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Imidazolium perchlorate task-specific ionic liquids (TSILs) were used for in-situ oxidation esterification of benzaldehydes and benzylalcohols in reaction with alcohols. CO 2 H functional group containing TSIL show dual role as catalyst and reaction media toward oxidative esterifications. Excellent yields of esters could be obtained for a series of benzaldehydes and benzylalcohols via the reaction with alcohols. This reaction can be regarded as a new method for the efficient oxidation esterification of benzaldehydes and benzylalcohols under mild catalyst and solvent-free conditions. Graphical abstract

Pine rosin, which is derived from Pinus merkusii resin, a natural product, has demonstrated potential as a road marking binder. Although pine rosin has an excellent shinning property, it has some limitations, such as instability and color change. To tackle these issues, modified rosin has been developed through sequential esterification and Diels–Alder reactions, and it has shown better properties than untreated rosin. In this study, from the evaluation of untreated and treated rosins, the treated rosin showed some improvements, such as a lower acid value and higher stability, as shown by the color consistency during the oxidation test at 150 °C for 24 h in open-air conditions. Additionally, as road marking paint, the modified rosin is blended with blending materials in the range of 18–28 wt.%. The modified rosin has a softening point of 170–210 °C, a hardness of 50–71 HD, and a weight loss of 1.33–5.12 mg during the wearing test. These results are comparable to or better than those of commercially available road marking products.

In this work, a dense and acid-resistant beta zeolite membrane was applied to improve the esterification of citric acid and n-butanol, for the first time. Through the continuous removal of the by-product water via pervaporation (PV), the conversion of citric acid was significantly enhanced from 71.7% to 99.2% using p-Toluenesulfonic acid (PTSA) as catalyst. PTSA was a well-known strong acid, and the membrane kept almost no change after PV-esterification, indicating the superior acid resistance of beta zeolite membrane. Compared to the use of acid-resistant MOR zeolite membrane by PV-esterification, a consistently higher conversion of citric acid was obtained using a high-flux beta zeolite membrane. The results showed that high water permeation on the beta zeolite membrane, with good acid resistance, had a strong promoting effect on esterification, leading to an improved conversion. In addition, the citric acid conversion of 97.7% could still be achieved by PV-esterification at a low reaction temperature of 388 K.

The vacuum autocatalytic esterification process and reaction kinetics of pentaerythritol and octanoic acid at the reaction temperature of 220℃ to 250℃ were studied by online sampling method. The kinetic parameters of the stepwise esterification reaction were calculated, and the reaction kinetic model was established. The results show that the synthesis of pentaerythritol octanoate by vacuum autocatalytic esterification method requires no catalyst, the reaction time is 4-5 h, the esterification rate is more than 98%, and the content of tetraester is over 96%. The reaction is endothermic and the activation energy of each step is 23.21~32.26 kJ⋅mol −1 . The calculated kinetic model is in good agreement with the experimental values.

• The cuticle is an essential and ubiquitous biological polymer composite covering aerial plant organs, whose structural component is the cutin polyester entangled with cell wall polysaccharides. The nature of the cutin-embedded polysaccharides (CEPs) and their association with cutin polyester are still unresolved • Using tomato fruit as a model, chemical and enzymatic pretreatments combined with biochemical and biophysical methods were developed to compare the fine structure of CEPs with that of the noncutinized polysaccharides (NCPs). In addition, we used tomato fruits from cutin-deficient transgenic lines cus1 (cutin synthase 1) to study the impact of cutin polymerization on the fine structure of CEPs. • Cutin-embedded polysaccharides exhibit specific structural features including a high degree of esterification (i.e. methylation and acetylation), a low ramification of rhamnogalacturonan (RGI), and a high crystallinity of cellulose. In addition to decreasing cutin deposition and polymerization, cus1 silencing induced a specific modification of CEPs, especially on pectin content, while NCPs were not affected. • This new evidence of the structural specificities of CEPs and of the cross-talk between cutin polymerization and polysaccharides provides new hypotheses concerning the formation of these complex lipopolysaccharide edifices.

Esterified nanofibrillated cellulose (eNFC) with varying degrees of substitution was prepared using fatty acid chloride. Furthermore, the effect of esterification on properties of pure NFC and its composites with polybutylene succinate (PBS) was investigated. Lauroyl chloride (LC) with 12 carbon atoms was used for esterification. An increase in the amount of LC increased the degree of substitution (DS), which significantly decreased the water contact angle and improved the hydrophobicity of NFC. The addition of fatty acid to NFCs lowered their crystallinity. However, the fatty acid increased the hydrophobicity of NFCs, thereby improving their dispersibility in nonpolar solvents. Compared with pure NFCs, eNFC exhibited enhanced compatibility with PBS, and the addition of eNFC with an appropriate DS increased the tensile strength and elastic modulus of PBS. These findings suggest the potential of NFC esterification for improving the performance of NFC-based composite materials.

