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Recently, after initial rectification, adsorption has become a viable method for further purification of SiHCl3, but much work remains to be done to find a suitable adsorbent. Quantum chemical calculations offers a feasible way to study the mechanism of adsorption, which help develop appropriate adsorbents. Aromatic amines are widely used as adsorbents for BCl3 in SiHCl3, but the adsorption mechanism remains unclear, which impedes the development of efficient adsorbents. In this work, density functional theory is used to investigate the adsorption configuration, adsorption energy and electronic properties of BCl3-SiHCl3 on aromatic amines and the mechanism of interaction between BCl3/SiHCl3 and aromatic amines is analyzed and discussed. The results show that BCl3/SiHCl3 could achieve the separation criteria after two-stage adsorption using aromatic amines (except diphenylamine and triphenylamine) as adsorbent. The adsorption performance decreases as the hydrogen on the nitrogen is gradually replaced by the aromatic ring. When the hydrogen on the benzene ring is substituted with methyl, the adsorption performance of adsorbents changes, which is also position specific. The adsorption energy (-30.63kJ/mol) of p-methylaniline for BCl3 is the highest at 298 K and 1atm. Besides, the desorption behavior of aromatic amines on BCl3 is investigated by increasing the temperature and lowering the pressure by evacuation, and it is found that varying pressure is less energy intensive than increasing the temperature. A combination of adsorption capacity and desorption degree considerations suggest that aromatic amines can be used as adsorbent materials. [ABSTRACT FROM AUTHOR]

In this article, Rh-doped SnO2 microspheres were prepared by a convenient hydrothermal treatment. Compared with the non-doped SnO2 microspheres, the Rh-doped SnO2 microspheres had larger specific surface area, faster electron transfer rate and increased oxygen vacancies, which is beneficial to improve the gas sensitivity of the material. The optimal sensitivity was observed of Rh-0.1 at 250 °C, and the response-recovery time of Rh-0.1 were 46 and 25 s, respectively. Besides, the Rh-doped SnO2 microspheres exhibited excellent gas selectivity and stability to benzene vapor. The novel Rh-doped SnO2 microspheres are potential gas detection materials for accessing benzene vapor. [ABSTRACT FROM AUTHOR]

Ethanol abuse is increasingly becoming a global issue, adversely affecting both society and families. In blood alcohol concentration (BAC) detection, traditional techniques have long experimental cycles and harsh experimental conditions and often fail to produce timely results. Consequently, achieving swift and precise on-site detection of ethanol poisoning in humans poses a formidable challenge in analytical science. We designed a novel assay for swift on-site analysis of ethanol and BTEX (benzene, toluene, ethylbenzene, and xylene) poisoning in humans using a custom portable headspace injector (portable HS) and portable gas chromatography-mass spectrometry (portable GC-MS). This setup, known for its lightweight design and speed, allows on-site sampling and delivers rapid results. We established a calibration curve (R2 > 0.99) for ethanol in blood using portable gas chromatography-mass spectrometry (portable GC-MS). This on-site blood alcohol concentration (BAC) assay proves simpler than traditional methods, enabling rapid analysis of each sample within a short timeframe and requiring only a small blood volume (0.1 ml). In addition to our investigation on ethanol, we developed a portable method for detecting BTEX in blood. This method provides a favorable coefficient of determination (R2 > 0.99) for various substances, thereby broadening the utility of portable mass spectrometry in areas such as traffic inspection and forensic identification. [ABSTRACT FROM AUTHOR]

The destruction of benzene in a dielectric barrier discharge (DBD) reactor was studied in this work. The effects of specific energy density, initial concentration and oxygen content on benzene degradation efficiency were investigated by experiment and matrix correlation analysis. The results showed that specific energy density was the most important factor on benzene removal with a Pearson's coefficient of 0.7, meanwhile both initial concentration and oxygen content presented the inverse influence. In addition, a model to study the plasma discharge process was developed by COMSOL simulation software and surface reactions were included in the model. The behavior of the plasma was described by the coupled equations of electron density, heavy matter density and electron mean energy, and the drift-diffusion equation was calculated. When the peak voltage is 30 kV, the terminal current obtained by the simulation is 0.03 A, and the corresponding output current measured by the experiment is 0.013 A. Simulated and experimental current change trends are the same, indicating that the method simulation is correct and reasonable. [ABSTRACT FROM AUTHOR]

Long-term exposure to Volatile Organic Compounds (VOCs) is a health risk for citizens. In this study, the cumulative health risk of exposure to VOCs in Tehran was assessed by investigating the concentration of these pollutants in ambient air in a five-year period. Health risk assessment was calculated by the quantitative method and the carcinogenic risk level was determined using the lifetime carcinogenic risk (LCR) method. The average concentration of benzene, toluene, ortho-xylene, and ethylbenzene was 1.4–1.8, 4.8–5.4, 5–6.5, and 3.6–4 ppb, respectively. Although HQ was not greater than 1, but it was very close in the case of benzene, ortho-xylene, meta-xylene, and para-xylene. Benzene and ethylbenzene had the largest effect in the assessed health risk. So the long-term exposure of Tehran citizens to VOCs has serious health consequences for them, which could be different according to the exposure time and spatial variations. [ABSTRACT FROM AUTHOR]

