Benzene Derivatives Research Articles

Kinetic Pathway Control in the Synthesis of Well‐Defined Ruthenium Coordination Oligomers

Ruthenium complexes with 2,2′‐bipyridine‐6,6′‐dicarboxylate (bda) ligands have emerged as highly potent catalysts for water oxidation. In this context, the accumulation of active Ru centers in macrocyclic arrays or coordination oligomers and polymers has proven to be very beneficial for an enhanced stability under operating conditions and to facilitate surface adhesion in heterogeneous systems. For a better insight into structure–activity relationships though, well–defined systems with a precise control over stoichiometry and constitution are highly desired. Herein, the synthesis and characterization of a series of structurally precise and monodisperse linear coordination oligomers [(Ru(bda))nLn−1pic2] (n = 4 or 5, L = 4,4′‐bipyridine or 1,4‐bis‐(pyridine‐4‐yl)benzene derivatives, pic = 4‐picoline), in excellent purity and yields are reported. Based on detailed mechanistic investigations, a complex network of interconnected and competing reactions is proposed that fully explains both the high overall turnover and the kinetic pathway selection between alternative endcapping and dissociation–elongation sequences.

The Significance of Thiophene in Medicine: A Systematic Review of the Literature

Thiophene nucleus has been established as the potential entity in the largely growing chemical world of heterocyclic compounds possessing promising pharmacological characteristics. The similar compounds synthesized through different routes bear variable magnitudes of biological activities.. An odor reminiscent of benzene characterizes this colorless liquid. It exhibits a majority of its reactions resembling those of benzene. Thiophene has a structure that is analogous to structure of pyrrole, and due to pie electron cloud, it behave like extremely reactive benzene derivative. The available analytical and informational data in literature indicate Thiophene constitute a notable class of chemicals in the medical domain, exhibiting a range of therapeutic potentials. These encompass antiviral, antimalarial, antihypertensive, antimicrobial, antioxidant anticonvulsant, anticancer, anti-inflammatory, antidepressant and antimycobacterial, properties. An examination of reveals literature that the moiety thiophene has garnered considerable attention from medicinal chemists and biochemists to formulate, design, and implement novel approaches for the discovery of new pharmaceuticals. This review article confirms that thiophene derivatives have the potential to be a valuable resource for developing new biologically active compounds. It is prudent to investigate this possibility by combining various substituted components, as this may lead to improved pharmacological effects. Therefore, it is necessary to persist in the pursuit of investigating numerous further alterations on the thiophene moiety.

Impact of Thermal Treatment and Aging on Lignin Properties in Spruce Wood: Pathways to Value-Added Applications.

Thermal modification is an environmentally friendly process that does not utilize chemical agents to enhance the stability and durability of wood. The use of thermally modified wood results in a significantly extended lifespan compared with untreated wood, with minimal maintenance requirements, thereby reducing the carbon footprint. This study examines the impact of varying modification temperatures (160, 180, and 210 °C) on the lignin of spruce wood using the ThermoWood process and following the accelerated aging of thermally modified wood. Wet chemistry methods, including nitrobenzene oxidation (NBO), size exclusion chromatography (SEC), thermogravimetry (TG), differential thermogravimetry (DTG), and Fourier transform infrared spectroscopy (FTIR), were employed to investigate the alterations in lignin. At lower modification temperatures, the predominant reaction is the degradation of lignin, which results in a reduction in the molecular weight and an enhanced yield of NBO (vanillin and vanillic acid) products. At elevated temperatures, condensation and repolymerization reactions become the dominant processes, increasing these traits. The lignin content of aged wood is higher than that of thermally modified wood, which has a lower molecular weight and a lower decomposition temperature. The results demonstrate that lignin isolated from thermally modified wood at the end of its life cycle is a promising feedstock for carbon-based materials and the production of a variety of aromatic monomers, including phenols, aromatic aldehydes and acids, and benzene derivatives.

