Mixture Of Phenol Research Articles

Activation of Persulfate by temperature and iron filings for the treatment of synthetic olive mill wastewater: Optimization of conditions with a box–Behnken design

The Persulfate (PS, S2O82-) activation by temperature and iron filings (IF) was analysed following the degradation of a five phenolic acids mixture: 3,4- Dihydroxybenzoic (3,4-DHB), 4-Hydroxybenzoic (4-HB), 3,4-Dimethoxybenzoic (3,4-DMB), 3,4,5 Trimethoxybenzoic (3,4,5-TMB) and Trans-cinnamic acid (TCA). Due to the high number of variables ruling this process, the Box-Behnken design (BBD) was used to examine the effect of each experimental variable (initial pH, dosage of PS, and operating temperature) keeping the IF load constant (1 g/L). The model obtained predicted as optimal conditions an initial pH 3, a PS dosage of 1000 mg/L, and an operating temperature of 49 °C. The optimal conditions allowed the removal of about 98.87 %, 12.58 %, 13.95 %, 25.69 %, and 81.34 % for 3,4-DHB, 4-HB, 3,4-DMB, 3,4,5-TMB and TCA, respectively. Thus, this process proved to be efficient in the degradation of 3,4- DHB and less suitable for the degradation of 4-HB. A removal of 35.09 % was measured for chemical oxygen demand (COD) for the optimal conditions after 3 h.. IF reuse studies were also addressed and it was verified that this heterogeneous catalyst maintains its efficiency for at least for three reuse cycles.

Eupatorium Odaratum: Potential Plant Used in Modern Cosmetics

Eupatorium odoratum, Chromolaena odorata, or Siam weed, is a lasting herbaceous plant broadly circulated across tropical and subtropical districts. Generally perceived for its therapeutic properties, this plant has acquired consideration in present-day beauty care products because of its rich phytochemical profile, including flavonoids, terpenoids, phenolic mixtures, and rejuvenating balms. These bioactive constituents display cell reinforcement, mitigating, and antimicrobial exercises, making Eupatorium odoratum an important normal element for skincare definitions. This audit investigates the likely utilization of Eupatorium odoratum in contemporary restorative items, stressing its part in advancing skin wellbeing, forestalling untimely maturing, and treating skin conditions. Moreover, the paper talks about the reasonable development and extraction strategies for Eupatorium odoratum, which is planning to coordinate this herbal asset into the corrective business. By connecting conventional information with present-day logical exploration, Eupatorium odoratum holds a guarantee as a multifunctional fixing those lines up with the developing interest for normal and eco-accommodating restorative arrangements.

Evaluation of Proximate Composition, Multielement, and Bioactive Phenolics Contents of Different Coix Seed Varieties using Multivariate Analysis Techniques

Coix lacryma-jobi L. is a plant that serves as a source of food, medicine, cosmetics, and forage in Asian countries. Due to the distinct geographic environments, Coix seed germplasm resources are extremely diverse. In this study, we evaluated the proximate composition, multi-elemental content by ICP-OES, and phenolic bioactives by UPLC-QTOF/MS of five varieties of Coix seeds from different Asian countries, including China, Thailand, Indonesia, and Malaysia. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) were used to classify the different varieties of Coix seeds. The C. lacryma-jobi var. ma-yuen seeds from Origin 1 (China) and Origin 2 (Thailand) contained high levels of energy, total fat, and calcium, while C. lacryma-jobi var. agrotis (Indonesia) and C. lacryma-jobi var. lacryma-jobi (Malaysia) had high levels of crude fiber and carbohydrates. Twenty-three phenolic compounds were identified. Protein, carbohydrate, crude fiber, magnesium, zinc, meliadanoside, and 3,4-dihydroxyphenethyl-3-O-β-D-glucopyranoside were the dominant variables and contributed the most to data variability in PCA. The HCA results were consistent with the PCA, classifying the samples into three groups: those rich in nutrients, those rich in phenolics, and those with a mixture of nutrients and phenolics. This comprehensive analysis provides valuable insights into the nutritional and bioactive composition of Coix seed varieties, with potential applications in nutrition, food science, and pharmaceuticals.