Synthesis and illicit use of designer benzodiazepines are growing concerns, with these new psychoactive substances (NPS) posing serious health consequences and new hurdles for toxicologists. Consumption marker identification and characterization is paramount in confirming their use. The benzodiazepine core structure is a fusion of benzene and a seven-membered heterocycle with two nitrogen atoms forming the diazepine ring. Minor variations on the core structure produce different classes of benzodiazepines with marked differences in physiological effects. The present review provides a comprehensive designer benzodiazepines metabolism overview and suggests suitable human consumption biomarkers for toxicology casework. A systematic literature search of PubMed®, ScopusTM, Web of ScienceTM, and Cochrane databases was conducted independently by two coauthors adhering to PRISMA guidelines. Data from 30 in vitro and in vivo models of designer benzodiazepines metabolism from January 2007 to February 2023 were included. 1,4-benzodiazepines (n = 10), 2,3-benzodiazepines (n = 1), triazolo-benzodiazepines (n = 9), and thieno-triazolo-benzodiazepines (n = 3) study design, sample pretreatment, analytical techniques, and major metabolites detected in various matrices are addressed. Metabolites following hydroxylation and phase II glucuronide conjugation were the most prevalent analytes. N-Glucuronidation of parent azole-fused benzodiazepines, and nitro-reduced and N-acetylated metabolites of nitro-containing designer benzodiazepines were also common. From these data, we propose a generic metabolic pathway for designer benzodiazepines. The sporadic illicit market presents challenges in toxicological casework and necessitates comprehensive biomarker investigations, especially in cases with legal implications. There are few metabolism data for many designer benzodiazepines, emphasizing the need for research focusing on closing these gaps. [ABSTRACT FROM AUTHOR]

Metabolic conversion of benzene (Bz) is thought to be required for the hematotoxic effects observed following Bz exposures. Most safe exposure limits set for Bz utilize epidemiology data on the hematotoxic effects of Bz for the dose–response assessments. These hematotoxic effects occurred among workers exposed to elevated Bz levels, thus dose extrapolation is required for assessing relevant risks for populations exposed orders of magnitude lower. Thus, understanding how Bz is metabolized over a wide range of air Bz levels is an important topic for risk assessments for Bz. Here, we analyze biomonitoring data for workers exposed to Bz to make evaluations of how the metabolism of Bz varies across a wide range of exposures. Our analysis indicates that the presence of metabolites derived from exposures to sources other than Bz (nonspecific metabolites of Bz) are significant confounders among biomonitoring studies and this precludes making any assessments of how Bz metabolism differs below approximately 3 ppm air Bz exposures using such nonspecific metabolites. [ABSTRACT FROM AUTHOR]

This work reports for the first time, the experimental densities and sound speeds for the ternary system {methyl tert-butyl ether + benzene + cyclohexane} within the temperature range (293.15 to 313.15) K and under ambient pressure conditions. The related binary subsystems have also been reported. Experimental data were used to derive excess molar volumes and excess isentropic compressibilities. Redlich-Kister and Cibulka’s equations correlated the binary and ternary excess properties, respectively, with standard deviations falling below the estimated uncertainties of the corresponding properties. The results have been interpreted in terms of molecular interactions between mixtures’ components and structural effects. Additionally, two symmetric (Kohler and Muggianu) and two asymmetric (Hillert and Toop) binary contribution models have been tested for their ability to predict the excess properties of the ternary excess properties. [ABSTRACT FROM AUTHOR]

Benzene is widely recognized as a potential carcinogen. Furthermore, the deficiency of specific nutrients may render individuals more vulnerable to cancer. For instance, β-cryptoxanthin, which possesses anti-inflammatory, antioxidant, and anticancer properties, has been identified as one such nutrient. Elevated benzene levels and reduced β-cryptoxanthin levels are reportedly correlated with an augmented susceptibility to cancer. To date, whether these 2 substances are linked with one another in the above correlation is yet to be determined. This study included 1358 participants with data on the serum concentration of β-cryptoxanthin as well as benzene and its derivatives. The data were sourced from the 2003–2004 National Health and Nutrition Examination Survey, a cross-sectional survey of the noninstitutionalized US population. Headspace solid-phase microextraction with gas chromatography and mass spectrometry was used to measure serum benzene and its derivatives, while high-performance liquid chromatography using multiwavelength photodiode-array absorbance detection was employed to quantify serum β-cryptoxanthin. In this study, male and female participants showed average β-cryptoxanthin levels of 9.10 ± 6.35 and 9.92 ± 8.95 ug/dL, respectively (p = 0.049). Styrene exhibited the strongest correlation with the change in β-cryptoxanthin concentration (β = −3.30, p for trend <0.001) upon comparing highest-quartile participants with those in the lowest quartile, followed by benzene (β = −2.95, p for trend <0.001), toluene (β = −2.90, p for trend <0.001), and ethylbenzene (β = −1.43, p for trend = 0.09). Subgroup analysis by sex displayed a statistically significant negative correlation of β-cryptoxanthin with benzene, styrene, and toluene in both the unadjusted and multivariate-adjusted models. The sera of noninstitutionalized US individuals exhibit a negative association of β-cryptoxanthin levels with benzene and its derivatives. Styrene demonstrates the strongest link with a substantial decline in serum β-cryptoxanthin levels, followed by benzene, toluene, and ethylbenzene. [ABSTRACT FROM AUTHOR]

Micropollutants of priority have gained significant attention due to their rising concentrations and persistence in aquatic environments. Among these significant micro-pollutants is benzene, released into the environment because of mining activities, thermal power plants, and certain industrial operations, thereby contributing to environmental contamination. This study monitored benzene concentrations in the Orhaneli River over a year, employing an artificial neural network (ANN) approach to formulate a predictive model for benzene micropollutant concentrations. To provide input to the ANN, Principal Component Analysis (PCA) was employed, utilizing parameters such as precipitation, temperature, humidity, pH, flow rate, dissolved oxygen, conductivity, total organic carbon, and total nitrogen. Eleven backpropagation algorithms were compared, with the Levenberg-Marquardt algorithm identified as the optimal training algorithm. For the selected training algorithm, an optimized number of 6 neurons in the hidden layer provided the best predictions for benzene concentrations. The three-layered optimized ANN model achieved an impressive correlation coefficient (R2) of 0.9889. [ABSTRACT FROM AUTHOR]