Laccase-Catalyzed Cycloaddition (LaCCA) Reaction: An Efficient Green Approach for Synthesizing Mono- and Bis-(1,4-Disubstituted-1,2,3-Triazoles) via Click Chemistry—In Silico Molecular Docking and Druglikeness Assessment

Background: Mono- and bis-(1,4-disubstituted-1,2,3-triazoles) were synthesized via a laccase-catalyzed reaction using Trametes versicolor. This methodology offers a convenient and efficient approach to triazole synthesis under mild conditions, achieving modest to good yields. Additionally, molecular docking studies were performed using PDB IDs 2W9S (antibacterial) and 3KHM (antifungal) to evaluate biological activities. The results of drug-likeness analysis further corroborated the findings from experimental biological evaluations. Methods: This study focuses on developing an eco-friendly method for synthesizing novel 1,2,3- triazole derivatives using a green catalyst. A co-solvent buffer and organic solvent facilitate the reaction, which performs well with various substrates, including substituted benzenes (-ortho, -meta & para-mono & bis-(2-propynyloxy), sodium azide, and aryl halides. Laccase enzymes from Trametes versicolor are used, leveraging naturally occurring copper metals instead of external transition metals, bound through histidine, methionine, and cysteine linkages. This method represents a sustainable approach to organic transformations. Result: New scaffolds of mono- and bis-(1,4-disubstituted-1,2,3-triazoles) were synthesized using eco-friendly green buffer solvents and laccase catalysis with aryl halides, sodium azide, and acetylene derivatives. Molecular docking studies revealed that the binding affinities of the synthesized compounds (1-14) show promising interactions with antibacterial and antifungal proteins. All others except for compounds 6, 7, 8, 12, and 13, meet Lipinski’s criteria, making them potential therapeutic candidates. Conclusion: In conclusion, this methodology is valuable for developing antibacterial and antifungal agents in medicinal chemistry. Additionally, microwave-assisted synthesis of (2-propenyloxy)benzene derivatives significantly reduced reaction times from hours to minutes. The approach is environmentally friendly and practical, particularly for handling flammable organic azides and hazardous solvents, making it both efficient and safer.

Synthesis of the Polymethoxyflavones Nobiletin, Tangeretin, Isosinensetin, and Gardenin A–D

We present a practical synthesis of 2’-hydroxy-3’,4’,5’,6’-tetramethoxyacetophenone, a multi-substituted benzene derivative, via CuCl-catalyzed Ullmann-type coupling reaction with MeONa. 2’-Hydroxy-3’,4’,5’,6’-tetramethoxyacetophenone is the key intermediate for the total synthesis of various polymethoxyflavones....

New Wine in Old Bottles: Fully Substituted Arylthio Effect Realizes High‐Efficiency Purely Organic Phosphorescence Light‐Emitting Diode With Single and Ultra‐Stable Spectra Under 2000 cd m−2

ABSTRACTOrganic light‐emitting diodes (OLEDs) based on purely organic room‐temperature phosphorescence (RTP) materials often encounter issues of relatively low efficiency and spectral instability. To overcome these limitations, three (arylthio)benzene derivatives (4S, 5S, and 6S) with gradually increased RTP component are designed and compared. Theoretical calculation and photophysical investigation reveal that the fully substituted arylthio effect could enhance the aggregation‐induced phosphorescence, enlarge the spin orbital coupling, and reduce the energy gap between S1 and T1 as much as possible. As a result, 6S can exhibit single spectra in films with a high phosphorescence efficiency of up to 76.7%, and its doped RTP‐OLED furnishes a high maximum external quantum efficiency (EQE) of 15.3% and ultra‐stable spectra with the brightness raised from 30 to 2000 cd m−2. Furthermore, serving 6S as the sensitizer, the RTP‐sensitized‐fluorescent OLEDs based on fluorescence dopant TBRb and multiple resonance type dopant BN3 both show near three times improvement in electroluminescence performance, with EQE values of 11.3% and 25.6%, respectively. These results demonstrate the feasibility of fully substituted arylthio effect in designing RTP materials and could advance the development of high‐performance RTP OLEDs.

