Search

A series of benzoquinoline-based heterocycles was synthesized using 2-((3-chlorobenzo[f]quinolin-2-yl)methylene)hydrazine-1-carbothioamide as a key material via condensation of 3-chlorobenzo[f]quinoline-2-carbaldehyde with thiosemicarbazide. The titled thiosemicarbazone scaffold was conducted with some carbon electrophilic reagents such as acetic anhydride, chloroacetyl chloride, chloroacetic acid, 2-bromo-1-(3-nitrophenyl)ethan-1-one, 2-chloro-N-phenylacetamide, and dimethyl but-2-ynedioate to obtain triazole thione, imidazolone, thiazolidinone, and thiazole derivatives. On the other hand, hydrazinolysis of thiosemicarbazone did not proceed as expected but it gave the azine derivative. The in vitro antitumor and antioxidant activity of the synthesized compounds were screened and revealed that triazole thione and thiazole derivatives were the most potent. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Acetic acid‐mediated three‐component double Friedel–Crafts alkylation reaction for the synthesis of α, α‐diaryl oxindole derivatives is demonstrated. The reaction is successful with various isatin, indole, and N, N‐disubstituted aniline derivatives. The efficiency of the reaction is further enhanced by a four‐component reaction of isatin, electrophiles and acetic anhydride for the synthesis of N‐acylated 3,3‐diaryl oxindole derivatives facilitated by dual activation of C3 and N1 acetylation in a single‐step. Various unsymmetrical and symmetrical 3,3‐diaryl oxindoles were prepared in single‐step MCR reaction under easy to operate reaction conditions. [ABSTRACT FROM AUTHOR]

L‐lactide (LA) is polymerized with ethyl L‐lactate or trifluoroethanol as initiators (LA/In = 30/1), and the resulting poly(L‐lactide) esters are acetylated with acetic anhydride. The acetylated PLA esters are mixed with SnOct2, dibutyltin bis(4‐chlorophenoxide), or dibutyltin bis(pentafluorophenoxide) in solution and crystallized at 120 °C. The doped crystals are annealed at 140 °C or at 160 °C for 7, 14, and 28 days, and the chemical modifications that occurred in the solid state are monitored by matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements. All catalysts promoted polycondensation, while no significant formation of cycles is observed. However, in the presence of SnOct2, disproportionation of chains occurred upon annealing at 120 or 140 °C, and crystallites consisting of extended chains with Mn values ≈3500 – 3600 and low dispersities (Ð < 1.5) are formed. [ABSTRACT FROM AUTHOR]

A mild strategy was developed for efficient preparation of acetylsalicylic acid (ASA) from the acetylation of salicylic acid (SA) and acetic anhydride (AA) assisted ultrasonic over Y-immobilized cation exchange resin (Y-CER). With this strategy, an ASA yield of 95.2% was obtained. The results showed that the increased yield was due to Lewis acidic sites (LAS) combined with ultrasonic assistance. The process reduced the AA reagent feed while lowering the reaction temperature. The characterization results showed that metal Y species were dispersedly anchored on the CER surface through S-O-Y triple-dentate bonds, resulting in abundant LAS and stable catalytic activity. Comparative experiments revealed that LAS was more favorable for the formation of ASA than Bronsted acidic sites (BAS). Furthermore, a plausible mechanism for the acetylation of SA and AA by Y-CER has been proposed. This work provided a practical protocol for improving ASA yield and reducing acid wastewater discharge, with potential application prospects. [ABSTRACT FROM AUTHOR]

Microcrystalline cellulose was subjected to acetylation by different agents in solvent mixtures, composed of the ionic liquids (ILs) 1-butyl-3-methylimidazolium X (X = acetate, BuMeImAcO; chloride, BuMeImCl), and the molecular solvents (MSs), N,N-dimethylacetamide (DMAc) and dimethyl sulfoxide (DMSO). The reactions were carried out under homogeneous conditions using the following acetylation agents: acetic anhydride ((Ac)2O), 1-acetyl-3-methylimidazolium acetate (AcMeImAcO), and vinyl acetate (VA). The efficiency of acetylation was judged by the degree of biopolymer substitution, DS. For all binary solvent mixtures, the order of DS was: AcMeImAcO > (Ac)2O > VA. For the same acetylating agent, the order of DS was: BuMeImAcO-DMSO > BuMeImAcO-DMAc > BuMeImCl-DMSO. We rationalize this dependence of DS on reaction conditions by considering our experimental data and the results of molecular dynamics simulations (MD). Thus, solvent-induced separation of cellulose chains leads to higher acetylation rates, hence larger DS values. The order of biopolymer dissolution/chain separation is attributed to a combination of hydrogen-bonding of the IL anion with cellulose hydroxyl groups, and biopolymer-solvent hydrophobic interactions. The results of MD simulations showed an additional important point: the compositions of the cellulose solvation layers are different from those of bulk solvent mixtures; they are richer in IL ions; this difference affects the values of DS. Thus, theoretical calculations help in choosing the best solvents for cellulose dissolution/derivatization. [ABSTRACT FROM AUTHOR]

An innovative SPME head space GC–MS method, in cooling mode, using a fully automated routine, was developed to detect 2-phenyl-2-propanol, a representative urinary metabolite of cumene. Following an acid hydrolysis and derivatization step with lowered quantities of reagents, acetic anhydride and pyridine, a 30 μm polydimethylsiloxane SPME fiber was used to sample derivatized 2-phenyl-2-propanol, such as benzenemethanol,α,α-dimethyl-acetate, from the headspace. Performances of the method, optimized through experimental design, provide an LOD of 0.034 mg/L and an LOQ 0.10 mg/L, with a short sampling time necessary per sample. The method, developed on standard solutions, will be applied to both occupationally exposed and non-exposed populations. [ABSTRACT FROM AUTHOR]

A series of substituted 2-aminotetrahydroquinolinecarbonitriles have been synthesized by the three-component condensation of diaryl(hetaryl)methylidenecyclohexanones, malononitrile, and ammonium acetate. Factors responsible for the reaction selectivity and product formation pathway have been revealed. The reaction of aminoquinolinecarbonitriles with acetic anhydride under acidic conditions afforded substituted hexahydro-pyrimido[4,5-b]quinolinones. The structure of the synthesized compounds has been determined by IR and 1H and 13C NMR spectroscopy, including HSQC two-dimensional correlation technique. [ABSTRACT FROM AUTHOR]

Bulk heterojunction solar cells are among the most promising organic solar cells (OSCs). One of the two important parts of OSCs are acceptors, and the development of the design and synthesis of non-fullerene acceptors involves an electron-deficient heterocyclic central core and anchor acceptor malonitrile derivatives of 3-methylene-2,3-dihydro-1H-inden-1-ones. In this communication, an intermediate for the synthesis of this compound, 1-(dicyanomethylene)-3-hydroxy-1H-indene-2-carboxylic acid, was prepared by the Perkin reaction of 2-(3-oxoisobenzofuran-1(3H)-ylidene)malononitrile with tert-butyl acetoacetate in the presence of acetic anhydride and triethylamine. The structure of the newly synthesized compound was established by means of elemental analysis, high-resolution mass spectrometry, 1H NMR, 13C NMR and IR spectroscopy, and mass spectrometry. [ABSTRACT FROM AUTHOR]