A coordination polymer (CP) based on Co(II), {[Co(Ox)(H2O)3] · 2H2O}n (KA@CP2_ARS), has been synthesized using 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (Timb) and potassium oxonate (OxK) at room temperature which was examined by single-crystal X-ray diffraction. KA@CP2_ARS contains a one-dimensional (1-D) helical chain that is extended through hydrogen-bonding interactions to form two-dimensional (2-D) and three-dimensional (3-D) supramolecular networks. KA@CP2_ARS demonstrates highly selective luminescent performance for IPA, Co2+, MnO4–, and uric acid with detection limits of 0.214, 0.16, 0.076, and 0.65 ppm, respectively, among the screened analytes. KA@CP2_ARS displays strong photocatalytic activities for degrading 88.6% of methyl violet dye under ultraviolet irradiation. [ABSTRACT FROM AUTHOR]

Two novel CoII metal–organic frameworks {[Co(BIMB)2(H2O)2](SO4)·EG·3 H2O}n (I) and {[Co(TIMB)2](SiF6)}n (II) were hydrothermally synthesized by corresponding metal salt with organic ligands 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (TIMB) or 1,4-bis((1H-imidazol-1-yl)methyl)benzene (BIMB). Crystal structural analysis reveals that they exhibit varied structures. Compound I contains two crystallographically unique CoII centers, each lying on an inversion center and having a slightly distorted octahedral environment. The BIMB ligands link the CoII cations to generate a three-dimensional porous framework with a 4-connected uninodal (65.8) topology. Compound II exhibits a two-dimensional sheeted metal-organic structure running parallel to the (0 0 1) plane, in which TIMB ligands join Co2+ centers having a six-coordinated octahedral structure. In the solid state, adjacent sheets are further bridged by guest SiF6- anions via C–H...F hydrogen-bonding interactions, giving rise to a three-dimensional supramolecular network structure with a 2-nodal (3-c)2(6-c) net. The topological analysis suggests that the point Schläfli symbol of compound II is (43)2(46.66.83). In addition, their thermal stabilities have also been investigated. [ABSTRACT FROM AUTHOR]

Compounds that possess a benzene sulfonamide structure are utilized in a wide range of fields. It is reported in the literature that many compounds belonging to this class of compounds exhibit various pharmacological properties such as antibacterial, antifungal, antiviral, anticancer, inflammatory, antiglaucoma, and anticholinergic effects. Carbonic anhydrase (CA) enzymes play a critical role in pH regulation, long-term synaptic turnover and are therefore thought to be associated with such diseases as mental retardation, Alzheimer's disease (AD) and Down syndrome. Studies have reported that there is an increase in the levels of hCA-I and hCA-II isoenzymes in AD. AD is a complex, multifactorial disorder, so therapy should probably address not only the cholinergic system but also additional systems. Based on these features, a series of novel substituted benzene sulfonamides were synthesized from 1,2,3-trimethoxy-5-methylbenzene. Sulfonyl chloride 9 was synthesized from the reaction of 1,2,3-trimethoxy-5-methylbenzene and excess chlorosulfonic acid. The reaction of the obtained sulfonyl chloride with NH3 and N-alkyl amines, aniline, and phenethylamine gave substituted benzene sulfonamide derivatives 10–16. The synthesized compounds were evaluated for their carbonic anhydrase (hCA I-II), acetyl cholinesterase (AChE) and butyryl cholinesterase (BChE) inhibitory properties. Some of the substituted benzene sulfonamide derivatives 10–16 showed inhibitory effect on hCA isoenzymes. The Ki values determined for the hCA I enzyme are in the range of 102.01–147.19 µM. Benzene sulfonamide derivatives 10–16 showed an inhibitory effect on AChE and BChE. The Ki values determined for AChE and BChE enzymes are in the range of 28.76–308.08 µM and 42.80–445.60 µM, respectively. It was determined that sulfonamides 15–16 were selective inhibitors for the hCA I and 10 showed 11-fold more selectivity on AChE than BChE. In addition, the in-silico SAR and ADME properties of the synthesized compounds were also investigated. [ABSTRACT FROM AUTHOR]

A coordination polymer (CP) based on Co(II), {[Co(Ox)(H2O)3] · 2H2O}n (KA@CP2_ARS), has been synthesized using 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (Timb) and potassium oxonate (OxK) at room temperature which was examined by single-crystal X-ray diffraction. KA@CP2_ARS contains a one-dimensional (1-D) helical chain that is extended through hydrogen-bonding interactions to form two-dimensional (2-D) and three-dimensional (3-D) supramolecular networks. KA@CP2_ARS demonstrates highly selective luminescent performance for IPA, Co2+, MnO4–, and uric acid with detection limits of 0.214, 0.16, 0.076, and 0.65 ppm, respectively, among the screened analytes. KA@CP2_ARS displays strong photocatalytic activities for degrading 88.6% of methyl violet dye under ultraviolet irradiation. [ABSTRACT FROM AUTHOR]

