Reaction Of Anhydride Research Articles

Gelation during Ring-Opening Reactions of Cellulosics with Cyclic Anhydrides: Phenomena and Mechanisms.

Cellulose esters are used in Food and Drug Administration-approved oral formulations, including in amorphous solid dispersions (ASDs). Some bear substituents with terminal carboxyl moieties (e.g., hydroxypropyl methyl cellulose acetate succinate (HPMCAS)); these ω-carboxy ester substituents enhance interactions with drug molecules in solid and solution phases and enable pH-responsive drug release. However, the synthesis of carboxyl-pendent cellulose esters is challenging, partly due to competing reactions between introduced carboxyl groups and residual hydroxyls on different chains, forming either physically or covalently cross-linked systems. As we explored ring-opening reactions of cyclic anhydrides with cellulose and its esters to prepare polymers designed for high ASD performance, we became concerned upon encountering gelation. Herein, we probe the complexity of such ring-opening reactions in detail, for the first time, utilizing rheometry and solid-state 13C NMR spectroscopy. Gelation in these ring-opening reactions was caused predominantly by physical interactions, progressing in some cases to covalent cross-links over time.

A Novel 2-Methylimidazole Promoted Oxyacyloxylation of α-Hydroxy Ketones and Anhydrides: An Easy Access to α-Acyloxy Ketones

An efficient and operationally simple method for the synthesis of α-acyloxy ketones through the readily available 2-methylimidazole-promoted reaction of α-hydroxy ketones and anhydrides is developed. In the reaction, the anhydrides act as both a substrate and a solvent. The new method features good substrate tolerance, mild reaction conditions, readily accessible starting materials, and excellent yields, providing facile and green access to the targets. Importantly, the reaction also avoids the use of reagents with pungent odors, such as pyridine, in traditional esterification, which may promote the development of organocatalysis using nitrogen-containing heterocyclic compounds as catalysts.

Sulfamic Acid Catalyzed One‐Pot Three‐Component Synthesis of Spiro‐Oxindole Fused Dihydroquinazolinone Derivatives in Aqueous Medium

AbstractA simple, efficient, and straightforward protocol has been developed for the synthesis of spiro‐oxindole fused dihydroquinazolinone derivatives from one‐pot three‐component reactions of isatoic anhydride, various primary anilines, and substituted isatins using a catalytic amount of sulfamic acid as an organocatalyst in water under refluxed conditions. All the synthesized compounds were formed within just 2 h and isolated pure by simple filtration with excellent yields (89%–94%). Gram scale production, use of commercially available low‐cost organocatalyst, green solvent, reusability of the medium, one‐pot three‐component reaction strategy, no column chromatography, and high atom economy are some of the major benefits of this newly developed protocol.

Effect of Reaction Time and Solvent Ratio on the Acetylation of Isolated Cellulose Fiber from Tropical Water Hyacinth

Abstract Isolated cellulose fibers from water hyacinth were used to create cellulose acetate (CA) polymers. The cellulose was acetylated using an acetic acid and acetic anhydride reaction, with sulfuric acid acting as the catalyst. The degree of substitution (DS) of synthetic CA was examined, along with the effects of acetylation time and solvent ratio. The study indicated that the appropriate DS for CA was found to be 2.47 and the matching ideal operating parameters included a reaction duration of 16 hours, and a ratio of 4:1 between acetic acid and acetic anhydride at temperature of 50°C. The results of the study showed that the cellulose isolated from water hyacinth was successfully acetylated, which was supported by the existence of distinct peaks in the Fourier transform infrared (FTIR) spectra. This suggests that the process of acetylating the isolated cellulose fibers is a straight-forward process that can be employed to create a cost-efficient and environmentally friendly CA. This CA has the potential to cost-effectively and sustainably replace expensive raw materials derived from fossil fuels in the polymer industry.

An Efficient Multi‐Component Double Friedel‐Crafts Alkylation of Isatin: Access to Unsymmetrical and Symmetrical 3, 3‐Diaryl oxindoles

AbstractAcetic 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.

