High Oxidative Stability Research Articles

Virgin flaxseed oil supplemented or not with tocopherols and phytosterols prevents liver steatosis induced by high‐fat diets in male Wistar rats

AbstractThis study aimed to investigate the effect of a virgin flaxseed oil (FO) rich in n − 3 polyunsaturated fatty acid, supplemented or not with a bioactive supplement (BS) containing tocopherols and phytosterols on the prevention of nonalcoholic fatty liver disease in a high‐fat (HF) animal model. Male Wistar rats were fed 60 days with a recommended (SO7, soybean oil 7%) or an HF diet (fat, 30%) containing soybean (SO30), corn (CO30), or FO (FO30) or the same oils supplemented with 1% of BS (SO30BS, CO30BS, or FO30BS, respectively). Hepatic and dietary FA composition, triacylglycerides (TAGs) content in serum and liver, nutritional parameters, in vivo TAG‐secretion rate, liver histology, mRNA levels of β‐oxidation‐related genes, and carnitine palmitoyl transferase‐1a (CPT‐1a) enzyme activity were determined. At HF levels, FO30 and FO30BS groups showed the highest total n − 3 PUFA levels in diets and were associated with lower weight gain, liver TAG content, and microsteatosis degree. The CPT‐1a activity was enhanced in FO30 and FO30BS, showing differences only by the type of dietary oil. The BS supplementation induced an increase in the β‐oxidation‐related gene expression. Virgin FO prevented liver steatosis and hepatomegaly induced by HF diets. The BS supplementation reduced body fat accumulation and enhanced expression of β‐oxidation related genes, without affecting hepatic TAG content.Practical Applications: Scientific knowledge of functional lipids with high oxidative stability and biological activity has great practical application in reducing non‐communicable chronic diseases. This study provides evidence on the potential synergic and complementary effects of virgin FO, TP, and PS to be used for the prevention of the metabolic hepatic disorders involved during the evolution of the different steps of NAFLD. Specifically, based on different biological mechanisms, this stable combination of bioactive lipids could prevent not only the development of exacerbated hepatic TAG accumulation but also the hepatocellular injury seen at different stages from hepatic steatosis to steatohepatitis.

Revealing the key role of non-solvating diluents for fast-charging and low temperature Li-ion batteries

Fast-charging and low temperature operation are of vital importance for the further development of lithium-ion batteries (LIBs), which is hindered by the utilization of conventional carbonate-based electrolytes due to their slow kinetics, narrow operating temperature and voltage range. Herein, an acetonitrile (AN)-based localized high-concentration electrolyte (LHCE) is proposed to retain liquid state and high ionic conductivity at ultra-low temperatures while possessing high oxidation stability. We originally reveal the excellent thermal shielding effect of non-solvating diluent to prevent the aggregation of Li+ solvates as temperature drops, maintaining the merits of fast Li+ transport and facile desolvation as at room temperature, which bestows the graphite electrode with remarkable low temperature performance (264 mA h g−1 at −20 °C). Remarkably, an extremely high capacity retention of 97% is achieved for high-voltage high-energy graphite||NCM batteries after 250 cycles at −20 °C, and a high capacity of 110 mA h g−1 (71% of its room-temperature capacity) is retained at −30 °C. The study unveils the key role of the non-solvating diluents and provides instructive guidance in designing electrolytes towards fast-charging and low temperature LIBs.

Wine lees as functional ingredient to produce biscuits fortified with polyphenols and dietary fibre