Causal epidemiology for regulatory risk analysis seeks to evaluate how removing or reducing exposures would change disease occurrence rates. We define interventional probability of causation (IPoC) as the change in probability of a disease (or other harm) occurring over a lifetime or other specified time interval that would be caused by a specified change in exposure, as predicted by a fully specified causal model. We define the closely related concept of causal assigned share (CAS) as the predicted fraction of disease risk that would be removed or prevented by a specified reduction in exposure, holding other variables fixed. Traditional approaches used to evaluate the preventable risk implications of epidemiological associations, including population attributable fraction (PAF) and the Bradford Hill considerations, cannot reveal whether removing a risk factor would reduce disease incidence. We argue that modern formal causal models coupled with causal artificial intelligence (CAI) and realistically partial and imperfect knowledge of underlying disease mechanisms, show great promise for determining and quantifying IPoC and CAS for exposures and diseases of practical interest. We briefly review key CAI concepts and terms and then apply them to define IPoC and CAS. We present steps to quantify IPoC using a fully specified causal Bayesian network (BN) model. Useful bounds for quantitative IPoC and CAS calculations are derived for a two-stage clonal expansion (TSCE) model for carcinogenesis and illustrated by applying them to benzene and formaldehyde based on available epidemiological and partial mechanistic evidence. Causal BN models for benzene and risk of acute myeloid leukemia (AML) incorporating mechanistic, toxicological and epidemiological findings show that prolonged high-intensity exposure to benzene can increase risk of AML (IPoC of up to 7e-5, CAS of up to 54%). By contrast, no causal pathway leading from formaldehyde exposure to increased risk of AML was identified, consistent with much previous mechanistic, toxicological and epidemiological evidence; therefore, the IPoC and CAS for formaldehyde-induced AML are likely to be zero. We conclude that the IPoC approach can differentiate between likely and unlikely causal factors and can provide useful upper bounds for IPoC and CAS for some exposures and diseases of practical importance. For causal factors, IPoC can help to estimate the quantitative impacts on health risks of reducing exposures, even in situations where mechanistic evidence is realistically incomplete and individual-level exposure-response parameters are uncertain. This illustrates the strength that can be gained for causal inference by using causal models to generate testable hypotheses and then obtaining toxicological data to test the hypotheses implied by the models—and, where necessary, refine the models. This virtuous cycle provides additional insight into causal determinations that may not be available from weight-of-evidence considerations alone. [ABSTRACT FROM AUTHOR]

Large volumes of wastewater are generated during petroleum refining processes. Petroleum refinery wastewater (PRW) can contain highly toxic compounds that can harm the environment. These toxic compounds can be a challenge in biological treatment technologies due to the effects of these compounds on microorganisms. These challenges can be overcome by using ozone (O3) as a standalone or as a pretreatment to the biological treatment. Ozone was used in this study to degrade the organic pollutants in the heavily contaminated PRW from a refinery in Mpumalanga province of South Africa. The objective was achieved by treating the raw PRW using ozone at different ozone treatment times (15, 30, 45, and 60 min) at a fixed ozone concentration of 3.53 mg/dm3. The ozone treatment was carried out in a 2-liter custom-designed plexiglass cylindrical reactor. Ozone was generated from an Eco-Lab-24 corona discharge ozone generator using clean, dry air from the Afrox air cylinder as feed. The chemical oxygen demand, gas chromatograph characterization, and pH analysis were performed on the pretreated and post-treated PRW samples to ascertain the impact of the ozone treatment. The ozone treatment was effective in reducing the benzene, toluene, ethylbenzene, and xylenes (BTEX) compounds in the PRW. The 60-min ozone treatment of different BTEX pollutants in the PRW resulted in the following percentage reduction: benzene 95%, toluene 77%, m + p-xylene 70%, ethylbenzene 69%, and o-xylene 65%. This study has shown the success of using ozone in reducing the toxic BTEX compounds in a heavily contaminated PRW. [ABSTRACT FROM AUTHOR]

AbstractThe ionization of benzene (C6H6) through helium low-temperature plasma (He-LTP) offers a promising solution to the pervasive issue of its pollution in our daily lives. This study aimed to optimize the conditions for generating specific compounds, namely M+ and [M + 30]+, during the ionization of benzene in low-temperature plasma (LTP) with determination by mass spectrometry (MS). When the discharge voltage is 2.5 kV, a sample gas to discharge gas flow rate ratio of 2:3 is the best condition for generating M+ ions. When the discharge voltage is 3.5 kV, the gas flow rate ratio of 1:3 is the most suitable for generating [M + 30]+ ions. The LTP exhibits optimal ionization efficiency at a total gas flow rate of 40 mL/min. Additionally, we conducted a comparative analysis on the optical emission of benzene in the LTP which revealed the generation of free radicals associated with N, H, and O. The produced nitroso radical (ON•) combines with ionized benzene to yield the [M + 30]+ ion, identified to be nitrosobenzene. Notably, 95% conversion was achieved in the transformation from benzene to nitrosobenzene. [ABSTRACT FROM AUTHOR]

The impact of the active site produced by the active metal V centre on the production of phenol from benzene was deduced from the cluster model structure of VAPO-5. In this work, the mechanism of benzene to phenol under the VAPO-5 model was explored. The transition states, intermediates, and reaction energy barrier throughout the reaction were evaluated by the ONIOM approach, which combines semi-empirical analysis with density functional theory. The outcomes demonstrated that this reaction was divided into four stages, with each stage's energy barriers being 59.9, 122, 204.8, and 60.7 kJ/mol, respectively. And a lower energy barrier of 204.8 kJ/mol must be surpassed to pass the determining speed phase's energy barrier of 296.8 kJ/mol. Additionally, the solvation of acetonitrile was looked into, resulting in the crossing of the energy barrier of 174.8 kJ/mol. [ABSTRACT FROM AUTHOR]