Pentafluoropyridine (PFPy)-mediated one-pot framework for the synthesis of pharmaceutically active 2,3-dihydroquinazolin-4(1H)-ones

This article describes the employment of commercially available, cheap pentafluoropyridine (PFPy) for a simple and straightforward one-pot synthesis of 2, 3-Dihydroquinazolin-4(1H)-ones. The reported protocol involves PFPy-mediated multicomponent condensation reaction of aldehyde, amine and isatoic anhydride at elevated temperature. This research work exploited the electron-withdrawing nature of fluorine atoms in PFPy for the nucleophilic substitution at para to the N-atom to produce fluoride ions that assisted the synthesis of the 2,3-Dihydroquinazolin-4(1H)-ones in excellent yield. The broad substrate scope, easy purification, short reaction times, high yields and ease of operation enhance the versatility of the protocol.

Flexible green synthesis of 2-benzyl-3‑hydroxy-1H-pyrazolo([1,2-b]phthalazine and [1,2-a]pyridazine)‑dione derivatives using CuI@KSF nanocatalyst under solvent-free conditions

In the frame of research that examines the use of task CuI@KSF nanoparticles as an efficient catalyst, new 1H-pyrazolo[1,2-b]phthalazine-5,10‑dione (HPPhD) and 1H-pyrazolo[1,2-a]pyridazine-5,8‑dione (HPPyD) derivatives were prepared. Using the four-multicomponent condensation reaction (4MCRs) of phthalic anhydride, hydrazine monohydrate, aromatic aldehydes, and ethyl 3-oxo-3-phenylpropanoate under solvent free conditions at 80 °C. This method has several advantages, including, operational, simplicity, mild conditions, and maximum product yield. To monitor the progress of the reactions, new organic salty catalysts were used. New catalysts are cheap, benign, recyclable, and environmentally friendly. In addition, they are easy to prepare and use. They also showed good catalytic activity, which in conclusion led to the synthesis of new phthalazine derivatives with good to excellent yields. The new catalysts were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). To check the possible effect of these compounds in anticancer therapy, two types of proteins were selected and examined through docking calculations. In the case of 1DHT as an oxidoreductase enzyme compound 7e with the score of amount -8.99 represent the highest tendency toward interaction with the desired enzyme, while in the case of 6LQA by the dominance hydrophobic character, compound 7c seems likely to be more efficient.

The effects of ACR/MAH ionic cross-linking on the cell morphology, mechanical properties, and dimensional stability of PVC foams

This study details a novel approach to enhance the dimensional stability of foamed polyvinyl chloride (PVC) materials through the introduction of a reversible cross-linking network. This is achieved via the carboxylation of acrylate polymers (ACR) utilizing the hydrolysis reaction of maleic anhydride (MAH) during the extrusion of PVC foam sheets. Subsequently, an ionic cross-linking network is formed using calcium-zinc (Ca-Zn) stabilizers. This paper elucidates the process of cell formation and the mechanisms underpinning the ACR/MAH ion network formation. Cell morphology of the foamed PVC was characterized using SEM, and the effects of ionic cross-linking on the plasticizing time, dimensional stability, and mechanical properties were analyzed through cell diameter distribution measurements and rheometry. The longitudinal and transverse dimensional shrinkage of PVC-F/MAH1 was reduced by 28.0 % and 28.9 %, respectively. The construction of the ACR/MAH ion cross-linking network not only augments the mechanical properties but also substantially enhances the dimensional stability of the material. This approach underscores the viability of ion cross-linking networks in advancing the performance parameters of PVC foams, suggesting a promising avenue for future research and development in polymer processing technology, and potentially expanding their application spectrum.