Associations of prenatal and concurrent exposure to phenols mixture with anthropometric measures and blood pressure during childhood: A time-varying mixture approach

BackgroundEnvironmental phenols were recognized as endocrine disrupting chemicals (EDCs). However, their impact on childhood anthropometric measures and blood pressure (BP) is still inconclusive. Limited studies have simultaneously considered prenatal and childhood exposures in analyzing mixtures of phenols. ObjectiveWe investigated the relationships between combined prenatal and childhood exposures (two periodic exposures) to phenol mixtures and anthropometric measure and BP, to further identify the vulnerable periods of phenol exposure and to explore the important individual contribution of each phenol. MethodsWe analyzed 434 mother-child dyads from the Sheyang Mini Birth Cohort Study (SMBCS). The urinary concentrations of 11 phenolic compounds were measured using gas chromatography tandem mass spectrometry. Generalized linear regression models (GLMs) and hierarchical Bayesian Kernel Machine Regression (hBKMR) were used to examine the effects of individual phenolic compounds at each period and of two periodic exposures. ResultsIn the single-chemical analysis, prenatal or childhood exposure to specific phenols, especially Benzopheone-3 (BP3), 4-tert-Octylphenol (4-tOP), and Benzyl paraben (BePB) were associated with BMI z-scores (BAZ), Waist-to-height ratio (WHtR), and BP. In the hBKMR models, two periodic exposures to phenol mixtures had a U-shaped association with WHtR, primarily driven by childhood BePB exposure. Moreover, among the phenol mixtures analysis, childhood 4-tOP exposure was identified as the primary contributor to the positive association with diastolic BP. Concurrent exposure to phenol mixtures resulted in greater susceptibility. ConclusionsWe found that prenatal and childhood exposure to phenol mixtures might influence childhood obesity and elevate blood pressure levels. Concurrent exposure to 4-tOP may be the primary driver of the positive associations with BP.

Mixtures of Urinary Phenol and Phthalate Metabolite Concentrations in Relation to Serum Lipid Levels among Pregnant Women: Results from the EARTH Study.

We examined whether mixtures of urinary concentrations of bisphenol A (BPA), parabens and phthalate metabolites were associated with serum lipid levels among 175 pregnant women who enrolled in the Environment and Reproductive Health (EARTH) Study (2005-2017), including triglycerides, total cholesterol, high-density lipoprotein (HDL), non-HDL, and low-density lipoprotein (LDL). We applied Bayesian Kernel Machine Regression (BKMR) and quantile g-computation while adjusting for confounders. In the BKMR models, we found no associations between chemical mixture and lipid levels, e.g., total cholesterol [mean difference (95% CRI, credible interval) = 0.02 (-0.31, 0.34)] and LDL [mean difference (95% CRI) = 0.10 (-0.22, 0.43)], when comparing concentrations at the 75th to the 25th percentile. When stratified by BMI, we found suggestive positive relationships between urinary propylparaben and total cholesterol and LDL among women with high BMI [mean difference (95% CRI) = 0.25 (-0.26, 0.75) and 0.35 (-0.25, 0.95)], but not with low BMI [mean difference (95% CRI) = 0.00 (-0.06, 0.07) and 0.00 (-0.07, 0.07)]. No association was found by quantile g-computation. This exploratory study suggests mixtures of phenol and phthalate metabolites were not associated with serum lipid levels during pregnancy, while there were some suggestive associations for certain BMI subgroups. Larger longitudinal studies with multiple assessments of both exposure and outcome are needed to corroborate these novel findings.

Experimental study on selected properties and microstructure of pine-based wood ceramics

Abstract Wood ceramics using biomass materials as templates possess the benefits of facile fabrication and versatile applicability. To investigate the physical properties, chemical properties and microstructure of wood ceramics prepared from biomass materials, the basic properties and potential applications of wood ceramics were expounded. In this paper, wood powder wood ceramics (WPWC) and wood fiber wood ceramics (WFWC) were prepared through the vacuum carbonization method, utilizing pine powder and pine fiber as raw materials. The impact of phenolic resin concentration and mixture filling mass on various properties of wood ceramics, including mass loss rate (MLR), volume shrinkage rate (VSR), apparent porosity (AP), and bending strength (BS) were investigated on this basis. The microtopography and pore structure of wood ceramics were also analyzed. The test results show that an increase in the concentration of phenolic resin led to a decrease in the MLR, VSR, and AP of WPWC and WFWC, while their BS exhibited an increase. When the concentration of phenolic resin was 60 %, the phenolic resin yielded a BS of 8.70 MPa and 9.20 MPa for WPWC and WFWC, respectively. Furthermore, the microstructures of both WPFC and WFWC reveal hierarchical porous structures. The difference is that WPFC has a dispersed three-dimensional network topology in its overall morphology, which is mainly formed by filamentous or long linear glass carbon in wood ceramics dominated by carbon. The natural and consistent pore structure of WFWC is comparable to a three-dimensional honeycomb structure, the primary mesoporous size was around 40.28 nm and the main macropore size was more than 10,000 nm. It elucidates the pore structure of WPWC and WFWC, characterized by “hierarchical porosity”, the differences and relationships between porous wood ceramics derived from powdery and fibrous biomass as raw materials were analyzed, which contributes to the advancement of the fundamental principles of wood ceramics and establishes a theoretical basis for the practical exploration and development of biomass materials.