This paper discusses robust control strategy for isopropyl benzene production process using the method of loop shaping $ {H_\infty } $ H ∞ technology. This cumene production process is a part of phenol plant in HOCL, Kochi. $ {H_\infty } $ H ∞ control of the propylene concentration is done here. The $ {H_\infty } $ H ∞ controller is derived from the linearised model of the reactor. The optimal $ {H_\infty } $ H ∞ controller is obtained by simplifying two algebraic Riccati equations. The proposed PID-like $ {H_\infty } $ H ∞ controller provides a single tuning parameter which makes the controller design more accurate. The proposed controller has been compared with other robust controllers like $ {H_2} $ H 2 and LQR. The $ {H_\infty } $ H ∞ controller is found to be superior in a wide frequency range and has a feature of low distortion and good regulating performance. The reactor model has been developed in COMSOL Multiphysics with the parameters obtained from HOCL plant, Kochi. The model extracted is reduced using model order reduction for the controller design. [ABSTRACT FROM AUTHOR]

In the present study, the white kaolin-derived silica (SA) and silica-carbon aerogel composite (CSA) were successfully synthesised as useful adsorbents for the effective removal of benzene from dry and wet gas streams. The physicochemical features of the adsorbents were characterised using SEM, BET, XPS, and TGA, and the adsorption properties of benzene were investigated through breakthrough time curves and equilibrium study. The specific surface areas of SA and CSA were 628 and 783 m2 g−1, respectively, demonstrating the high porosity of the synthesised adsorbents. The dynamic adsorption and isotherm performances of SA and CSA confirmed that both adsorbents have superior adsorption properties and Khan isotherm for both developed adsorbents were the fittest model among the two- and three-parameter isotherm models studied and provided a maximum adsorption capacity of 366.2 and 224.4 for SA and CSA mg g−1, respectively. Furthermore, the reusability tests revealed that the SA and CSA could be efficiently recovered at 180°C. Our experimental outcomes indicated that the prepared SA and CSA can be applied as efficient and inexpensive adsorbents for the removal of benzene from gaseous streams. [ABSTRACT FROM AUTHOR]

Background. Benzene is a known human carcinogen. Human exposure to benzene can be assessed by measuring trans, trans-muconic acid (MUCA) in urine. Golestan Province in northeastern Iran has been reported to have high incidence of esophageal cancer linked to the use of tobacco products. This manuscript evaluates the urinary MUCA concentrations among the participants of the Golestan Cohort Study (GCS). Methods. We analyzed MUCA concentration in 177 GCS participants' urine samples and performed nonparametric pairwise multiple comparisons to determine statistically significant difference among six different product use groups. Mixed effects model was fitted on 22 participants who exclusively smoked cigarette and 51 participants who were classified as nonusers. The urinary MUCA data were collected at the baseline and approximately five years later, and intraclass correlation coefficient (ICC) was calculated from the model. Results. Compared with nonusers, tobacco smoking was associated with higher urinary MUCA concentrations. Based on the nonparametric test of pairwise multiple comparisons, MUCA concentrations among participants who smoked combusted tobacco products were statistically significantly higher compared to nonusers. Urinary MUCA collected five years apart from the same individuals showed moderate reliability (ICC = 0.41), which was expected given the relatively short half-life (∼6 h) of MUCA. Conclusion. Our study revealed that tobacco smoke was positively associated with increased levels of urinary MUCA concentration, indicating that it is a significant source of benzene exposure among GCS participants. [ABSTRACT FROM AUTHOR]

Upward trend in the use of food supplements urged the assessment of their safety. Eighty-eight liquid herbal supplements collected in Novi Sad (Serbia) in 2018 (36 samples) and 2021 (52 samples) were analysed for the presence of benzoates and sorbates (HPLC-UV) and benzene (HS-GC/MS). Benzoic acid varied from 599 to 9253 mg/kg and sorbic acid between 185 and 1658 mg/kg. The acceptable daily intake of sorbic acid was not reached, but in case of benzoic acid, it was exceeded by 5.3% of the samples. The presence of benzene was confirmed in 41.2% of benzoate preserved supplements (0.9–51.7 µg/kg). Benzene exposure revealed no health concern: maximum hazard quotients ranged from 0.39% (toddlers) to 0.84% (adolescents); minimum margins of exposure were between 35,680 (adolescents) and 77,419 (toddlers); estimates of lifetime cancer risk did not reach one extra cancer case per 100 000 persons. However, measures to mitigate benzene presence in food should be considered. [ABSTRACT FROM AUTHOR]

A series of novel 2-oxo-2-(arylamino)ethyl 4-formylbenzoates were prepared via the reaction of the potassium salt of p-formylbenzoic acid with 2-chloro-N-aryl-acetamide in DMF at reflux. A new series of 1,4- dihydropyridin-3,5-dicarbonitriles, hexahydroacridine-1,8-diones, decahydropyrimido[4,5-b]quinolines, and hexahydrobenzo[4,5]imidazo[2, 1-b]quinazolines which are linked to N-aryl-benzoyloxyacetamide were obtained through the Hantzsch reaction of various 2-oxo-2-(arylamino)ethyl 4-formylbenzoate with the respective 3-aminocrotononitrile or a mixture of 1,3-dicarbonyl compounds and amine source. The structures of the novel compounds were confirmed using a variety of spectra. [ABSTRACT FROM AUTHOR]