A composite based on Fe3O4 nanoparticles, graphene oxide, and a ionic liquid (1-butyl-3-methylimidazolium-2-carboxylate) is proposed as a sorbent for the extraction of bisphenol A (BPA) from bottom sediments by matrix solid-phase dispersion (MSPD). The saturation magnetization of the synthesized sorbent is 34 emu/g. Grinding of bottom sediments and subsequent grinding with a sorbent was carried out in a ball mill. Some stages of MSPD were partially automated, in particular, the procedures of magnetic separation, BPA desorption, and sorbent regeneration. The recovery of BPA under the experimentally selected conditions (sorbent mass 0.5 g, time required to grind the sorbent 5 min) was 94%. The sorbent can withstand four sorption-desorption cycles without a loss of sorption capacity. To purify the matrix from interferents, washing with n-heptane was proposed. Bisphenol A was determined by gas chromatography–mass spectrometry after derivatization with acetic anhydride. The analytical characteristics of the method were established using model samples of bottom sediments artificially contaminated with BPA. The limit of determination using the developed method is 0.1 μg/kg, the linearity range of the calibration curve is 0.3–12 μg/kg (r2 = 0.994). As real samples for analysis, we used bottom sediments selected near the discharge of wastewater treatment plants in the city of Voronezh (Voronezh River and Don River). The BPA concentration in bottom sediments is 3.83–6.52 μg/kg. [ABSTRACT FROM AUTHOR]

The aim of the current study is to modify water hyacinth fibre (WHF), which are then used to produce novel oil sorption polymers. Two synthetic materials were derived from acetylation by acetic anhydride using N-bromosuccinimide (NBS) as a catalyst and the graft co-polymerisation of butyl acrylate (BA) using 2,2′-azobisisobutyronitrile (AIBN) as an initiator. Physicochemical properties were comprehensively characterised by Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction, contact angle, and thermogravimetric analysis. In the seawater/crude oil system, the best oil sorption capacity values of the raw WHFs and their acetylated-WHF and graft co-polymer WHF-g-BA were 7.46 g/g, 20.16 g/g, and 25.47 g/g, respectively. The sorption kinetic and isotherm studies exhibited that the oil sorption of the co-polymer WHF-g-BA is ruled by pseudo-second-order kinetic and Freundlich isotherm models. The reusability of the WHFs and their synthetic materials has reached 6 cycles of sorption/desorption, and this property of the co-polymer is always better than that of acetylated and original fibres. [ABSTRACT FROM AUTHOR]

The high value‐added utilization of the fluorinated silica slag (FSS) waste, an associated by‐product of the anhydrous HF production from the accompanying fluorine resources in phosphate ore, is of great importance, but it remains a challenge. In this work, the Mg modified and unmodified Hβ zeolites from FSS waste were successfully prepared by a green dry gel conversion crystallization method with tetraethylammonium hydroxide (TEAOH) as a structure‐directing agent (SDA). The in situ Mg modified Hβ zeolite (Mg−Hβ) shows much superior catalytic performance to unmodified (Hβ) and post Mg‐modified Hβ (Mg/Hβ) zeolites for acetylation of 2‐methoxynaphthalene (2‐MN) to 6‐acetyl‐2‐methoxynaphthalene (2,6‐AcMN), and the 40.2 % of conversion for 2‐MN with 66.3 % of selectivity for 2,6‐AcMN were achieved, ascribed to the high amount of B acidic sites and the promoted shape‐selective catalysis effect by higher surface area and volume of micropores. This work not only opens a new avenue for the high value‐added utilization of fluorinated silica slag waste, but also generates an efficient solid acid catalyst for the clean production of 2,6‐AcMN through the acetylation of 2‐MN with acetic anhydride. [ABSTRACT FROM AUTHOR]

A series of some new 1,3,4‐oxadiazole derivatives was synthesized. Hydrazide derivative 4 was reacted with some sugar aldehydes to give the corresponding sugar hydrazones 5 a–c. Acetylation of 5 a–c with acetic anhydride in pyridine, managed the per‐O‐acetyl derivatives 6 a–c while refluxing in acetic anhydride gave the corresponding 1,3,4‐oxadiazolines 7 a–c. On the other hand, 1,3,4‐oxadiazoles 8 a,b, 9, 10, 12, 14, and 15 were synthesized via the reaction of 4 with different reagents including p‐chlorobenzoic acid, nicotinic acid, methyl iodide, morpholine, phenyl isothiocyanate, potassium iodide, chloroacetyl chloride, and phosphorus oxychloride, respectively. The new compounds were assessed for their anticancer and antioxidant activities. Compounds 8 a,b, 10, and 12–15 displayed the most antioxidant activity. In addition, compounds 8 a, 8 b, and 13 showed strong cytotoxic activity. [ABSTRACT FROM AUTHOR]

The reaction of p-aminophenol with acetic anhydride under microwave irradiation in the presence of H-clinoptilolite was studied to continue the search for effective, economically favorable, and environmentally friendly methods for synthesizing acetaminophen (paracetamol). The proposed system, which provided a rapid synthesis of the most important drug with a high yield and purity, was demonstrated to be efficient. [ABSTRACT FROM AUTHOR]

Summary: Proteins are commonly used ingredients to impart certain non‐nutritional properties to foods. Consequently, the industry is constantly seeking to enhance proteins that provide these attributes to food products. Therefore, the aim of this research was to extract the protein from sesame seeds and evaluate the effect of chemical modification through acylation with lauroyl chloride and acetic anhydride on functional properties (solubility index, emulsifying, foaming, swelling and water‐holding and oil‐holding capacity). Chemical modification was successfully demonstrated using FTIR spectroscopy and X‐rays. It was found that acylation with lauroyl chloride or acetic anhydride altered the physicochemical and functional properties, particularly at pH 10. Both reactions exhibited substitution degrees exceeding 20%. Chemical modification via acylation resulted in significant improvements in water and oil retention capacity, emulsifying activity and foaming activity. Thermal analysis revealed significant changes in the modified samples, altering their denaturation temperature, leading to the conclusion that chemical modifications through acylation with lauroyl chloride or acetic anhydride offer benefits in certain functional properties relevant to the food industry. They also represent an opportunity to diversify the application of a by‐product obtained from sesame oil extraction. [ABSTRACT FROM AUTHOR]

In this study, coumarin derivatives were synthesized from coumarin 3-carbohydrazide (1) and 4-(pyrimidin-2-yl diazenyl)-antipyrine (2), leading to the intermediate compound (3). The final compounds were synthesized through the cyclocondensation of compound (3) with mercaptoacetic acid, acetic anhydride, sodium azide, 2-aminobenzoic acid, and maleic anhydride. This process resulted in the formation of five spiro heterocyclic coumarins (4a-e) respectively. The novel compounds were purified by column chromatography, and were identified by FTIR, ¹H, and 13C-NMR. The antibacterial activity of the prepared compounds was evaluated in vitro using the disk diffusion method against Escherichia coli and Staphylococcus aureus bacteria. Compound (4b) showed significant antibacterial activity, among others. Furthermore, the docking study of (4b) with DNA gyrase for both bacterial strains was investigated using (Auto Dock Vina), and (Discovery Studio software), which revealed vital interactions and binding conformations. [ABSTRACT FROM AUTHOR]

