Esterification Reaction Research Articles

Direct carbonyl reductive functionalizations by diphenylphosphine oxide.

Reductive functionalization of aldehydes and ketones is one of the most challenging but ultimately rewarding areas in synthetic chemistry and related sciences. We report a simple and extremely versatile carbonyl reductive functionalization strategy achieving direct, highly selective, and efficient reductive amination, etherification, esterification, and phosphinylation reactions of (hetero)aryl aldehydes and ketones, which are extremely challenging or unattainable to achieve by traditional strategies, using only diphenylphosphine oxide and an inorganic base. It enables modular synthesis of functionally and structurally diverse tertiary amines, ethers, esters, phosphine oxides, etc., as well as related pesticides, drug intermediates, and pharmaceuticals. Compared to phosphorus-mediated name reactions, this strategy firstly transformed C═O bonds into C-element single bonds. Mechanistically, phosphinates are formed as intermediates, which undergo unconventional nucleophilic substitution at the C atom within their C─O─P unit. Thus, this work provides important strides in the field of reductive functionalization of aldehydes/ketones, phosphorus-mediated transformation, and various fundamental reactions.

Asymmetric Synthesis and Bioactivity Evaluation of Chiral Oxazoline Skeleton Molecules.

The utilization of novel organic synthesis methods is increasingly critical in the development of innovative agrochemicals. In this study, we designed and synthesized a series of chiral oxazoline derivatives using a one-pot method. This method involved first catalyzing the asymmetric aldol addition reaction of oxazolinyl esters with paraformaldehyde, followed by esterification with various pharmacophore-containing carboxylic acids. Unexpectedly, many of the target compounds exhibited promising antifungal and antioomycete activities, with their absolute configurations showing pronounced enantioselective activities. Notably, compound (R)-5c demonstrated significant biological activities against Valsa mali and Phytophthora capsica (EC50 = 1.023 mg/L and EC50 = 0.149 mg/L, respectively), which were markedly superior to its enantiomer (S)-5c (EC50 = 9.565 mg/L and EC50 = 0.924 mg/L, respectively). In vivo experiments confirmed that this compound exhibited both curative and protective effects against V. mali and P. capsici. CLSM and SEM analyses further indicated that compounds 5c had distinct physiological effects on P. capsici hyphae. Moreover, acute toxicity tests in zebrafish (Danio rerio) revealed that compound (R)-5c had significantly lower toxicity compared to the control drugs tebuconazole and dimethomorph. Consequently, this study provides valuable insights for the development of novel chiral oxazoline analogues as potential antifungal and antioomycete agrochemicals.

Sodium Carboxymethylcellulose/Polydopamine Biocellulose Coatings with Enhanced Wet Stability for Implantable Medical Devices.

Sodium carboxymethylcellulose (CMC) is a biocompatible and biodegradable derivative of cellulose, making it a promising material for biomedical applications. However, its poor stability in aqueous environments has significantly limited its use in long-term biomedical devices. Here, we present for the first time a simple and controllable method to enhance the wet stability of CMC coatings by cross-linking of CMC and polydopamine (PDA) and self-polymerization of PDA for widespread applications in biomedical devices. A series of CMC/PDA coatings were fabricated on the initial PDA layers by using dip coating and subsequently heated at 200 °C. The performance of the CMC/PDA coatings and their chemical and structural stability in aqueous media have been systematically analyzed, and the mechanisms underpinning their robust performance have been revealed. FITR, X-ray photoelectron spectroscopy (XPS), and gel permeation chromatography (GPC) results showed that CMC/PDA coatings involved amidation and esterification reactions as well as self-polymerization of PDA. Degradation studies in phosphate-buffered saline (PBS) solution at 37 °C indicated degradation via ester and amide bond cleavage, with the stability of CMC/PDA coatings surpassing that of individual PDA and CMC coatings over a 30-day immersion period. The CMC/PDA coating with a CMC concentration of 15 mg/mL exhibited the highest adhesion strength in an aqueous environment, which was attributed to the high cross-linking of CMC and PDA, as well as the intrinsic stability of PDA. The CMC/PDA coatings demonstrated favorable viability, growth, and proliferation of endothelial cells. The stable and biocompatible biocellulose coatings can be easily applied from aqueous solutions onto almost any type of solid metal and ceramic material, providing a promising dimension for surface engineering of vascular scaffolds and tissue engineering constructs.