Benzene pyrolysis chemical kinetic mechanism has been of interest as benzene and phenyl radicals are important species for polycyclic aromatic hydrocarbons (PAHs) growth. Also, valuable industrial species such as biphenyl can be produced from benzene pyrolysis. This work aims to study the effect of additives (biphenyl and acetylene) on benzene pyrolysis at intermediate temperatures (900–1250 K). However, significant soot was noticed at high temperatures (1200–1250 K), which may affect the measurements. Nitrogen and a blend of nitrogen and carbon dioxide were used for dilution. The experiments were performed using a jet-stirred reactor (JSR) coupled with gas chromatography (GC) at atmospheric pressure. A residence time of 3 s was considered, as a long residence time is needed to collect enough samples at intermediate temperatures. The concentration-temperature profiles from the experimental measurements were compared with three selected models, Hamadi et al., Ranzi et al. and Sun et al. models. In general, Sun et al. model performs better than the other two models, especially for the prediction of light hydrocarbon concentrations. The results show an apparent influence of additives on benzene pyrolysis. The experiments and Sun et al. model illustrate a noticeable formation of methane and ethylene. Hamadi et al. and Ranzi et al. models demonstrate minor formation of light hydrocarbons under our experimental conditions. Sensitivity analyses of benzene, biphenyl, methane and ethylene were conducted at 1175 K using Sun et al. model. [ABSTRACT FROM AUTHOR]

M(cyclobutylamine)2Ni(CN)4 (M=Ni or Co) host and M(cyclobutylamine)2Ni(CN)4.nG (M=Ni or Co; cba=cyclobutylamine; G=benzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene and naphthalene; n=the number of guest) host-guest compounds were synthesized and characterized by infrared spectroscopy. The spectral results were found to be consistent with the structure of the Hofmann-dma-type hosts. The absorption and release studies of certain aromatic guests (benzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, 1,4-dichlorobenzene, and naphthalene) molecules in the host complexes were investigated by gravimetric and spectroscopic methods at room temperature. The liberation of guest molecule benzene against time has been examined. The structures of M(cyclobutylamine)2Ni(CN)4 host do not affect when the guest molecule is included and liberated. It is thought that the host compounds will guide as sorbents for isomeric separations. [ABSTRACT FROM AUTHOR]

Benzene is aromatic organic compound having six membered ring. Molecular studies provide evidence of presence of three alternative double bond providing exceptional stability to the molecule. Being basic unit of organic chemicals, benzene is widely used in pharmaceuticals, rubber, pesticides, dyes, lubricants, explosives and additives. Benzene derivatives are used in production of dyes, deodorants, pesticides, organic solvents, dispersants, plasticizers, and drugs. Keeping in view the extensive applications of benzene derivatives, we made use of QSPR analysis for predicting the multiple chemical and physical properties of organic compounds. By using SPSS software, correlation between newly introduced entropies and the Physico-chemical properties of benzene derivatives is examined. Our acquired consequences demonstrated that two physical properties of chemical structures, ie Boiling Point and enthalpy can be best predicted from the fifth ND entropy, and the other two properties namely Pie-electron Energy and molecular weight predicted from the neighborhood version of redefined first Zagreb entropy and neighborhood version of redefined second Zagreb entropy, respectively. [ABSTRACT FROM AUTHOR]

Hydroquinone (HQ), one of the main active metabolites of benzene, can induce the abnormal expression of long non-coding RNA (lncRNA). Studies have shown that lncRNA plays an important role in the occurrence of hematologic tumors induced by benzene or HQ. However, the molecular mechanism remains to be elucidated. Here, we investigated the molecular mechanism by which poly(ADP-ribose)polymerase 1 (PARP-1) interacts with DNA methyltransferase 1 (DNMT1) to regulate promoter methylation mediated linc01132 expression in HQ-induced TK6 malignant transformed cells (HQ-MT). The results revealed that the expression of linc01132 was increased in benzene-exposed workers and HQ-MT cells. The methylation of linc01132 promoter region was inhibited. Furthermore, in HQ-MT cells treated with 5-Aza-2′-deoxycytidine (5-AzaC) (DNA methyltransferase inhibitor) or trichostatin A (TSA) (histone deacetylation inhibitor), the expression of linc01132 was increased due to the regulation of DNA promoter methylation level by inhibiting DNMT1 expression. The methylation level of linc01132 promoter was correlated negatively with the expression of linc01132 in benzene-exposed workers, indicating that DNA methylation may contribute the expression of linc01132. Knockout of DNMT1, not DNMT3b, increased the expression of linc01132 as well as the demethylation of linc01132 promoter in HQ-MT cells. It was found that by knockdown PARP-1, the expression of DNMT1 in the nucleus was increased by immunofluorescence confocal microscopy, leading to the inhibition of hypermethylation in the promoter region of linc01132. Therefore, PARP-1 inhibits DNA methyltransferase (DNMT)-mediated promoter methylation and plays a role in linc01132 expression in benzene-exposed workers or HQ-MT cells, and is associated with benzene or HQ induced leukemia progression. [ABSTRACT FROM AUTHOR]

Process simulators are commonly used for effective modeling, simulation, and optimization of separation techniques. A novel mathematical model was developed to determine the component fluxes, separation factor and pervaporation separation index (PSI) considering the effects of different physico-chemical parameters (temperature, pressure, feed concentration), on the pervaporative separation of benzene from model pyrolysis gasoline (benzene/1-octene) with a fabricated insitu(nano)silver/polyvinyl alcohol membrane. The simulation was done using MATLAB R2013 software. Estimation of PSI, the unique performance parameter, precisely provides the pervaporation separation efficiency. The maximum simulated and experimental PSI values for 0.3 mole fraction of benzene in feed at 303 K and 1 mm Hg downstream pressure are 14.25 kg/m2/h and 14.26 kg/m2/h, respectively. The error functions are presented in terms of Objective Function, Standard Deviation, Standard Error and Root Mean Square Error; all of them were ≪1. Good agreement between the experimental and simulated values endorsed the validity of the model. [ABSTRACT FROM AUTHOR]