Secondary Metabolites from the Mangrove Ecosystem-Derived Fungi Penicillium spp.: Chemical Diversity and Biological Activity.

Mangrove ecosystems have attracted widespread attention because of their high salinity, muddy or sandy soil, and low pH, as well as being partly anoxic and periodically soaked by tides. Mangrove plants, soil, or sediment-derived fungi, especially the Penicillium species, possess unique metabolic pathways to produce secondary metabolites with novel structures and potent biological activities. This paper reviews the structural diversity and biological activity of secondary metabolites isolated from mangrove ecosystem-derived Penicillium species over the past 5 years (January 2020-October 2024), and 417 natural products (including 170 new compounds, among which 32 new compounds were separated under the guidance of molecular networking and the OSMAC approach) are described. The structures were divided into six major categories, including alkaloids, polyketides, terpenoids, benzene derivatives, steroids, and other classes. Among these natural products, the plausible biosynthetic pathways of 37 compounds were also proposed; 11 compounds have novel skeleton structures, and 26 compounds contain halogen atoms. A total of 126 compounds showed biological activities, such as cytotoxic, antifungal, antibacterial, anti-inflammatory, and α-glucosidase-inhibitory activities, and 11 compounds exhibited diverse biological activities. These new secondary metabolites with novel structures and potent bioactivities will continue to guide the separation or synthesis of structurally novel and biologically active compounds and will offer leading compounds for the development and innovation of pharmaceuticals and pesticides.

A Comprehensive Review on Construction of Biologically Active α‐Carbolines From Synthetic And Natural Origin.

Abstractα‐Carboline is an important scaffold present in various synthetic and naturally obtained bioactive compounds possessing a wide range of pharmacological properties. Hence, in the current comprehensive review, we intend to present the main routes to the synthesis of α‐carboline analogs based on various pathways such as pyrrole, benzene, and pyridine ring annulation. The pathways include either or combinations of transition metal‐catalyzed amination/arylation, Graebe‐Ullmann reaction (thermal pyrolysis, photochemical cyclization), Diels‐Alder cycloaddition and condensation reactions, N‐Heterocyclic carbene catalysed reactions, decarboxylative annulation, etc. of substituted benzene, pyridine, quinoline, and indole derivatives in order to compare the potential of synthetic routes of this series and consolidate the development, current status and perspectives for the design of α‐carboline analogs. Various pharmacological and spectroscopy functions of the compounds belonging to this class are summarized herewith. It also discusses the synthesis of functionalized bioactive naturally obtained hetero‐annulated α‐carbolines.

Effects of industrial solid waste on the generation of PCDD/Fs, dl-PCBs and PAHs tuned by waste pseudo-components during engineering co-combustion

Co-combustion of municipal solid waste (MSW) with industrial solid waste (ISW) is becoming prevailing. But its effects on generation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs) and polycyclic aromatic hydrocarbons (PAHs) remain unclear, hindering their efficient control. Hence, six batches of engineering incineration tests containing diverse blending types and ratios of ISW were designed in an incinerator of 650 t/d. To target the relationship between complex waste components and contaminants, a pseudo-component matrix model was innovatively incorporated, with nine plastic and biomass pseudo-components quantitatively extracted. Compared to raw MSW incineration, co-combustion generally increased generation of 17 PCDD/Fs and 12 dl-PCBs in fly ash up to six-fold, with the highest TEQ concentrations of 843 ng/kg and 68.1 ng/kg, respectively, while exerted less impact on generation of 16 PAHs. Among nine pseudo-components, polyethylene glycol terephthalate (PET), polyvinyl chloride (PVC) and cellulose were identified as the key to generation of PCDD/Fs and dl-PCBs. Combustion of PET and cellulose served to provide benzene derivatives, while PVC contributed more chlorine. Tracking the original waste, blending with waste plastics, polyester textile, artificial leather and paper should be strictly regulated. This study was of significance to optimize co-combustion for source reduction of toxic pollutants.