A Solvent-Free 2-Chloro-1-methylpyridinium Iodide (CMPI)-Mediated Biginelli Reaction for the Construction of 3,4-Dihydropyrimidin-2(1H)-ones/thiones

AbstractThe Biginelli product dihydropyrimidinones (DHPMs) and their derivatives have enormous biological significance. This article describes the exploration of 2-chloro-1-methylpyridinium iodide (CMPI) reagent for the development of an environmentally safe, solvent-free protocol to construct the functionalized 3,4-dihydropyrimidin-2(1H)-ones/thiones. The protocol involves the three-component condensation reaction of β-keto ester, aldehyde, and urea or thiourea at elevated temperature. The key advantages of the protocol are its capacity to provide both environmental and economic benefits owing to its solvent-free conditions, short reaction times, simple workup, and good to excellent isolated yield of DHPMs.

The research progress on the esterification reaction of dicarboxylic acids

The research progress on the esterification reaction of dicarboxylic acids

Effects of glycosidases and GSH pretreatments, fermentation temperatures, and aging time on the physicochemical, organic acids, and aroma profiles of perry.

The lack of sufficient flavour in perry represents a barrier to its further industrialization. This study aimed to investigate the effects of glutathione (GSH), β-glucosidase (Glu), and α-L-rhamnosidase (Rha) pretreatments, the fermentation temperature from 16°C to 28°C, and the aging time of 1, 2, and 3years (PA1, PA2, and PA3) on the physicochemical properties, organic acids, and aroma profiles were investigated. The results demonstrated that the synergistic effect of Glu, Rha, and GSH was more effective than their individual or paired applications in enhancing the varietal aromas. The contents of terpenes, phenols, acetate and ethyl esters in the Glu+Rha+GSH treatment were significantly increased in comparison to the control, with improvements of 60.77%, 118.64%, 77.02%, and 32.82%, respectively. The OAV flavor profile showed rich floral, fruity, and citrus aromas. The contents of tartaric acid and quinic acid decreased from 16°C to 28°C, whereas lactic acid was the opposite. Except for phenethyl acetate and ethyl decanoate, the contents of acetate and ethyl esters exhibited a decline at elevated temperatures, whereas isopentanol and phenylethyl alcohol increased. The contents of esters and phenols at 16°C increased significantly, whereas those of alcohols decreased. This contributed to banana, floral, fruity, orange peel, and spices aromas to the fermentation aromas. The difference in organic acid profiles between PA3 and PA1, PA2 were obvious, the contents of acetic acid and citric acid in PA3 decreased significantly, whereas those of tartaric acid, L-malic acid, and lactic acid increased. The contents and proportions of acetate and medium-chain fatty acid ethyl esters decreased from PA1 to PA3, while the ethyl esters resulted from esterification reactions increased, and the contents of alcohols and acids constituents were different between the three years. The contents of esters, phenols, and total volatiles increased significantly, while the aging aroma was markedly enhanced in PA3. It can be concluded that the Glu+Rha+GSH pretreatment, fermentation at 16°C, and aging for three years exhibited the great aroma potential of perry, which enhanced the flavor intensity through the regulation of varietal, fermentation, and aging aromas.

Design of dual active site composites of HPW@MOF-199 embedded in SBA-15 functionalized with -COOH groups: Efficient catalysts for esterification reactions

Design of dual active site composites of HPW@MOF-199 embedded in SBA-15 functionalized with -COOH groups: Efficient catalysts for esterification reactions

Synthesis of Esters Using Modified Waste Copper Slag: A Sustainable Approach for Waste Valorisation

ABSTRACTThe active sites of waste copper slag were moulded using BaO and used as a catalyst for the esterification reaction without solvent. Various concentrations of BaO were doped over the copper slag and investigated for the esterification of various model components of flavour, fragrance and biofuel. The catalyst was characterised by X‐ray photoelectron spectroscopy, attenuated total reflectance‐Fourier transform infrared spectroscopy, surface area analysis and X‐ray diffraction to examine the impact of BaO addition on the structural and morphological characteristics of BaOX/Cp‐Sl. BaO increases the grain size and enhances the BaOX/Cp‐Sl catalyst's activity and selectivity to flavour, fragrance and biofuel. The BaO2.5%/Cp‐Sl catalyst showed the maximum conversion of oleic acid to the methyl ester. The esterification of various commercially important substrates like geraniol, citronellol, menthol, isoamyl acetate, palmitic acid and waste cooking oil using a catalyst has been explained in detail. The kinetic study of the esterification has been explained with turnover number (TON) and turnover frequency (TOF). The mechanism pathway of the catalyst with various active sites of waste copper slag has been explained using adsorption studies.