Molecular graph theory is crucial in model development and design of any molecular topologies. The mathematical polynomials of chemical graphs are called topological indices and they are highly valuable for determining their physicochemical characteristics. In this manuscript, we have developed the physical relationship between heat of formation (and entropy) and topological indices using curve fitting method of innovative planar metal-organic frameworks T M - TCNB. Surprisingly, the T M - TCNB frameworks are basically metals in every respect inside 1-turn heading and ultimately exhibit ferromagnetic coupling to appealing nanostructures, implying ideal candidates and a novel promise of unusual electromagnetic applications. [ABSTRACT FROM AUTHOR]

The limitations of visual inspection and interpretation of Infrared (IR) spectra from either laboratories or astronomical observations to cover a wide range of molecular types motivated us to apply a mathematical approach via a matching method called spectra similarity to identify the carriers of UIE bands in a sample of astronomical objects. The reliability of such a purely mathematical approach in targeting the correct molecular structures was tested by applying two sets of experimental IR spectra against the large pool of theoretical IR databases composed of 300,000 organic, organometallic, and, inorganic molecules. Spectra similarity calculations show that the second-row elements C, H, N, and O dominate the elemental composition of HD 44179, M 82, NGC 7023, NGC 7027, and Orion bar. In addition, the signatures of third-row elements S and Si were also identified. Our preliminary results confirm the signatures of complex organic molecules in interstellar environments. These are composed of benzene rings, five-membered rings, and side chain aliphatic groups in the cited astronomical sources. In some cases, the similarity approach suggested the fully aliphatic structures as the origin of UIE carriers. [ABSTRACT FROM AUTHOR]

This work reports experimental densities and sound speeds at (293.15, 298.15, 303.15, 308.15, and 313.15) K and viscosities at 298.15 K for the binary liquid mixtures methanol + pyridine, methanol + benzene, and pyridine + benzene over the entire range of compositions and atmospheric pressure. The excess properties, namely the excess molar volume V m E , excess isentropic compressibility κ S E , and excess Gibbs energy for activation of viscous flow G*E were calculated from experimental data and are fitted to Redlich-Kister polynomials. The results obtained were discussed in terms of molecular interactions between the mixing components and structural effects. [ABSTRACT FROM AUTHOR]

Investigation of mesomorphic properties of new 1,3,4-thiadiazolines (which are synthesised via many steps in Scheme 1) was carried out in this study. These compounds are designed to have a heterocyclic unit, a carboxylate linkage group and a polar ether chain at the end of the molecule adjacent to the benzene ring, which enhance the dipolar interactions forces (varied from one to eight carbons) to investigate the association properties of their phases. The structure of the target compounds and the intermediates were confirmed by 1H NMR, 13C NMR, mass and FTIR spectral techniques. Polarised microscopic studies revealed that all the compounds in the series exhibited enantiotropic liquid crystalline properties. This was further confirmed using differential scanning calorimetric experiments. The synthesised compounds type [V]n in this study displayed different liquid crystalline mesophases and the homologous [V] having an alkoxy terminal group (n = 1–3) exhibited nematic phase, whilst the last derivatives of the series (4–8), displayed smectic A phase. [ABSTRACT FROM AUTHOR]

Toward the treatment of waste solution containing heavy metals, direct precipitation of the metal ions from an acidic solution without alkaline neutralisation is still the greatest challenge. Based on the ligand properties of benzene tricarboxylic acid (BTC) to copper ions, a simple ball milling with 90 min at 400 rpm was used to activate BTC to enhance its capacity for copper removal from the pH of the original solution around 3–4. A set of analytical methods were used to characterise the activated BTC sample and BTC-Cu precipitate before and after copper precipitation. Compared with the raw BTC, the activated BTC could efficiently remove copper ions over 90% from an initial copper concentration of 100 mg/L in a shorter time from an acidic media with lower pH of around 2.60 and the maximum adsorption capacity can be stable at about 111.70 mg/g, resulting from probably the enhanced deprotonation effect for copper incorporation. Furthermore, at controlled dosage, the activated BTC demonstrated much high selectivity on precipitating copper ions from other heavy metals of Ni, Mn, Zn and Cd and provided a new approach for easy copper recycling from waste solution as secondary sources. This process may serve the purpose of recycling both metal and acidic solutions after the purification. [ABSTRACT FROM AUTHOR]

This study aimed to assess the possible non-cancer and cancer risks associated with BTEX in a composite manufacturing plant for the first time. Air samples of BTEX were gathered from the breathing zone of participants based on the method of NIOSH 1501 using an adsorbent tube containing activated coconut charcoal and a pump at the recommended flow rate between 50 and 200 milliliters per min. After the preparation, the samples were analyzed using GC mass spectrometry. To evaluate the non-cancer and cancer risks of the pollutants, the method proposed by the United States environmental protection agency (USEPA) was applied. The mean concentrations of BTEX were found lower than the threshold limit values (TLV). The non-carcinogenic risk values of benzene, ethylbenzene, and xylene were found to be 46.00, 6.96, and 22.4 times, respectively, higher than the threshold levels set by the US EPA. Whereas the risk of toluene was lower than the acceptable limit. Moreover, the results point to a specific risk of cancer for the workers exposed to benzene and ethylbenzene in this industry, indicating a potential for 1.66 and 1.91 additional cases per 100 workers exposed to benzene and ethylbenzene, respectively. [ABSTRACT FROM AUTHOR]

A palladium-catalyzed cross-coupling of benzene sulfonyl hydrazides with benzyltrimethylammonium salts via C–S bond and C–N bond cleavage is reported. This reaction proceeds under mild reaction conditions and provides a new strategy for the synthesis of various diarylmethanes with broad functional group tolerance in moderate to good yields. [ABSTRACT FROM AUTHOR]

