Methyl Esterification Reaction Research Articles

Rice bran phytosterol nanoparticles: A promising approach to enhance yogurt quality and nutrition

AbstractThis study aimed to improve the comprehensive utilization value of rice bran by investigating catalysts for the methyl esterification reaction of rice bran oil deodorized distillates and preparing phytosterol nanoparticles for addition to yogurt. Fe2(SO4)3 was found to be an effective catalyst, achieving a methyl esterification rate of 98.07 ± 0.23% under optimal conditions. Then, phytosterol nanoparticles were prepared and added to yogurt, resulting in stable addition with the pH decreased from 4.23 ± 0.01 to 4.02 ± 0.01 and the titratable acidity increased from 106.48 ± 0.85 °T to 117.07 ± 0.82 °T during storage. The addition of phytosterol nanoparticles increased the apparent viscosity from 0.68 ± 0.01 Pa s to 0.72 ± 0.02 Pa s and the G* from 80.01 ± 5.50 Pa to 91.80 ± 1.99 Pa, resulting in thicker and more elastic texture. Phytosterol nanoparticle improves the dispersion and stability of phytosterols in yogurt, thus making it stable to be added to yogurt. Fe2(SO4)3 is a suitable catalyst for the methyl esterification reaction of rice bran oil deodorized distillates, and the addition of rice bran phytosterol nanoparticles to yogurt can enhance its texture and nutritional value, offering a promising strategy for producing high value‐added products from rice bran.

S2O82−/CeO2 Solid Superacid Catalyst Prepared by Radio-Frequency Plasma-Assisted Hydrothermal Method

CeO2 was prepared using a hydrothermal method, modified by radio-frequency plasma in the form of glow discharge, and then the solid superacid S2O82−/CeO2 was prepared by the impregnation method. A series of properties such as pore structure was characterized by N2 adsorption–desorption experiments, surface morphology was characterized by TEM, crystal phase was characterized by XRD, and surface acidity of the catalyst was characterized by Py-IR and Hammett titration. The methyl esterification reaction of tryptophan was used to evaluate the activity of the solid superacid. The results showed that the catalyst modified by radio-frequency plasma had a larger specific surface area, more surface oxygen vacancies, smaller particle size, and higher total acid content. The yield of tryptophan methyl ester reached a higher level of 94.5% (150 °C, 1 MPa, 2 h), catalyzed by the modified S2O82−/CeO2. This work verified the feasibility of plasma technology in the field of catalytic activity enhancement of solid superacid.

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.

Advanced copper based nanostructured materials for oxidative methylesterification reactions- A mini review

Copper due to its natural abundance, cost effectiveness has been effectively used for the selective organic transformation. Copper based nanocomposite materials have been extensively investigated for the synthesis of valuable chemicals and pharmaceuticals. Esterification of organic compounds has significantly contributed towards the synthesis of valuable natural products and polymers. Amongst all, methylesters are important moiety present in multifarious organic and bioactive organic compounds. Additionally, the copper based heterogeneous catalysts have been effectively used for the synthesis of valuable methylesters. Herein, the present review we address the recent advancements within past five years for the synthesis of valuable methylesters using copper based heterogeneous catalysts.

The Preparation and Application of Diaryliodonium Salts Derived from Gemfibrozil and Gemfibrozil Methyl Ester

AbstractThe diaryliodonium salts derived from gemfibrozil and gemfibrozil methyl ester were synthesized from ArI(OH)OTs or bis(4-methoxyphenyl)iodonium diacetate with good regioselectivity. These iodonium salts were successfully used in the derivatization of gemfibrozil or gemfibrozil methyl ester, including fluorination, alkynylation, aryl­ation, etherification, esterification, and iodination reactions.

