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An enzymatic approach for the synthesis of intermediate alcohol of the drug tegoprazan in 99% ee at 20 °C in hexane has been developed utilizing commercially available immobilized Thermomyces lanuginosus lipase (TL lipase) as a biocatalyst and vinyl acetate as a acyl donor. This method involves the enantioselective esterification of (RS)-5,7-difluorochroman-4-ol with vinyl acetate using TL Lipase. This enzymatic approach provides the (S)-chiral alcohol in 44% yield with 99% enantiomeric excess (ee) and the (R)-acetate in 43% yield and >99% ee. It is a sustainable approach for the synthesis of enantiopure tegoprazan intermediate, contributing to the advancement of green chemistry. The recovered TL lipase was reused in 13 subsequent runs without loss of activity. [ABSTRACT FROM AUTHOR]

BACKGROUND: The preparation of malic acid starch ester (MSE) is mostly carried out using a high temperature method, but there are problems such as high energy consumption, long preparation time, and uneven heating. Microwave technology can be used to overcome these limitations. The semi‐crystalline structure of starch granules hinders the modifier's access to the matrix, thus limiting the esterification reaction. Physical techniques can act on the interior of the starch to create a number of active sites, thereby facilitating the reaction of the starch with esterification reagents. Therefore, this study investigated the effect of starch pretreatment by microwave, heat‐moisture, and ultrasonic techniques on the degree of substitution (DS), structure, and physicochemical properties of MSE synthesized by the microwave method. RESULTS: The DS of MSE was increased after pretreatments. The modified starch obtained by different pretreatment methods did not show new characteristic peaks, while the MSE synthesized showed new absorption peaks near 1735 cm−1. The granular structure and morphology of the modified starch obtained by microwave and heat‐moisture pretreatment were gelatinized and aggregated, while some of the starch particles of the modified starch obtained by ultrasonic pretreatment appeared pore‐sized. The relative crystallinity and gelatinization enthalpy of the MSE were reduced, but the crystallization pattern remained as A‐type. CONCLUSION: Overall, the results suggest that various pretreatment methods can enhance the DS of MSE by disrupting the structure of starch. The findings of this study provide theoretical support for improving the DS of esterified starch. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Wood modification processes based on citric acid in combination with various copolymers have gained in importance in recent years. These processes also include modification with citric acid (CA) and sorbitol, a sugar alcohol, which is currently in the industrial realisation phase in Germany (SorCA) and Norway (CIOL). The modification of wood with sorbitol and citric acid (SorCA) can significantly improve the dimensional stability and durability of the wood. It is hypothesised that the addition of a copolymer may improve the fixation of the chemicals within as well as the flexibility of the modified wood matrix. In this study, the macroscopic changes, the fixation of the chemicals and the impact bending properties of wood modified with CA and SorCA are compared. Both modifications cause a permanent increase in mass (WPG) and volume (CWB). The fixation of the chemicals was comparable for both modifications; at high chemical concentrations, the SorCA polyester fixed slightly better within the wood matrix. Both modifications led to embrittlement of the wood, measured by a decrease in the impact bending strength (IBS). This embrittlement was clearly concentration-dependent and slightly more pronounced for the modification with CA. [ABSTRACT FROM AUTHOR]

Imidazolium perchlorate task-specific ionic liquids (TSILs) were used for in-situ oxidation esterification of benzaldehydes and benzylalcohols in reaction with alcohols. CO2H functional group containing TSIL show dual role as catalyst and reaction media toward oxidative esterifications. Excellent yields of esters could be obtained for a series of benzaldehydes and benzylalcohols via the reaction with alcohols. This reaction can be regarded as a new method for the efficient oxidation esterification of benzaldehydes and benzylalcohols under mild catalyst and solvent-free conditions. [ABSTRACT FROM AUTHOR]

Texture is one of the most critical quality attributes to directly influence consumer acceptance of frozen foods. Controlling ice crystal growth is an effective strategy to regulate the texture of frozen materials. It is essential to explore the inhibitory effect of pectin's structure on ice recrystallization in the formulation design. Particularly, the quality of frozen products can be preserved during storage and thawing. Pectin, a natural polysaccharide commonly found in plant cell walls, has demonstrated significant inhibition effects on ice crystals; However, the structure-activity relationship behind them still remains unclear. This study aimed to investigate the influence of pectin esterification and amidation on ice crystal inhibition. Pectin was constructed with varying degrees of esterification and amidation using enzymatic de-esterification and amidation modifications. Splat tests and molecular dynamic (MD) simulations were employed to delineate the potential mechanisms, by which methyl esterification and amidation of pectin are influenced by ice crystal growth. The results indicated that the lower esterified pectin shared the stronger ice recrystallization inhibition (IRI), whereas the amidation diminished the IRI capability. Specifically, the average diameter of the largest ice crystals was 29.19 μm in 51% esterified Pectin, approaching that in a sucrose solution (mean largest grain size, MLGS, 19.4% larger). MD simulations revealed that the number of ice molecules in different systems of amidated pectin reached equilibrium around 52 ns, while the ice crystal growth in pectin with varying degrees of esterification concluded later, reaching completion at 62 ns. A more robust ability of pectin was achieved with the lower esterification degrees to inhibit ice crystal growth. The amidated pectin chains were adopted as a concave shape when spliced with adjacent periodic images. Ice crystals tended to grow preferentially along the sides of amidated pectin. There was no observed in Pectin with different degrees of esterification. Therefore, the amidated pectin reduced the contact surface with ice crystals, leading to being enveloped by the growing ice interface. There was a higher interaction energy between pectin and water molecules. An increasing number of hydrogen bonds then led to the tighter association for the strong inhibition of ice crystal growth. Consequently, the pectin with a lower degree of esterification shared the stronger interactions with water molecules, and then hindered their binding to ice crystal growth interfaces, thus facilitating ice crystal inhibition. There were three impacts of esterification and amidation degrees on the inhibition mechanisms of the ice crystal growth, including: 1) hydrophilic groups, such as hydroxyl and carboxyl, of pectin were bound to the ice crystal growth interface, while hydrophobic groups, such as methyl, inhibited the attachment of water molecule; 2) Hydrophilicity of pectin was enhanced its interaction with water molecules, thereby inhibiting their migration; 3) Alterations in pectin hydrophilicity were resulted in the conformational changes at the ice crystal growth interface, thus affecting the contact area with ice crystals. These findings were significant implications for the more effective design and formulation of frozen food products, leading to the high texture, stability, and quality. The insights were greatly contributed to a better understanding of mechanisms behind pectin's IRI activity, in order to explore other polysaccharides and their derivatives. Novel cryoprotectants can be expected for the various industrial applications in the high quality and shelf life of frozen foods, particularly on the consumer preferences for healthier and natural ingredients. [ABSTRACT FROM AUTHOR]

