Synergic thermal and light responsive self-healing smart coatings: A combination of dynamic transesterification reactions with azobenzene isomerization

Chiral pesticides and herbicides (CPHs) show significant enantioselective differences in bioactivity, toxicity, and environmental behavior, making single-enantiomer production highly desirable for better efficacy and lower ecological risk. Among existing methods, lipase-catalyzed kinetic resolution is a more environmentally friendly alternative to chemical and chromatographic separations, as it has advantages of mild reaction conditions, low toxic and harmful byproducts, and excellent catalytic performance. Lipases have been broadly utilized for the production and processing of various CPHs, including organophosphorus pesticides, aryloxypropionate herbicides, pyrethroids, and aromatic amides. During the processing carried out through esterification, transesterification, and hydrolysis reactions, strategies such as solvent engineering, tailored reaction media, enzyme immobilization, and membrane-assisted processes can improve the catalytic efficiency, stereoselectivity, and stability. Artificial intelligence (AI)-assisted design of lipase, such as rational design, semirational design, and de novo design, will greatly change the prospects of enzyme engineering for the lipase-catalyzed enantioselective resolution of CPHs.

This study employs molecular dynamics simulations to investigate the influence of functionalized UiO-66 materials (with -H, -NH2, -NO2, and -(OH)2 groups) on the adsorption and diffusion behaviors of ethanol and waste oil before transesterification reactions. A multi-scale modeling approach, including a three-layer interfacial model, surface adsorption, and intra-framework adsorption, was utilized to systematically evaluate the effects of functionalization on structural properties, molecular diffusion, adsorption performance, and interfacial interactions. The simulation results reveal that functionalization enhances the intrinsic diffusivity of the metal–organic framework but generally suppresses the diffusion of ethanol and waste oil. The -(OH)2 group exhibits the most significant diffusion hindrance due to steric effects and strong hydrogen bonding. Adsorption of waste oil is dominated by coordination and hydrophobic interactions, while ethanol adsorption relies on hydrogen bonding. Within the framework, functionalization does not improve ethanol adsorption capacity; instead, pristine UiO-66 shows the highest uptake due to its optimal pore size. Adsorption energy calculations on the (002) surface indicate that the -NO2 group exhibits the strongest affinity for oleic acid, owing to its strong electronegativity and synergistic effects with metal sites. For polyunsaturated fatty acids, adsorption performance depends critically on the compatibility between the hydrophobic pore environment and molecular conformation. Ethanol adsorption is governed primarily by hydrogen bonding and metal coordination. This study provides molecular-level insights into the structure–function relationships governing pre-reaction adsorption and mass transport mechanisms of functionalized UiO-66 in transesterification reactions, providing a theoretical foundation for the rational design of efficient pre-reaction microenvironments in biodiesel catalysts.

The steady rise in energy demand around the global coupled with the environmental pollution associated with fossil fuel have given rise to an increase in search for alternative sources of energy that is sustainable and environmentally friendly. Biodiesel is a renewable, clean energy that can be produced from vegetable oils and animal fats. This research was aimed at synthesizing and analyzing biodiesel from micro green algae (Chlorodesmis fastigiata), to determine its potential as an alternative to petrol diesel. The algae samples were collected, identified, cultured, flocculated, harvested, sun-dried and ground prior to the oil extraction. Soxhlet extraction method was used to extract the oil from the algae biomass with n-hexane as the solvent. The oil was characterized of acid value, % FFA, % moisture content, iodine value, density and was converted to biodiesel via transesterification reaction. The biodiesel produced was also characterized of Acid value, Saponification value, Iodine value, Peroxide value, SG etc. The oil yield of the algal oil was 18.77%, Acid value was 3.40mg/g, Specific Gravity was 1.230. The biodiesel yield was 92%, other properties of the biodiesel were acid value 2.20mg/g, SG was 0.984, flash point was 105oC, Cloud point – 6oC, Pour point was -10oc, Cetane number was 49, pH was 6.7 e.t.c. The values of the properties gotten from the analysis were within the American standard (ASTMD6751) and this showed that biodiesel from Chlorodermis fastigiata (green algae) can serve as a good alternative to petro-diesel.