Wine lees, a by-product of winemaking process, still contains bioactive molecules (especially fibres and polyphenols) with potential functional properties. Considering the high frequency of consumption and high versatility of biscuits, the purpose of this work was to replace wheat flour with 10% (F10) and 20% (F20) of wine less flour (WLF) to produce biscuits with an improved nutritional profile. This study assessed the impact of substituting 10 and 20% of WLF on the physico-chemical, nutritional, textural, sensory, and volatile aroma compound characteristics. These results were compared with those of a control biscuit exclusively made with wheat flour (F0). The statistical comparison allowed for demonstrating how the fortified biscuits (F10 and F20) had significantly higher values of fibres, proteins, phenolic compounds, antioxidant activity, and higher oxidative stability than the control (F0). Different flavonoids and anthocyanins were detected in F10 and F20, such as ellagic acid and malvidin-3-acetil glucoside with a concentration greater than 200 mg/kg. The increased fibres and polyphenols in the F20 led to a significant lowering in glycaemic index (pGI) and starch hydrolysis (HI). Based on simulated colonic fermentation, F20 also exhibited a slight prebiotic effect supported by the significant increase in lactic acid bacteria cell density compared to F0.

Molecular anchoring of free solvents for high-voltage and high-safety lithium metal batteries

Constraining the electrochemical reactivity of free solvent molecules is pivotal for developing high-voltage lithium metal batteries, especially for ether solvents with high Li metal compatibility but low oxidation stability ( <4.0 V vs Li+/Li). The typical high concentration electrolyte approach relies on nearly saturated Li+ coordination to ether molecules, which is confronted with severe side reactions under high voltages ( >4.4 V) and extensive exothermic reactions between Li metal and reactive anions. Herein, we propose a molecular anchoring approach to restrict the interfacial reactivity of free ether solvents in diluted electrolytes. The hydrogen-bonding interactions from the anchoring solvent effectively suppress excessive ether side reactions and enhances the stability of nickel rich cathodes at 4.7 V, despite the extremely low Li+/ether molar ratio (1:9) and the absence of typical anion-derived interphase. Furthermore, the exothermic processes under thermal abuse conditions are mitigated due to the reduced reactivity of anions, which effectively postpones the battery thermal runaway.

Development of poly(butylene adipate‐co‐terephthalate) composites with high thermal oxidation stability using Chrysanthemum morifolium extract as a natural additive

AbstractPoly(butylene adipate‐co‐terephthalate) (PBAT) is one of the solutions to the energy crisis and white pollution. However, the poor thermo‐oxidative stability limits its wide applications. In this work, Chrysanthemum morifolium extract (CME) as a natural additive was used to modify the PBAT. The oxidation onset temperature (OOT) results showed that the CME could provide PBAT with high thermal oxidation stability. By the presence of 2.5 wt% CME, the OOT value of PBAT‐CME2.5 increased by 52°C compared with the neat PBAT. The outstanding antioxidant capacity is attributed to the excellent free radical quenching capacity of CME, whose main components consist of six kinds of phenolic compounds. Moreover, the PBAT‐CME1.5 composite could achieve the balance between the mechanical property and thermo‐oxidative stability, the OOT result of PBAT‐CME1.5 increased by 42°C, the tensile strength reached 103.1%, and the elongation at break could retain 91.4% of that of neat PBAT. Besides, the processing property, degradation performance, and surface hydrophobic nature of modified PBAT samples were all improved. This work proposes a facile method to obtain completely natural biodegradable composites to expand the practical applications of PBAT.Highlights The main components in CME are phenolic compounds. CME showed high free radical scavenging efficiency. CME improved the thermal oxidation stability of the PBAT matrix. The addition of CME could still maintain good mechanical properties of PBAT. The introduction of CME promoted the degradation of PBAT films.

Unveiling the Role of Fluorination in Hexacyclic Coordinated Ether Electrolytes for High-Voltage Lithium Metal Batteries.