A GaCl3‐catalyzed [3 + 2]‐cycloaddition/intramolecular esterification cascade of donor–acceptor cyclopropane‐1,1‐diesters with salicylaldehydes has been reported. A wide range of tetrahydro‐4H‐furo[3,2‐c]chromen‐4‐ones have been efficiently delivered in moderate to good yields. Mechanistic studies suggest that the reaction involves the [3 + 2]‐cycloaddition followed by intramolecular esterification to access 4H‐furo[3,2‐c]chromenones. [ABSTRACT FROM AUTHOR]

In this study, three polycarboxylic acids with varying numbers of carboxyl groups were employed to crosslink polyvinyl alcohol (PVA): malonic acid as a diacid (MA), citric acid as a triacid (CA), and 1,2,3,4-butane tetracarboxylic acid as a tetraacid (BTCA). The crosslinking abilities of these acids were compared using physical, chemical, mechanical, morphological, thermal, and swelling measurements to assess their impact on the physicochemical properties of the resulting films. Based on the degree of crosslinking, mechanical strength, and thermal stability, tetra acid demonstrated superior crosslinking performance compared to di and tri acids. The highest strength was observed in the tetra acid crosslinked film, which exhibited a 127% increase over neat PVA. Regarding thermal stability, the decomposition temperature followed the order of tetraacid (450 °C) > triacid (378 °C) > diacid (350 °C). However, in terms of swelling behavior, triacid-crosslinked film, i.e., P-CA, exhibited the highest swelling. Further, the tetra acid-crosslinked film exhibited the lowest crystallinity and a higher contact angle (104.9°) than diacid and triacid crosslinked films. Additionally, the crosslinked films displayed enhanced elasticity compared to pure PVA, with the elasticity order being diacid > triacid > tetraacid, possibly due to differences in available crosslinking sites among the crosslinkers. [ABSTRACT FROM AUTHOR]

There is a continuing search for materials having desirable fragrance properties. Such materials are sought either to replace costly natural materials or to provide new fragrances or perfume types, which have not heretofore been available. Hence, the objective of this paper is the synthesis and olfactory characterization of new fragrant materials through chemical modification of methyleugenol (ME) molecular framework by introducing Ester functional groups using appropriate standard procedures. ME is a common phenylpropanoid found in many plant species, particularly in spices and medicinal plants. It is used as a flavouring agent in food and as a fragrance in cosmetics. In this research, methyleugenol was modified to obtain esters. The transformations involve the opening of 2-(4-ethyl-3-methoxybenzyl) oxirane (epoxide ring) to yield 3-(3,4-dimethoxyphenyl)propane-1,2-diol (Dihydroxy). 1-(3,4-dimethoxyphenyl)-3-hydroxypropan-2-yl acetate (53.33% yield) derivatives, was synthesized from the Dihydroxy. The results showed that the odour characteristic of 3-(3,4-dimethoxyphenyl)propane-1,2-diol [floral, pungent, Caramel and sweet] compounds, is clearly different from the odours of the 1-(3,4-dimethoxyphenyl)-3-hydroxypropan-2-yl acetate [fresh, pungent, lime-like, sweet]. Our findings show that double bond substitution and functional alterations to methyl eugenol modify the perceived odour of methyl eugenol derivatives. Thus, overall structural alteration increased odour potency. [ABSTRACT FROM AUTHOR]

The increasing global energy demand has sparked a search for sustainable fuel sources. Biodiesel from organic waste offers a promising solution to reduce carbon emissions. Hence, the objective of this paper was to synthesize biodiesel production from used cooking oil using nickel-modified calcium phosphate scum (Ni-CaPs) from sugar refining industry as a catalyst. X ray diffraction analysis revealed the crystalline structure of CaO, NiO, and SiO2. X-ray fluorescence showed a composition of 50.316 % CaO, 4.61 % NiO, and 18.60 % SiO2. Fourier Transform Infrared spectroscopy identified functional groups associated with C-N, C-Cl, and C-H stretching bonds. Scanning Electron Microscopy and Energy Dispersive X-ray analysis confirmed the catalyst's morphological and compositional properties. Response Surface Methodology (RSM) optimized the reaction conditions: 55°C, 90 mins, 1 wt. % catalyst loading, and 12:1 methanol-to oil molar ratio. This yielded 93.2 % biodiesel, with an R² value of 0.9886. The Ni-CaPs catalyst offers cost-effectiveness, simple synthesis process, stability, and widespread availability of raw materials. This study demonstrates the potential of Ni-CaPs as a sustainable, efficient catalyst for biodiesel production from waste materials, contributing to a more environmentally friendly energy solution. [ABSTRACT FROM AUTHOR]

Acetylsalicylic acid (aspirin) is a popular over-the-counter medication possessing anti-inflammatory and antipyretic properties. Given the large amount of aspirin manufactured annually worldwide, any modification of the manufacturing process that could increase its yield or purity would have industrial implications. In this study, we prepared aspirin through the esterification of salicylic acid with acetyl anhydride in the presence of phosphoric acid over a duration of 20 min while varying the temperature from 50 to 80 °C at 10 °C intervals. We observed increases in the percentage purity and yield of 1.25- and 1.28-fold, respectively, upon increasing the temperature from 50 to 80 °C at intervals. Linear relationships existed in the yield and purity of the synthetic aspirin, with both increasing upon increasing reaction temperature. [ABSTRACT FROM AUTHOR]

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In current times, the diminishing reserves of petroleum, increased energy consumption across various sectors, and their consequential environmental impact have become apparent. Consequently, it is necessary to develop sustainable and eco-friendly energy sources to meet growing demands. The article aimed to blend castor and neem oils (in a 50:50 ratio) to rectify the drawbacks present in castor biodiesel such as elevated kinematic viscosity and density. Response surface methodology was used to study the optimization of the two-step biodiesel production process through the use of a central composite design (CCD). For the esterification step, a methanol-to-oil molar ratio of 7.5:1, 1.75 wt.% of H2SO4, and a temperature of 55 °C were optimal. In the transesterification step, optimized conditions included a methanol-to-oil molar ratio of 9:1, 2.50 wt.% of calcium oxide, a temperature of 55 °C, and a stirring speed of 900 rpm, resulting in a 93% yield of methyl ester. Different properties of produced biodiesel were examined using the standard values provided by EN 14214 and ASTM D6751. The production of biodiesel from a mixture of castor and neem oils did not have any adverse impacts on food security. [ABSTRACT FROM AUTHOR]

Abstract 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.