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 selective acceptorless dehydrogenation of the γ‐hydroxy group, subsequent retro‐aldol reaction cleaving 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% 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 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.

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.

Characterization of Olive Oil Phenolic Extracts and Their Effects on the Aggregation of the Alzheimer's Amyloid-β Peptide and Tau.

The dietary consumption of extra virgin olive oil (EVOO) is believed to slow the progression of Alzheimer's disease (AD) symptoms. Its protective mechanisms are unclear, but specific EVOO phenolic compounds can individually impede the aggregation of amyloid-β (Aβ) peptides and the microtubule-associated protein tau, two important pathological manifestations of AD. It is unknown, however, whether the numerous and variable phenolic compounds that are consumed in dietary EVOO can collectively alter tau and Aβ aggregation as effectively as the individual compounds. The activity of these complex mixtures against Aβ and tau may be moderated by competition between active and nonactive phenolic components and by extensive derivatizations and isomerization. Here, phenolic mixtures extracted from two different EVOO sources are characterized and tested for how they modulate the aggregation of Aβ40 peptide and tau peptides in vitro. The chromatographic and NMR analysis of Greek and Saudi Arabian EVOO phenolic extracts reveals that they have different concentration profiles, and over 30 compounds are identified. Thioflavin T fluorescence and circular dichroism measurements show that relatively low concentrations (<20 μg/mL) of the Greek and Saudi extracts reduce the rate of Aβ40 aggregation and fibril mass, despite the extracts having different phenolic profiles. By contrast, the Greek extract reduces the rate of tau aggregation only at very high phenolic concentrations (>100 μg/mL). Most compounds in the extracts bind to preformed Aβ40 fibrils and release soluble Aβ oligomers that are mildly toxic to SH-SY5Y cells. Much higher (500 μg/mL) extract concentrations are required to remodel tau filaments into oligomers, and a minimal binding of phenolic compounds to the preformed filaments is observed. It is concluded that EVOO extracts having different phenol profiles are similarly capable of modulating Aβ40 aggregation and fibril morphology in vitro at relatively low concentrations but are less efficient at modulating tau aggregation. Over 2 M tonnes of EVOO are consumed globally each year as part of the Mediterranean diet, and the results here provide motivation for further clinical interrogation of the antiaggregation properties of EVOO as a potential protective mechanism against AD.

Disproportionation and Transalkylation of Phenol and Dimethylphenol on Zeolite Catalysts

AbstractSubstantial amounts of phenolic compounds are present in medium‐low temperature coal tar (MLCT), of which dimethylphenol (DMP) is not as valuable to be utilized as the more abundant cresol due to its complex composition and difficulty in isolation. In this study, the disproportionation and transalkylation reactions of MLCT‐related model compound, i.e., 2,6‐DMP, in phenol over zeolite catalysts are investigated using a fixed‐bed reactor for sustainable new option to utilize MLCT‐derived phenolic mixtures. Reactivity is promoted at high temperatures and associated with zeolite acidity and pore structure. Since disproportionation and transalkylation reactions have certain spatial requirements, the micropores of MFI‐type zeolite may cause spatial barriers that make it difficult to carry out the reactions. MCM‐22, characterized by MWW‐type zeolite, maximized the conversion of 2,6‐DMP due to its strong Bronsted acidity and large mesopore volume. FAU‐type zeolite HY with a 3D large 12‐ring through‐channel shows relatively small spatial confinement and certain molecular sieving ability, which enables bimolecular reactions while allowing cresols to flow out of the pores efficiently to obtain the highest cresol selectivity. The addition of phenol significantly inhibits the spontaneous disproportionation of 2,6‐DMP to tricresol. Besides, o‐cresol dominate the cresol products, suggesting that the selectivity of o‐cresol is kinetically controlled.