Atmospheric photo-oxidation of acetic anhydride: Kinetic study and reaction mechanism. Products distribution and fate of CH3C(O)OC(O)CH2O· radical

The rate coefficient for the gas-phase reaction of acetic anhydride (Ac2O) with chlorine atoms at 298 K and atmospheric pressure was experimentally determined (kAc2O+Cl= (1.3 ± 0.4) × 10-12 cm3molec−1s−1), while the rate coefficient for the reaction with the hydroxyl radical was estimated (kAc2O+OH=1.9 x 10-13 cm3molec−1s−1). For the Structure-Activity Relationship method, a value of 0.02 was determined for the −C(O)OC(O) group. The mechanism of photo-oxidation of acetic anhydride initiated by chlorine atoms was determined and CO, CO2, CH3C(O)OH (32 %), CH3C(O)OC(O)C(O)H, and 3-hydroxy-1,4-dioxane-2,6-dione (20 %) were identified as products by infrared spectroscopy. Here we determined for the first time the relative energies of the primary reaction pathways for the CH3C(O)OC(O)CH2O· radical using computational methods, which confirmed our experimental data. Finally, the environmental implications of acetic anhydride emissions were calculated, showing an atmospheric lifetime between 31 and 220 days for the reaction with atmospheric radicals, while its wet deposition lifetime is 1.5 years.

Novel Metal-Free Synthesis of 3-Substituted Isocoumarins and Evaluation of Their Fluorescence Properties for Potential Applications.

A novel metal-free synthesis of 3-substituted isocoumarins through a sequential O-acylation/Wittig reaction has been established. The readily accessible (2-carboxybenzyl)-triphenylphosphonium bromide and diverse chlorides produced various 1H-isochromen-1-one in the presence of triethylamine, employing sequential O-acylation and an intramolecular Wittig reaction of acid anhydride. Reactions using these facile conditions have exhibited high functional group tolerance and excellent yields (up to 90%). Moreover, the fluorescence properties of isocoumarin derivatives were evaluated at the theoretical and experimental levels to determine their potential application in fluorescent materials. These derivatives have good photoluminescence in THF with a large Stokes shift and an absolute fluorescence quantum yield of up to 14%.

Direct Measurements of Covalently Bonded Sulfuric Anhydrides from Gas-Phase Reactions of SO3 with Acids under Ambient Conditions.

Sulfur trioxide (SO3) is an important oxide of sulfur and a key intermediate in the formation of sulfuric acid (H2SO4, SA) in the Earth's atmosphere. This conversion to SA occurs rapidly due to the reaction of SO3 with a water dimer. However, gas-phase SO3 has been measured directly at concentrations that are comparable to that of SA under polluted mega-city conditions, indicating gaps in our current understanding of the sources and fates of SO3. Its reaction with atmospheric acids could be one such fate that can have significant implications for atmospheric chemistry. In the present investigation, laboratory experiments were conducted in a flow reactor to generate a range of previously uncharacterized condensable sulfur-containing reaction products by reacting SO3 with a set of atmospherically relevant inorganic and organic acids at room temperature and atmospheric pressure. Specifically, key inorganic acids known to be responsible for most ambient new particle formation events, iodic acid (HIO3, IA) and SA, are observed to react promptly with SO3 to form iodic sulfuric anhydride (IO3SO3H, ISA) and disulfuric acid (H2S2O7, DSA). Carboxylic sulfuric anhydrides (CSAs) were observed to form by the reaction of SO3 with C2 and C3 monocarboxylic (acetic and propanoic acid) and dicarboxylic (oxalic and malonic acid)-carboxylic acids. The formed products were detected by a nitrate-ion-based chemical ionization atmospheric pressure interface time-of-flight mass spectrometer (NO3--CI-APi-TOF; NO3--CIMS). Quantum chemical methods were used to compute the relevant SO3 reaction rate coefficients, probe the reaction mechanisms, and model the ionization chemistry inherent in the detection of the products by NO3--CIMS. Additionally, we use NO3--CIMS ambient data to report that significant concentrations of SO3 and its acid anhydride reaction products are present under polluted, marine and polar, and volcanic plume conditions. Considering that these regions are rich in the acid precursors studied here, the reported reactions need to be accounted for in the modeling of atmospheric new particle formation.

Machine-Learning-Based Kinetic-Free Hybrid Gray-Box Model to Predict Sulfuric-Acid-Catalyzed Esterification Reaction.