Efficient Green Synthesis and Characterization of Benzil and its Derivatives Using Microwave Irradiation

The main aim of the present work was to conduct the one-pot microwave-assisted green synthesis of benzil and its derivatives. Benzil is acknowledged as a pivotal scaffold in the realm of medicinal and organic chemistry, owing to its extensive utilities. Due to the various merits of the green technology approach compared to classical methodology and the provision of sustainable chemistry, this reaction has received renewed interest for preparing benzil derivatives in an environmentally friendly manner with improved yields. We have, herein, presented a highly efficient route for the synthesis of benzil derivatives utilizing acetophenone and benzene derivatives as primary substrates. Notably, this synthesis obviates the necessity for any potentially hazardous catalyst and employs microwave irradiation and iodine green oxidant to facilitate the reaction. All synthesized compounds were characterized by spectroscopic techniques, such as IR, 1H NMR, and mass spectrometry. A green and efficient microwave-assisted synthesis methodology for benzil and its derivatives has been developed using iodine green oxidant. This approach has yielded the desired benzil derivatives with remarkable efficiency, achieving yields ranging from 91% to 97% within a short time of 10-15 minutes; the derivatives have been characterized using spectral techniques, viz., IR, 1H NMR, and mass spectrometry. It is noteworthy that the entire reaction optimization process has been conducted in an environmentally friendly manner, thereby exemplifying a synthetic methodology being both environmentally sustainable and economically viable, compared to conventional techniques.

Preparation and solid-state characterization of two novel berberine chloride cocrystals with benzene derivatives

In this study, two novel salt-cocrystals of berberine chloride (BCl) with structurally similar benzene derivatives, i.e., 3-hydroxybenzoic acid (3HBA) and isophthalic acid (IA), were prepared. Their solid-state properties were characterized by complementary techniques, including single-crystal and powder X-ray diffractometry, thermogravimetric-differential scanning calorimetry, Fourier-transformed infrared spectroscopy, and dynamic moisture sorption analysis. Both cocrystals had lower hygroscopicity than BCl. An analysis of the properties of these cocrystals along with a previously published berberine chloride-resorcinol cocrystal suggests that a greater number of hydroxyl groups in these cocrystal formers may favor faster dissolution, measured by both intrinsic dissolution rate and powder dissolution.

Hydrothermal liquefaction of diverse plastics using water and seawater

In this study, a variety of plastics are converted to their monomers, fuel range hydrocarbons and other platform chemicals using hydrothermal liquefaction (HTL) at sub-critical (350 °C), near-critical (400 °C) and super-critical (450 °C) temperatures. The effect of seawater as a medium on the HTL of plastics is also studied. Polymers like polycarbonate (PC), acrylonitrile–butadiene–styrene (ABS), polyamides (PA-6, PA-66), and polyoxymethylene (POM) liquefied effectively at 350 °C, while polyolefins like polyethylene (PE) and polypropylene (PP) required ≥ 400 °C. HTL of polystyrene (PS) resulted in the highest oil yield (93 wt%) and energy recovery from oil (93.5 %) at 450 °C. HTL of PC, PS and ABS led to the formation of phenols and benzene derivatives, while polyethylene terephthalate (PET) and PA-6 formed their monomers terephthalic acid and caprolactam, respectively. Crude oils from PP and PE contained fuel grade aliphatic hydrocarbons with carbon chain length ranging between C7 and C36. Highest calorific value was recorded for the oil from PP (46.3 MJ kg−1) at 400 °C. The use of seawater generally reduced the oil yields from all the plastics, except ABS, PET and PP. The production of benzoic acid from PET was enhanced, while the selectivity to caprolactam from PA-6 decreased when seawater was used, possibly due to the enhanced decarboxylation and aromatization reactions induced by the ions in the aqueous phase. In general, the crude oil from HTL of PC, PS, ABS and polyamides are suitable for sustainable production of specialty chemicals and monomers, while that from PE and PP are good candidates for sustainable transportation fuels.