Ultrasound is a powerful tool for monitoring real-time online transesterification reaction

Reducing anthropogenic CO2 emissions is crucial, and converting CO2 into value-added chemicals offers a sustainable solution. In this work, a series of metal-substituted CeO2 catalysts were synthesized for the cascade synthesis of glycerol carbonate via cycloaddition and transesterification reactions using CO2, propylene oxide, and glycerol. XRD and FE-SEM analyses confirmed the formation of core-hollow nanospheres architecture, while complementary physicochemical characterizations verified their structural and surface properties. Among the catalysts, the Mg-substituted CeO2 (CHNS-Mg/CeO2) exhibited the highest catalytic activity under solvent and additive-free conditions, achieving a 96% glycerol carbonate yield at 160 °C and 20 bar CO2 after 8 h, along with moderate yields of propylene carbonate and propylene glycol. Systematic studies revealed that the incorporation of Mg into the CeO2 lattice enhanced Lewis basic sites and oxygen vacancies, as evidenced by XPS analysis, thereby improving the levels of CO2 activation and reactants adsorption. The CHNS-Mg/CeO2 catalyst demonstrated excellent recyclability, maintaining both structural integrity and activity over 10 cycles. Comparative evaluations with other monometallic and bimetallic oxide/hydroxide catalysts confirmed its superior performance. A plausible multistep mechanism, supported by experimental data and DFT calculations, highlights the synergistic role of Ce and O lattice sites as Lewis's acid and base centers in activating CO2, glycerol, and propylene oxide. Overall, this study establishes a robust and scalable catalytic system for efficient CO2 utilization and glycerol valorization, combining experimental evidence and theoretical validation to advance sustainable carbon conversion technologies.

ABSTRACT Nanocomposites based on epoxy vitrimer offer a facile preparation process and recyclability, making them attractive for use in strain sensors. However, current research in this area often prioritizes the construction of conductive nanomaterial layers over a fundamental understanding of their integration into the vitrimer matrices. Here, amino‐functionalized multi‐walled carbon nanotubes (MWCNTs‐NH 2 ) are incorporated into transesterification reactions (TERs)‐based epoxy vitrimers to develop conductive vitrimer (CV) nanocomposites. Due to the rigid structure and steric hindrance of MWCNTs‐NH 2 , the stress relaxation time is longer from 445 to 861 s with the addition of MWCNTs‐NH 2 from 3 to 5 wt%. Nevertheless, topological network rearrangements through TERs remained active, as evidenced by a comparable activation energy (121 kJ mol −1 ) to that of conventional TERs‐based vitrimers. The resulting CV nanocomposites allow for fragment recycling and chemical degradation in ethylene glycol, achieving a carbon nanotube recovery efficiency of 69%. Notably, these composites exhibit a non‐monotonic yet highly reproducible electrical response under strain, enabling their application in real‐time human motion monitoring. This work elucidates the role of functional nanomaterials in modulating vitrimer networks, thereby paving the way for fabricating reprocessable nanocomposites with precise strain sensing capabilities.

Biocatalysis and enzymatic reactions play a very important role in students’ everyday life, but they are often overlooked in current chemistry curricula. Here, we present a set of easy-to-implement experiments that can be used in high school classrooms. An immobilized lipase is used as biocatalyst in esterification, hydrolysis, and transesterification reactions, with conversion monitored and optimized via instrumental analytics. We also propose experiments that demonstrate reusability of the lipase and how it can be washed off the carrier material. All of the optimized procedures we developed can be tracked via odor or vision in the classroom. Furthermore, the experiments were tested and refined in learning settings with high school and undergraduate students as well as in-service teachers where they received a positive evaluation for their perceived attractiveness.