The sulfuric-acid-catalyzed esterification reaction of 2-butanol and propionic anhydride is a vital industrial process. In this paper, several experiments are conducted via reaction calorimetry to validate that both sulfuric and propionic acids have discernible catalytic effects on the reaction. This finding complicates the accurate description of the reaction kinetics through traditional methods. So this paper turns to a kinetic-free black-box model, Gaussian process regression (GPR) model via 24 experiments, as a more adaptable approach. Besides, the best GPR model is combined with traditional heat balance model to generate a hybrid gray-box model, which can give complete knowledge of reaction process. The hybrid gray-box model finally achieves maximum root-mean-square error (RMSE) of 0.0069 for conversion, 0.6535 for temperature, and 10.6087 for heat flow rate, underscoring its pretty good predictive ability.

Functional and ultrastretchable thermoplastic elastomeric materials: Influence of carbon dots on fluorescence, dielectric and mechanical properties

AbstractCarbon dots (CDs) are an interesting nanomaterial due to their tunable photoluminescence and other functional properties. Herein, by introducing amine‐functionalized CDs nanoparticles onto macromolecular chains of maleic anhydride grafted styrene‐ethylene‐butylene‐styrene (SEBS‐g‐MA) via a possible ring‐opening reaction of anhydride with amine, a mechanically robust and ultrastretchable thermoplastic elastomeric materials with fluorescence and dielectric functionality was developed. The amine‐functionalized CDs nanoparticles were synthesized from pyrene precursor by hydrothermal treatment. The transmission electron micrograph, Raman, Fourier transform infrared, and x‐ray photoelectron spectra confirmed the formation of highly crystalline graphitized structure of the CDs nanoparticles. Fluorescence and UV–Vis spectroscopy were used to evaluate the optical properties of the developed materials. The developed CDs/SEBS‐g‐MA nanocomposites exhibited strong intense green fluorescence compared with the pure SEBS‐g‐MA film. The thermal stability of the developed nanocomposites was improved by an increase of the Tmax by about 18°C. In addition, the developed composite showed high stretchability (strain at break ~1000%), good mechanical strength, and dielectric properties (room temperature dielectric constant ~5.2). The enhanced dielectric property of the developed composites may be due to the space charge accumulation and induced interfacial polarization at the filler–matrix interface.

Catalytic synthesis of aspirin by a single crystal of cadmium phosphomolybdate with (412·612·84)(46)2 topological structure

To green-catalyze the synthesis of aspirin, we designed and synthesized a novel and unreported cadmium phosphomolybdate crystal compound (C2N2H10)4{Cd3[P4Mo6O26(OH)5]2}·6H2O as a catalyst for the synthesis reaction of aspirin using hydrothermal synthesis, and structurally characterized. Single-crystal X-ray diffraction analysis showed that the compound has a 4,8-connected inorganic open topology (412·612·84)(46)2. The optimal process conditions for the reaction of salicylic acid and acetic anhydride were determined by screening the catalyst dosage, temperature, and reaction time. The reaction temperature was set at 80 °C, the catalyst dosage was 0.09 g, and the reaction time was 25 min. The industry's most often utilized catalyst for aspirin manufacturing is concentrated sulfuric acid, which has strong oxidizing and corrosive qualities, resulting in difficult issues such as low synthetic product yield, large equipment needs, and substantial environmental damage. The experimental results of the (C2N2H10)4{Cd3[P4Mo6O26(OH)5]2}·6H2O catalytic synthesis of aspirin reveal that as a solid acid catalyst, its catalytic activity is similar to the commonly used catalyst concentrated H2SO4. Synthetic catalysts, on the other hand, have the advantages of high efficiency, selectivity, conversion rate, ease of recovery, and the ability to be recycled several times without polluting equipment, all of which are consistent with modern ``green'' catalysts. The results of this work suggest that the supramolecular compounds of polymetallic oxonate that we designed and produced hydrothermally can serve as catalysts in drug synthesis reactions to mitigate environmental pollution, hence providing new opportunities for the development of environmentally friendly medications.