Deep eutectic solvent-assisted starch acetylation within stale bread particles to improve water resistance.

Building up from our previous findings on deep eutectic solvents (DES) as reaction promoters for the acetylation of pure wheat starch, the current work explored combinations of reaction time, temperature and acetic anhydride: bread molar ratios to acetylate macromolecules within bread particles relying solely on macromolecule solvation and the slightly basic environment provided by the eutectic mixture. High degree of substitution with acyl groups (DSacyl, 0.73-1.09 as quantified by 1H NMR and confirmed by 13C NMR, and FTIR) was achieved within a short timeframe of 36 min and < 16 acetic anhydride: bread molar ratio. Spectroscopy discarded a major presence of side-reaction products starch carbamates and acetyl urea in reacted samples. Nevertheless, DES acetylation resulted in reacted samples with starch weight average molecular weight (Mw) ranging from 2.62 × 106 to 1.39 × 106 g/mol for the most degraded sample and the partial wash-off of starch and cell wall polysaccharides, which resulted in increased gluten content. Notably, TGA (coupled to real-time FTIR analysis of the evolved gases) suggested a potential enhancement in hydrophobicity and glass transition temperature (Tg) in the reacted samples, with a positive correlation between DSacyl and Tg. These findings emphasize the potential of DES as reaction promoters in complex starchy matrices for esterification reactions.

Self-Cleaning Leather

This work evaluated the use of polycarboxylic acids as chemical binders to immobilize TiO2 to produce “crust” vegetable-tanned leather with self-cleaning properties. A methodology was developed with immersion of leather samples in a solution of polycarboxylic acids, followed by curing of the binder. Subsequently, photocatalyst deposition was performed through immersion, followed by a second curing process. Additionally, the samples were subjected to a wind tunnel to remove TiO2 layers overlapping the chemically bonded layer on the surface. To evaluate photocatalytic activity, a methylene blue photocatalyst activity indicator ink (PAII) was applied on the leather surface, being reduced by UV light. Photodegradation was registered through digital images and evaluated by RGB spectra. This methodology has never been used before for leather samples. Results showed that polycarboxylic acids acts like binder to collagen fibers through esterification reaction. Furthermore, it was found that increasing the photocatalyst cure temperature enhances the bonding between the carboxylic groups of succinic acid and TiO2, thereby increasing the photocatalytic activity. However, there is a temperature limit (60°C) above which the leather loses its properties. These results demonstrated that the methodology was efficient, being able to produce self-cleaning vegetable-tanned leather with photocatalytic activity and good reproducibility.

“One Pot” Enzymatic Synthesis of Caffeic Acid Phenethyl Ester in Deep Eutectic Solvent

Caffeic acid phenethyl ester (CAPE) represents a valuable ester of caffeic acid, which, over time, has demonstrated remarkable pharmacological properties. In general, the ester is obtained in organic solvents, especially by the esterification reaction of caffeic acid (CA) and 2-phenylethanol (PE). In this context, the purpose of this study was the use of the “one pot” system to synthesize CAPE through biocatalysis with various lipases in a choline-chloride-based DES system, employing the “2-in-1” concept, where one of the substrates functions as both reactant and solvent. The synthesis process of CAPE is contingent on the molar ratio between CA and PE; thus, this factor was the primary subject of investigation, with different molar ratios of CA and PE being studied. Furthermore, the impact of temperature, time, the nature of the biocatalyst, and the water loading of the DES system was also examined. This ‘green’ synthesis method, which has demonstrated encouraging reaction yields (%), could secure and maintain the therapeutic potential of CAPE, mainly due to the non-toxic character of the reaction medium.