Fluorinated ethers have become promising electrolyte solvent candidates for lithium metal batteries (LMBs) because they are endowed with high oxidative stability and high Coulombic efficiencies of lithium metal stripping/plating. Up to now, most reported fluorinated ether electrolytes are -CF3-based, and the influence of ion solvation in modifying degree of fluorination has not been well-elucidated. In this work, we synthesize a hexacyclic coordinated ether (1-methoxy-3-ethoxypropane, EMP) and its fluorinated ether counterparts with -CH2F (F1EMP), -CHF2 (F2EMP), or -CF3 (F3EMP) as terminal group. With lithium bis(fluorosulfonyl)imide as single salt, the solvation structure, Li-ion transport behavior, lithium deposition kinetics, and high-voltage stability of the electrolytes were systematically studied. Theoretical calculations and spectra reveal the gradually reduced solvating power from nonfluorinated EMP to fully fluorinated F3EMP, which leads to decreased ionic conductivity. In contrast, the weakly solvating fluorinated ethers possess higher Li+ transference number and exchange current density. Overall, partially fluorinated -CHF2 is demonstrated as the desired group. Further full cell testing using high-voltage (4.4 V) and high-loading (3.885 mAh cm-2) LiNi0.8Co0.1Mn0.1O2 cathode demonstrates that F2EMP electrolyte enables 80% capacity retention after 168 cycles under limited Li (50 μm) and lean electrolyte (5 mL Ah-1) conditions and 129 cycles under extremely lean electrolyte (1.8 mL Ah-1) and the anode-free conditions. This work deepens the fundamental understanding on the ion transport and interphase dynamics under various degrees of fluorination and provides a feasible approach toward the design of fluorinated ether electrolytes for practical high-voltage LMBs.

Esters of 1,1,1-trimethylolpropane as a base and component of lubricating oils

Symmetrical, unsymmetrical esters of 1,1,1-trimetilolpropan (TMP) with C6-C8 aliphatic monocarboxylic acids have been synthesized. Their physicochemical, viscosity-temperature, thermal-oxidative (TOS) properties have been studied. It was found that esters have relatively low viscosities at 100 oC (3.55–4.39 mm2/s), high flash points (198–220 oC) and viscosity index (110–121 units), low freezing temperature (minus 50 oC ÷ minus 58 oС) and viscosity at – 40 oС (2800–3310 mm2/s). Also, the esters are distinguished by high thermal and oxidative stability: low volatility – 0.18–0.40 wt %, sediment amount – 0.18–0.32 wt %, viscosity increase at 100 oC – 0.0031–0.0042 %. The dependence between the chemical structure and performance characteristics of the obtained compounds was also studied. It was found that these esters meet requirements for low-viscosity aviation oils and are proposed as the basis and component of new oils.

Influence of Selected Compositions of Wall Materials and Drying Techniques Used for Encapsulation of Linseed Oil and Its Ethyl Esters

The aim of the study was to compare the encapsulation of linseed oil and its ethyl esters using two coating materials (maltodextrin with whey protein concentrate (WPC) vs. maltodextrin with gum arabic) and two drying methods (spray-drying vs. freeze-drying) to obtain powders with the highest oxidative stability. A comparison was made based on the properties of emulsions (morphology, particle size distribution, and stability) and powders (morphology, physicochemical properties, fatty acid composition, and oxidative stability). The powder’s oxidative stability was determined based on the Rancimat protocol. The most uniform distribution of oil droplets in prepared emulsions was stated for ethyl esters in a mixture of maltodextrin and gum arabic. Emulsions with WPC had a bimodal character, while those with gum arabic had a monomodal character. Gum arabic promoted emulsion stability, while in samples containing WPC, sedimentation and creaming processes were more visible. Powders obtained using spray-drying had a spherical shape, while those obtained by freeze-drying were similar to flakes. Although encapsulation efficiency was the highest for freeze-dried powders made of linseed ethyl esters with gum arabic, the highest oxidative stability was stated for powders made by spray-drying with WPC as wall material (independently of linseed sample form). These powders can be easily applied to various food matrices, increasing the share of valuable α-linolenic acid.

Liquid Metal Mediated Heterostructure Fluoride Solid Electrolytes of High Conductivity and Air Stability for Sustainable Na Metal Batteries.