This research investigates the enhancement effects of basalt fibers (BFs) and kraft lignin (KL) as natural additives on the mechanical properties of acrylonitrile–butadiene–styrene (ABS)‐based composites. Initially, BF was incorporated into ABS as a fiber reinforcement, and its mechanical properties were evaluated. It was observed that an increase in BF content in ABS led to an increase in the tensile strength while the impact strength tended to decrease. Subsequently, the potential of lignin or modified lignin as interfacial compatibilizers was assessed to improve the miscibility between ABS and BF. The modification of lignin was achieved via esterification by using esterifying agents (acetic anhydride [C2_Ac], propionic anhydride [C3_Pr], and butyric anhydride [C4_Bu]). At the optimal conditions (30 wt% of BF, 15phr of AcKL), the mechanical properties of ABS/BF/AcKL composite presented a 48.1% improvement in tensile strength and a 27.4% enhancement in impact strength compared to those of ABS/BF composite. The fracture surface analysis of the composite revealed that the esterified lignin enhances the compatibility between components, thereby filling the gaps present at the matrix‐fiber interface. These results suggest promising applications for multi‐component composite materials. [ABSTRACT FROM AUTHOR]

The reaction of ethyl pyridine-2-ylcarbamate with phenacyl bromides in acetonitrile gave 2-aryl-1-(ethoxycarbonyl)-2-hydroxy-2-phenyl-2,3-dihydro-1H-imidazo[1,2-a]pyridine-4-ium bromides which were con--verted into 2-arylimidazo[1,2-a]pyridines by heating in acetic anhydride, followed by treatment with potassium carbonate. [ABSTRACT FROM AUTHOR]

This paper presents a novel and reliable approach for the determination of tilmicosin residues in poultry muscle and pork via gas chromatography–tandem mass spectrometry after precolumn derivatization. The samples were subjected to a quick, easy, cheap, effective, rugged, and safe preparation method, solid-phase extraction, hydrogenation, gel chromatography separation, acid hydrolysis, and derivatization with pyridine and acetic anhydride. For the blank spiked samples at the limit of quantification, 0.5 times the maximum residue limit (MRL), the MRL, and 2.0 times the MRL, the recoveries were from 76.91 to 87.99% with a precision of 2.04–5.47%. The limits of detection and quantification were 2.3–4.4 and 6.2–9.8 µg kg−1, respectively. The protocol was validated and real samples analyzed to demonstrate its practical application. [ABSTRACT FROM AUTHOR]

Sulfonamide compounds with functional group -SO2NH- show a wide range of biological activities and medicinal properties. The synthesis of sulfonamides has been of interest to medicinal chemists for a long time. In this article, the selective acylation of sulfanilamide with acetic anhydride was carried out using some catalysts with Lewis acid properties. In this research, the one-pot selective method of N-acylation of -SO2NH2 group in sulfanilamide molecule using stannous oxide nanoparticles as an efficient recyclable catalyst has been used. In this method, THF was replaced with expensive toxic amine solvents. The acylated product was identified by FTIR, 1HNMR, 13CNMR and MASS spectra. The best results with 85% efficiency, 95% selectivity were obtained using stannous oxide nanoparticles as catalyst (0.5 g) in tetrahydrofuran as solvent, at 60°C in 60 minutes. The catalyst was recycled three times and maintained its efficiency. Using this method is completely green and has economic and environmental benefits. [ABSTRACT FROM AUTHOR]

Plastic film is widely produced and applied in many daily applications. Although it provides many benefits to human activity, the disposal of commercial plastics has always been a serious problem as it will contribute to landfilling issues and environmental pollution. Bioplastic film was invented to resolve part of this issue, as most of the plastic film produced from natural sources is biodegradable. However, the biodegradability and characteristics of the film are highly dependent on the type of raw material, production procedure, and chemical composition. In this study, extracted kapok cellulose was acetylated into cellulose acetate (CA) with various levels of acetic acid (17.5, 20, and 22.5 mL), acetic anhydride (5, 7.5, and 10 mL) and acetylation time (30, 45 and 60 min). The Box–Behnken design was applied to evaluate the quality of the produced film. The design showed that the level of acetic acid has a strong impact on CA's yield, acetic anhydride has a greater influence on tensile strength, and CA's solubility has a stronger connection with the acetylation time. All modeling equations developed were validated with the coefficient of determination, R2 more than 0.6. The optimized factor levels for the ductile-like film on acetic acid, acetic anhydride, and acetylation time are 20.530 mL, 9.546 mL, and 55.45 min, respectively. Whereas for brittle-like film, the optimized factor level is 22.399 mL, 10 mL, and 60 min, respectively. The ductility and brittleness of a plastic film can be modified by adjusting these level factors. [ABSTRACT FROM AUTHOR]

BACKGROUND: Collagen is a biomedical material with good biocompatibility, low toxicity, low immunoactivity, and high cellular affinity. However, the defects such as hydrophilicity and poor thermal stability are the key technical problems that need to be solved urgently in biomedical, tissue engineering, and other applications. OBJECTIVE: To elaborate on the preparation method, characterization, and application progress of acylated collagen. METHODS: PubMed, X-mol, and CNKI databases were used to search the literature on acylated collagen preparation methods, characterization, and application. The search time was from January 1992 to May 2023. The English search terms were “acylated collagen, modified collagen, water-soluble collagen, acetic anhydride”. Chinese search terms were “acylated collagen, modified collagen, water-soluble collagen”. After an initial screening of all articles according to inclusion and exclusion criteria, 53 articles with high relevance were retained for review. RESULTS AND CONCLUSION: (1) The preparation of acylated collagen is mainly obtained by the acylation reaction of acid anhydride, and the reaction sites are mainly ε-amino and N-terminus-amino of collagen, and the reaction environment of acylation reaction needs to be carried out in an alkaline environment. (2) Succinic anhydride is the preferred reactant of acylated collagen. Carbonic anhydride, citric anhydride, and bifunctional modifiers with acylation ability have been excavated in recent years to meet various requirements, but it is still limited to laboratory preparation; complex preparation process is difficult to industrialize, and follow-up research is needed to continuously improve. (3) The characterization methods of acylated collagen are similar to those of collagen, but there is still a lack of standards for the water-soluble characterization of acylated collagen. (4) In recent years, acylated collagen has been gradually used in the preparation of lenses, hydrogels, and dressings, as well as cosmetic raw materials. However, there is still little research on the application of acylated collagen, and there is a lack of complete in vivo experiments to verify the practicality of acylated collagen. [ABSTRACT FROM AUTHOR]