Powder coatings represent an environmentally friendly alternative to conventional liquid coatings, offering solvent-free application, high material efficiency, and excellent mechanical performance. However, they still face several sustainability challenges, including reliance on fossil-derived resources, the use of toxic curing agents, and limited repairability after damage. In this study, three carboxy-functional polyester resins (PES) containing increasing amounts of internal tertiary amine moieties were synthesized from renewable succinic acid and isosorbide. The resins were subsequently blended with a resveratrol-derived epoxy (REP) curing agent to produce biobased powder coatings with enhanced sustainability and intrinsic self-healing capability. All formulations contained at least 86.7% renewable content and exhibited excellent solvent resistance as well as strong adhesion to metal substrates. Importantly, the incorporated tertiary amine moieties act as internal catalysts for dynamic transesterification reactions, imparting repairability to the cured coatings. Without applied pressure, the coating with the highest tertiary amine content achieved a repair ratio of 85.7% after heating at 200 °C for 10 min. This study presents a promising strategy for developing catalyst-free powder coatings that combine high performance, high biocontent, and intrinsic self-healing capability.

The use of organocatalysts for the ring-opening polymerization (ROP) to achieve high-molecular-weight poly(ε-caprolactone) (PCL) remains challenging. In this study, we present a mechanochemical hydrogen-bond-catalyzed ROP (mechano-HROP) strategy. This approach combines a tris-urea/base co-catalysis together with ball milling to achieve rapid and controlled solid-state polymerization of ɛ-caprolactone (ɛ-CL) at room temperature. The mechano-HROP demonstrated exceptional polymerization activity (kobs = 0.053 min-1) while suppressing transesterification reactions compared to conventional bulk ROP. This method enabled the complete conversion of monomers into high-molecular-weight PCLs with Mn up to 185.0kDa and narrow distribution (Ð < 1.28). The PCL synthesized via mechano-HROP exhibited high chain-end fidelity, as evidenced by MALDI-TOF analysis and successful chain extension from its active chain ends. Density functional theory calculations confirmed the presence of an intramolecular hydrogen-bonding self-activated imidate species under solvent-free condition. Furthermore, we introduced a mechanochemical methanolysis method for PCL recycling under solvent-free and room temperature conditions. Kinetic comparisons with stirred methanolysis highlight the efficiency of mechanochemistry in PCL depolymerization. In summary, this work establishes a highly efficient mechanochemical route for the synthesis and recycling of high-molecular-weight PCLs.

Solid-state molecular motion (SSMM) plays a critical role in enriching material properties and functions, yet visualizing its detailed dynamics including direction, progression, and velocity to thoroughly elucidate its mechanism remains a great challenge. Herein, an intermolecular charge transfer (ICT)-mediated fluorescence strategy is developed to visualize and regulate SSMM in binary cocrystal systems, utilizing 6-methoxy-2-acetylnaphthalene (MA)/1,2,4,5-tetracyanobenzene (TCNB) as modeling platform. This approach leverages the reversible transformation between MA/TCNB = 1/1 (MT1, yellow emission) and MA/TCNB = 1/2 (MT2, green emission) crystalline phases, enabling real-time visualization of detailed SSMM information via localized dichromatic fluorescence signatures. It reveals an unexpected significant disparity in diffusion rates between electron donor MA and electron acceptor TCNB during the diffusion process at their interface, even exhibiting unidirectional diffusion from MA to TCNB within a restricted time. Applications demonstrated include pretreatment-free impurity analysis of MA (a key impurity in naproxen) down to 0.1% leveraging the fluorescence shift, and real-time monitoring of transesterification reactions based on the differing interaction capabilities of various naproxen esterification derivatives with TCNB. This study not only provides fundamental insights into SSMM and cocrystallization mechanisms but also demonstrates the potential of charge transfer cocrystallization for molecular sensing and dynamic reaction monitoring.

This study focuses on demonstrating the changes that occur in the transesterification reaction of methanol and African palm oil (Elaeis guineensis) when mixed with rapeseed oil. All changes were analyzed both at the kinetic level and in terms of the technical feasibility of large-scale production in a basic medium, catalyzed by sodium hydroxide. The best reagent concentration conditions were determined statistically in each case and then used to obtain the reaction kinetics through chromatographic analysis at regular time intervals. The quality of the product obtained was compared with the specifications of the ASTM D6751 standard, demonstrating compliance with these standards. Once the necessary data had been obtained, the production process for this biofuel was simulated using the SuperPro Designer® simulator. The results obtained show that modifying the fatty acid content by adding rapeseed oil to palm oil favorably changes its reaction kinetics, improving its energy produced to energy consumed ratio.