Calophyllum is a potential plant in Indonesia where the area is very wide spread besides almost all parts of Calophyllum plants can be utilized. The study aims to produce alkyd resin from Calophyllum oil so the usefulness of Calophyllum plants can be optimized. The synthesis of alkyd resin was carried out by variations in oil to glycerol mole ratio (1:3, 1:4, and 1:5) and temperature (230 and 250C). Acid and iodine values, density, viscosity, drying time, color, solubility, thermal stability, and functional groups analyzed the alkyd resin quality. The oil-to-glycerol mole ratio and temperature variations affected the acid value, viscosity, color, and drying time. Higher temperatures and more glycerol affected the reaction time, and the drying time of alkyd resin became faster. In addition, its viscosity decreased, and its thermal stability was stable. With the high addition of glycerol at low temperatures, the color of alkyd resin was bright, but it became darkened at higher temperatures. Calophyllum-based resins owned the fastest alkyd resin drying time without passing through the drying and purifying process, which was 60 minutes at 50°C

Imidazo[1,5- a ]pyrid-3-ylidene (IPC)-catalyzed oxidative esterification of aldehydes was investigated. A series of IPCs showed good catalytic activity, in particular, sterically hindered ones. Substituents on the 3-position of imidazo[1,5- a ]pyridine ring significantly influenced its catalytic activity, and electron-withdrawing substituent accelerated the reaction. [ABSTRACT FROM AUTHOR]

Upon treatment of chiral β-trifluoromethyl-α,β-unsaturated N -acylated oxazolidin-2-ones with a range of alcohols using phosphazene base as a catalyst, the unexpected cascade esterification/stereoselective aza-Michael addition was observed. The reactions proceeded with high diastereoselectivities (up to >99:1) to give a series of enantioenriched aza-Michael addition products in good to high yields. The structure and stereochemistry of the representative aza-Michael adduct were confirmed by X-ray crystal structure analysis. The plausible mechanism was proposed on the basis of the experimental results.The synthetic transformations of chiral aza-Michael addition products were also demonstrated highlighting the synthetic application of the present work. [ABSTRACT FROM AUTHOR]

The investigation of the process of converting levulinic acid (LA) into ethyl levulinate (EL) using tungstic acid (TA)-functionalized activated natural zeolite (AZ) was systematically conducted. The aims of this work were to synthesize and characterize the activated zeolite modified by tungstic acid (TA-AZ) and also evaluate its performance in LA esterification. We employed the wet impregnation approach and ultrasonication-assisted method to produce TA-AZ catalyst with different concentrations of TA (15, 20, and 25 wt%). Fourier transform infrared (FTIR), ammonia-temperature programmed desorption (NH3-TPD), X-ray diffraction (XRD), scanning electron microscope with an energy dispersive X-ray spectrometer (SEM-EDX), transmission electron microscope (TEM), and surface area analyzer (SAA) were among the analytical methods used to investigate the chemical and physical characteristics of AZ and TA-AZ catalysts. The liquid yields from LA esterification were analyzed by GC-FID. The findings indicated that the 25TA-AZ catalyst exhibited the highest acidity, reaching 3.65 mmol/g. The presence of TA in AZ resulted in an enhancement of LA conversion and an increase in EL yield. The LA esterification process, employing a 25TA-AZ catalyst with a reaction temperature of 150 °C and a weight% of 0.5 wt%, produced 91.72% for LA conversion and 82.65% for EL yield. [ABSTRACT FROM AUTHOR]

The immobilization of Candida antarctica lipase B (CALB) within xerogels synthesized through the sol-gel method was investigated, employing the ionic liquid 1-octyl-3-methylimidazolium bromide (C8MI.Br) as an additive to enhance enzymatic performance. The optimization of enzyme mass and ionic liquid concentration, using a central composite experimental design, identified optimal conditions of 0.27 g/mL enzyme and 1.53% ionic liquid, yielding a maximum total esterification activity exceeding 500 U. Structural characterization, including BET surface area analysis and X-ray diffraction, confirmed the formation of a porous, amorphous matrix conducive to enzyme stability and activity. The incorporation of the ionic liquid significantly enhanced the xerogels' thermal and operational stability. Residual esterification activity was maintained at approximately 80% after 100 days under refrigeration, and the xerogels exhibited reusability for up to eight catalytic cycles with residual activity above 50%. Furthermore, thermal stability assessments demonstrated superior resistance of the immobilized enzyme to elevated temperatures compared to its free counterpart. This study underscores the critical role of ionic liquids as additives, facilitating the formation of structurally optimized xerogels while preserving enzyme activity and stability. The findings suggest significant potential for industrial biocatalytic processes, offering a sustainable and efficient approach to enzyme immobilization for applications requiring enhanced catalytic performance and longevity. Highlights: The study immobilized lipase using the sol-gel method with 1-octyl-3-methylimidazolium bromide as an additive. A central composite design optimized enzyme and ionic liquid amounts for xerogel immobilization. The additive increased esterification activity, peaking at 501.84 U in central tests. Thermal stability improved with the ionic liquid, showing 60% residual activity at 60 °C (compared to 40% for free enzyme). The immobilized xerogel was reusable up to 8 times with 50% residual activity. [ABSTRACT FROM AUTHOR]

Single-atom catalysts are highly effective in catalyzing a wide range of reactions owing to their capacity to have precise coordination patterns and fully leverage the potential of metal atoms. Although several techniques have been reported for the preparation of single-atom catalysts, adopting a convenient method to construct them still has a challenge. In this work, we report a convenient method for the preparation of Zr-based single-atom catalyst that takes advantage of the nanoconfined environments between the template and silica wall in template-occupied silica SBA-15. After introducing Zr-containing precursor into the nanoconfined environments of the template-occupied silica SBA-15 using solid-phase milling, Zr-based single-atom catalysts were produced via the following calcination step. Density functional theory calculations and experimental findings show that Zr atoms form Zr–O–Si structure in the silica walls. The Zr single-atom catalyst synthesized using the nanoconfined environments exhibited notably superior catalytic performance in the synthesis of benzyl acetate from the esterification reaction between acetic acid and benzyl alcohol (63.3% yield), outperforming the counterpart that synthesized without such nanoconfined environments (19.8% yield). [ABSTRACT FROM AUTHOR]

In current times, the diminishing reserves of petroleum, increased energy consumption across various sectors, and their consequential environmental impact have become apparent. Consequently, it is necessary to develop sustainable and eco-friendly energy sources to meet growing demands. The article aimed to blend castor and neem oils (in a 50:50 ratio) to rectify the drawbacks present in castor biodiesel such as elevated kinematic viscosity and density. Response surface methodology was used to study the optimization of the two-step biodiesel production process through the use of a central composite design (CCD). For the esterification step, a methanol-to-oil molar ratio of 7.5:1, 1.75 wt.% of H2SO4, and a temperature of 55 °C were optimal. In the transesterification step, optimized conditions included a methanol-to-oil molar ratio of 9:1, 2.50 wt.% of calcium oxide, a temperature of 55 °C, and a stirring speed of 900 rpm, resulting in a 93% yield of methyl ester. Different properties of produced biodiesel were examined using the standard values provided by EN 14214 and ASTM D6751. The production of biodiesel from a mixture of castor and neem oils did not have any adverse impacts on food security.