Biodiesel, comprising mono alkyl fatty acid esters or methyl ethyl esters, is an encouraging option to fossil fuels or diesel produced from petroleum; it has comparable characteristics and its use has the potential to diminish carbon dioxide production and greenhouse gas emissions. Manufactured from recyclable and sustainable feedstocks, e.g., oils originating from vegetation, biodiesel has biodegradable properties and has no toxic impact on ecosystems. The evolution of biodiesel has been precipitated by the continuing environmental damage created by the deployment of fossil fuels. Biodiesel is predominantly synthesised via transesterification and esterification procedures. These involve a number of key constituents, i.e., the feedstock and catalytic agent, the proportion of methanol to oil, the circumstances of the reaction and the product segregation and purification processes. Elements that influence the yield and standard of the obtained biodiesel encompass the form and quantity of the feedstock and reaction catalyst, the proportion of alcohol to feedstock, the temperature of the reaction, and its duration. Contemporary research has evaluated the output of biodiesel reactors in terms of energy production and timely biodiesel manufacture. In order to synthesise biodiesel for industrial use efficaciously, it is essential to acknowledge the technological advances that have significant potential in this sector. The current paper therefore offers a review of contemporary progress, feedstock categorisation, and catalytic agents for the manufacture of biodiesel and production reactors, together with modernised processing techniques. The production reactor, form of catalyst, methods of synthesis, and feedstock standards are additionally subjects of discourse so as to detail a comprehensive setting pertaining to the chemical process. Numerous studies are ongoing in order to develop increasingly efficacious techniques for biodiesel manufacture; these acknowledge the use of solid catalytic agents and non-catalytic supercritical events. This review appraises the contemporary situation with respect to biodiesel production in a range of contexts. The spectrum of techniques for the efficacious manufacture of biodiesel encompasses production catalysed by homogeneous or heterogeneous enzymes or promoted by microwave or ultrasonic technologies. A description of the difficulties to be surmounted going forward in the sector is presented.

Over the past 130 years, Fischer-Speier esterification has been established as the benchmark method for synthesizing esters from organic acids and alcohols. The reaction’s versatility, arising from the vast combinations of starting materials and the numerous catalytic alternatives to the traditional H2SO4, has maintained its relevance, with a steady flow of publications addressing new developments. This review highlights the most significant contributions to Fischer-Speier esterification over the past five years, with a particular emphasis on mechanistic advancements and innovative catalytic systems. Both homogeneous and heterogeneous catalytic approaches are discussed, including novel catalysts leveraging hydrogen-bonding interactions and systems offering fresh insights into specific reaction mechanisms and atypical methodologies. Some of these catalytic systems, as ionic liquids or sulfonated heterogeneous catalytic precursors, reached excellent yields (>90%), e.g., in the synthesis of fatty acids methyl esters. Also, classic catalysts such as H2SO4 and para-toluen sulfonic acid were optimized for quantitative conversions (e.g., in the esterification of trans-cinnamic acid with methanol). A consistent number of catalysts was studied with model substrates (as benzoic acid in combination with methanol, ethanol, and ethylene glycol), and new activation pathways were presented.

The catalytic oxidative esterification of 1, 2-propanediol to methyl lactate in a base-free methanol system over Cu-modified Au/HAP catalysts was investigated. The catalysts demonstrated efficient activity in converting 1, 2-propanediol to methyl lactate without any base additives, achieving a conversion of 91.2% and a selectivity of 45% for methyl lactate under optimized conditions of 160 °C, 2 h, and 1.0 MPa O.sub.2 over 2Au12Cu/HAP catalyst. The Au sites were identified as pivotal in catalyzing the oxidation of 1, 2-propanediol, and the basic sites of HAP was hypothesized to play a similar role with base additives to enhance the catalytic activity of Au. Furthermore, modification of Cu to Au was observed to promote the oxidation of the hydroxyacetone intermediate to methyl lactate while effectively suppressing the over-oxidation of methyl lactate, thus increased selectivity of methyl lactate.

With incidence of antimicrobial resistance rising globally, there is a continuous need for development of new antimicrobial molecules. Phenolic compounds having a versatile scaffold that allows for a broad range of chemical additions; they also exhibit potent antimicrobial activities which can be enhanced significantly through functionalization. Synthetic routes such as esterification, phosphorylation, hydroxylation or enzymatic conjugation may increase the antimicrobial activity of compounds and reduce minimal concentrations needed. With potent action mechanisms interfering with bacterial cell wall synthesis, DNA replication or enzyme production, phenolics can target multiple sites in bacteria, leading to a much higher sensitivity of cells towards these natural compounds. The current review summarizes some of the most important knowledge on functionalization of natural phenolic compounds and the effects on their antimicrobial activity.