The increasing use of diesel fuel in Indonesia has prompted the need for more environmentally friendly alternative energy sources, one of which is through the use of used cooking oil as a raw material for biodiesel. This study aims to determine the effectiveness of activated bagasse as a catalyst and adsorbent in improving biodiesel quality. The method used is a laboratory experiment that includes the process of purifying used cooking oil with RBD adsorption, transesterification reaction using activated bagasse catalyst, and testing biodiesel quality through ALB, density, flash point, and yield parameters. The results showed that activated bagasse was able to reduce the free fatty acid content from 0.20224% to 0.04096% after purification, and in biodiesel it decreased further to 0.0256%. The transesterification process took 65 minutes, close to the standard 60 minutes, with the resulting biodiesel having a density of 0.86 g/mL, a flash point of 98°C, and a yield of 74%. Based on these results, activated sugarcane bagasse is considered quite effective as an environmentally friendly catalyst in the production of biodiesel from waste cooking oil and has the potential to be a more beneficial solution for the utilization of biomass waste.

Abstract Magnetic fields constitute an efficient, remote heating source with a wide range of potential applications. In this work, magnetic shape memory polymers (MSMPs) are developed by incorporating Fe₂O₃ nanoparticles into a dual-cure vitrimeric matrix based on a click thiol-epoxy reaction. This dual-curing approach enables the fabrication of a solid, easily transportable material with tunable thermomechanical properties, allowing subsequent thermoforming without the need for additional chemical processing, thereby reducing costs and complexity. Moreover, hydroxyl groups interact with ester groups to form dynamic covalent bonds through transesterification reactions. The influence of Fe 2 O 3 nanoparticles on the thermomechanical properties, curing kinetics, and memory performance of the polymeric matrix is analyzed. Results show that Fe 2 O 3 enhances mechanical strength, increases thermal conductivity, and catalyzes reactions at low concentrations. The shape-memory properties are further improved by the addition of nanoparticles. By adjusting the Fe₂O₃ content, the composite achieves self-heating up to approximately 180 °C under an alternating magnetic field, making it highly effective for shape-memory activation. Furthermore, this study presents a proof-of-concept de-icing strategy employing a dual-curing polymeric system activated by magnetic induction, enabling rapid and contactless ice detachment with high thermal efficiency. Even at the lowest Fe₂O₃ concentration, the material reaches temperatures above 120 °C, sufficient to trigger both shape-memory recovery and de-icing within seconds. Finally, an analytical model is proposed to quantitatively describe the de-icing mechanism, establishing a correlation between the critical thickness of the melted water layer necessary for ice detachment and key physical parameters such as ice thickness, surface angle, and magnetic field strength. Graphical abstract

The increasing demand for sustainable energy solutions has intensified research into biodiesel production, which relies on chemical catalysts that have an environmental impact. This study investigates the alternative methods of biodiesel production by utilizing agricultural waste, specifically rice husk, coconut husk, and chicken manure as a catalyst for biodiesel production. Laboratory experiments were conducted to extract metal oxide from agricultural waste to be used as a catalyst in the transesterification process. The obtained ash was characterized, and it was revealed that rice husk ash contained 98% SiO 2 , coconut husk ash had 72.62% of K 2 O, and chicken manure ash had 46.56% CaO, with higher metal oxide compositions in each material. The transesterification reaction was conducted by varying alcohol to oil ratio from 3:1, 6:1, 9:1, and 12:1, temperature (40-80°C), catalyst concentration (1.5-4.5%wt), and reaction time (20-120min) to assess catalyst efficiency. Pure CaO was used as a control catalyst for comparison. Characterization of the produced biodiesel from all catalysts was conducted and compared to ASTM D6751 standards. The results for acid value, moisture content, density, viscosity, free fatty acid, flash point, pour point, and cloud point were analyzed and found to comply with ASTM D6751 standards. On quantity determination of produced biodiesel, the most effective catalyst was chicken manure ash with a yield of 80% and the least effective catalyst was rice husk ash with 68% yield. Using agricultural waste reduces up to 40% production cost.