Fluoride-based solid electrolytes (SEs) have emerged as a promising component for high-energy-density rechargeable solid-state batteries (SSBs) in view of their wide electrochemical window, high air stability, and interface compatibility, but they still face the challenge of low ion conductivity and the lack of a desired structure for sodium metal SSBs. Here, we report a sodium-rich heterostructure fluoride SE, Na3GaF6-Ga2O3-NaCl (NGFOC-G), synthesized via in situ oxidation of liquid metal gallium and in situ chlorination using low-melting GaCl3. The distinctive features of NGFOC-G include single-crystal Na3GaF6 domains within an open-framework structure, composite interface decoration of Ga2O3 and NaCl with a concentration gradient, exceptional air stability, and high electrochemical oxidation stability. By leveraging the penetration of gallium at NaF grain boundaries and the in situ self-oxidation to form Ga2O3 nanodomains, the solid-phase reaction kinetics of NaF and GaF3 is activated for facilitating the synthesis of main component Na3GaF6. The introduction of a small amount of a chlorine source during synthesis further softens and modifies the boundaries of Na3GaF6 along with Ga2O3. Benefiting from the enhanced interface ion transport, the optimized NGFOC-G exhibits an ionic conductivity up to 10-4 S/cm at 40 °C, which is the highest level reported among fluoride-based sodium-ion SEs. This SE demonstrates a "self-protection" mechanism, where the formation of a high Young's modulus transition layer rich in NaF and Na2O under electrochemical driving prevents the dendrite growth of sodium metal. The corresponding Na/Na symmetric cells show minimal voltage hysteresis and stable cycling performance for at least 1000 h. The Na/NGFOC-G/Na3V2(PO4)3 cell demonstrates stable capacity release around 100 mAh/g at room temperature. The Na/NGFOC-G/FeF3 cell delivers a high capacity of 461 mAh/g with an excellent stability of conversion reaction cycling.

Catalytic Upgrading of Biodiesel by Partial Hydrogenation of Its FAME Composition: A Systematic Review

Biodiesel is one of the most popular biofuels as it is a promising substitute for conventional diesel fuel, but for now, it cannot be used as a stand-alone fuel due to its low oxidative stability. For this reason, there have been efforts to upgrade biodiesel in the last few years through the partial hydrogenation of its fatty acid methyl esters (FAMEs). This procedure succeeds in resolving the problem of low oxidative stability, but in some cases, a new issue arises as non-selective hydrogenation deteriorates the fuel’s cold flow properties, which are crucial for vehicle’s operation without damaging the vehicle’s engine. More specifically, the problem of deteriorated cold flow properties is caused by the formation of trans-monounsaturated and fully saturated FAMEs during the hydrogenation reaction. Hydrogenated biodiesels are preferred to contain more cis-monounsaturated FAMEs because these are considered to have the best combination of high oxidative stability and good cold flow properties. As a result, various systems and methods have been tested to achieve selective partial hydrogenation of biodiesel FAMEs. In this review article, the catalytic systems and processes that stood out in various research studies are presented, and the factors that lead to the best possible outcome are investigated and discussed.

Optimizing solid electrolytes with 3d transition metal doped Li3YCl6 for Li-ion batteries

Li3YCl6 is a promising candidate for solid electrolytes (SEs) in all-solid-state Li-ion batteries due to its high ionic conductivity, electrochemical stability, and compatibility with metal-oxide electrodes. The monoclinic and trigonal crystal structures of Li3YCl6 with space groups C2/c and P-3m1 have been studied extensively, while little attention has been given to the trigonal P-3c1 phase (space group no. 165). Additionally, Li-ion diffusion mechanism in 3d transition metal (TM) substituted compounds along with their structural stability are interesting to study. Therefore, we investigate the Li diffusion mechanism in Li3YCl6 and TM substituted Li3YCl6 in the P-3c1 phase using first-principles calculations. We have found that all the substituted compounds are thermodynamically stable at room temperature and show high oxidation stability. Li3Y0.875Co0.125Cl6 exhibits the lowest activation energy (0.11 eV) for Li-ion diffusion and the highest Li-ion mobility (σ = 0.39 mS cm−1 at room temperature), which is strongly anisotropic. We used the Crystal Orbital Hamilton Population method to analyze the bonding characteristics of Li3YCl6 and 3d TM substituted Li3YCl6 and found that the Co–Cl bond is weaker than the Cr–Cl bond. This may explain the lower activation energy observed for Li3Y0.875Co0.125Cl6. Our results provide insights into the substitution effect in Li3YCl6 superionic conductors, which could guide the design and development of high-performance SEs for Li-ion batteries.

