Epoxidation of Limonene and Pinenes by Dimethyldioxirane in Microemulsions

Facile and Efficient Production of Biomass-Derived Isosorbide Dioxides via Epoxidation Using In situ-generated DMDO under Ultrasonication

Herein, we present a facile synthetic process for producing biomass-derived isosorbide (ISB) dioxides using dimethyl dioxirane (DMDO) as an efficient oxidizing agent, which was generated in situ from acetone and KHSO5 . To achieve high conversion and product yield, the KHSO5 concentration, KHSO5 flow rate, and reaction temperature were optimized. Under the optimal conditions, rapid and efficient epoxidation using the in situ-generated DMDO was observed under ultrasonication, yielding the desired product within 35 min at 0 °C. This study offers a convenient and efficient method for generating biomass-derived ISB building blocks, which have significant potential for the fabrication of bioplastics.

Recent advances in catalytic and non-catalytic epoxidation of terpenes: a pathway to bio-based polymers from waste biomass

Epoxides derived from waste biomass are a promising avenue for the production of bio-based polymers, including polyamides, polyesters, polyurethanes, and polycarbonates. This review article explores recent efforts to develop both catalytic and non-catalytic processes for the epoxidation of terpene, employing a variety of oxidizing agents and techniques for process intensification. Experimental investigations into the epoxidation of limonene have shown that these methods can be extended to other terpenes. To optimize the epoxidation of bio-based terpene, there is a need to develop continuous processes that address limitations in mass and heat transfer. This review discusses flow chemistry and innovative reactor designs as part of a multi-scale approach aimed at industrial transformation. These methods facilitate continuous processing, improve mixing, and either eliminate or reduce the need for solvents by enhancing heat transfer capabilities. Overall, the objective of this review is to contribute to the development of commercially viable processes for producing bio-based epoxides from waste biomass.

Latest Advancements in the Development of High-Performance Lignin- and Tannin-Based Non-Isocyanate Polyurethane Adhesive for Wood Composites

The depletion of natural resources and increasing environmental apprehension regarding the reduction of harmful isocyanates employed in manufacturing polyurethanes (PUs) have generated significant attention from both industrial and academic sectors. This attention is focused on advancing bio-based non-isocyanate polyurethane (NIPU) resins as viable and sustainable substitutes, possessing satisfactory properties. This review presents a comprehensive analysis of the progress made in developing bio-based NIPU polymers for wood adhesive applications. The main aim of this paper is to conduct a comprehensive analysis of the latest advancements in the production of high-performance bio-based NIPU resins derived from lignin and tannin for wood composites. A comprehensive evaluation was conducted on scholarly publications retrieved from the Scopus database, encompassing the period from January 2010 to April 2023. In NIPU adhesive manufacturing, the exploration of substitute materials for isocyanates is imperative, due to their inherent toxicity, high cost, and limited availability. The process of demethylation and carbonation of lignin and tannin has the potential to produce polyphenolic compounds that possess hydroxyl and carbonyl functional groups. Bio-based NIPUs can be synthesized through the reaction involving diamine molecules. Previous studies have provided evidence indicating that NIPUs derived from lignin and tannin exhibit enhanced mechanical properties, decreased curing temperatures and shortened pressing durations, and are devoid of isocyanates. The characterization of NIPU adhesives based on lignin and tannin was conducted using various analytical techniques, including Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), matrix-assisted laser desorption/ionization with time-of-flight (MALDI-TOF) mass spectrometry, and gel permeation chromatography (GPC). The adhesive performance of tannin-based NIPU resins was shown to be superior to that of lignin-based NIPUs. This paper elucidates the potential of lignin and tannin as alternate sources for polyols in the manufacturing of NIPUs, specifically for their application as wood adhesives.

Liquid-Liquid Interfacial Nanoarchitectonics

Science in the small world has become a crucial key that has the potential to revolutionize materials technology. This trend is embodied in the postnanotechnology concept of nanoarchitectonics. The goal of nanoarchitectonics is to create bio-like functional structures, in which self-organized and hierarchical structures are working efficiently. Liquid-liquid interface like environments such as cell membrane surface are indispensable for the expression of biological functions through the accumulation and organization of functional materials. From this viewpoint, it is necessary to reconsider the liquid-liquid interface as a medium where nanoarchitectonics can play an active role. In this review, liquid-liquid interfacial nanoarchitectonics is classified by component materials such as organic, inorganic, carbon, and bio, and recent research examples are discussed. Examples discussed in this paper include molecular aggregates, supramolecular polymers, conductive polymers film, crystal-like capsules, block copolymer assemblies, covalent organic framework (COF) films, complex crystals, inorganic nanosheets, colloidosomes, fullerene assemblies, all-carbon π-conjugated graphite nanosheets, carbon nanoskins and fullerphene thin films at liquid-liquid interfaces. Furthermore, at the liquid-liquid interface using perfluorocarbons and aqueous phases, cell differentiation controls are discussed with the self-assembled structure of biomaterials. The significance of liquid-liquid interfacial nanoarchitectonics in the future development of materials will then be discussed.

Stepwise and Microemulsions Epoxidation of Limonene by Dimethyldioxirane: A Comparative Study

Limonene dioxide is recognized as a green monomer for the synthesis of a wide variety of polymers such as polycarbonates, epoxy resins, and nonisocyanate polyurethanes (NIPU). The developed green technologies for its synthesis over heterogeneous catalysts present a challenge in that the selectivity of limonene dioxide is rather low. Homogeneous epoxidation in the presence of dimethyldioxirane for limonene dioxide synthesis is a promising technology. This study reports the epoxidation of limonene by dimethyldioxirane (DMDO) using two approaches. The isolated synthesis of DMDO solution in acetone was followed by epoxidation of limonene in another reactor in 100% organic phase (stepwise epoxidation). Following this procedure, limonene dioxide could be produced with almost 100% conversion and yield. A second approach allowed using in situ generated in aqueous-phase DMDO to epoxidize the limonene forming a microemulsion with a solubilized surfactant in the absence of any organic solvent. The surfactants tested were hydrosulfate (CTAHS), bromide (CTAB), and chloride (CTAC) cetyltrimethylammonium. All these surfactants showed good stability of microemulsions at aqueous surfactant concentrations above their critical micellar concentrations (CMC). Stability is obtained at the lowest concentration when using CTAHS because of its very low CMC compared to CTAB and CTAC. The major advantages of epoxidation in microemulsions compared to DMDO stepwise epoxidation are the absence of an organic solvent (favoring a low reaction volume) and the very high oxygen yield of 60 to 70% versus 5% in a stepwise approach. The epoxides formed are easily separated from the aqueous medium and the surfactant by liquid-liquid extraction. Therefore, the developed in situ epoxidation process is a green technology conducted under mild conditions and convenient for large-scale applications.