Abstract Research on polymer matrix composites has become increasingly important in both the academic and industrial sectors. The study of polymer-natural fiber composites, known for their eco-friendly properties, has gained significance. Sugarcane bagasse fibers, abundant as discarded agricultural byproducts, offer improved properties such as density, rigidity, strength, and cost-effectiveness, enhancing sustainability. As a result, experiments were performed on cellulose fibers pre-treated from sugarcane bagasse using 5% NaOH solution by simply soaking them for 4–5 h followed by washing with water. Further modifications involved esterification using phthalic anhydride and phthaloyl chloride via steam baths at 90 °C and oxidation using sodium percarbonate with a phase transfer catalyst (Adogen) at 80 °C. These chemically altered cellulose fibers exhibited significant peak changes in the FTIR spectra, a reduced crystallinity index in the XRD pattern, increased thermal stability as evidenced by TGA curve, and improved surface roughness in the SEM analysis. This paper emphasizes successful pretreatment procedures for isolating cellulose fibers from sugarcane bagasse and introduces three chemical treatments for surface functionalization which might find applications in the preparation of biocomposites.

旨在为米糠酸化油的产业化应用提供参考，以米糠酸化油为原料，经丙酮提取预处理后，采用酶法催化制备生物柴油。通过单因素实验考察脂肪酶种类、酶添加量、醇油物质的量比和反应温度对生物柴油产率的影响，结合正交实验对生物柴油制备的工艺条件进行优化，并采用分子蒸馏对生物柴油进行精制，同时对精制生物柴油进行表征。结果表明：米糠酸化油经预处理后，过氧化值、谷维素及不皂化物含量无显著变化，酸值、皂化值显著升高，水分及挥发物含量、磷脂含量、灰分和皂含量显著降低；生物柴油制备的最优工艺条件为醇油物质的量比3∶ 1、液体脂肪酶Lipozyme TL100L添加量4%、反应温度30 ℃、反应时间4 h，在此条件下生物柴油产率达（86.77±0.54）%，经分子蒸馏纯化后脂肪酸甲酯含量达（97.00±0.04）%；精制生物柴油理化指标均符合GB 25199—2017 要求；傅里叶红外光谱分析证实了产物中含脂肪酸甲酯，热重分析表明精制生物柴油在178.0~293.2 ℃区间内失重最快，差示扫描量热分析表明-37.5～-47.2 ℃的峰与不饱和脂肪酸甲酯的晶体有关，-7.9～-3.7 ℃的峰与饱和脂肪酸甲酯的晶体相关，生物柴油的结晶起始温度为-8.87 ℃。综上，以米糠酸化油为原料采用酶法制备生物柴油具有极大的发展潜力。Aiming to provide reference for the industrial application of acidified rice bran oil, biodiesel was prepared by enzyme catalysis of acetone extract of acidified rice bran oil. The effects of lipase type, enzyme dosage, alcohol-oil molar ratio and reaction temperature on biodiesel yield were investigated through single factor experiments. The process conditions for biodiesel preparation were optimized by orthogonal experiments. The biodiesel prepared was refined by molecular distillation, and the refined biodiesel was characterized. The results showed that after the pretreatment of the acidified rice bran oil with acetone extraction, the peroxide value, oryzanol content and unsaponifiable matters content did not change significantly, the acid value and saponification value increased significantly, and the contents of moisture and volatile matter, phospholipid, ash and soap reduced significantly. The optimal process conditions for biodiesel preparation were as follows: alcohol-oil molar ratio 3∶ 1, liquid lipase Lipozyme TL100L dosage 4%, reaction temperature 30 ℃, and reaction time 4 h. Under the optimal conditions, the biodiesel yield reached (86.77±0.54)%, and the content of fatty acid methyl ester reached (97.00±0.04)% after purification by molecular distillation. The physicochemical indexes of refined biodiesel were in accordance with the requirements of GB 25199-2017. Fourier infrared spectroscopy (FTIR) analysis confirmed that the product contained fatty acid methyl ester, thermogravimetric (TG-DTG) analysis showed that the weight loss of refined biodiesel was the fastest in the temperature interval of 178.0-293.2 ℃; differential scanning calorimetry (DSC) analysis showed that the peaks at temperatures from -37.5 ℃ to -47.2 ℃ were related to the crystals of unsaturated fatty acid methyl ester, and the peaks at temperatures from -7.9 ℃ to -3.7 ℃ were related to the crystals of saturated fatty acid methyl ester, and the crystallisation starting temperature of biodiesel was -8.87 ℃. In conclusion, the enzymatic preparation of biodiesel from acidified rice bran oil has great potential for development.