Catalyst-free self-healing fully bio-based vitrimers derived from tung oil: Strong mechanical properties, shape memory, and recyclability

Vegetable oil-based vitrimers are innovative renewable polymers that show promising applications. However, their applications are limited by their poor mechanical properties and the need for the use of a catalyst in their preparation. In this study, the renewable tung oil underwent the methyl esterification reaction, Diels-Alder reaction, and epoxidation reaction to obtain TOTGE with terminal epoxy groups. TOTGE was cured with citric acid (CA) to obtain catalyst-free, self-healing, high mechanical strength fully bio-based TOTGE–CA vitrimers. Due to the high reactivity of their terminal epoxy groups, the vitrimer networks have a high density of crosslinks, and thus show good thermal stability and mechanical properties. The curing agent CA introduces a large number of hydroxyl (−OH) groups into the vitrimers and these form abundant hydrogen (H) bonds. The −OH groups in the vitrimers act as a catalyst, allowing topological network rearrangement of the materials in the absence of an external catalyst. Due to their dynamic ester and H bonds, the vitrimers exhibit good self-healing, recyclability, and shape memory properties, making them promising candidates for use as repairable and recyclable adhesives.

Preparation and Synthetic Application of Naproxen-Containing Diaryliodonium Salts.

The synthesis of naproxen-containing diaryliodonium salts has been realized from naproxen methyl ester and ArI(OH)OTs activated by trimethylsilyl trifluoromethanesulfonate (TMSOTf) in a solvent mixture comprising dichloromethane and 2,2,2-trifluoroethanol (TFE). Those iodonium salts have been successfully used in the functionalization of an aromatic ring of naproxen methyl ester, including fluorination, iodination, alkynylation, arylation, thiophenolation, and amination and esterification reactions. Moreover, further hydrolysis of the obtained 5-iodo-naproxen methyl ester afforded 5-iodo-naproxen.

Catalysis Preparation of Biodiesel from Waste Schisandra chinensis Seed Oil with the Ionic Liquid Immobilized in a Magnetic Catalyst: Fe3O4@SiO2@[C4mim]HSO4.

The purpose of this study was to synthesize a magnetic material that could be easily separated by a magnetic field and combined the catalytic function of an acid/base ionic liquid with silicon for biodiesel preparation. A kind of magnetic catalyst-immobilized ionic liquid was synthesized by a three-step method. The synthesis conditions in each step were optimized by single-factor analysis. Under the optimum conditions, 206.83 mg of ionic liquid (>43.63%) was immobilized on SiO2 (per gram). Heating under reflux was applied to extract Schisandra chinensis seed oil with an average yield of 10.9%. According to the biodiesel yields, Fe3O4@SiO2@[C4mim]HSO4 was the most efficient catalyst in the methyl esterification reaction. Under the optimum reaction conditions, seed oil (10.0 g) was mixed with methanol (70 mL) under continuous mechanical stirring for 3 h, and the yield of biodiesel was 0.557 g/g (the catalyst efficiency was about 89.2%). Also, the thermal value was increased from 32.14 kJ/g (seed oil) to 38.28 kJ/g (biodiesel). The catalytic efficiency of Fe3O4@SiO2@[C4mim]HSO4 was 87.6% of the first being used after four reuse cycles, and 71.4% of the first being used after six reuse cycles in the methylation reaction. The yields and physical and chemical properties of biodiesel were determined.

Brazilian Mineral Clays: Classification, Acid Activation and Application as Catalysts for Methyl Esterification Reactions

In this study, three raw Brazilian clays from Joao Pessoa, Paraiba State (Aco AP, AVL and Verde Lodo) were characterized before and after purification and acid activation. Several instrumental techniques were used, and the raw clays were classified as dioctahedral smectites with different compositions, where the AVL sample had the highest content of montmorillonite. In addition, analyses showed modification in clay mineral compositions, mainly due to removal of impurities and octahedral sheet cation leaching during acid activation, which resulted in specific areas ranging from 42 to 93 m2 g-1 and increase of the Bronsted/Lewis acid site ratio, until 1.52 (AVL). Then, methyl esterification reactions were performed using the acid-activated clays as catalysts. The maximum acid conversions obtained were of 92 and 64%, for acetic acid using activated AVL and for lauric acid using activated Verde Lodo, respectively, and these data were correlated mainly to the Bronsted-Lowry acidity.