Balancing salt concentration and fluorinated cosolvent for graphite cathode-based dual-ion batteries

High-concentration electrolytes (HCEs) are favored in graphite cathode-based dual-ion batteries (DIBs) due to their high oxidative stability and good interphase compatibility with both anode and cathode. Although a localized high-concentration electrolyte (LHCE) with the similar solvation structure as HCE is proposed for graphite cathode by adding weakly solvated fluorinated cosolvents, the balance between salt concentration and fluorinated cosolvent has not been investigated. Herein, various electrolytes were prepared by introducing tris(2,2,2-trifluoroethyl) phosphate (FTEP) into the HCE composed of potassium bis(fluorosulfonyl)imide (KFSI) and triethyl phosphate (TEP), and the moderate concentrated electrolyte at the TEP/FTEP volume ratio of 5:1 can stabilize K/graphite DIBs with the capacity of 45 mAh g−1 after 300 cycles at 0.5 A g−1. The abundant ion–solvent complexes as HCE and the entrance of FTEP contribute to building stable FSI−-derived cathode/electrolyte interphase with the KF-rich inner layer. Importantly, FTEP replaces partial TEP solvents to coordinate with FSI−, enhancing the electrolyte oxidative stability, whereas their weak interaction further suppresses the solvent co-intercalation. As a proof, this electrolyte enables high output voltage (3.75 V) and good cyclability of dual-ion full cells coupled with tellurium anode. This work will promote the development of fluorinated cosolvent-modified LHCEs for high-performance DIBs.

High oxidative stability of a complex fish liver oil nano-capsules in response to long-term storage, and to hyperthermal and sunlight exposure.

In this study, a biocompatible nano-carrying platform using chitosan (ChI) and chondroitin sulfate (ChS) was developed for the encapsulation of cobia liver oil (CBLO) to prevent its oxidation and improve its absorption. An ionic gelation method was applied to encapsulate CBLO with different weight ratios (from 1.0 to 1.5) to obtain ChS-ChI nano-capsules (ChS-ChI@CBLO NCs). Morphological observations of the nano-capsules revealed a spherical shape and diameter around 267-381 nm. The maximum loading capacity (LC) and encapsulation efficiency (EE) for ChS-ChI@CBLO NCs estimated by thermogravimetric analysis (TGA) and derivative thermogravimetric (DTG) analysis were 25.7% and 56.2%, respectively. The structural stability of ChS-ChI@CBLO NCs was confirmed through differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis; moreover DSC also further confirmed the oxidative stability of ChS-ChI@CBLO NCs. Fourier-transform infrared (FTIR) spectra confirmed the excellent stability of ChS-ChI@CBLO NCs against high temperature and sunlight exposure. Biocompatibility analysis also verified the non-toxicity of ChS-ChI@CBLO NCs, further indicating safety and potential application in complex-nutritional supplements. Nano-degree of ChS-ChI@CBLO NCs has a loading capacity and encapsulation efficiency of around 16.5 ~ 25.7% and 33.4 ~ 56.2%, respectively, for encapsulation of CBLO. Characterization results also indicate that ChS-ChI@CBLO NCs display high oxidative stability against long-term, hyperthermal, and sunlight exposure. Bioassay results confirm that the ChS-ChI@CBLO NCs are safe and non-toxic. This study demonstrates that nano-capsules are also beneficial in preventing sensitive compounds from metamorphosis, and are non-toxic. These materials are suitable for use in the food and pharmaceutical industries. © 2023 Society of Chemical Industry.