Diboradiazene compounds, derived in one step from the boron‐mediated reduction of dinitrogen (N2), were treated separately with sulfur and acetic anhydride, providing heterocyclic compounds that are BN isosteres of thiophene and 1,3‐oxazole, respectively. These simple reactions represent the final steps in two‐step routes to complex heterocycles from N2 that both circumvent the need for transition metal reagents and completely bypass the traditional intermediate ammonia. [ABSTRACT FROM AUTHOR]

BACKGROUND: Starch is the main component of quinoa seeds. However, quinoa starch has poor solubility in cold water and poor mechanical resistance and is easily aged, which limit its application. Therefore, modification of its structure to improve its functional properties is necessary. RESULTS: This research used acetic anhydride and sodium trimetaphosphate to modify the structure of starch molecules and investigated their influence on bread quality. The results showed that both esterification and crosslinking prevented the aggregation behavior of starch molecules. Moreover, they both decreased the gelatinization enthalpy change and relative crystallinity of the starch. Compared with native starch, modification significantly decreased the gelatinization temperature from 57.01 to 52.01 °C and the esterified starch exhibited the lowest enthalpy change with a 44.2% decrease. Modified starch increased the specific volume and decreased the hardness and chewiness of bread. Modification did not influence the moisture content in bread but impacted the water retention capacity, depending on the degree of modification. Low and medium degrees of modification improved the water retention capacity during storage. By contrast, a high degree of modification (10 g kg−1 crosslinking agent) decreased the water retention capacity. The dually modified quinoa starch (esterified and crosslinked) showed no influence on the textural properties of bread. CONCLUSION: This study demonstrated that both esterification and crosslinking significantly improved the functional properties of quinoa starch. Crosslinked or esterified quinoa starches have the potential to improve the textural properties of bakery products. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The mechanochemical hydrogenation of 4-nitrophenol was examined in a ball mill reactor. Hydrogen gas flows through the reactor at ambient temperature and pressure in the presence of Pd/C catalyst and acetic anhydride. Under optimized conditions, simultaneous hydrogenation and acetylation in one pot increased paracetamol selectivity by avoiding undesirable side reactions of 4-aminophenol. Side product formation was further reduced through a novel bubbler configuration allowing for the delivery of acetic anhydride vapor to the reaction vessel. Ball mill results were compared to traditional stirred tank hydrogenations in a Parr reactor and shown to have superior yield and process mass intensity. [ABSTRACT FROM AUTHOR]

The significant medicinal and pharmacological facts about chromenes (benzopyran) nucleus prompted us to focus on constructing unique chromenes with biological value. New chromene derivatives 2–15 were synthesized, and their antibacterial effectiveness was studied. The reaction of the 2-amino-4H-chromene derivative 1 with a variety of reagents such as acetic anhydride, formic acid, chloroacetyl chloride, cyclopentanone, ethyl acetoacetate, diethyl malonate, aldehydes, and isatin produced derivatives 2–13. Compound 1 was also treated with aromatic amines such as p-toluidine and/or benzene-1,4-diamine with formaldehyde, yielding derivatives 14 and 15, respectively; spectral techniques were used to confirm the predicted structures of all compounds. The antibacterial activity of the recently synthesized compounds was assessed against two types of bacteria, Bacillus subtilis and Escherichia coli. There is encouraging antibacterial activity in compounds 5 and 7. [ABSTRACT FROM AUTHOR]

The main aim of this work was to study the role of the acetylation process of wheat straw pulp on its ability to rheologically modify two of the most important non-polar engineering fluid: bitumen and oil. Pulp was produced by a pilot-scale kraft pulping process from local wheat straw. Pulp was functionalized with acetic anhydride and sulfuric acid as a catalyst by modifying (temperature, pulp/acetic anhydride mass ratio, and reaction time. Further, chemical, morphological and thermal changes induced by the acetylation process were properly assessed. Acetylated wheat straw pulp dispersions in oil showed gel-like behaviour, with a mechanical spectrum characterized by higher values of the storage modulus (G′) and a minimum in the loss modulus (G″) at intermediate frequencies. The complex modulus (G*) for bitumen dispersions formulated with acetylated samples was up to 4 times higher than neat bitumen, and the phase angle (δ) indicated an enhancement in the elastic behavior parameters. The rheological response of these systems was associated with the microstructural network formed by pulp fibers and the balance between the physical and chemical changes of wheat straw fibers. According to the experimental results obtained, it can be concluded that acetylation is a relevant chemical treatment to modulate the rheological properties of wheat straw pulp dispersions in non-polar fluids, improving the compatibility between pulp fibers and these engineering fluids. Accordingly, this study provides valuable insights into the development of sustainable multiphasic materials (bitumen binders and semi-solid lubricants) for industrial applications. [ABSTRACT FROM AUTHOR]

A novel series of 1,3,4-oxadiazole derivatives of mefenamic acid was obtained by reacting hydrazones of mefenamic acid with anhydrous acetic anhydride. The mefenamic hydrazones were obtained by reacting different substituted aldehydes with mefenamic acid hydrazide. All the compounds were characterized by spectral data and elemental analysis. Molecular docking studies of all the compounds were performed against COX-1/COX-2 enzymes. Compound 4 and compound 10 were found to have the highest potential to bind with COX-1 while compound 3, compound 6, and compound 10 were found to have the highest potential to bind with COX-2 enzyme. [ABSTRACT FROM AUTHOR]

The objectives of this study are to investigate the structural and physicochemical properties of a novel acetylated lotus seed starch (LSA). LSA is successfully prepared using an aqueous phase method. Fourier transform infrared spectroscopy (FTIR) proves that a carbonyl C=O vibration at 1737 cm−1 are due to the introduced acetyl groups. X‐ray diffraction (XRD) indicates that the acetylation treatment does not change the crystal structure, but reduces the relative crystallinity of starch. Scanning electron microscopy (SEM) shows that the surface of LSA with 12% of acetic anhydride (LS‐12A) becomes the roughest. Moreover, compared with lotus seed starch (LS), the particle size, transparency, swelling power, and solubility of LSA are increased to 18.01 ± 0.66 µm, 15.30% ± 0.30%, 9.59 ± 1.78 g g−1, and 6.06% ± 0.99% at 55 °C with the additional content of acetic anhydride. However, differential scanning calorimetry (DSC) shows that the melting enthalpy of LSA decreases compared with LS. This work provides some theoretical basis for the study and development of acetylated starch. [ABSTRACT FROM AUTHOR]