Biodiesel merupakan biofuel generasi pertama, bersifat terbarukan, dan ramah lingkungan yang dapat menggantikan bahan bakar diesel. Bahan bakunya dapat berupa distilat asam lemak sawit (DALMS) yang merupakan produk samping pengolahan minyak sawit mentah, memiliki kadar asam lemak tinggi dan bersifat nonedible. Sintesis biodiesel dari DALMS dilakukan melalui reaksi esterifikasi menggunakan katalis nikel fosfida berpenyangga zeolit alam (NiP/Za). Tujuan penelitian ini adalah menentukan karakteristik katalis dan kondisi optimum esterifkasi DALMS menjadi biodiesel menggunakan Response Surface Methodology-Box Behnken Design (RSM-BBD). Zeolit alam diberi perlakuan desilikasi dan aktivasi serta katalis disintesis dengan impregnasi basah. Esterifikasi dilakukan pada waktu 2 – 4 jam, suhu 45 – 65 ℃, konsentrasi katalis 5% – 15% (b/b). Hasil karakterisasi menunjukkan bahwa katalis memiliki fase kristal Ni2P dengan munculnya puncak pada 2θ: 40,5; 44,5; dan 47,21o, ukuran kristal 28,64 nm, luas permukaan 35,577 m2/g, volume pori 0,094 cc/g, dan diameter pori 3,8306 nm. Parameter waktu dan suhu berpengaruh signifikan terhadap konversi. Kondisi optimum esterifikasi DALMS menjadi biodiesel didapatkan pada suhu 45 ℃, waktu 4 jam, dan konsentrasi katalis 6% dengan konversi 4,67%. The Use of Natural Zeolite-Supported Nickel Phosphide Catalyst to Optimize the Esterification Reaction of Palm Fatty Acid Distillate into Biodiesel using Response Surface Methodology-Box Behnken Design. Biodiesel is a renewable and environmentally friendly first-generation biofuel that can replace diesel fuel. The raw material can be Palm fatty acid distillate (PFAD), a by-product of crude palm oil processing, which has a high fatty acid content and is nonedible. An activated natural zeolite-supported nickel phosphide catalyst (NiP/NZ) makes the esterification reaction easier, which turns PFAD into biodiesel. This study aimed to determine the characteristics of the catalyst and the optimum conditions for the esterification of PFAD into biodiesel using the Response Surface Methodology-Box Behnken Design (RSM-BBD). Natural zeolite was desilicated and activated. Then, the catalyst was synthesized by wet impregnation. Esterification was performed for 2 ‒ 4 h at a temperature of 45 – 65 ℃ and a catalyst dosage of 5% – 15% (w/w). The tests revealed that the catalyst consists of Ni2P crystals, exhibiting diffraction peaks at 2θ 40.5, 44.5, and 47.21°. The crystals are 28.64 nm in size, and the catalyst has a surface area of 35.577 m2/g, a pore volume of 0.094 cc/g, and a pore diameter of 3.8306 nm. Time and temperature parameters significantly affected the conversion of PFAD. The optimum condition for PFAD esterification into biodiesel was obtained at 45 ℃, 4 h, and 6% catalyst concentration with 4.67% conversion

Cellulose obtained from oat hulls by bleaching with peracetic acid was modified, employing an ultrasound method that resulted in an esterification reaction with different vegetable oils (soybean, sunflower, and coconut) to produce modified cellulose (MC) with increased hydrophobicity. MC samples were characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, scanning electron microscopy, and their wettability and oil and water absorption capacities. FTIR indicated that the reaction occurred with all oils, which was observed by forming a new band associated with ester carbonyl groups at 1747 cm−1. The modification did not affect the crystalline structure or surface morphology of the cellulose. MC samples modified with all oil sources showed a 6 to 9-fold decrease in water absorption capacity, a 3-fold increase in oil absorption capacity, and a higher affinity for nonpolar solvents. The modified samples adsorbed lower amounts of water at a slower rate. Different oil sources did not affect the main properties of MC. The ultrasonication-assisted process was not only effective in modifying cellulose by esterification with vegetable oils but was also an eco-friendly and simple strategy that does not require toxic reagents, providing reassurance of its sustainability.

Sulfonated hierarchical H-ZSM-5 monoliths were synthesized via ice-templating as solid acid catalysts for biodiesel production. Characterization confirmed successful –SO3 group grafting, increasing acid density. The catalysts achieved over 90% conversion of oleic acid in esterification, with easy recovery and reuse, and the relationship between porosity and acid density was explored. [ABSTRACT FROM AUTHOR]

A p‐toluenesulfonic acid (p‐TsOH)‐catalyzed cascade acylation–cyclization–acylation reaction of polyols with carboxylic acids has been developed, which affords polyacyloxy cyclic ethers without the need for the removal of water. The mild reaction conditions in the presence of p‐TsOH•H2O (10 mol%) permitted the use of a variety of carboxylic acids and polyols. In particular, when polyols with 1,4‐dihydroxy moieties were used, the present catalysis efficiently provided the corresponding polyacyloxy tetrahydrofuran derivatives in good‐to‐high yield without loss of optical purity. Furthermore, the concise synthesis of bicyclic isosorbide esters, which are of interest in an industrial and pharmaceutical context, was achieved using commercially available biomass‐derived d‐sorbitol and d‐mannitol via double cascade acylation–cyclization–acylation reactions. [ABSTRACT FROM AUTHOR]

Molnupiravir (1) is one among the limited therapeutic options for treating COVID‐19 infection and exhibits pan‐antiviral potency. Because of urgent demands during the COVID‐19 pandemic, a number of methods were developed to offer more efficient routes. In this report, we present a facile 2‐step and scalable synthesis of molnupiravir for batch processing and show the implementation of continuous flow biocatalysis to improve the efficiency in synthesis. Our key step entails immobilized lipase and isobutyric anhydride to facilitate regioselective esterification. In batch process, transamination of cytidine (2) provides N4‐hydroxycytidine (NHC, 3) with 75 % yield followed by esterification of NHC to give molnupiravir with 64 % yield, providing 48 % overall yield and 99.98 % purity (HPLC). Compared to batch approach in the esterification step, the continuous flow process provides similar product yield and purity and highlights the advantages including 2.42‐fold better productivity (mol/day), 2.47‐fold improved reaction time, and 30‐fold higher space‐time‐yield. The optimized batch and continuous flow biocatalysis enhance synthesis efficiency and reduce environmental impact, offering a sustainable approach for industrial molnupiravir production. [ABSTRACT FROM AUTHOR]

Cellulose is the most abundant and renewable biopolymers on earth. The hydrophilic nature of cellulose endows cellulosic materials with good compatibility with polar matrices, but it also leads to their poor dispersion in non-polar matrices. Regulating the surface hydrophobicity of cellulosic materials via surface esterification can greatly extend their applications. However, the existing surface esterification methods for cellulosic materials are time-consuming and costly, which makes them less attractive for practical application. Here we found that when vinyl esters were used as esterifying agents, various alkalis can be used to catalyze the ultrafast surface esterification of cellulose materials in aqueous media at room temperature within seconds or minutes, which is highly attractive for the surface esterification of nanocellulose in suspension state. Surface acetylated cellulose nanofibers (ACNF) and surface acetylated cellulose nanocrystals (ACNC) with acetyl group content (Ac%) up to 10.7% and 6.5%, respectively, were successfully prepared within 5 min in aqueous diethylamine solution. Additionally, this method can also be used to achieve the rapid acetylation of phenol hydroxy group in aqueous media. [ABSTRACT FROM AUTHOR]