OXIDATIVE EFFECTS OF MAHANARAYAN TAILA ON AMERICAN COCKROACH, PERIPLANETA AMERICANA L. (BLATTIDAE: BLATTODEA)

The American cockroach (Periplaneta americana), a prevalent household pest originating from tropical regions like India, poses a significant public health risk as a carrier of human pathogens. The present study investigated the effectiveness of ?Mahanarayan Taila (MT),? an herbal oil, as an alternative solution. The repellent activity of the oil and its impact on biomolecules such as lipids and proteins in cockroaches was determined. Cockroaches were exposed to sub-lethal concentrations of MT over 24, 48, 72, and 96 h to assess repellency. The oil at 1% concentration resulted in a 50% mortality of adults. Mortality data were analyzed using GraphPad software. The study revealed significant changes in lipid peroxide levels, correlating with the oil concentration, and a dose-dependent depletion in protein sulfhydryl levels alongside the formation of protein carbonyls. Behavioral changes were also documented, including a knockdown effect and the appearance of black residues on cockroaches. These findings highlight the potential of MT herbal oil as an effective and safer alternative for cockroach control. With its complex mixture of phenols, monoterpenes, and sesquiterpenes, MT shows promise for surface treatments or fumigation in cockroach control programs.. KEYWORDS :Lipid peroxidation, Mahanarayan Taila, Mortality, Oxidative stress, Periplaneta americana

Integrated Membrane Process in Organic Media: Combining Organic Solvent Ultrafiltration, Nanofiltration, and Reverse Osmosis to Purify and Concentrate the Phenolic Compounds from Wet Olive Pomace.

Phenolic compounds from a hydroalcoholic extract of wet olive pomace were purified and concentrated by an integrated membrane process in organic media. First, UF010104 (Solsep BV) and UP005 (Microdyn Nadir) membranes were tested to be implemented in the ultrafiltration stage, with the aim of purifying the extract and obtaining a permeate enriched in phenolic compounds. Despite the high flux observed with the UF010104 membrane (20.4 ± 0.7 L·h-1·m-2, at 2 bar), the UP005 membrane was selected because of a more suitable selectivity. Even though some secoiridoids were rejected, the permeate stream obtained with this membrane contained high concentrations of valuable simple phenols and phenolic acids, whereas sugars and macromolecules were retained. Then, the ultrafiltration permeate was subjected to a nanofiltration step employing an NF270 membrane (DuPont) for a further purification and fractionation of the phenolic compounds. The permeate flux was 50.2 ± 0.2 L·h-1·m-2, working at 15 bar. Hydroxytyrosol and some phenolic acids (such as vanillic acid, caffeic acid, and ferulic acid) were recovered in the permeate, which was later concentrated by reverse osmosis employing an NF90 membrane. The permeate flux obtained with this membrane was 15.3 ± 0.3 L·h-1·m-2. The concentrated phenolic mixture that was obtained may have important applications as a powerful antioxidant and for the prevention of diabetes and neurodegenerative diseases.

Maternal concentrations of environmental phenols during early pregnancy and behavioral problems in children aged 4 years from the Shanghai Birth Cohort