Microencapsulation of fish oil with brewer’s spent grain proteins: Effect of citric acid and emulsion pH

The use of brewer’s spent grain (BSG) proteins as wall material for encapsulating fish oil was investigated for the first time. This study also demonstrated the effect of citric acid (CA)-crosslinking and emulsion pH on the encapsulating ability of BSG proteins. Four different BSG microcapsules were prepared, including non-crosslinked and crosslinked BSG microcapsules at pH either above or below the isoelectric point (pI) of BSG proteins, and their performance was compared with OSA-starch. Crosslinked BSG emulsions had larger droplet size than non-crosslinked ones. The largest droplet sizes were found in emulsions where pH < pI due to some degree of protein aggregation. Encapsulation efficiency of BSG microcapsules ranged from 81 to 93%. BSG microcapsules, regardless of crosslinking, showed considerably higher oxidative stability than OSA-starch microcapsules. CA-crosslinking further enhanced their oxidative stability. The highest and the lowest oxidative stabilities among BSG microcapsules belonged to the microcapsules prepared at pH < pI, where some degree of protein aggregation occurred in the emulsions. Crosslinked BSG microcapsule prepared at pH < pI exhibited the highest oxidative stability with peroxide and thiobarbituric acid reactive substances (TBARS) values remaining in the range allowed for fresh oils even after 15 days of storage at 40 °C. It was attributed to its denser shell matrix due to CA-crosslinking and multilayer formation resulting from protein aggregation. Non-crosslinked microcapsules prepared at pH < pI represented the lowest oxidation stability among BSG microcapsules due to larger pores. The results suggest a synergistic effect of CA-crosslinking and protein aggregation, which significantly reinforced shell matrix and effectively reduced oxygen permeability.

Proximate, nutraceutical composition and antimicrobial activities of Uvaria chamea (Udagu) seeds and oil

The study investigated proximate, nutraceutical composition and Antimicrobial activities of Uvaria chamea (Udagu) seeds. Standard methods were used to analyze the plant seeds for the present of nutraceutical and proximate component of the plant Uvaria chamea (Udagu) seeds. While disk diffusion method was employed to assay the the potent of the seed oil as an antimicrobial agent. Result of the proximate revealed that Uvaria chamea (Udagu) seeds contains ash (10.19 %), moisture (5.2 %), crude protein (0.09 %), crude fiber (51.81 %), total fat (26.19 %) and carbohydrate (6.52 %). While nutraceutical study showed that Uvaria chamea (Udagu) seeds contains cardiac glycosides (0.046 %), tannins (0.2 %), saponins (0.01 %) and alkaloids (0.45 %).The proximate result implies that the plant contains essential component such as crude fiber, total fat and ash in significant quantities, and can be utilized as food and in treating several ailments. The presences of alkaloids, tannins, Cardiac glycoside, and saponins in the plant seed indicate it can be used as a medicinal source. The oil presented no antimicrobial and antibiotic activities against Staphylococcus aureus and Salmonella typhi. The results suggest that Uvaria chamae seed have a potential role as a new source of health-promoting diets (can be used as a dietary fiber supplement in obesity management) with high oxidative stability. And the oil is a fixed oil that could be an acceptable substitute for cooking vegetable oil that do not have antimicrobial/antibiotic activities. Keywords: Proximate; nutraceutical; fiber; alkaloids; tannins

Thermal processing of pomegranate seed oils underscores their antioxidant stability and nutritional value: Comparison of pomegranate seed oil with sesame seed oil.