A Comparative Metabolomics Study of the Potential Marker Compounds in Feces from Different Hybrid Offspring of Huainan Pigs.

As a notable native Chinese genetic population, the Huainan pig has an exceptional meat quality but a low percentage of lean meat and subpar genetic performance. To better exploit the superior genetic traits of the Huainan pig and address knowledge gaps regarding the optimization of its hybrid offspring, this study used Huainan pigs as the maternal line and bred them with Yorkshire, Landrace, and Berkshire sires. This approach produced three hybrid combinations: Yorkshire × Huainan (YH), Landrace × Huainan (LH), and Berkshire × Huainan (BH). The body size, fat ratio, and average backfat thickness of these hybrid progeny were evaluated under the same feeding management and nutritional circumstances. The results revealed that the average backfat thickness of YH was significantly lower than that of LH and BH. In order to better understand the causes of these variations, fecal samples were taken from three pigs in each group for metabolomic analysis. A total of 2291 metabolites were identified, including benzene derivatives (16.6%), amino acids and their metabolites (14.5%), and organic acids (13.4%), with pyruvaldehyde and norethindrone acetate elevated in YH compared to LH and BH. In addition, the three hybrid pig groups commonly exhibited differences in the "glycerophospholipid metabolism" pathway. This variation may also contribute to differences in their fat ratio and backfat thickness. Our findings provide a novel perspective on the role of hybrid vigor in advancing the genetic population of Huainan pigs, while also revealing the unique metabolic characteristics of the YH with regard to fat deposition. This study is expected to enhance the conservation and effective utilization of genetic resources within the Huainan pig population.

Polyurethane waste valorization: A Two-Phase process using Ozonization and Rhodococcus pyridinivorans fermentation for biofertilizer production

A circular economy process has been developed to convert polyurethane waste into biofertilizing microorganisms through a sequential chemical/biological process. The chemical phase involves the complete depolymerization of polyurethane using ozone attack, generating an aqueous extract (OLE) composed of small, bioavailable molecules such as polyols, isocyanate derivatives, and carboxylic acids. The biological phase utilizes OLE for the generation of biomass with biofertilizing functional activity through Rhodococcus pyridinivorans fermentation. The metabolic-proteomic expression during the biodegradation of OLE involves the synthesis of numerous enzymes such as cutinases, hydrolases, proteases, esterases and oxidoreductases, which participate in the degradation of chemical compounds like benzene derivatives, phenols, or plastic polymers. OLE has been converted into microorganisms with biofertilizing properties, including nitrogen fixation, phytohormone production and siderophores. This process contributes to sustainability by diverting polyurethane waste from landfills, reducing the environmental impact of chemical fertilizers and promoting a more sustainable agricultural system.

One-Pot Catalytic Cascade for the Depolymerization of the Lignin β-O-4 Motif to Non-phenolic Dealkylated Aromatics.

Aromatic monomers obtained by selective depolymerization of the lignin β-O-4 motif are typically phenolic and contain (oxygenated) alkyl substitutions. This work reveals the potential of a one-pot catalytic lignin β-O-4 depolymerization cascade strategy that yields a uniform set of methoxylated aromatics without alkyl side-chains. This cascade consists of the selective acceptorless dehydrogenation of the γ-hydroxy group, a subsequent retro-aldol reaction that cleaves the Cα-Cβ bond, followed by in situ acceptorless decarbonylation of the formed aldehydes. This three-step cascade reaction, catalyzed by an iridium(I)-BINAP complex, resulted in 75 % selectivity for 1,2-dimethoxybenzene from G-type lignin dimers, alongside syngas (CO : H2≈1.4 : 1). Applying this method to a synthetic G-type polymer, 11 wt % 1,2-dimethoxybenzene was obtained. This versatile compound can be easily transformed into 3,4-dimethoxyphenol, a valuable precursor for pharmaceutical synthesis, through an enzymatic catalytic approach. Moreover, the hydrodeoxygenation potential of 1,2-dimethoxybenzene offers a pathway to produce valuable cyclohexane or benzene derivatives, presenting enticing opportunities for sustainable chemical transformations without the necessity for phenolic mixture upgrading via dealkylation.