BackgroundPrenatal exposure to environmental phenols such as bisphenol (BPs), paraben (PBs), benzophenone (BzPs), and triclosan (TCS) is ubiquitous and occurs in mixtures. Although some of them have been suspected to impact child behavioral development, evidence is still insufficient, and their mixed effects remain unclear. ObjectivesTo explore the association of prenatal exposure to multiple phenols with child behavioral problems. MethodIn a sample of 600 mother–child pairs from the Shanghai Birth Cohort, we quantified 18 phenols (6 PBs, 7 BPs, 4 BzPs, and TCS) in urine samples collected during early pregnancy. Parent-reported Strengths and Difficulties Questionnaires were utilized to evaluate child behavioral difficulties across four subscales, namely conduct, hyperactivity/inattention, emotion, and peer relationship problems, at 4 years of age. Multivariable linear regression was conducted to estimate the relationships between single phenolic compounds and behavioral problems. Additionally, weighted quantile sum (WQS) regression was employed to examine the overall effects of the phenol mixture. Sex-stratified analyses were also performed. ResultsOur population was extensively exposed to 10 phenols (direction rates >50 %), with low median concentrations (1.00 × 10−3–6.89 ng/mL). Among them, single chemical analyses revealed that 2,4-dihydroxy benzophenone (BP1), TCS, and methyl 4-hydroxybenzoate (MeP) were associated with increased behavior problems, including hyperactivity/inattention (BP1: β = 0.16; 95 % confidence interval [CI]: 0.04, 0.30), emotional problems (BP1: β = 0.11; 95 % CI: 0.02, 0.20; TCS: β = 0.08; 95 % CI: 0.02, 0.14), and peer problems (MeP: β = 0.10; 95 % CI: 0.02, 0.18); however, we did not identify any significant association with conduct problems. Further phenol mixture analyses in the WQS model yielded similar results. Stratification for child sex showed stronger positive associations in boys. ConclusionOur findings indicated that maternal phenol levels during early pregnancy, specifically BP1, TCS, and MeP, are associated with high behavioral problem scores in 4-year-old children.

Ionic liquid-functionalized pillar[6]arene: A novel stationary phase of high selectivity towards a wide range of isomers

In this work, a novel pillar[6]arene bonded with octyl-imidazolium ionic liquids (IMP6A-C4) as a stationary phase for gas chromatographic (GC) separations was designed, synthesized, and characterized. The IMP6A-C4 capillary column, prepared by the static coating method, had medium polarity (133) and relatively high column efficiency of 4982 plates/m determined by n-dodecane at 120 ℃. As demonstrated, through the separation of the mixture of 17 aliphatic analytes and the mixture of 20 analytes with different polarities, the IMP6A-C4 column exhibited privileged retention and high resolving capacity for H-bonded and aromatic analytes, suggesting advantages over the P6A-C4 column and common polysiloxane HP-5 and HP-35 columns. Strikingly, it implemented high resolutions with good peak shapes for isomer mixtures of phenols, anilines, and benzaldehydes. These findings demonstrated that the excellent resolving performance of the IMP6A-C4 column can be attributed to the comprehensive interactions of its rigid 3D aromatic cavities and polar imidazolium ionic liquids, including π-π, ion-π, H-bonding, dipole–dipole interactions. On the other hand, the IMP6A-C4 capillary column exhibited good repeatability and reproducibility with the RSD% values in the range of 0.01–0.03% for run-to-run, 0.09–0.32% for day-to-day, and 2.72–5.23% for column-to-column. The satisfactory separation performance reveals the promising prospects of the IMP6A-C4 stationary phase in separation science.

The potential of Stenotrophomonas maltophilia KB2 for 1 phenol degradation 2 under exposure to heavy metal

The large diversity of chemical substances present in air, water, or soil makes it necessary tostudy their mutual impact on the effectiveness of microbiological decomposition ofcontaminants. This publication presents the results of the studies aimed at evaluating the effect of two biogenic heavy metals - zinc and copper - on the phenol biodegradation by the Stenotrophomonas maltophilia KB2 strain. The tests were carried out for concentrations ofmetals significantly exceeding the legally permitted wastewater values: for zinc up to13.3 g·m -3, and copper up to 3.33 g·m -3. In the tested metal concentration range, phenol biodegradation by the S. maltophilia KB2 strain was not significantly influenced by theintroduced dose of zinc. While the presence of copper inhibited both biomass growth andsubstrate degradation. Kinetic data of metal and phenol mixtures were analyzed and very goodcorrelations were obtained for the proposed equations. An equation consistents with the Hanand Levenspiel model was proposed for the system S. maltophilia KB2-phenol-copper, whilean equation consistents with the Kai model for the system St. maltophilia KB2-phenol-zinc. The simultaneous presence of Zn and Cu ions in the culture resulted in a stronger inhibition ofphenol biodegradation.

Personal Care Products, Socioeconomic Status, and Endocrine-Disrupting Chemical Mixtures in Black Women.

