Composition and Structure of Ethanol-Lignins of Coniferous and Deciduous Wood and Products of their Catalytic Telomerization with 1,3-Butadiene

The composition and structure of ethanol-lignins of coniferous (abies, pine) and deciduous (aspen, birch) wood and products of their catalytic telomerization with 1,3-butadiene has been studied with use of the methods 31P-NMR, gel-permeation chromatography, scanning electron microscopy and elemental analysis. Data on the nature and content of hydroxyl groups in ethanol-lignins were obtained using phosphorylation of lignins with 2-chloro‑4,4,5,5,-tetramethyl‑1,3,2-dioxaphospholane.The studied lignins differ from each other in the content of aliphatic, phenolic and carboxyl groups. The total content of hydroxyl groups increases in the series of ethanol-lignins: birch < aspen < pine < abies. For the modification of ethanol-lignins, the reaction of catalytic telomerization with 1,3-butadiene was used at 70 °C and 90 °C in the presence of a complex of palladium (II) diacetate with the sodium salt of triphenylphosphine trisulfate. By comparing the number of aliphatic, phenolic and carboxyl OH- groups in the initial and telomerized ethanol-lignins, it was found that only aliphatic and phenolic hydroxyl groups participate in the telomerization reaction. Telomerization of ethanol-lignins with 1,3-butadiene increases their average molecular weight and reduces polydispersity. The morphology of telomerized and initial samples of ethanol-lignins varies significantly

Immobilized Fe3O4-Polydopamine-Thermomyces lanuginosus Lipase-Catalyzed Acylation of Flavonoid Glycosides and Their Analogs: An Improved Insight Into Enzymic Substrate Recognition

The conversion of flavonoid glycosides and their analogs to their lipophilic ester derivatives was developed by nanobiocatalysts from immobilizing Thermomyces lanuginosus lipase (TLL) on polydopamine-functionalized magnetic Fe3O4 nanoparticles (Fe3O4-PDA-TLL). The behavior investigation revealed that Fe3O4-PDA-TLL exhibits a preference for long chain length fatty acids (i.e., C10 to C14) with higher reaction rates of 12.6–13.9 mM/h. Regarding the substrate specificity, Fe3O4-PDA-TLL showed good substrate spectrum and favorably functionalized the primary OH groups, suggesting that the steric hindrances impeded the secondary or phenolic hydroxyl groups of substrates into the bonding site of the active region of TLL to afford the product.

An Investigation into the Interaction between Double Hydroxide-Based Antioxidant Benzophenone Derivatives and Cyclooxygenase 2

Cyclooxygenases 2 (COX2) is a therapeutic target for many inflammation and oxidative stress associated diseases. A high-throughput technique, biolayer interferometry, was performed to primarily screen the potential COX2 binding activities of twelve newly synthesized double hydroxide-based benzophenone derivatives. Binding confirmation was achieved by molecular docking and multi-spectroscopy studies. Such a combined method provided a comprehensive understanding of binding mechanism and conformational changes. Compounds DB2, SC2 and YB2 showed effective COX2 binding activity and underlined the benefits of three phenolic hydroxyl groups adjacent to each other on the B ring. The twelve tested derivatives were further evaluated for antioxidant activity, wherein compound SC2 showed the highest activity. Its concentration for the 50% of maximal effect (EC50) value was approximately 1000 times greater than that of the positive controls. SC2 treatment effectively improved biochemical indicators caused by oxidative stress. Overall, compound SC2 could serve as a promising candidate for further development of a new potent COX2 inhibitor.

Synthesis of Azacalixarenes and Development of Their Properties

This review focuses on the synthesis, structure, and interactions of metal ions, the detection of some weak interactions using the structure, and the construction of supramolecules of azacalixarenes that have been reported to date. Azacalixarenes are characterized by the presence of shallow or deep cavities, the simultaneous presence of a basic nitrogen atom and an acidic phenolic hydroxyl group, and the ability to introduce various side chains into the cyclic skeleton. These molecules can be given many functions by substituting groups on the benzene ring, modifying phenolic hydroxyl groups, and converting side chains. The author discusses the evidence of azacalixarene utilizing these characteristics.

Removal of Ions From Produced Water Using Powder River Basin Coal

Although becoming less attractive as an energy source, coal has significant potential for other, more sustainable uses including water treatment. In this study, we present a simple approach to treat water that was produced during oil production and contained a total dissolved solids (TDS) content of over 150 g/L using Powder River Basin (PRB) coal. PRB coal used as packing material in a flow-through column effectively removed 60-80% of the cations and anions simultaneously. Additionally, 71-92% of the total organic carbon in the produced water was removed as was all of the total suspended solids. The removal mechanisms of both cations and anions were investigated. Cations were removed by ion exchange with protons from oxygen-containing functional groups such as carboxylic and phenolic hydroxyl groups. Anions, mainly Cl-1, appeared to be removed through either the formation of resonance structures as a result of delocalization of electrons within coal molecules or through ion-π interactions. We propose that coal is a “pseudo-amphoteric” exchange material that can remove cations and anions simultaneously by exchanging ions with both ionized and non-ionized acids that are ubiquitous in coal structure or resonance effect.

Phenolic Hydroxyl Groups in the Lignin Polymer Affect the Formation of Lignin Nanoparticles

Alkaline soda lignin (AL) was sequentially fractionated into six fractions of different molecular size by means of solvent extraction and their phenolic hydroxyl groups were chemoselectively methylated to determine their effect on nanoparticle formation of lignin polymers. The effect of the lignin structure on the physical properties of nanoparticles was also clarified in this study. Nanoparticles were obtained from neat alkaline soda lignin (ALNP), solvent-extracted fractions (FALNPs, i.d. 414–1214 nm), and methylated lignins (MALNPs, i.d. 516–721 nm) via the nanoprecipitation method. Specifically, the size properties of MALNPs showed a high negative correlation (R2 = 0.95) with the phenolic hydroxyl group amount. This indicates that the phenolic hydroxyl groups in lignin could be influenced on the nucleation or condensation during the nanoprecipitation process. Lignin nanoparticles exhibited high colloidal stability, and most of them also showed good in vitro cell viability. This study presents a possible way to control nanoparticle size by blocking specific functional groups and decreasing the interaction between hydroxyl groups of lignin.

Progress in electrochemical analysis of flavonoids: a scientometric analysis in CiteSpace

Background: Flavonoids are a large class of phenolic compounds, which generally refer to two benzene rings (A ring, B ring) with phenolic hydroxyl groups connected to each other through three central carbon atoms, that is, a series of C6-C3-C6 basic core compounds. Because of its potential medicinal value, the research on flavonoids has aroused great interest. Methods: This review aims to identify the research progress and development trends of electrochemical analysis of flavonoids. We retrieved published papers (1998–2020) from Scientific Citation Index Expanded (SCIE) database of the WoS with a topic search related to electrochemical analysis of flavonoids. Results: In this paper, the research progress in electrochemical analysis of flavonoids has been reviewed. Antioxidant activity of flavonoids is the hot area that attracted considerable attention because it directly affects the application of flavonoids. Different analytical methods also received attention of researchers, such as cyclic voltammetry and capillary electrophoresis. This is because advanced analysis technology can be useful for evaluating the property of flavonoids. Conclusion: The research progress and development trends were analyzed based on CiteSpace software of text mining and visualization. Three peaks of this research area can be found as 2004-2005, 2011-2013 and 2016-2018. Although the different countries are conducting research on electrochemical analysis of flavonoids, most of these institutions are not related to each other.