Polymer Ligands with Multi-Nitrogen Heterocyclic Carbenes for Enhanced Stability and Reactivity in Nanoparticle Surface Functionalization.

Nitrogen heterocyclic carbenes (NHCs) are emerging as effective substitutes for conventional thiol ligands in surface functionalization of nanoparticles (NPs), offering exceptional stability to NPs under harsh conditions. However, the highly reactive feature of NHCs limits their use in introducing chemically active groups onto the NP surface. Herein, we develop a general yet robust strategy for the efficient surface functionalization of NPs with copolymer ligands bearing various functional groups. The polymer ligands consist of a multiple NHCs block, utilized for surface binding on NPs, alongside a poly(reactive ester) block intended for incorporating functional groups. The multiple NHCs block enables NPs with excellent colloidal stability across a broader range of pH values (0-14), temperature variations (-78°C-100°C), and electrolyte concentrations (0-1000 mM). Through the in situ ammonolysis of the poly(reactive ester) block, various active functional groups can be individually or together introduced on the NP surface. We further demonstrate the chemical reactivity of these functionalized NPs, including addition polymerization, Diels-Alder and Schiff base reactions. This method is applicable to various types of NPs, including metal NPs, metal oxide NPs, and even upconversion NPs, thereby paving new pathways for the design and creation of nanoparticle-based functional materials.

Polymer Ligands with Multi‐Nitrogen Heterocyclic Carbenes for Enhanced Stability and Reactivity in Nanoparticle Surface Functionalization

Nitrogen heterocyclic carbenes (NHCs) are emerging as effective substitutes for conventional thiol ligands in surface functionalization of nanoparticles (NPs), offering exceptional stability to NPs under harsh conditions. However, the highly reactive feature of NHCs limits their use in introducing chemically active groups onto the NP surface. Herein, we develop a general yet robust strategy for the efficient surface functionalization of NPs with copolymer ligands bearing various functional groups. The polymer ligands consist of a multiple NHCs block, utilized for surface binding on NPs, alongside a poly(reactive ester) block intended for incorporating functional groups. The multiple NHCs block enables NPs with excellent colloidal stability across a broader range of pH values (0‐14), temperature variations (–78°C‐100°C), and electrolyte concentrations (0‐1000 mM). Through the in situ ammonolysis of the poly(reactive ester) block, various active functional groups can be individually or together introduced on the NP surface. We further demonstrate the chemical reactivity of these functionalized NPs, including addition polymerization, Diels‐Alder and Schiff base reactions. This method is applicable to various types of NPs, including metal NPs, metal oxide NPs, and even upconversion NPs, thereby paving new pathways for the design and creation of nanoparticle‐based functional materials.

Optimization of the Esterification Process of Crude Palm Oil (CPO) with Natural Zeolite Catalyst Using Response Surface Methodology (RSM)

Esterification is one of the important processes in the production of biodiesel. This is done to ensure that the FFA content in CPO is less than 3%. The esterification reaction can be accelerated by using natural zeolite as a catalyst. Optimization needs to be carried out to select the appropriate conditions to reach the optimal region quickly. The purposes of this research are to analyze the impact of esterification time and the natural zeolite catalyst size on the reduction of FFA levels and find the optimal parameters in the CPO esterification through RSM. Esterification is operated by maintaining the reaction temperature at 60 °C, agitation speed at 150 rpm, and using a molar ratio of methanol:CPO of 6:1. The independent variables used in the research are esterification time (90, 110, 130, 150, and 170 minutes) and natural zeolite size (20, 40, 60, 80, and 100 mesh). The optimization results using RSM indicate that the optimum points in the study are at an esterification time of 170 minutes and a natural zeolite size of 97.3909 mesh.