Personal care products (PCPs) are sources of exposure to endocrine-disrupting chemicals (EDCs) among women, and socioeconomic status (SES) may influence these exposures. Black women have inequitable exposure to EDCs from PCP use, but no study has investigated how exposure to EDCs through PCPs may vary by SES, independent of race. Using data from the Study of Environment, Lifestyle, and Fibroids, a cohort of reproductive-aged Black women (n = 751), we quantified associations between PCPs and urinary biomarker concentrations of EDC mixtures (i.e., phthalates, phenols, parabens) within SES groups, defined using k-modes clustering based on education, income, marital status, and employment. Information about PCP use and SES was collected through questionnaires and interviews. We used principal component analysis to characterize the EDC mixture profiles. Stratified linear regression models were fit to assess associations between PCP use and EDC mixture profiles, quantified as mean differences in PC scores, by SES group. Associations between PCP use and EDC mixture profiles varied by SES group; e.g., vaginal powder use was associated with a mixture of phenols among lower SES women, whereas this association was null for higher SES women. Findings suggest that SES influences PCP EDC exposure in Black women, which has implications for public health interventions.

Вплив вмісту фенолів на деякі експлуатаційні властивості вбирних олив

DOI: 10.31081/1681-309X-2024-0-1-15-21 Specialty 161. U.D.C. 66.074.382:665.004.12 INFLUENCE OF PHENOL CONTENT ON SOME OPERATIONAL PROPERTIES OF ABSORBENT OILS © S.V. Nesterenko, Ph.D. in Technical Sciences, (State Enterprise “Ukrainian State Research Institute for Carbochemistry (UKHIN)”, 7 Vesnina str., Kharkiv, 61023, Ukraine), A.L. Bannikov (National Technical University "Kharkiv Polytechnic Institute", 2, Kyrpychova str., Kharkiv, 61002, Ukraine) The shutdown of centralized processing of phenolic raw materials once again raises the issue of the need to implement the process of dephenolization of the wash oil and to consider the feasibility of standardizing the phenol content in it. This problem has a history as long as the use of a coal tar wash oil as absorbent for capturing benzene hydrocarbons. Recent studies have emphasized the importance of studying the effects of oil degradation initiators such as ammonia, hydrogen sulfide, resins, iron and corrosion products. The purpose of this study was to conduct an experiment to determine the effect of phenol content in the absorbing oil on certain characteristics. This was intended to provide additional arguments to justify the feasibility of implementing the process of dephenolization of benzene hydrocarbon absorbers. A mixture of phenols was added to the sample of working oil in the following approximate ratio, in which they are in the absorbing fraction, namely 30 % xylenol isomers, 5 % cresol isomers, 65 % higher phenols (β-naphthol). Electrochemical determination of the corrosion rate of the solution obtained from aqueous extracts of oil samples showed that the presence of phenols does not increase corrosion processes caused by the presence of aggressive components. It can even be argued that the presence of phenols somewhat reduces corrosion processes by forming a film on the metal surface or reducing the concentration of active components near its surface. It was found that oil with phenol additives above the usual phenol content does not show a significant increase in the tendency to coke formation. On the contrary, higher phenols are inhibitors of radical oxidation reactions, which occur up to a certain limit in the processes of coke formation. Moreover, phenols show some inhibitory effect in a fairly wide temperature range (430-800 °C). Keywords: absorbent oil, phenols, dephenolization of the heavy fraction, corrosion rate, coke number. Corresponding author: S.V. Nesterenko, e-mail: nesterhnamg@gmail.com