This report expresses a sustainable methodology for the in situ synthesis of Ag nanoparticles (NPs) adorned carboxymethyl lignin (CML) functionalized Fe3O4 nanocomposite (Fe3O4@CML/Ag) and its subsequent chemical and biological applications. Structural and physicochemical features of such novel material was evaluated through a number of analytical techniques like FT-IR, FE-SEM, TEM, EDS, XRD, ICP and VSM. The nanomaterial was a competent catalyst towards the N-acylation of diverse amines using acetic anhydride at solvent-free conditions. The material was isolated by magnet and reused for 8 consecutive times. Furthermore, the material was employed in the biological evaluation of anti-oxidant properties by DPPH method as well as the anticancer studies of against HT-29 and Caco-2 colon cell lines following MTT method. The DPPH assay afforded a significant IC50 value that suggested the material to have good anticancer properties. Interestingly, % cell viability of the malignant cell lines was found to decrease dose-dependently over Fe3O4@NaLS/Ag nanocomposite. MTT assay afforded the corresponding IC50 values to be 395.4 μg/ml and 287.3 μg/ml respectively against the two cell lines. The absorbance rate was evaluated at 545 nm, which represented toxicity on normal cell line (CHO) even up to 2000 μg/mL. [ABSTRACT FROM AUTHOR]

BACKGROUND: Wheat bran is rich in dietary fiber (DF), particularly insoluble dietary fiber (IDF). Although the benefits for human health following the consumption of these DFs have been documented, the lower water retention capacity (WRC) and other properties still limit the applications of DF. Therefore, the current research investigated the impact of acetylation on the changes in the corresponding physicochemical and functional properties of DF. RESULTS: The current results indicated the acetylated group restricted the alignment of the molecular chains, which led to an increased amorphous phase in the fiber structure, followed by an enhanced thermal sensitivity and a reduced crystallinity as evidenced by X‐ray diffraction (XRD). Moreover, the acetylation of the IDFs enhanced the cholesterol absorption capacity, but the corresponding antioxidant capacity and cation exchange capacity were reduced, which might be due to the partial loss of the phenolic compounds onto the polysaccharides during the modification. Interestingly, a lower degree of substitution (DS) of the IDF achieved from water‐acetic anhydride modification led to a higher WRC and water swelling capacity (WSC). In contrast, a higher DS from acetic anhydride modification demonstrated a greatly improved in vitro hypoglycemic performance of the IDF, including α‐amylase inhibitory activity and glucose dialysis retardation index (GDRI), compared to the other samples. CONCLUSION: This study highlights a new approach to modify the functionality of IDFs via acetylation and the design of a novel IDF with hypoglycemic activity. © 2023 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Acetylation is a wood modification used to increase the durability. Although it is known that the wood moisture content is lowered, the exact mechanisms behind the increased durability are not known. However, since fungi need water in different locations for different purposes the location and state of water is most probably of importance in addition to the total moisture content. In a previous study, we used targeted acetylation to alter the wood–water interactions in different parts of the wood structure in water saturated and hygroscopic moisture states. The main range for fungal degradation is, however, between these moisture ranges. This study investigated the effect of targeted acetylation on location, state and amount of water at non-saturated, high moisture states using the pressure plate technique. Specimens were modified using acetic anhydride by two approaches: (1) uniform modification (2) interface modification acting on the cell wall-lumen interface. They were then conditioned to eight moisture states between 99.64 and 99.98% relative humidity in both absorption and desorption and the location and state of water was studied using Low Field Nuclear Magnetic Resonance, X-ray computed tomography and Differential Scanning Calorimetry. Capillary water was present at all the included moisture states for all specimen types, but the amounts of capillary water in absorption were small. Increasing degree of interface modification increased the amount of capillary water compared to untreated wood. In addition, the uniformly modified wood often had higher amounts of capillary water than the untreated wood. The amount of cell wall water was decreased by uniform modification, but slightly or not reduced by the interface modification. The combination of targeted modification and conditioning to high well-defined moisture states thus gave very different amounts of capillary water and cell wall water depending on the conditioning history (absorption or desorption) and choice of modification. This opens new possibilities for designing materials and moisture states for fungal degradation experiments of wood. [ABSTRACT FROM AUTHOR]

A phosphine, base and additive free cross-coupling of arylboronic acid is reported via C–O bond cleavage of acetic anhydride using a switchable ferrocene functionalized n-heterocyclic carbene (NHC) palladium complex. The novel redox active catalytic system afforded the corresponding arylketones with good to excellent yields. [ABSTRACT FROM AUTHOR]

Drugs emerge in an endless stream; the global drug supply is increasing, and the number of drug users is steadily rising, so the detection of acetic anhydride, a raw material for drug preparation, is of great significance for controlling the spread of drugs. The crystal phase of semiconductor metal oxides has an important impact on oxygen vacancy, microscopic morphology, specific surface area, and high-energy surface exposure, which in turn affect the catalytic and gas-sensing effects of materials. Ion doping can sometimes achieve the purpose of changing the crystal phase. In this study, Cd-doped biphase (cubic phase and hexagonal phase) In2O3 nanospheres sensitive to acetic anhydride were synthesized via one easy hydrothermal process and the proportion of cubic phase and hexagonal phase is controlled by the amount of Cd element. The ion-doped biphase structure can save the consumption of expensive metals and provide a heterojunction structure as well as more oxygen vacancy to enhance gas sensing properties. The fabricated sensors not only have high sensitivity (372) to 100 ppm of acetic anhydride in the dry environment of 220 °C but also keep excellent selectivity and good stability. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) analysis, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used to observe the crystal phase, elemental information, nanoscale appearance, and existing state of the elements of the prepared compounds. The gas-sensitive mechanism was briefly analyzed according to the characterization information. The enhancing acetic anhydride sensing properties are owing to the change of internal electronic channels, abundant oxygen vacancy, and the crystal structure of In2O3 material caused by Cd doping. [ABSTRACT FROM AUTHOR]

Functionalized ionic liquids (FILs) are efficient ILs for the protection of various functionalities such as aldehydes, phenol, and alcohols with acetic anhydride under neat conditions. The attracted rising interest and the subject of active research in the field of catalysis is the variety of expanded applications and yet reports on ILs are still quickly increasing. This work reports a sulfonic acid functionalized ionic liquid is an environmentally friendly, easy handling, and reusable ionic liquid catalyst for the protection of aldehydes and phenols. The catalyst was characterized with different spectroscopic techniques which indicates the fabricated IL is matching with the reported methods. The catalyst can be recycled up to eight times without substantial loss in activity. Furthermore, no chromatographic separations were needed to obtain the desired products. [ABSTRACT FROM AUTHOR]

In this paper, we present the synthesis of new selenoloquinoxaline derivatives starting from 2‐chloroquinoxaline‐3‐carbonitrile 1. The compound 1 was subjected to a reaction with selenium metal in the presence of NaBH4 as a reducing agent in ethanol, under a nitrogen atmosphere. This reaction resulted in the formation of the sodium salt of 3‐cyanoquinoxaline‐2‐selenolate, which was subsequently reacted with α‐halogenated carbonyl compounds in situ. This reaction produced a series of newly synthesized 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐substituents. Ethyl 3‐aminoselenolo[2,3‐b]quinoxaline‐2‐carboxylate 3a was hydrolyzed by sodium hydroxide to give the corresponding sodium salt 9. This salt was then refluxed with acetic anhydride to produce oxazinone compound 10. The reaction of compound 10 with ammonium acetate afforded pyrimidoselenolo[2,3‐b]quinoxaline derivative 11. Compound 11 was then chlorinated using phosphorous oxychloride to give the corresponding chlorocompound. [ABSTRACT FROM AUTHOR]