Catalytic synthesis of vitamin E acetate using metal organic framework material ZIF-8

Vitamin E is an important fat soluble antioxidant, its acetate is the main derivative product of vitamin E. Using metal organic framework material ZIF-8 as a catalyst, vitamin E acetate (VEA) was prepared by catalyzing the esterification reaction of D-α-tocopherol and acetic anhydride in a solvent-free system. Firstly, the preparation conditions of metal organic framework materials were studied: different imidazole ligands, different zinc ion ligands, molar concentration ratio of Zn2+ to 2-methylimidazole(2-mIM), and preparation time. The results showed that the catalytic performance of ZIF-8 was optimal when Zn(CH3COO)2·2H2O was used as the zinc source, 2-mIM was used as the imidazole ligand, the molar concentration ratio of Zn2+ / 2-mIM was 1:20, and the preparation time was 1 hour. The yield of vitamin E acetate was 86.85%. The synthesis process of VEA was optimized by single factor experiments such as substrate molar ratio, reaction time, dosage of nano enzyme, reaction temperature and so on. The results showed that the yield of vitamin E acetate reached 96.31% under the optimal conditions of n (D-α-tocopherol) =1mmol, [n (D-α-tocopherol) : n (Acetic anhydride)] =1:15, reaction time 24 h, ZIF-8 dosage 0.05 g, reaction temperature 50 °C.

Design of an efficient magnetic brush solid acid and its catalytic use in organic reactions

In this research, with the Green Chemistry approach, to load more sulfonic acid active sites on catalyst surfaces, a nanocomposite material based on core-shell magnetite coated with vinyl silane and a sulfonated polymeric brush-like structure is designed and synthesized as a new class of efficient solid acid catalysts, referred to as Fe3O4@VS-APS brush solid acid. The synthesized catalyst was comprehensively characterized by a range of instrumental techniques, including XRD, SEM, TEM, FT-IR, EDX, TGA, and VSM. The activity of the catalyst was evaluated in Biginelli, Strecker, and esterification reactions. The Fe3O4@VS-APS brush solid acid has special features, such as easy reusability when a simple magnet is used for four reaction runs, an appropriate balance between hydrophobic and hydrophilic properties on the catalyst surface, and effective catalytic performance in the production of 3,4-dihydropyrimidin-2-one(thione) derivatives, 2-phenyl-2-(phenylamino)acetonitrile and octyl acetate.

Catalytic and Tribological Performances of a Novel Bi-Functional Ionic Liquid in Lubricating Ester Oil

To address the detrimental effects of the residue of catalysts on the tribological performances of ester lubricants, a novel and efficient bi-functional ionic liquid 1-(3,5-di-tert-butyl-4-hydroxybenzyl)-3-methylimidazole di(2-ethylhexyl) phosphate ([(BHT-1)MIM][DEHP]) was prepared. The catalyst not only facilitates the synthesis of pentaerythritol tetra-hexanoate (PETH) through the catalytic esterification reaction—achieving up to 96% conversion with a 94% yield—but also enhances the tribological performance of ester oil PETH when used as a lubricant additive. The tribological property has been improved remarkably: the mean friction coefficient for PETH + [(BHT-1)MIM][DEHP] is notably lower, at 0.110, compared to the PETH, which has a coefficient of 0.180. Meanwhile, the wear scar diameter of the steel ball, when lubricated with PETH + [(BHT-1)MIM][DEHP], is notably smaller than that of a steel ball lubricated solely with PETH. Especially, the reduction in the wear volume at 100 °C is up to 81.46% compared with the base oil PETH. [(BHT-1)MIM][DEHP], PETH + [(BHT-1)MIM][DEHP], and the worn track of the upper running ball and lower disc were systematically characterized by using Nuclear Magnetic Resonance (NMR) spectra, a Fourier Transform Infrared Spectrometer (FT-IR), a field emission scanning electron microscope (FESEM), Thermal gravity analysis (TG), X-ray photoelectron spectroscopy (XPS), and an optical microscope (OM). The wear mechanism of the tailored lubricant oil was discussed in terms of the chemical composition of the worn surface.

Selective synthesis of triacylglycerols by the ADS-17-supported Candida antarctica lipase B through esterification of oleic acid and glycerol.

