetric analyzer (TGA). The results verified that equimolar TPAB and boric acid formed DES [TPAB:B(OH)3] with the lowest freezing point and very good thermal stability could efficiently intensify the Fischer esterification of GL and LA to GML. The hydrogen bond accepter TPAB of the DES made the esterification system homogeneous, which promoted the selective esterification process. In addition, the hydrogen bond donor B(OH)3 of the [TPAB:B(OH)3] combined with diol unit of GL to cyclic boric esters and led to a special selective space effect, which also improved the selectivity to GML. Thus, the esterification intensified of GL and LA by 20 wt% DES achieved GML selectivity of 85.7 % and yield of 76.4 % under the optimal reaction conditions. The esterification kinetics suggested the reaction followed pseudo-second-order model and the reaction activation energy was 33.98 kJ mol−1, similar to and/or lower than those reported works. Furthermore, DES and unreacted glycerol were readily recovered and reused through temperature controlled gravity-based separation due to the ability of homogeneity under reaction conditions and splitting phase behavior during the DES recovery. The results can expand the boric acid-based DESs for other potential intensification applications.

Enzymatic esterification of lauric acid to give monolaurin in a microreactor

Monolaurin is a naturally occurring compound widely utilized in food and cosmetics. In this paper, we present a new method for the synthesis of monolaurin by esterification between lauric acid and glycerol catalyzed by Novozym® 435 using a microreactor. The conversion of lauric acid is 87.04% in 20 min, compared with 70.54% via the batch approach in 5 h. Using an optimized solvent system consisting of t-BuOH/ tert-amyl alcohol (1:1, v/v), the selectivity using the microreactor method is enhanced to 90.63% and the space–time yield of the process is 380.91 g/h/L. This newly devised method has the potential for application to other multiphase and enzymatic reactions.

Esterification of anthocyanins isolated from floral waste: Characterization of the esters and their application in various food systems

Anthocyanins were extracted from red rose petals collected from floral waste, and were esterified with fatty acids using the lipase Fermase CALB™ 10000 to enhance their lipophilicity. The process parameters for the extraction of anthocyanin were optimized for extraction time, nature of the solvent, substrate to solvent ratio, and concentration of citric acid. Anthocyanins were purified using resins. Acylated anthocyanins were primarily detected using TLC followed by confirmation using LC-MS analysis. Optimization of the reaction parameters was carried out by one-factor-at-a-time method using HPTLC. An optimized molar conversion of 63% of anthocyanins to its fatty acid esters was achieved in acetonitrile at 40 °C with a cyanidin:lauric acid molar ratio of 1:100 and an enzyme and molecular sieve load of 20 mg/mL and 100 mg/mL, respectively, in 24 h. The antioxidant activity of anthocyanin and its fatty acid esters assessed using DPPH, ABTS and FRAP assays showed retention in the activity upon acylation. The use of lauric acid esters of anthocyanins was studied as a colorant in emulsion-based foods such as cupcakes and sandwich biscuit cream (filling). The antioxidant effect of the esterified anthocyanins assessed by TGA, manifested improved stability on the thermo-oxidative lipid peroxidation of the biscuit cream. Anthocyanins and its fatty acid esters were also studied as pre-extrusion colorants in rice extrudates, where the esters showed superior color stability to thermal processing in comparison to anthocyanins. Anthocyanin fatty acid esters can thus find application in functional foods.

Kinetics of methyl esterification of lauric acid catalysed by Bronsted acids

Kinetics of methyl esterification of lauric acid catalysed by Bronsted acids

Kinetics for the biodiesel production from lauric acid over Keggin heteropolyacid loaded in silica framework

Kinetic models were developed to describe the esterification reaction of lauric acid and ethanol over heterogeneous catalysts, which is a reaction of special interest in the biodiesel production. Vanadium Keggin heteropolyacid was included on a silica framework by sol–gel procedure, using different loadings. The synthesized materials were characterized by FT-IR, XRD, SEM, nitrogen adsorption/desorption isotherms, and potentiometric titration, and tested as solid catalysts in the esterification of lauric acid. Best performance was achieved with SiO2@20PMoV, which was used in the esterification of others fatty acid and alcohols. The reuse was successfully tested in five consecutive runs. Kinetic data using SiO2@20PMoV were obtained at different temperatures (48–78°C), fatty acid:alcohol molar ratios (4mmol of lauric acid and 2.5, 5, 10 and 15mL of ethanol), and catalyst amounts (12.5, 25 and 50mg). The best heterogeneous models were LH3 (surface reaction as rate-limiting step) and ER3 (desorption of ethyl laurate as rate-limiting step when the adsorbed reactant is lauric acid). The activation energies were 56.1kJmol−1 and 64.8kJmol−1, and the reaction rate constants at 78°C were 0.2791molg−1h−1 and 0.0768molg−1h−1 for LH3 and ER3, respectively.