• Epoxy alcohols were converted to the corresponding 1,2,3-triacetate derivatives in a one-pot manner using the NaBH4/Ac20 system for the first time and in high yield. • The exact configuration of 2-methyl-1,3-dioxooctahydro-1H-isoindole-4,5,6-triyltriacetate was determined by X-ray diffraction analysis. • Theoretical computations were carried out to explain the regioselectivity in the ring opening reaction of epoxy alcohols. • Theoretical studies and experimental findings are quite compatible with each other. The formation of products occurs under thermodynamic control. Isoindole-1,3‑dione derivatives containing an epoxy alcohol unit were synthesized. Epoxy alcohols were converted to the corresponding 1,2,3-triacetate derivatives in a one-pot manner using the NaBH4/Ac20 system for the first time and in high yield. C-3 selective ring-opening products were obtained with good yield and with stereospecificity with the NaBH 4 /Ac 2 O system at 139–140 °C. The exact configuration of 2-methyl-1,3-dioxooctahydro-1H-isoindole-4,5,6-triyltriacetate was determined by X-ray diffraction analysis which was obtained from the reaction of epoxy alcohol by hydride transferring agent in acetic anhydride. On the other hand, theoretical computations were carried out to explain the regioselectivity in the ring opening reaction of epoxy alcohols. The results showed that the ring-opening reaction of epoxy alcohol proceeds in a thermodynamically controlled manner and regioselectivity occurs depending on the stability of the products. [Display omitted] [ABSTRACT FROM AUTHOR]

• Microchannel reactor combined with green nitration for safe and green synthesis. • Process was optimized by response surface methodology. • Exothermic behavior of nitration reaction was investigated in the semi-batch mode. • Effect of volumetric flow rate during scale-up of the process was investigated. Aromatic nitro compounds are an important class of basic chemical raw materials, while traditional nitration methods may cause safety accidents and environmental pollution due to strong exothermicity and presence of sulfuric acid. In this work, aiming to alleviate these issues, the nitration of toluene was conducted in a microchannel reactor with nitric acid and acetic anhydride. The effect of temperature, molar ratio of nitric acid to toluene, mass fraction of acetic anhydride, and residence time on the conversion and selectivity of reaction were systematically investigated, and response surface methodology was used to optimize the process. A mononitrotoluene yield of 99.21 % can be achieved under optimum condition. Meanwhile, in order to better understand the exothermic behavior, toluene nitration by HNO 3 -AC 2 O was investigated in the semi-batch calorimeter. Finally, the optimized process was scaled up and effect of volumetric flow rate was investigated. At the selected maximum volumetric flow rate, the overtemperature of the system was 10.9 °C with a 98.3 % yield of mononitrotoluene. Continuous flow mode had a space-time yield nearly two orders of magnitude greater than semi-batch mode. This work can provide guidance for safe, efficient and green synthesis of mononitrotoluene. [Display omitted] [ABSTRACT FROM AUTHOR]

ZSM-5- and β-zeolite-containing two-layered hierarchical catalysts (2 L-Z and 2 L-β) were prepared using a template of malic acid and novel three-layered hierarchical catalysts were also prepared combining mesoporous silica derived from the gel skeletal reinforcement (GSR) method with hexamethyldisiloxane (HMDS) - acetic anhydride (AA) as reinforcing agents. 2 L-Z and 2 L-β catalysts contained mesoporous silica of 50 wt% and microporous zeolite of 50 wt% and were called 2 L-Z-(Z50) and 2 l-β-(Z50) in which the amount of zeolite is shown in parenthesis. 3 L-co-gel and 3 L-mix, two types of three-layered hierarchical catalysts, were prepared by making GSR-silica in the presence of a 2 L catalyst for the former and by combining GSR-silica-gel with 2 L catalyst for the latter. 3 L catalysts contained 50 wt% of the 2 L catalyst and 50 wt% large-mesoporous GSR-silica and revealed three layered properties of microporous zeolite, small mesoporous silica and large mesoporous silica. Signals of zeolite crystals and amorphous phase were observed in XRD measurement for 3 L catalysts. Both smaller size of mesopores and larger size of mesopores were observed in N 2 adsorption-desorption measurement. Vacuum gas oil (VGO) was catalytically cracked using 2 L and 3 L hierarchical catalysts with the use of Curie point pyrolyzer (CPP) method. ZSM-5-containing 3 L catalysts exhibited the lower conversions than corresponding 2 L catalyst, kaolin-mixed catalyst and ZSM-5 single while 3 L-co-gel-β-(Z25), which included 25 wt% of β-zeolite, exhibited the highest activity among β-zeolite-containing catalysts. The higher selectivity for p -xylene in xylene mixture was detected in catalytic cracking using 3 L-co-gel-Z-(Z25) and 3 L-mix-Z-(Z25) catalysts. When the relative activity against XRD integral intensity and amounts of acid sites was plotted against average pore diameter derived from N 2 adsorption-desorption measurement, the strong correlation was observed, suggesting that the intrinsic activity of active sites of zeolite could be related to the pore size of the whole catalyst. [Display omitted] • ZSM-5- and β-zeolite-containing three-layered (3 L) hierarchical catalysts were prepared. • Meso-SiO 2 derived from GSR method was effectively combined to make 3 L catalysts. • Catalytic cracking of VGO was performed using 3 L catalysts by Curie point pyrolyzer. • Higher selectivity for p-xylene was detected using ZSM-5-containing 3 L catalysts. • Plots of relative activity against average pore diameter exhibited the strong correlation. [ABSTRACT FROM AUTHOR]

Pectin, a polysaccharide found in plant cell walls, is characterized by a high abundance of hydroxyl groups and carboxylic acid groups, which results in a strong affinity for water and limits its suitability as a film material. This study aimed to modulate the esterification degree of PEC films by adjusting the concentration of acetic anhydride, and assess the impact of acetic anhydride esterification modification on the properties of the resultant PEC films. The results demonstrated successful grafting of acetic anhydride onto the galacturonic acid ring in the PEC molecule through the esterification process. The hydrophobicity, thermal stability, barrier properties, and mechanical properties of the esterified PEC films were investigated. Among the various concentrations tested, the E-PEC-0.25 film exhibited the highest contact angle of 103.46° and tensile strength of 33.44 MPa, showcasing optimal performance. The E-PEC-0.1 film achieved the highest esterification degree of 0.94 and elongation at a break of 21.11 %. It also exhibited the transparency of 11.66 and the lowest water vapor transmission rate of 0.56 g·mm/(m2·h·kpa). Additionally, TGA and DSC tests revealed enhanced thermal stability of the esterification-prepared films. These findings highlight the potential of acetic anhydride tuning as a promising strategy for optimizing pectin film production. [ABSTRACT FROM AUTHOR]