Levulinic acid, which can be obtained from biomass, has sparked great interest as a biologically-based chemical building block with wide versatility and potential. Its esterification with alcohols of different chain lengths is a promising valorization process for obtaining esters with various applications in the areas of biofuels/biolubricants, food and cosmetics, among others. In this work, the enzymatic esterification of levulinic acid and 1-octanol using a biocatalyst derived from Araujia sericifera latex was studied in systems with and without solvent. The influence of the molar ratio between alcohol and acid (ranging from 2:1–1:9), the biocatalyst loading (between 7.5 % and 17.5 % relative to the acid), the volume of n -heptane used as reaction solvent (from 0 to 4 ml), and the reaction time (6 hours) were investigated. The activity and stability of the biocatalyst in successive uses were also analyzed. A conversion of 49 % was achieved when the reaction was carried out in a solvent-free system, using an alcohol/acid molar ratio of 1:7 and after 5 h of reaction. On the other hand, the conversion was 65.1 % when the reaction was conducted in a system containing 1 ml of n -heptane as solvent, an alcohol/acid molar ratio of 1:8, and 5 h of reaction. In both cases, a temperature as low as 30 °C and an agitation speed of 300 RPM were used. • Enzymatic route for levulinic acid esterification using biocatalyst. • Araujia sericifera latex-derived biocatalyst demonstrates high activity. • Achieved 65.1 % conversion of levulinic acid in the synthesis of octyl levulinate. • Solvent-free and n-heptane solvent systems investigated. • Studied reaction parameters for optimal conversion. [ABSTRACT FROM AUTHOR]

We present a theoretical investigation on the esterification process for boron ester synthesis, considering boric acid and 2(R),4(S)-pentanediol as model boron and diol derivatives, respectively. We report an unprecedented mechanistic pathway, able to rationalise, in contrast with the reported ones, the relatively low Gibbs energies of activation and the pH dependence experimentally observed in the formation of boron esters. We believe that these findings will improve the possibility to predict cross-link reaction rates of boron esters as a fundamental tool in the rational design of functional materials based on boron–oxygen linkages. [ABSTRACT FROM AUTHOR]

Global concerns regarding the depletion and strategic importance of phosphorus resources have increased demand for the recovery and recycling. However, waste‐derived phosphorus compounds, primarily as chemically inert phosphoric acid or its salts, present a challenge to their direct conversion into high‐value chemicals. We aimed to develop an innovative technology that utilizes the large quantities of sewage waste, bypasses the use of white phosphorus, and enables esterification of phosphoric acid to produce widely applicable phosphate triesters. Tetraalkyl orthosilicates emerged as highly effective reagents for the direct triple esterification of 85 % phosphoric acid, as well as the esterification of organophosphinic and phosphonic acids. Furthermore, we achieved esterification of recovered phosphoric acid with tetraalkyl orthosilicate, thus pioneering a recycling pathway from sewage waste to valuable phosphorus chemicals. Experimental and theoretical investigations revealed a novel mechanism, wherein tetraalkyl orthosilicates facilitate multimolecular aggregation to achieve alkyl transfer from tetraalkylorthosilicate to phosphoric acid via multiple proton shuttling. [ABSTRACT FROM AUTHOR]

A facile palladium‐catalyzed cascade carbonylation/Heck reaction/esterification has been developed. A large variety of alcohols and phenols were all tolerated well to access a series of benzofuran‐3(2H)‐one‐containing γ‐ketoesters in moderate to good yields, broadening the application of carbonylation. The current research exhibits broad substrate scope, good functional‐group compatibility and straightforward scale‐up. [ABSTRACT FROM AUTHOR]

The valorization of humins side streams from bio‐refineries holds significant economic and sustainability potential. One plausible strategy involves using them as building blocks to create new materials. However, humins pose conceptual challenges in their natural state due to their high viscosity, processing difficulties, and temperature sensitivity. This article presents a synthetic strategy for modifying humins properties to make them thermally stable and processable. Employing a sequence of esterification reactions and varying the reagent steric length, we showcase the selective transformation of humins into thermally‐stable fine powders and low‐viscosity liquids. We extend this approach by reacting humins with polyesters such as polylactic acids and polycaprolactone. In particular, we detail a one‐pot single‐step synthesis of micro‐phase separated compatibilized blends of polylactic acid and humins capped with the polylactic acid arms. Processed via solution‐casting, the obtained materials behave as high‐strength thermoplastic elastomers having uniform foam morphologies and material characteristics superior to the pure polylactic acid. By varying the content of D‐enantiomers, we demonstrate an additional possibility of manipulating the cellular structures of the foams. Finally, we provide a solution to product circularity by reporting a dissolution recycling method. [ABSTRACT FROM AUTHOR]

Background. The selection and production of non-steroidal biologically active substances is relevant. Purpose: synthesis of 3-(2-thioxobenzo[d]oxazole-3(2H)-yl) propanenitrile. Methodology: traditional methods of organic chemistry, spectral (IR, 1H NMR spectroscopy) methods. Originality. 3-(2-thioxobenzo[d]oxazole-3(2H)-yl)propanehydrazide was obtained for the first time, its reactions with aldehydes were studied. Findings. Modifications of the genetic series - nitrile, carboxylic acid, ester, hydrazides were studied, the structure was proven. [ABSTRACT FROM AUTHOR]

The legal obligation to swiftly adopt renewable energies has been increased because of the continuous usage of fossil fuels. In this perspective, biomass serves as a pillar to improve the current conditions over different heterogeneous catalysts due to their known advantages. This work is focused on the synthesis of a novel catalyst comprising mono lacunary phosphotungstate and zeolite HY. The catalyst was characterized by number of physicochemical techniques and evaluation of the activity of catalyst for the esterification of most promising bio platforms, levulinic acid and succinic acid to produce fuel additives. After a detailed optimization of both reactions, remarkable conversions of levulinic acid (77%) and succinic acid (96%) with turnover numbers of 2749 and 3427 respectively, were obtained. The order of the reaction and activation energy for the said reactions were calculated in the kinetic study. The sustainable nature of the catalyst was confirmed via regeneration and viability towards other bio-based molecules which enhances its industrial importance. [ABSTRACT FROM AUTHOR]

In the context of emerging engineering education, chemistry courses emphasize not only the development of students’ solid foundational skills in chemistry but also the integration of multidisciplinary knowledge to foster an innovative scientific spirit. “The Preparation of Benzocaine” is a classic undergraduate experiment in comprehensive organic chemistry. However, the original reaction procedure involves the generation of substantial waste acid during esterification, a cumbersome and time-consuming reduction step, and lacks engagement. To enhance efficiency, environmental friendliness, expansiveness and exploratory nature of the experiment, cutting-edge scientific advancements have been integrated into the preparation reaction. In the improved experiment, a deep eutectic solvent is utilized as a catalyst in the esterification reaction, which is recyclable and environmentally friendly. For the reduction step, tetrahydroxydiboron serves as the reducing agent and 4,4’-bipyridine as the catalyst, enabling the reaction to take place at room temperature with a noticeable color change, thereby making it engaging. This improved experiment not only stimulates students’ interest in learning, but also improves students’ scientific research literacy, and cultivates students’ green chemistry concept, independent thinking, and problem-solving skills. [ABSTRACT FROM AUTHOR]