Efficacy and feasibility of a breath sensor for detecting driver fatigue and drowsiness

Objectives Drowsiness has been shown to impair reaction times, decision-making abilities, and awareness of hazards critical to driving in a manner similar to the effects of driving under the influence of alcohol.1 Drowsy driving has been estimated to cause thousands of fatal crashes per year and has resulted in billions of dollars in lost revenue.2 However, while breathalyzers and ignition interlock devices can be used to mitigate the risk of drunk driving, no such devices are commercially available for roadside or behind-the-wheel diagnostics for drowsiness. To address this gap, the objective of this study was to demonstrate the efficacy and feasibility of a breath sensor to detect fatigue and drowsiness in a simulated driving environment. Data and methods Solid state breath sensors calibrated to previously identified breath biomarkers of fatigue and drowsiness were arrayed to determine changes in the breath profiles of subjects undergoing a full-motion driving simulation designed to elicit driver fatigue. A multi-sensor approach was used rather than relying on a single biomarker. The biomarker profile targeted compounds such as benzene derivatives (e.g., benzene, benzaldehyde, toluene, phenol), 2-butanone, and 2-ethyl-1-hexanol, among others. To address potential confounders such as eating/drinking, cigarette smoke, alcohol, and medical conditions like COPD or diabetes, the study was conducted under controlled conditions: participants refrained from eating for a couple of hours before the experiment, were nonsmokers, had not consumed alcohol for the past day, and had no known medical conditions. The breath biomarker profiles were then correlated with established drowsiness metrics, specifically the PERCLOS (Percentage of Eye Closure) and the Karolinska Sleepiness Scale (KSS). Results The breath sensor array collected breath biomarker profiles for 61 subjects. The biomarker profiles demonstrated a trend consistent with increasing PERCLOS and KSS responses (see Figure). During the 60-minute driving simulation designed to elicit driver fatigue, the PERCLOS showed a steady increase in response over time, while the KSS did not show an increase in perceived sleepiness until the 60 min mark. Similarly, the breath biomarker sensor response showed a significant increase at the 60-minute timepoint, consistent with increases in both the PERCLOS and the KSS, demonstrating evidence of increased driver fatigue and drowsiness. Conclusions These findings suggest that integrating drowsiness breath sensor arrays into vehicle systems could significantly enhance drowsiness detection, thereby reducing crashes, injuries, and fatalities. Moreover, the scalability and non-invasiveness of the proposed system lays the groundwork for broader applications, extending beyond vehicles to fields such as aviation and healthcare.

Metal‐Free Photooxidation of Toluene Derivatives into the Corresponding Carboxylic Acids and Aldehydes by a HBr/NaOCl·5H2O System

AbstractPhotobromination of toluene derivatives using blue LED (454 nm) or UV LEDs (365, 385, 395 nm) with aqueous HBr and NaOCl·5H2O in trifluoromethyl benzene afforded the corresponding benzoic acids derivatives. The intermediates were (dibromomethyl)benzene derivatives, isolated in a nitrogen atmosphere. The dibromomethyl benzene derivatives afforded the corresponding aldehydes. After the reaction with HBr, the aqueous layer could be recovered and reused.