THE SYNERGY OF THE ANTIRADICAL ACTION OF NATURAL PHENOLS IN MIXTURES WITH MONO- AND OLIGOSACCHARIDES

It has been established that in an acidic medium with pH = 2, the rate of deactivation of the 2,2'-diphenyl-1-picrylhydrazyl radical in the reaction with natural phenolic compounds significantly increases in the presence of mono- and oligosaccharides compared to the additive action of the mixture. The maximum antiradical synergistic effect (65% and more) was shown by the binary compositions caffeic acid–maltotriose and dihydroquercetin–maltotriose in the ratio of 80:20% and 70:30%, respectively. Mixtures of saccharides with protocatechuic and pyrocatechuic acids turned out to be less active. For all groups of phenols, the synergistic activity increases with the transition from mono- to di- and trisaccharides. An increase in the medium pH from 2 to 9 actually leads to a complete leveling of antiradical synergism (up to 10%) in all studied phenol-saccharide mixtures, as well as to the appearance of antagonism effects at a high carbohydrate content in the composition. Using NMR spectroscopy, it has been established that the mechanism of synergism consists in the formation of a phenol–saccharide donor-type hydrogen complex between the reactants, which interacts with the radical more effectively than the corresponding monomers. An increase in sugar percentage in the mixture, as well as an increase in the medium pH, leads to the growth of the content of H-complexes of the acceptor-type when phenol acts as a proton acceptor, thus the reducing properties of the complexes and the synergistic effect of the compositions in the reaction with hydrazyl radical will decrease. As a structural parameter associated with the synergistic effect of the composition, the ionization potential of the phenolic component of the mixture, calculated by the DFT method, was used. The established linear relationship between the maximum synergistic effect of the phenol-saccharide mixture and the ionization potential of phenols can later be used to form semi-empirical models for predicting the effectiveness of the antiradical action of natural phenol-carbohydrate synergistic compositions. A comprehensive study of phenol-saccharide mixtures will expand the range of natural synergistic systems with expressed antiradical activity for practical use in pharmacy, perfumery, and the food industry.

Phenolic Screening and Mixture Design Optimization for In Vitro Assessment of Antioxidant and Antimicrobial Activities of Honey, Propolis, and Bee Pollen

The current study used a design of experiments to evaluate the potential synergistic effects of three Moroccan bee products (honey (H), propolis (P), and bee pollen (BP)) on the free radical inhibition and antibacterial activity against clinical strains of Staphylococcus aureus and Escherichia coli. The phytochemical contents of these three bee products were first evaluated using HPLC‐DAD with 20 identified compounds (9 in both H and P extracts and 13 in BP extract). The P extract had the highest phytochemical content, with high levels of flavanone pinocembrin, flavanol catechin, lignan pinoresinol, and simple phenolics (p‐coumaric and gallic acids). Then, the optimized mixtures were determined using an augmented simplex‐centroid design. The optimized formulations (H33%:P43%:BP24%) and (H21%:P47%:BP32%) presented the optimal total phenolic content and DPPH‐IC50 with 226.88 mgGAE/g and 10.64 µg/mL, respectively, whereas the formulations (H26%:P52%:BP22%) and (H35%:P40%:BP25%) showed the optimal antimicrobial activity against S. aureus (MICS.aureus equal to 4.34 µg/mL) and E. coli (MICE.coli equal to 5.70 µg/mL), respectively. The predicted responses from these mixture proportions were also experimentally validated. Compared to the single free radical activity and antibacterial effect of each isolated bee product, these optimized formulations demonstrated an increased biological activity, and the determination of the fractional inhibitory concentrations revealed a synergistic effect between these products. This study emphasizes the interest in optimized bee product mixtures for practical applications beyond the pharmaceutical and food industries. Their potential can be extended to nutraceuticals, cosmeceuticals, animal health, environmental sustainability, and advanced biomedical research, offering holistic solutions for diverse challenges across various sectors. Exploring these applications further can unlock new avenues for innovation and sustainable development.

Experimental and modelling study of phenol combustion and oxidation

Despite of its central importance in the chemistry of aromatic compounds and fuels derived from biomass, only few experimental studies on phenol combustion can be found in literature. In this paper, unique measurements of the adiabatic laminar burning velocities of phenol are presented, together with the first experimental study of the oxidation of this molecule in a jet-stirred reactor. The burning velocities were measured with a flat-flame burner using the heat-flux method for a fresh gas temperature of 398 K and equivalence ratios from 0.7 to 1.35. In the reactor experiments, the oxidation of a stoichiometric mixture of phenol highly diluted in helium was investigated at temperatures between 600 and 1100 K at near-atmospheric pressure. The mole fraction of the reactants, as well as 32 products, mainly carbon monoxide, carbon dioxide, methane, acetylene ethylene, acrolein, cyclopentadiene, benzene, naphthalene and dibenzofuran, were recorded.Based on previous literature work, a new detailed kinetic model is developed based on several published sub-mechanisms and updated considering rate constants taken from recent literature studies or calculated at the CBS-QB3 or G4 level of theory. This model leads to a significantly improved prediction of the phenol burning velocities compared to literature models, as well as a reasonable prediction of most species mole fractions during phenol oxidation in the jet-stirred reactor. Sensitivity analyses as well as flow rate analyses are discussed to explain the obtained model improvements.