Nodupetide, a cyclodepsipeptide with the potential as an antimicrobial agent, was isolated from the fermentation of the fungi Nodulisporium sp strain IFB-A163. It possessed antibacterial activity against Pseudomonas aeruginosa and revealed an insecticidal activity. In our effort to synthesized nodupeptide, the preparation of the (3S,4S)-3-hydroxy-4-methylhexanoic acid (HMHA) as one of the nodupetide residue was found to be challenging, where it is not commercially available and the synthetic trial of the HMHA was not successful. This led us to synthesize nodupetide derivative by replacing HMHA with its α-hydroxy acid to give the analogue [(2S,3S)-Hmp]²-nodupetide. A combination of solid- and solution-phase peptide synthesis was applied in the synthesis nodupetide analogue. Esterification on the resin for synthesis [(2S,3S)-Hmp]²-nodupetide was achieved by placing the reaction at the last stage of the linear peptide synthesis and obtained in overall yield of 4.3%. We also conducted antimicrobial activity screening for [(2S,3S)-Hmp]²-nodupetide and its linear precursor, showing inactive activity. The alter of hydrophobicity on the nodupetide analogue has very important role in the difference of bioactivity compared to their parent compound. [ABSTRACT FROM AUTHOR]

The current research work incorporates the synthesis, spectroscopic analysis, and in silico studies to evaluate anti-ovarian cancer potential and theoretical studies of 3-β-(2-(6 methoxynaphthalene-2yl)propionoxy)-stigmast-5-en (2). Synthesis of compound 2 was carried out by conjugating β-sitosterol (1) with Naproxen through highly efficient Steglich esterification. The structure elucidation of the synthesised compound has been done using 1H NMR, IR and UV as well as mass spectrometry. Anti-ovarian cancer potential of the compound 2 has been evaluated using its interaction with the ovarian cancer protein 2UZR (binding energy (ΔG) of -6.0 Kcal/mole) with the help of molecular docking studies. Topological parameters have been analyzed by "Atom in molecule" AIM theory. High value of first hyper polarizability (βo =6.071 × 10-30esu) of compound 2 indicates that it can be utilized as an ideal material for NLO applications. [ABSTRACT FROM AUTHOR]

Astaxanthin palmitate diester was synthesized by esterification of astaxanthin and palmitic acid, and the optimum reaction conditions were as follows: 50 mg of astaxanthin, 45 mg of palmitic acid, 1 mL of dichloromethane, 80 mg of 1 -ethyl-3 - (3 -dimethylaminopropyl) carbodiimide and 40 mg of 4-dimethylaminopyridine, under nitrogen protection at 25 °C for 12 h ・ Astaxanthin palmitate diester and astaxanthin palmitate monoester were purified by column chromatography with purities of 98. 9% and 97.4%, respectively. The structure of the product was characterized by IR, NMR and high-resolution mass spectrometry・ The antioxidant experiments showed that the overall antioxidant effect was astaxanthin palmitate monoester > astaxanthin > astaxanthin palmitate diester・ [ABSTRACT FROM AUTHOR]

Several approaches have been reported that aim to achieve simplified standardizations of the kinetic behavior of immobilized enzymes under specific experimental conditions. We have previously published simplified rate equations based on the kinetics of immobilized enzymes. Recently, new experimental results have become available on the kinetics and mechanisms of esterifications catalyzed by immobilized lipase in unconventional media, and consequently, a reformulation of their kinetics is necessary. In this work, we report the development of simplified rate equations relating the aforementioned reaction conditions on a new basis, considering our kinetic and mechanistic results. We provide experimental evidence that two different mechanisms describe the esterifications catalyzed by immobilized lipase, either in anhydrous organic solvent (n-hexane) or under non-solvent conditions. A ping-pong bi–bi mechanism with double dead-end substrate inhibition by both the fatty acid and the alcohol has been found to apply in the former case, while in the latter case the esterification proceeds via an ordered bi–bi mechanism with single dead-end substrate inhibition by ethanol. This study may be biotechnologically useful, as the increased use of immobilized enzymes, whether in academic research or in industry, requires sustainable development of new and environmentally friendly synthetic processes. [ABSTRACT FROM AUTHOR]

This work presents the synthesis and characterization of materials that contain Sn metal clusters formed by ligands of trimesic acid (Sn-BTC) or 5-sulfobenzene-1,3-dicarboxylic acid (Sn-H3-5-SIP). These catalysts were used to convert levulinic acid with ethanol to produce ethyl levulinate under mild reaction conditions. The characterization results confirmed that Sn is mainly present in the cassiterite crystalline phase with a tetragonal rutile structure in octahedral and tetrahedral coordination in the materials. The assembly of trimesic acid (a hard base) with metal species (Sn) results in the formation of acid and thermally stable metal–organic frameworks. The use of 5-sulfobenzene-1,3-dicarboxylic acid instead of trimesic acid in the synthesis incorporates sulfonic groups in the material, enhancing the total acidity of the Sn-H3-5-SIP catalyst compared to the Sn-BTC material. The Sn-H3-5-SIP catalyst exhibited the highest catalytic activity when converting levulinic acid with ethanol, resulting in a turnover frequency (TOF) of 0.0495 s−1, which is a 50% increase compared to the TOF of the Sn-BTC catalyst (0.0329 s−1). This result can be attributed to its higher concentration of acid sites (2.23 ± 0.05 mmol H+/gcat) and specific area (139 m2/g). Thus, materials containing tin metal clusters and sulfonic groups are promising materials that could be used as catalysts for synthesizing ethyl levulinate under mild reaction conditions. [ABSTRACT FROM AUTHOR]

Herein, we detail an extension of our research on the synthesis of a small library of furanoheliangolides and the characterization of the covalent interaction between goyazensolide and IPO5. Using a build‐couple‐pair strategy, we assembled a small library of germacrene‐type lactones and diversified them into eight groups of structurally different analogues. The germacrene lactones were synthesized using Sonogashira coupling and Barbier‐type macrocyclization, while the furanoheliangolides were further elaborated through gold‐catalyzed transannulation followed by esterification. This synthetic approach enabled the generation of a goyazensolide alkyne‐tagged cellular probe, which was used to identify the selective binding between goyazensolide and the oncoprotein importin‐5 (IPO5). Mass spectrometry analysis of the proteolytic digest from the reaction between the goyazensolide probe and a recombinant IPO5 indicated a covalent engagement at Cys560 of IPO5, which was confirmed by site‐directed mutagenesis. [ABSTRACT FROM AUTHOR]