One‐Pot Catalytic Cascade for the Depolymerization of the Lignin β‐O‐4 Motif to Non‐phenolic Dealkylated Aromatics

AbstractAromatic monomers obtained by selective depolymerization of the lignin β‐O‐4 motif are typically phenolic and contain (oxygenated) alkyl substitutions. This work reveals the potential of a one‐pot catalytic lignin β‐O‐4 depolymerization cascade strategy that yields a uniform set of methoxylated aromatics without alkyl side‐chains. This cascade consists of the selective acceptorless dehydrogenation of the γ‐hydroxy group, a subsequent retro‐aldol reaction that cleaves the Cα−Cβ bond, followed by in situ acceptorless decarbonylation of the formed aldehydes. This three‐step cascade reaction, catalyzed by an iridium(I)‐BINAP complex, resulted in 75 % selectivity for 1,2‐dimethoxybenzene from G‐type lignin dimers, alongside syngas (CO : H2≈1.4 : 1). Applying this method to a synthetic G‐type polymer, 11 wt % 1,2‐dimethoxybenzene was obtained. This versatile compound can be easily transformed into 3,4‐dimethoxyphenol, a valuable precursor for pharmaceutical synthesis, through an enzymatic catalytic approach. Moreover, the hydrodeoxygenation potential of 1,2‐dimethoxybenzene offers a pathway to produce valuable cyclohexane or benzene derivatives, presenting enticing opportunities for sustainable chemical transformations without the necessity for phenolic mixture upgrading via dealkylation.

Effect of weak intermolecular interactions on the ionization of benzene derivatives dimers.

The interactions between π-systems in dimers of aromatic molecules lead to particularly stable conformations within the relative orientations of the monomers. Extensive research has been conducted on the properties of these complexes in the neutral state. However, in recent decades, there has been a significant surge in applications harnessing these structures for electrical purposes. Therefore, this study places particular emphasis on a deeper understanding of the redox properties of these compounds and how to modify them. To achieve this, we have focused on modeling the effect of a wide range of functional groups on the redox properties of benzene derivatives, observing a correlation between these properties and the change in the molecular dipole moment. Then, we investigated the effect of π-stacking interactions on these properties in dimers formed by either identical or different monomers. In both cases, there is an enhancement of the reducing character of the systems due to these interactions. Upon oxidation, the charge is distributed proportionally to the redox potential of each monomer. Therefore, if there is heterogeneity in these potentials, the properties of the complete cationic system will be influenced by the monomer with a greater tendency to undergo oxidation. The considered models serve as an excellent example for studying the behavior of nucleobases in DNA or aromatic amino acids, among others.

Comparative study of volatile compounds of cold-pressed oils extracted from three different oilseeds after gamma irradiation.

To investigate the effect of gamma irradiation on the volatile compounds of edible oils. Three types of oilseeds, including peanut, sesame, and flaxseed, were subjected to 8 kGy gamma irradiation, followed by cold pressing to extract their oils. The volatile compounds of the oils were isolated by simultaneous distillation extraction and analyzed by gas chromatography-mass spectrometry. A total of 91 volatile compounds were identified, which can be grouped into eight categories: hydrocarbons, aldehydes, ketones, alcohols, acids, esters, furans, and benzene derivatives. Irradiation treatment resulted in a significant increase in the levels of hydrocarbons, aldehydes, and ketones in all oil samples (p<0.05), with the greatest increase observed in hydrocarbons (4-14 times). In contrast, changes in alcohols, acids, esters, furans, and benzene derivatives were related to oilseed type. The increased hydrocarbons mainly originated from the degradation of palmitic, stearic, oleic, and linoleic acids. The irradiation resistance of the three oilseeds varied considerably, in the order: flaxseed>sesame>peanut. Based on the odor activity value, 11 key aroma compounds were selected, and (E)-2-decenal (tallow, oily, and orange), 1-octanol (soapy and oily), and 1-nonanol (floral and soapy) were only detected in the irradiated samples. Principal component analysis revealed that the oil samples of the three oilseeds could be well classified based on their key aroma compounds, and that the irradiation treatment had no remarkable effect on their intrinsic aroma.