Ring Opening Copolymerization of Epoxides with CO2 and Organic Anhydrides Promoted by Dinuclear [OSSO]‐type Metal Complexes

AbstractThe ternary copolymerization of a series of cyclic anhydrides with epoxides and carbon dioxide using dinuclear [OSSO]‐type chromium (III),1, and ‐iron(III), 2, complexes (0.1 mol %) in combination with (bis(triphenylphosphine)iminium chloride) (PPNCl, 0.5–1.0 mol with respect to catalyst) as co‐catalyst is reported in this study. The results have yielded copolymers with polyester and polycarbonate segments with high molecular weights and narrow dispersity. The catalytic systems 1–2/PPNCl were tested in the copolymerization of different epoxides, such as propylene oxide (PO), cyclohexene oxide (CHO), and vinylcyclohexene oxide (VCHO), with a variety of cyclic anhydrides, such as phthalic (PA), diglycolic (DGA) and succinic (SA), with CO2 pressure of 20 bar, temperature range of 45–80 °C in 24 h. Anhydride reaction, affording the polyester segments, exceeded the conversion of 99 % in all the explored cases. On the other hand, in the case of epoxide copolymerization with CO2, for the propylene oxide (PO) reaction, the selectivity towards polypropylene carbonate (PPC) without polyether linkage consistently was >99 %. For the terpolymerization of PO, CO2 and diglycolic anhydride (DGA), a notable epoxide conversion of 86 %, selectively to polycarbonate, with TOF value as high as 36 h−1, was achieved.

Chemical separation of petroleum crude oil emulsions using two new poly(ionic liquid)s

AbstractThis work aims to prepare new poly(ionic liquid)s (PILs) and use them for crude oil emulsion separation (EES). PILs were synthesized by an opening ring reaction of hexadecylsuccinic anhydride (HAS) using polyethyleneimine branched MW 600 (PEI) and triethylenetetramine (TTA) in a one‐step procedure, obtaining PILs, HSPI‐PIL, and HSTA‐PIL, respectively. Chemical structure, interfacial tension, aggregate size, and thermal behavior were verified using several techniques. The efficiency of HSPI‐PIL and HSTA‐PIL toward EES was explored using different parameters, including water content (WC), demulsifier concentration, temperature, and pH value. The results indicated that EES proportionally increased with increased WC and temperature. The data also revealed that increased demulsifier concentration improved EES at low WC, for example, 10% and 30%; however, this parameter showed no significant effect with crude oil emulsion containing high WC, for example, 50%. Furthermore, HSPI‐PIL and HSTA‐PIL gave the maximum EES values at a pH of 7, while they decreased in acidic and basic mediums.

Comparative analysis of bio-based amino acid surfactants obtained via Diels–Alder reaction of cyclic anhydrides

Abstract Current changes in environmental legislation and customer demands set an urge for the development of more sustainable surfactants. Thus, the objective of this work was the development of novel environmentally friendly amino acid surfactants. Combining Diels–Alder cyclization of myrcene with maleic or citraconic anhydride followed by ring opening with amino acids enabled a synthesis route with a principal 100% atom economy. Variation of amino acids resulted in a large structural variety of anionic and amphoteric surfactants. Lysine gave access to either a mono-acylated product bearing a cationic side chain or a bi-acylated gemini surfactant. First, anhydride precursors were synthesized in yields of >90% in a Diels–Alder reaction under microwave radiation and subsequent amino acid coupling in aqueous environment gave fully bio-based surfactants in good yields and purity. Physicochemical characterization showed an enhanced decrease in surface tension upon addition of amino acids to the myrcene–anhydride backbone, resulting in a minimal value of 31 mN·m−1 for gemini–lysine. Foamabilitiy and foam stability were significantly increased at skin-friendly pH 5.5 by incorporation of amino acids. The carboxylic groups of surfactants with arginine were esterified with ethanol to access cationic compounds. Comparative analysis revealed moderate antimicrobial effects against yeast, Gram-positive bacteria, and Gram-negative bacteria.