Imidazole is one of the most important heterocyclic rings. This nucleus can be found in a plethora of substances in different knowledge areas such as medicinal, agrochemical, polymer, and dyestuff. N‐alkylation reactions involving N − 1 atom is a remarkable tool to synthesize many imidazole derivatives which can be attached to a great variety of functional groups. In this work, we synthesized 10 new intermediates 4‐chlorobutyl 1‐aryl‐1H‐pyrazole‐4‐carboxylates 3(a–j) from 1‐aryl‐1H‐pyrazole‐4‐carbonyl chlorides, obtained from 1‐aryl‐1H‐pyrazole‐4‐carboxylic acids 4(a–j), and 4‐chlorobutan‐1‐ol 1, generated by THF ring‐opening promoted by hydrochloric acid. Compounds 3(a–j) promoted N‐alkylation of 4(5)‐nitro‐1H‐imidazole to afford the targets 4‐(4‐nitro‐1H‐imidazol‐1‐yl)butyl 1‐aryl‐1H‐pyrazole‐4‐carboxylates 2(a–j) in 18%–85% yields. [ABSTRACT FROM AUTHOR]

Esterified starch was prepared by nonenyl succinic anhydride as esterification agent, 4-dimethylaminopyridine (DMAP) as catalyst, and ionic liquid (1-ethyl-3-methylimidazole chloride) aqueous solution as solvent. Esterified starch and polylactic acid (PLA) were mixed to prepare composites. The structure and properties of esterified starch and its PLA composites were characterized by a Fourier transform infrared spectrometer (FTIR), a scanning electron microscope (SEM), and a contact angle goniometer. The results indicated that the optimal process for preparing esterified starch was reaction time of 2.5 h, reaction temperature of 85 °C, catalyst dosage of 2% of starch, n(ionic liquid) : n(water) of 1 : 10, and n(esterification agent) : n[dehydrated glucose unit (AUG) in starch] of 1 : 3. Under the optimal reaction conditions, the degree of substitution was 0.92 mmol/g. FTIR analysis indicatesd that the starch has been successfully esterified. The contact angle test showed that the hydrophilicity of esterified starch decreased, similar to the contact angle of PLA. The DMA results showed that esterification modification improved the compatibility between starch and PLA. The mechanical property test results showed that when the mass fraction of esterified starch was 25%, the tensile strength, bending strength, and impact strength of the composites were increased by 4.7%, 132% and 26.5% compared to the PLA/ original starch composites, respectively. SEM results showed that the surface morphology of the esterified starch changed, and the compatibility between the esterified starch and PLA was improved. [ABSTRACT FROM AUTHOR]

The potentially wide application of Phenolic acids (PAs) in industries was severely limited by their inadequate solubility and stability in polar/non-polar media. To overcome these limits, studies on the enzymatic esterification of PAs with glycerol were carried out to reach a yield of 95% of phenolic acid glycerols (PAGs) under the following reaction conditions: 1:150 molar ratio of PAs to glycerol; 25% of Lipozyme 435 relative to the weight of total substrates; 80°C, 500 rpm, 86.7 kPa and 10 h. Three resulting PAGs including caffeoyl glycerol (CG), feruloyl glycerol (FG), and p-hydroxycinnamoyl glycerol (p-HCG) were confirmed by MS, ¹H NMR and 13C NMR. Among them, CG showed a comparative free radical scavenging ability to CA, indicating its potential use as a water-soluble antioxidant alternative to CA for food and cosmetic applications. [ABSTRACT FROM AUTHOR]

Polyethylene glycol (PEG) ester is a non ionic surfactant compound that could use a pour point depressant (PPD) for crude oil. Synthesis of PEG-ester with reflux and mono wave-50 methods through esterification fatty acid such as oleic acid, stearic acid, and palmitic acid with adding p-toluene sulfonic acid (p-TSA) as a catalyst. The product of esterification could be a mixture of monoester and diester. Synthesized PEG ester by reflux method resulted in higher yield than by mono wave-50 method. IR spectra analysis of PEG400-oleate, PEG400-stearate, and PEG400-palmitate show the presence of an absorption band at a wavenumber of around 1100 cm-1 that indicates the stretching vibration of the C-O ester. (LC-MS/MS) analysis that shows the molecular weight of PEG400-oleate was 845.6154 g/mol and, PEG400-stearate was 785.5952 g/mol. Mean, while PEG400-palmitate produced three ester compounds with different molecular weights: 741.5669 g/mol, 685.5057 g/mol, and 734.5208 g/mol. The pour point measurement results show that the PEG-fatty acid product in the range of 0.1% to 1% has not been able to reduce the pour point of the crude oil sample. [ABSTRACT FROM AUTHOR]

An MFI zeolite (Si/Al = 40) was desilicated by alkaline treatment in order to generate mesopores. Temperature, alkali concentration and treatment duration were adjusted to maximize mesoporosity while preserving the zeolite structure. Special attention was paid to the characterization of the strength and accessibility of the acid sites. The catalysts were tested in the isobutane/butene alkylation, a reaction that is typically catalyzed by zeolites but limited by coke deposition. Additionally, glycerol esterification with acetic acid was used as a test reaction due to the required participation of large pores. The results confirmed that mesopores were successfully generated in the MFI zeolite, and the diffusion through the solid was enhanced, but the active sites were mainly confined to the micropores. [ABSTRACT FROM AUTHOR]

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The regularities of extraction of adsorbate from spent bleaching earth (SBE) of sunflower oil by the esteraldehyde fraction (EAF) have been established. The content of the substances adsorbed by SBE was 34.1%, including 19.2% free fatty acids (FFA) and 11.1% moisture. The influence of temperature (50 and 700 C), extraction duration (60 and 120 min), and the mass ratio of EAF to SBE ((2–4):1) on the extraction parameters has been determined. It was found that increasing these process parameters enhances the extraction degree of the adsorbate and FFA from the bleaching earth, reaching 41.9% and 34.4%, respectively, at a temperature of 700 C, extraction duration of 120 min, and a mass excess of EAF to SBC at a ratio of 4:1. Optimal conditions for the removal of FFA from SBE were identified. It was established that strong acidic sites are present on the surface of the bleaching earth, with the acidity of fresh, spent, and EAF-treated bleaching earth being 0.79, 0.77, and 0.74 mmol H+ per gram, respectively. The basicity of fresh bleaching earth was 0.073 mmol OH– per gram, indicating the ability of bleaching earth to catalyze the esterification of FFA with ethanol. The suitability of the obtained extract for the production of FFA ethyl esters was demonstrated. [ABSTRACT FROM AUTHOR]