Immobilized enzyme possessing both high activity and good selectivity is important in practice. In this study, Candida antarctica lipase B (CALB) was immobilized onto the macroporous resin ADS-17 for triacylglycerol (TAG) synthesis through esterification of oleic acid and glycerol. The reaction conditions were optimized by single-factor study and orthogonal test, and the reusability of the immobilized CALB (CALB@ADS-17) was evaluated. In addition, the mechanism of lipase immobilization was studied and the catalytic mechanism of CALB@ADS-17 was investigated. Oleic acid conversion up to 99.20% and TAG content at 91.58 wt% could be obtained under optimal conditions. In addition, the CALB@ADS-17 retained 84.28% of its initial activity after 11 cycles of reuse. The mechanism of lipase immobilization was through hydrophobic adsorption. The relationship between temperature and oleic acid conversion was lnV0 = 6.3316 - 4.3321/T, and the activation energy (Ea) was 36.02 kJ mol-1. CALB@ADS-17 did not exhibit an obvious interfacial activation phenomenon. Its kinetic behavior can be described by the Michaelis-Menten model, whose kinetic parameters of vmax, kcat, Km, Ki, and kcat/Km were 0.01265 μmol L-1 s-1, 9310.72 s-1, 0.4907 mmol L-1, 3.997 mmol L-1, and 1.90 × 104 L mmol-1 s-1, respectively. CALB@ADS-17 showed good esterification performance and exhibited good selectivity towards TAG generation. In addition, CALB@ADS-17 exhibited good reusability in esterification reactions and has potential in practical applications. © 2025 Society of Chemical Industry.

Preparation and physicochemical properties of OSA modified Cyperus esculentus starch nanoparticles.

The aim of this study was to investigate the Octenyl succinic anhydride (OSA) modification and nanonization of Cyperus esculentus starch (CES) on its physicochemical properties. Cyperus esculentus starch nanoparticles (SNPs) were prepared by nanoprecipitation method and modified with OSA. The results showed that the average particle size of the prepared SNPs was 125.25nm, and the OSA modified nanoparticles (OS-SNPs) were between 411.16 and 442.07nm. Chemical group analysis indicated the successful esterification reaction of OSA. Crystallographic structure analysis showed that the crystalline type of CES remained unchanged after OSA modification, but the crystallinity was slightly decreased. Moreover, SNPs exhibited a V-type diffraction peak. Morphological observation results showed that the hydrophobic groups introduced after OSA modification of SNPs had caused particle deformation and formed a network structure. In addition, the gelatinization temperature of starch decreased after OSA modification, and the gelatinization temperature could no longer be measured after nanonization. The OSA modified CES (OS-CES) had shown higher viscosity, swelling power and solubility during the gelatinization process. While the nanonized samples had no obvious viscosity change during the heating process, the solubility remained at a relatively high level of 70-90%.

Functionalization of polymeric nanomicelles and mixed nanomicelles for targeted retinal delivery in the management of retinoblastoma.

The current research discusses polymer conjugation, formulation development, and evaluation of sorafenib-loaded polymeric nanomicelles of conjugated soluplus (solu-tin) and polymeric mixed nanomicelles of conjugated soluplus (solu-tin) with conjugated poloxamer 188 (polo-tin) for site-specific posterior segment delivery to the retina in managing retinoblastoma. Firstly, the soluplus and poloxamer 188 were conjugated with biotin by Fischer esterification reaction and evaluated by FTIR and 1H NMR for confirmation of covalent bond formation involving the carboxyl group of biotin and hydroxyl group of polymers. Secondly, the sorafenib-loaded solu-tin nanomicelles and mixed nanomicelles of solu-tin with polo-tin were formulated by the thin film hydration method. Thereafter, these nanomicelles were evaluated and displayed suitable outcomes for particle size (78.53nm and 73.17nm), PDI (0.089 and 0.074), zeta potential (-3.65mV and -4.17 mv), entrapment efficiency (99.23% and 99.83%), in vitro drug release (4h and 8h), solid-state analysis, osmolality (290mOsm/kg and 293mOsm/kg), pH (7.4 and 7.4), TEM (spherical) and residual solvent analysis (287.90ppm and 363.49ppm). The ex vivo transcleral permeation at 8h was found to be 548.45ng/cm2 and 281.61ng/cm2, respectively. Both the drug-loaded nanomicelles displayed a dose-dependent anticancer effect on Y-79 cells at all time points i.e. 6, 12, 18, and 24h, and were non-toxic to normal retinal pigmented epithelial cell line (ARPE-19) when incubated for 24h. Furthermore, the formulations were non-irritant (HET-CAM) and stable for 6months. Hence, the developed technology is safe and efficacious for targeting the retina in managing retinoblastoma.