Fabrication of a new type of polyvinyl alcohol/sulfosuccinic acid/glutaric anhydride cation exchange membrane for desalination using membrane capacitive deionization

Nowadays, the lack of clean water is becoming a serious problem, due to the increasingdemand for clean water, along with global climate change. Desalination of sea water orbrackish water has been considered as a practicable method to supply clean water. Amongdesalination technologies, membrane capacitive deionization has emerged for the last 15years as an alternative method and received a lot of research attention since then. In thisstudy, low-cost and ecofriendly polyvinyl alcohol/sulfosuccinic acid/glutaric anhydridecomposite membranes were fabricated through the crosslinking reaction of sulfosuccinicacid and glutaric anhydride with polyvinyl alcohol. The effect of sulfosuccinic acid andglutaric anhydride content was investigated. The presence of SSA in the cation exchangemembrane, which was proven by FT-IR, helps improve its water uptake (98.5 % comparedto 38.2 %) as well as cation exchange capacity (1.993 mM/g compared to 0.156 mM/g).The polyvinyl alcohol/sulfosuccinic acid/glutaric anhydride composite solution wascoated on the electrode, and the membrane's ability to desalinate water was assessed. Themembrane-coated electrode exhibited enhanced salt adsorption capacity and shorterdesalination time (13.4 minutes compared to 85.3 minutes) in comparison with theuncoated commercial electrode, indicating that the polyvinyl alcohol/sulfosuccinicacid/glutaric anhydride membrane is a suitable candidate to be utilized in the membranecapacitive deionization systems.® 2022 Journal of Science and Technology - NTTU

Improved viability of probiotics by encapsulation in chickpea protein matrix during simulated gastrointestinal digestion by succinylated modification

The potential application of succinylated chickpea protein (SCP) as a wall material for spray-dried microencapsulated probiotics was investigated. The results showed that succinylation increased the surface charge of chickpea proteins (CP) and reduced the particle size of the proteins. Meanwhile, succinylated modification decreased the solubility of protein under acidic conditions and increased the solubility in alkaline conditions. The effects of spray drying and in vitro gastrointestinal digestion on probiotics were investigated by microencapsulating chickpea protein with different degrees of N-succinylation. The results showed that all microcapsules had similar morphology, particle size and low water content. The microcapsules prepared by succinylated chickpea protein showed better stability and viability during spray drying and gastrointestinal digestion. The protective effect of probiotics was better as the degree of N-succinylation increased. In particular, the SCP-3-P sample (10 % succinic anhydride modified CP and maltodextrin) lost only 0.29 Log CFU/g throughout gastrointestinal digestion. The superior protective effect provided by succinylated CP in simulated gastric fluid (SGF) was mainly attributed to the reaction of succinic anhydride with protein to cause protein aggregation under gastric acidic conditions, reducing the infiltration of gastric acid and pepsin and maintaining the structural integrity of the microcapsules. Therefore, these findings provide a new strategy for probiotic intestinal delivery and application of chickpea protein.

High performance epoxy cresol novolac photocuring resins: Tailoring performance through adamantane modification

With the development of high-frequency communication technology, higher heat resistance and lower dielectric constant requirements have been put forward on solder resins. The introduction of rigid groups is expected to meet these requirements. Adamantane has an alicyclic hydrocarbon with a large spatial structure, which can be introduced into solder resist resins to improve their overall performance. In this paper, 3-amino-1-adamantanol (AD) was introduced into the epoxy cresol novolac (EOCN). Firstly, amino reacted with epoxy groups, followed by the reaction of anhydride with hydroxyl groups. The carboxyl groups introduced after the anhydride reaction can further react with glycidyl methacrylate (GMA). Finally, a new type of photocuring resin was obtained by adjusting the type of anhydride. Intriguingly, when the anhydride is maleic anhydride (MA), the higher crosslinking density and the tuning of the flexible molecular chain densification during the curing process allow the resin to possess high Tg and high storage modulus properties. As a consequence, the optimized UV-curable film has a strong storage modulus (2615.84 MPa), excellent heat resistance (Tg: 181.57 °C), and low dielectric constant (2.7 at 1 Hz). It also provides an effective strategy for the design and fabrication of high-performance EOCN-based photocuring materials.