• Capsaicin was determined by GC–MS system after derivatization by acetic anhydride. • SFDF-LPME method was established to concentrate capsaicin at trace levels. • ID4 method was performed to boost accuracy and precision of the developed method. • LOD and LOQ for the developed method were 0.33 and 1.10 µg/kg, respectively. • Excellent recovery results were achieved for pepper, saliva and wastewater samples. Despite the therapeutic properties of capsaicin for some diseases, it shows some side effects for human health. The goal of this study was to develop a precise and accurate analytical strategy for the trace determination of capsaicin in different food, biological and environmental samples including pepper, saliva and wastewater by gas chromatography–mass spectrometry (GC–MS) after spraying-based fine droplet formation-liquid phase microextraction (SFDF-LPME) and quadruple isotope dilution (ID4) method. Acetic anhydride was used as derivatizing agent, and the extraction method was used to enrich the analyte derivative to reach low detection limits. Under the optimum conditions, limit of detection (LOD) and limit of quantitation (LOQ) were determined to be 0.33 and 1.10 µg/kg, respectively. Percent recoveries calculated for SFDF-LPME-GC-MS method ranged between 84.1 and 131.7 %. After the application of ID4-SFDF-LPME-GC-MS method, percent recoveries were obtained in the range of 94.9 and 104.0 % (%RSD ≤ 2.8) for the selected samples. It is obvious that the isotope dilution-based method provided high accurate and precise results due to the elimination of errors during the derivatization, extraction and measurement steps. [ABSTRACT FROM AUTHOR]

[Display omitted] • A flow calorimeter capable of measuring spatial temperature profile is presented. • It offers a wealth of reaction dynamics data by detecting temperature in real time. • Hydrolysis of acetic anhydride is performed as a test reaction. • Spatially resolved temperature profiles are used to determine the rate constants. Continuous flow calorimeters are considered an emerging technique due to their ability to reduce safety issues associated with highly exothermic rapid reactions. In this study, a custom-made isoperibolic flow calorimeter was constructed, which uses a pyroelectric IR Sensor for temperature profile recording. The objective of this study is to validate the reactor concept for the determination kinetic parameters. Residence time distribution (RTD) analysis was conducted to assess the mixing performance of the packed-bed reactor employed in the calorimeter. This calorimeter was connected to a custom-made conductivity flow cell (CFC), to measure the in-line conductivity of the outlet stream. An axially dispersed plug flow reactor model (AD-PFR) is required to be able to incorporate the non-ideal behaviour of the flow. The experimental apparatus design and methodology was validated by conducting the hydrolysis of acetic anhydride. The activation energy, E A and the pre-exponential factor, ln(k 0) for the hydrolysis of acetic anhydride were found to be 52.05 kJ mol−1 and 12.26 (s−1), respectively, which falls within the range of reported values. The new flow calorimeter proved to be effective, and accurate. [ABSTRACT FROM AUTHOR]

PBAT (poly(butylene adipate- co -terephthalate) is an important player in the field of bioplastics for its biodegradability performance and good mechanical properties. Awareness of the forecasted increased use of PBAT has prompted researchers to develop methods for its analysis in a variety of samples. Py-GC-MS, conventional or with derivatising agents, is a technique of excellence for the analysis of polymers that relies on a detailed structural knowledge of the evolved products. This study presents a comprehensive investigation on the chemical composition of the pyrolysate of PBAT evolved at 600 °C alone and in the presence of various reagents (hexamethyldisilazane, HMDS; acetic anhydride, Ac 2 O, tetramethylammonium hydroxide, TMAH). Identification of relevant pyrolysis products was confirmed through the analysis of pure standards and associated reagents/byproducts. A GC-MS data set of about 50 compounds was compiled, including open chain fragments of the polymer and their derivatives as well as single and mixed subunit cyclic dimers. A compound distinctive of PBAT (but-3-en-1-yl (4-((6-(but-3-en-1-yloxy)-6-oxohexanoyl)oxy)butyl) terephthalate) containing the adipic, terephthalic and butylene units was tentatively identified by its mass spectrum. Pyrolysis products with active hydrogens (alcoholic and carboxylic) were efficiently silylated by HMDS. Two pyrolysis products containing the hydroxybutyl moiety could be acetylated by pyrolysis with Ac 2 O. Thermally assisted hydrolysis and methylation with TMAH caused important transmethylation of the ester groups of the polymer chain with the formation of dimethyl adipate and dimethyl terephthalate. The importance of the results for the analysis of PBAT in commercial bioplastics and environmental samples was discussed. • GC-MS data of several pyrolysis products of PBAT. • Two pyrolysis products highly specific of PBAT were proposed. • Pyrolysis with HMDS successfully silylated pyrolysis products OH groups. • Derivatisation of hydroxybutyl terephathalate adipate by pyrolysis with acetic anhydride. [ABSTRACT FROM AUTHOR]

[Display omitted] • Microwave spectra of acetic and acetic difluoroacetic anhydride have been observed. • An intramolecular hydrogen bonding interaction forms a six-membered ring. • Calculations explore the effects of internal rotation on the heavy atom frame. Microwave spectra of acetic anhydride, D6-acetic anhydride, and acetic difluoroacetic anhydride have been observed in a supersonic jet. In conjunction with accompanying DFT and MP2 calculations, these systems are shown to adopt a nonplanar configuration in which the C=O groups point in approximately orthogonal directions. Methyl group internal rotation was fully analyzed for both species. The observed conformation of these systems appears to result from an interaction between a CH 3 hydrogen (in acetic anhydride) or the CF 2 H hydrogen (in acetic difluoroacetic anhydride) with the carbonyl group to which it is not directly bound, forming a six-membered ring. The fitted rotational constants for both systems are in reasonably good agreement with calculated values, but for acetic anhydride, the agreement is somewhat worse than that previously observed for a series of syn anhydrides. The calculations indicate a pronounced flexing of the heavy atom frame as the CH 3 group in the six-membered ring undergoes internal rotation, and this likely influences the level of agreement between the theoretical and vibrationally averaged experimental constants. The other CH 3 group does not interact with a carbonyl oxygen because of its orientation in the molecule, and its internal rotation does not induce similar changes in the molecular frame. In the acetic difluoroacetic anhydride, it is the CF 2 H hydrogen that interacts with its remote carbonyl oxygen, leaving the internally rotating CH 3 group unaffected by participation in a six-membered ring and giving rise to much smaller deviations in the rotational constants as it moves along its internal rotation coordinate. Correspondingly better agreement between experimental and theoretical spectroscopic constants is obtained. [ABSTRACT FROM AUTHOR]

Bromophenols (BPs) are a class of ubiquitous emerging halogenated pollutants. Their 19 congeners are problematically separated and detected. This work described the separation and detection of 19 BP congeners by gas chromatography-mass spectrometry (GC-MS). Investigations into the derivatization of bromophenols were carried out using two silylation reagents (N,O-bis(trimethylsilyl)trifluoroacetamide and N-methyl-N-(trimethylsily)trifluoroacetamide), two alkylation reagents (methyl iodide and trimethylsilyldiazomethane) and acetic anhydride prior to GC-MS analysis. Optimal chromatographic separation, sensitivity, and linearity were achieved after BP derivatization using acetic anhydride, featuring the equipment detection limits of 0.39–1.26 pg and correlation coefficients of 0.9948–0.9999 (linear range: 0.5–250 ng mL−1) for all 19 BP congeners. Furthermore, the simultaneous determination of 19 bromophenols and 19 bromoanisoles, common environmental transformation products of BPs, is also demonstrated. The improved analytical performance on GC-MS after derivatization would benefit investigations on the environmental origins, behaviors and fates of BPs and their environmental metabolites. [Display omitted] • Five derivatization reagents were compared for bromophenol analysis. • Acetylation achieved the best selectivity, linearity, and sensitivity. • All bromophenols and bromanisoles can be resolved on GC-MS using acetylation. [ABSTRACT FROM AUTHOR]