A clean approach of biodiesel production from waste cooking oil by using single phase BaSnO3 as solid base catalyst: Mechanism, kinetics & E-study

The current policies of govt. of India on biodiesel production and commercialization have encouraged to explore this area widely. In this study barium stannate perovskite was synthesized to evaluate its activity and stability as a solid base catalyst in biodiesel synthesis from waste cooking oil (WCO). Physicochemical characterizations of the catalyst and feedstock were thoroughly investigated by various techniques. Experimental planning was executed to investigate the impact of various parameters on methyl esterification reaction. 98% fatty acid methyl ester (FAME) conversion was achieved at following optimum reaction condition: Ba: Sn atomic ratio 1:1, catalyst activation temperature 850 °C, oil to methanol molar ratio 1 : 16, catalyst concentration 2.5 wt%, temperature 65°C, time 25 min. Catalyst endurance test suggested that the BaSnO3 has the appreciable catalyzing potency and stability for several times use. The characteristic difference in FTIR of fresh catalyst and used catalyst indicated the mode of interaction between catalyst and reactants. On this basis a plausible E-R mechanism has been proposed. Kinetic study of the transesterification process by using BaSnO3 revealed that this process was base catalyzed transesterification and followed non spontaneous endothermic pathway. High turnover frequency and low E-factor of the catalyst implied that biodiesel production from waste cooking oil by using BaSnO3 was fast, efficient and benign to all environmental prospective.

Immobilization of Lipozyme TL 100L for methyl esterification of soybean oil deodorizer distillate.

An immobilization method for binding cross-linked enzyme aggregates of Lipozyme TL 100L on macroporous resin NKA (CLEA-TLL@NKA) was developed in this study. The esterification activity of CLEA-TLL@NKA reached 6.4 U/mg. The surface structure of immobilized lipase was characterized by scanning electron microscopy. Methyl esterification reaction of soybean oil deodorizer distillate (SODD) was catalyzed by CLEA-TLL@NKA, which the conversion rate reached 98% and its activity retained over 90% after 20 batches of reaction. Compared with the commercial enzyme Lipozyme TLIM, half-life (t 1/2) of CLEA-TLL@NKA increased by 25 times and the catalytic activity increased by approximate 10 times. Thus, CLEA-TLL@NKA had high catalytic activity, good operational stability, and potential industrial application in the field of oil processing.

SO42−/ZrO2 as catalyst for upgrading of pyrolysis oil by esterification

Pyrolysis oil of rubber seed oil (RSO) was upgraded by methyl esterificationusingSO42−/ZrO2 solid acid as catalyst. The activity and reusability of SO42−/ZrO2 solid acid were investigated and the experiment indicated that the esterification rate could reach 99.62% and was still above 95% in the third reaction. The component of SO42−/ZrO2 solid acid changed little after the third used. The properties of the obtained biofuel were studied and the results showed they were superior to pyrolysis oil and biodiesel, and similar to 0# diesel. The methyl esterification reaction kinetics was researched. The kinetics calculation indicated that the reaction order of the methyl esterification is 1.058, and Arrhenius equation can be expressed as k1=7.711×106e-47.913RT.

Synthesis of the Magnetic Nanoferrites of Spinel Type and Use in Esterification Reaction for Biodiesel Obtaining

Nanotechnology has been important in improving of the properties of the materials used in the manufacture of magnetic devices, electromagnetic radiation absorbers, cell telephony, pigments and lately in catalysis in transesterification and esterification reactions to biodiesel obtaining. The objective of this work was to synthesize and characterize magnetic materials of spinel type compound of CuFe2O4, CoFe2O4, MnFe2O4, NiFe2O4and FeFe2O4and to check the catalytic effect on the methyl esterification reaction of soybean oil. The samples were obtained by combustion reaction and characterized by XRD, FTIR, BET and SEM. The results analysis revealed for nanoferrites the spinel phase formation and higher specific area to the sample CoFe2O4. Generally the samples presented in irregular agglomerates form. All samples were catalytically active in the esterification reaction, with the highest conversion obtained by the sample MnFe2O4with 57%.

ChemInform Abstract: Copper‐Catalyzed Methyl Esterification Reactions via C—C Bond Cleavage.

The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C–C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.