In the present study, the oxidative stability and antioxidant activity of seed oils were investigated in three Iranian pomegranate cultivars, Shirin Khafr, Torsh Sabz, and Rabab, along with the sesame (Sesamum indicume L. cv Dezful) seed oil. Punicic acid was the primary fatty acid in the pomegranate seed oils, with contents ranging from 75.5 to 80.9% (w/w). The tocopherol levels in pomegranate seed oils ranged from 1439 to 2053 mg/kg, whereas the phenolics ranged from 130 to 199.3 mg/kg, respectively. Comparatively, in the seed oil of sesame "Dezful," these substances' contents were 1053 and 79 mg/kg, respectively. Contrary to common perception, the seed oil of the three pomegranate cultivars cultivated in Iran had high oxidative stability and antioxidative activity during the 32 h of thermal processing at 170°C. The oxidation stability assayed by peroxide value, p-anisidine value, and TOTOX index revealed that the pomegranate seed oils had a much higher resistance to the oxidation process than the sesame oil. The content of tocopherols increased during thermal processing due to the regeneration phenomenon. Tocopherols are not always free and may form a matrix with themselves or other compounds. Changes in the antioxidant activity during the thermal processing assessed by DPPH free radical scavenging power and by the FRAP test were consistent with those for the antioxidants. Therefore, these oils can be added to other edible oils as a natural antioxidant to improve their oxidative stability.

Sodium halide solid state electrolyte of Na3YBr6 with low activation energy.

Halide solid-state electrolytes (SSEs) are considered promising candidates for practical applications in all-solid-state batteries (ASSBs), due to their outstanding high voltage stability and compatibility with electrode materials. However, Na+ halide SSEs suffer from low ionic conductivity and high activation energy, which limit their applications in sodium all-solid-state batteries. Here, sodium yttrium bromide solid-state electrolytes (Na3YBr6) with a low activation energy of 0.15 eV is prepared via solid state reaction. Structure characterization using X-ray diffraction reveals a monoclinic structure (P21/c) of Na3YBr6. First principle calculations reveal that the low migration activation energy comes from the larger size and vibration of Br- anions, both of which expand the Na+ ion migration channel and reduce its activation energy. The electrochemical window of Na3YBr6 is determined to be 1.43 to 3.35 V vs. Na/Na+, which is slightly narrower than chlorides. This work indicates bromides are a good catholyte candidate for sodium all solid-state batteries, due to their low ion migration activation energy and relatively high oxidation stability.

New chemistry of alkynyl trifluoroborates under transition metal catalyst-free conditions

This review summarizes recent advances in alkynyl trifluoroborate chemistry, emphasizing their unique reactivity and stability in organic synthesis and biological applications under transition metal catalyst-free conditions.

Synthesis and structural characterization of stable coinage metal (Cu, Ag, Au) cyclopentadienyl complexes.

The electron withdrawing and oxidatively stable perfluorinated Cp* ligand [C5(CF3)5]- allowed for the isolation of rare and unusually stable coinage metal complexes [M(C5(CF3)5)(PtBu3)] (M = Cu, Ag, Au), representing the first complete and structurally comparable series of group 11 Cp coordination compounds. Full characterization and structure analysis revealed distinct and partly unknown coordination motifs with hapticities ranging from η1, η3/η1 and η3/η2 for gold, silver and copper, respectively. Quantum-chemical studies using DFT methods confirm these findings and connect them to the unique electronic structure of the given ligand system.

Influence of NR/EPDM Ratios on the Performance of Pneumatic Fenders in Seawater

The performance of pneumatic fenders in seawater is crucial to ensure safety and serviceability. Hence, the objective of this study is to investigate the performance of compound formulations of two different types of carbon black N660 and N220 at various NR/EPDM (Natural Rubber/Ethylene Propylene Diene Monomer) ratios of 100/0; 90/10; 80/20, and 70/30 in artificial seawater at 95°C for 30 days. The mechanical properties of rubber compounds were measured and compared before and after aging in seawater. Comparing two types of carbon black, no significant difference in tensile, elongation, tear strength, and compression set at the same blend ratios after aging in seawater. Nevertheless, the abrasion resistance of N220 is lower than that of N660 before and after aging in seawater due to insufficient dispersion. Adding high crystalline EPDM in the blend results in lower mechanical properties change than pure NR after aging in seawater. In addition, the blend contains EPDM imparts high abrasion resistance in seawater. Using EPDM up to 30 phr in the blend with NR indicates the possibility of utilizing this high oxidation stability of rubber as a pneumatic fender.