Enzymatic synthesis of d -α-tocopherol acetate is a promising approach for cost-effective production of liposoluble food and pharmaceutical antioxidant. In this study, we developed an efficient and environmentally friendly process that employed plant-derived Carica papaya lipase (CPL) as biocatalyst for the synthesis of d -α-tocopherol acetate in a solvent-free system. The optimum conditions were: 400 mg/mL d -α-tocopherol, 125 mg/mL CPL (44 U, aw = 0.328), with acetic anhydride as acyl donor, at 60°C and 200 rpm for 30 h. Interestingly, yields of 90.7%, 77.7%, 60.3% and 48.1% of d -α-tocopherol acetate were achieved after the "naturally immobilized" CPL recycled for 4 times, indicating a novel enzyme immobilization mechanism. Moreover, the synthetic product was purified from scale-up reaction, and confirmed by FTIR and GC-MS analysis, providing a total of 97.5% purity (91.1% d -α-tocopherol acetate plus 6.4% d -α-tocopherol). Overall, this work provided an efficient alternative method for green production of d -α-tocopherol acetate probably being applied in food and pharmaceutical industries, and this could also enhance the comprehensive utilization of Carica papaya. • CPL was naturally extracted from Carica papaya latex. • CPL was a superior enzyme for the acetylation of d -α-tocopherol. • A yield of 90.7% of d -α-tocopherol acetate was achieved under the optimum conditions. • The synthetic d -α-tocopherol acetate was purified and confirmed by FTIR and GC-MS. [ABSTRACT FROM AUTHOR]

Acetylation of Cellulose nanocrystal (CNC) can reduce its surface polarity and therefore extends its application in biomedical and chemical fields. A method combining uniform design (UD) and response surface methodology (RSM) was developed to produce the acetylated CNC with arbitrary degree of substitution (DS) and crystallinity index (CrI). The effects of three factors (i.e., temperature, reaction time and the volume of acetic anhydride) on DS and CrI were investigated in their respective ranges (i.e., 60–90 oC, 1.0–5.0 h and 1.0–5.0 mL). Both mathematical models for DS and CrI were developed by multiple stepwise regression (MSR) based on UD data and their significances were evaluated by analysis of variance. The controllable acetylation of CNC was realized by using either UD alone or the combination of UD and RSM. Eight verification experiments show that the relative errors between the predicted and the measured results are less than 16.77 % and 6.08 % for DS and CrI, respectively, confirming the reliability and validity of the method. This developed methodology is ingenious and expected to be expanded to any other fields that controllable preparations are required. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Rh-catalyzed hydroformylation of bio-renewables terpenes and propenylbenzenes. • Formic acid and acetic anhydride as syngas (CO/H 2) surrogate. • 2-MeTHF as an eco-friendly solvent alternative. • Tandem hydroformylation/hydrogenation with double O-acylation. • One-pot polyfunctionalization of propenylphenols at two remote reactive sites. The introduction of aldehyde and acetate functionalities in renewable terpenes and propenylbezenes provides useful feedstocks for fine chemicals, especially in the flavor and fragrance segment. Herein we report the rhodium catalyzed hydroformylation and the tandem hydroformylation/hydrogenation/O-acylation of biomass based propenylbenzenes and terpenes with a mixture of formic acid (FA) and acetic anhydride (Ac 2 O) as a cheaper and less dangerous alternative for flammable and toxic syngas (carbon monoxide and hydrogen mixture) used in the conventional hydroformylation. In addition, we were able to perform the consecutive aldehyde hydrogenation, followed by O-acetylation, formally adding a methyl acetate molecule in a C-C double bond in a tandem process, which was not feasible with the conventional hydroformylation. For propenylbenzenes containing a phenol moiety, the parallel acetoxylation of this group also took place. The protocol allowed to obtain aldehydes and mono- or diacetate esters, which are potentially valuable as fragrance components. [ABSTRACT FROM AUTHOR]

In response to the pressing demand for acetic anhydride gas detection, this study introduces a novel gas sensor for precisely detecting acetic anhydride concentrations. The optimum conditions for the synthesis of cobalt hydroxyfluoride/cobalt oxide (CHFCO) heterojunctions with good acetic anhydride gas sensitivity were determined by carefully adjusting the calcination time, hydrothermal time and ammonium fluoride content. The best performing composite CHFCO sensor with porous rod particles was tested at 180 ℃ and achieved a response rate of 260 for 100 ppm acetic anhydride gas, with response and recovery times of 60 and 40 s, respectively. In comparison to other prepared sensors, the detection response for acetic anhydride was improved by a factor of 4.30–23.63. Moreover, the CHFCO sensor reliably detected acetic anhydride at a concentration of 500 ppb, exhibiting a response value of 1.56. Notably, the sensor demonstrated great selectivity, moisture resistance, and stability. The findings highlight the significant enhancements in gas-sensitive performance to acetic anhydride achieved by the abundant hydroxyl bonds on the surface of CHFCO heterojunction, the presence of fluorine ions, and the modulation of the band gap. These results provide valuable insights for the advancement of acetic anhydride gas sensors based on CHFCO heterojunction. • Controlled synthesis of porous rod-like Co(OH)F/Co 3 O 4 heterojunction. • The sensor exhibits a high gas response of 260 at 180 °C for 100 ppm acetic anhydride. • The sensor has good selectivity and stability with detection limits as low as 500 ppb for acetic anhydride. • The combination of the catalytic activity of Co(OH)F and the adsorption properties of Co 3 O 4 produced a synergistic effect. [ABSTRACT FROM AUTHOR]

Oligonucleotide therapeutics are generally prepared via solid-phase synthesis, and many impurities derived from the synthesis process are present in crude oligonucleotides. Among the various impurities typical of oligonucleotide synthesis, shortmers, which lack a few residues from the desired oligonucleotide therapeutics, are difficult to remove using conventional high-performance liquid chromatography (HPLC) purification because they have similar structures and physical properties to the desired oligonucleotide. In this study, we developed a simple purification method for oligonucleotide therapeutics. In our strategy, the retention of shortmers on the reversed-phase HPLC column was increased by using a highly lipophilic phosphoramidite, which is a reagent for 5′-end modification of oligonucleotides, instead of acetic anhydride during solid-phase synthesis, and only the target oligonucleotide could be eluted from a reversed-phase HPLC pretreatment column. [Display omitted] [ABSTRACT FROM AUTHOR]