Synthesis, Characterization and Catalytic Performance of Nanoferrites Subjected to the Esterification Reaction

Ni0.5Zn0.5Fe2O4, Mn0.5Zn0.5Fe2O4and Ni0.2Cu0.3Zn0.5Fe2O4nanoferrites were synthesized, characterized and evaluated in terms of their performance as catalysts in the methyl esterification reaction of soybean oil. The nanoferrites were synthesized by combustion and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). The XRD patterns show the presence of inverse spinel B(AB)2O4phase. The EDX results confirmed the stoichiometry of the nanoferrite systems, whose morphology consisted of large block-like agglomerates with a brittle aspect and a wide agglomerate size distribution. The results indicate that the Ni0.5Zn0.5Fe2O4nanoferrite was the most active catalyst in the esterification reaction, with conversion rates ranging from 40 to 91%.

Copper-Catalyzed Methyl Esterification Reactions via C–C Bond Cleavage

The highly effective synthesis of methyl esters from benzylic alcohols, aldehydes, or acids via copper-catalyzed C-C cleavage from tert-butyl hydroperoxide is reported in this paper for the first time. Our protocol is easily accessible and practical, making it a possible supplement for the traditional way.

Evaluation of Catalyst Ni<sub>0.4</sub>Cu<sub>0.1</sub>Zn<sub>0.5</sub>Fe<sub>2</sub>O<sub>4 </sub>on Methyl Esterification of Free Fatty Acid Present in Cottonseed Oil

This study aimed to assess the performance of the solid catalyst Ni0.4Cu0.1Zn0.5Fe2O4, synthesized by combustion reaction, over the methyl esterification reaction of the fatty acids present in cottonseed oil. The catalyst was characterized by XRD, FTIR pyridine absorption, Raman spectroscopy, and SEM. The reactions were conducted at 140 and 180°C with molar ratios of 1:3, 1:6 and 1:9, with 2% of catalyst and reaction time of 2 h. The XRD results showed that the single phase ferrite was obtained with surface area of 87 m2/g and with mesoporous characteristic. It was observed from the FTIR pyridine absorption only the presence of Lewis acid sites. The Raman spectra confirm the presence of the inverse spinel phase. The results indicated that at 180°C and molar ratio of 1:9, the conversion of free fatty acids was about 87%.

Optimization of Synthesis Process for Sodium Ascorbate

With 2-keto-L-gulonic acid(2KLG) and methanol as raw materials, 98% concentrated sulfuric acid as catalyst, the methyl esterification reaction is occurred. Then with sodium carbonate as a transforming agent, a conversion reaction sodium carbonate is obtained. In this experiment, the effects of reaction time, reaction temperature and reactant ratio on conversion rate of sodium ascorbate were studied. The results showed that sodium carbonate as the reactant of lactonization reaction can effectively shorten the reaction time and improve reaction yield. By experiment under the optimum process conditions: the reaction temperature is 65 °C, reaction time is 150 minutes and the molar ratio of 2-keto-L-gu methyl to sodium carbonate is 1:0.6, the conversion rate reaches 98 % and the effect is better than with sodium bicarbonate as transforming agent.

Layered metal laurates as active catalysts in the methyl/ethyl esterification reactions of lauric acid

In this work we report the synthesis, characterization and investigation of the catalytic activity of layered copper(II), manganese(II), lanthanum(III) and nickel(II) laurates in the methyl and ethyl esterification reactions of lauric acid. In the methyl esterification, conversions between 80 and 90% were observed for all catalysts, while for the ethyl esterification only manganese laurate showed reasonable catalytic activity, with conversions close to 75%. Reuse of copper and lanthanum laurates in three cycles of reaction was also investigated and both catalysts preserved the structure and retained catalytic activity close to that observed for the first reaction cycle.

Montmorilonita modificada como catalisador heterogêneo em reações de esterificação (m)etílica de ácido láurico

ABSTRACT Montmorillonite was modified with zirconium polyoxycations in the presence of ammonium sulphate. The material was characterized and used as a catalyst in the esterification of lauric acid, the reactions being accompanied by 23 factorial design. Conversions of up to 95.33 and 83.35% were observed for the methyl and ethyl esterification reactions respectively, proving superior to results obtained by thermal conversion. The material was submitted to three reaction cycles and similar conversions were observed, indicating the catalyst is not significantly deactivated after reuse. The catalyst was also tested under reflux conditions, yielding a maximum conversion of 36.86%.