Valorisation of non-edible and waste cooking oils into hybrid biolubricants: A tribological study

Transesterification reactions are fundamental transformations in organic chemistry, yet performing them in aqueous media is challenging because of the competing hydrolysis reaction. In this study, we describe a mutant of alcohol oxidase from Phanerochaete chrysosporium (PcAOx-VPN) that also exhibits transesterification activity. Moreover, PcAOx-VPN displays no detectable hydrolytic activity, owing to its hydrophobic active site, which effectively excludes water. These characteristics make PcAOx-VPN a promising catalyst for transesterification reactions in aqueous media, a context that is typically compromised by competing hydrolysis.

The multistep conversion of CO2 into high-value-added chemicals has emerged as a promising pathway for achieving carbon neutrality. However, this approach critically depends on catalysts with exceptional robustness and versatile functionality to overcome the inherent challenges of CO2 activation and selectivity control. In this study, we successfully synthesized a series of imidazolium-based poly(ionic liquids) (Im-PILs) via conventional free radical polymerization. These polymeric catalysts exhibited exceptional bifunctional catalytic activity, enabling efficient promotion of both CO2 cycloaddition and methanol transesterification reactions without the need for cocatalysts. Notably, their structural versatility and robust performance highlight their potential for sustainable catalytic applications in green chemistry. Under optimized reaction conditions, the catalytic system demonstrated outstanding performance, achieving nearly quantitative yields of 99.40% for propylene carbonate (PC) and 74.6% for dimethyl carbonate (DMC). Comprehensive structural characterization, combined with systematic comparative experiments, unequivocally confirmed the superior catalytic activity, exceptional recyclability (at least five cycles with <7% activity loss), and long-term stability of the Im-PILs. This work establishes a novel design paradigm for constructing porous catalytic systems that facilitate cost-effective CO2 fixation, offering significant potential for industrial-scale carbon capture and utilization applications.

Solid base catalysts hold significant promise for replacing traditional homogeneous bases with green chemical processes. However, the construction of their strong basic sites typically relies on high-temperature calcination, which often leads to the collapse of the carrier structure and high energy consumption. This study proposes a novel “carrier reducibility tuning” strategy, which involves endowing the carrier with intrinsic reducibility to induce the low-temperature decomposition of alkali precursors via a redox pathway, thereby enabling the mild construction of strong basic sites. Low-valence Cr3+ was doped into a mesoporous zirconia framework, successfully fabricating an MCZ carrier with a mesostructure and reducible characteristics. Characterization results indicate that a significant redox interaction between the Cr3+ in the carrier and the supported KNO3 occurs at 500 °C. This interaction facilitates the complete conversion of KNO3 into highly dispersed, strongly basic K2O species, while Cr3+ is predominantly oxidized to Cr6+. This activation temperature is approximately 300 °C lower than that required for the conventional thermal decomposition pathway and effectively preserves the structural integrity of the material. In the transesterification reaction for synthesizing dimethyl carbonate, the prepared catalyst exhibits superior catalytic activity, significantly outperforming classic solid bases like MgO and other reference catalysts.

Global population growth has led to the use of fossil fuels and global pollution problems. Biodiesel, a renewable and environmentally friendly alternative to petroleum fuel, is produced from organic oils and animal fats, causing food safety issues. Unprocessed crude oils are inexpensive raw materials with a high content of free fatty acids. Ionic liquids (ILs) are used as catalysts for biodiesel production to solve the problems of traditional catalysts. This manuscript proposes the COSMO-RS model and machine learning as predictive tools for screening ILs as catalysts for fatty acid methyl esters (FAME) synthesis. COSMO-RS activity coefficient model was used to obtain the ILs sigma profile and interaction energies (electrostatic-misfit (Emisfit), hydrogen bond (EHB), and van der Waals (EvdW)) to correlate the yield of reaction. The machine learning models, such as K-nearest neighbor, Random Forest Regressor, Decision Tree Regressor model, Gradient Boosting Regressor, and Multilayer Perceptrons model, were applied to correlate the above-mentioned properties. The Gradient Boosting Regressor model, using the analysis of the anion and cation sigma profiles, proved to be more efficient than the same model, using the approach of the interaction energies. Based on the screening study, the ILs [l-arginine][Acetate], [l-arginine][HSO3], and [l-arginine][NO3] were selected, synthesized, and characterized.