Study of structural properties of acid-treated natural sediment and its application as a sustainable catalyst

This paper aims to characterize a natural sediment from Bahía Blanca estuary (Argentina) as a new clay source and determine the catalytic capacity after its structural modification by an acid activation process. The acid treatment was performed by employing H2SO4 at different concentrations at 353 K and 60 min. The raw material and acid-activated samples were characterized by XRD, XRF, FTIR, N2 physisorption, TGA, SEM, EDX, potentiometric titration and pyridine adsorption monitored by FTIR. Moreover, the catalytic activity on lauric acid esterification with methanol was evaluated as a test reaction. From the structural characterization, it was determined that the material studied contains mainly Ca-montmorillonite, illite, albite and quartz. Likewise, the results obtained showed that the acid-treatment impacts the material characteristics, predominantly surface acidity and textural properties. Particularly, it was evidenced that the samples treated under medium acid activation conditions lead to an increase in acid site number and strength and specific surface area and consequently improve the catalytic activity. The results obtained evidenced that this low cost and widely available raw material presents an interesting mineralogical composition with a high clay mineral content. Additionally, the catalytic performance showed a good conversion in the test reaction regarding other heterogeneous catalysts. Hence, considering these results, this natural sediment merits further research on its purification and application.

Efficient Production of Biodiesel from Esterification of Lauric Acid Catalyzed by Ammonium and Silver Co-Doped Phosphotungstic Acid Embedded in a Zirconium Metal-Organic Framework Nanocomposite.

A novel solid acid nanocatalyst (Ag1(NH4)2PW12O40/UiO-66) comprising ammonium and silver co-doped H3PW12O40 and zirconium-based metal–organic frameworks (UiO-66) was synthesized and characterized by Fourier transform infrared spectroscopy, N2 adsorption/desorption, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, and ammonia temperature-programmed desorption. The catalytic activity was evaluated for the synthesis of biodiesel via esterification of lauric acid and methanol. The effect of the operating parameters including the molar ratio of lauric acid to methanol, catalyst amount, and reaction temperature and time on the lauric acid conversion was also investigated to obtain optimum reaction conditions. Also, the composite (Ag1(NH4)2PW12O40/UiO-66) was recyclable and reused up to six cycles. Kinetics of the lauric acid esterification has been assumed to be of a pseudo-first order, and the results showed that the activation energy for the esterification process was found to be 35.2 kJ/mol.

Highly Active Silver ion-Exchanged Silicotungstic Acid Catalysts for Selective Esterification of Glycerol with Lauric Acid

A series of highly active silver ion-exchanged silicotungstic acid (H4SiW12O40; STA) catalysts, AgxH4−xSiW12O40 (x = 1–4), were successfully synthesized and applied for the production of glycerol monolaurate (GML) via esterification of lauric acid (LA) with glycerol (GL). The physicochemical properties of these Ag-promoted STA were characterized by TGA, FE-SEM, XRD, and FT-IR, and their acidic properties were studied by a solid-state 31P NMR probe molecule method using trimethylphosphine oxide (TMPO) as the probe. Among various catalysts, the Ag2H2SiW12O40 catalyst showed extraordinary activity owing to the strong Bronsted acidity, Bronsted–Lewis acid synergy, as well as the unique Keggin structure possessed by the catalyst. A Box–Behnken design (BBD) based on response surface methodology (RSM) was exploited for the optimization of process variables. A maximum GML yield of 80.2% was achieved for the Ag2H2SiW12O40 catalyst under a GL/LA molar ratio of 4.4, catalyst amount of 4.6 wt%, reaction temperature of 429 K, and reaction time of 153 min, which was in conformity with those predicted by the mathematical model. Further recyclability and kinetic studies confirmed that the Ag2H2SiW12O40 catalyst was reusable, robust, and highly efficient for the synthesis of GML with an activation energy (Ea) of 38.14 kJ/mol. Due to the strong acidity and synergy of B/L acid sites, Ag ion-exchanged silicotungstic acid catalysts show superior activity and durability for the synthesis of glycerol monolaurate.