Catalytic use of benzene-1,3-disulfonic acid at an ordinary condition gets restricted due to its high hygroscopic and moisture sensitive nature. In the present study, a new catalytic material silica bonded bis(hydrogensulphato)benzene (SiO2-BHSB) was synthesized through a sequence of reactions, where the active catalytic part benzene-1,3-disulfonic acid was grafted on the surface of micro-sized silica by the chemical bonding. Structural features, purity, thermal stability, and acid strength of the synthesized SiO2-BHSB material were confirmed by the adequate analytical techniques such as FT-IR, solid-state CP-MAS 13C-NMR, CP-MAS 29Si-NMR, EDX, DTG, TGA, and volumetric studies. The synthesized material SiO2-BHSB was observed as an efficient and sustainable reaction promoter for a tandem reaction between 4-hydroxy-1-methyl-2(1H)-quinolone, malononitrile, and structurally diverse aldehydes to offer pyrano[3,2-c]quinolone scaffolds. An environmentally benign catalytic protocol in aqueous based solvent and at ordinary energy conditions was developed, wherein a tiny amount (3 mol%) of SiO2-BHSB was observed sufficient to catalyze the synthesis pyrano[3,2-c]quinolone scaffolds. Structures of the synthesized pyrano[3,2-c]quinolone derivatives were established from their physical and spectrometric data. Catalyst recovery and reuse study revealed that SiO2-BHSB sustains its catalytic activity even after five runs of its reuse. Use of aqueous-based solvent, environmentally compatible reaction conditions, ease of catalyst recovery and reuse are the additional salient features of the present protocol. [ABSTRACT FROM AUTHOR]

The correction notice from the journal "Toxicology Mechanisms & Methods" clarifies that the article titled "The molecular mechanisms of liver and islets of Langerhans toxicity by benzene and its metabolite hydroquinone in vivo and in vitro" focuses on the study of benzene's effect on the liver, while a separate article examines its impact on the pancreas. The updated information provides a more accurate understanding of the research conducted by authors Haji Bahadar, Faheem Maqbool, Sara Mostafalou, Maryam Baeeri, Mahdi Gholami, Elmira Ghafour-Boroujerdi, and Mohammad Abdollahi. The article was published in Volume 25, Number 8 of the journal and can be accessed through the DOI link provided. [Extracted from the article]

The immobilization of homogeneous catalytic material over the inert heterogeneous support is a recent strategy to overcome the drawbacks and unite the merits associated with the homogeneous as well as heterogeneous catalysts. However the physisorption-induced immobilization does not serve the purpose because of its sensitive reversible nature, a tiny change in reaction parameters may revert the physisorption and so the immobilization. In this work, a new catalytic material silica chemisorbed bis(hydrogensulphato)benzene (SiO2-BHSB) was achieved through the chemisorption of bis(hydrogensulphato)benzene as an active catalytic part on the surface of porous silica. Structural features, purity, thermal stability, and acid strength of the synthesized SiO2-BHSB material were established by adequate analytical techniques, such as FT-IR, solid-state CP-MAS 13C NMR, solid-state CP-MAS 29Si NMR, EDX, DTG, TGA, and acid–base volumetric studies. An environmentally benign catalytic protocol for the synthesis of biscoumarin scaffolds through a tandem reaction between 4-Hydroxycoumarin and structurally diverse aldehydes was developed in which the synthesized material SiO2-BHSB was observed to work as an efficient and reusable catalyst. The structures of the synthesized biscoumarin derivatives were established from their physical and spectrometric data. The synthesized catalytic material was observed to show sustained catalytic activity even after five cycles of its recovery and reuse. In comparison with the earlier reported methods, a tiny amount (2.5 mol%) of catalyst is sufficient to bring out the transformation smoothly in an aqueous-based solvent, ease of recovery, and reusability of the catalyst are additional salient features of the present protocol. [ABSTRACT FROM AUTHOR]

Sufficient evidence supports a relationship between certain myeloid neoplasms and exposure to benzene or formaldehyde. DNA methylation could underlie benzene- and formaldehyde-induced health outcomes, but data in exposed human populations are limited. We conducted two crosssectional epigenome-wide association studies (EWAS), one in workers exposed to benzene and another in workers exposed to formaldehyde. Using HumanMethylation450 BeadChips, we investigated differences in blood cell DNA methylation among 50 benzene-exposed subjects and 48 controls, and among 31 formaldehyde-exposed subjects and 40 controls. We performed CpG-level and regional-level analyses. In the benzene EWAS, we found genome-wide significant alterations, i.e., FWER-controlled P-values <0.05, in the mean and variance of methylation at 22 and 318 CpG sites, respectively, and in mean methylation of a large genomic region. Pathway analysis of genes corresponding to benzene-associated differential methylation sites revealed an impact on the AMPK signalling pathway. In formaldehyde-exposed subjects compared to controls, 9 CpGs in the DUSP22 gene promoter had genome-wide significant decreased methylation variability and a large region of the HOXA5 promoter with 44 CpGs was hypomethylated. Our findings suggest that DNA methylation may contribute to the pathogenesis of diseases related to benzene and formaldehyde exposure. Aberrant expression and methylation of HOXA5 previously has been shown to be clinically significant in myeloid leukaemias. The tumour suppressor gene DUSP22 is a potential biomarker of exposure to formaldehyde, and irregularities have been associated with multiple exposures and diseases. [ABSTRACT FROM AUTHOR]

Isopropoxy benzene guanidine (IBG) is a novel substituted benzene guanidine analogue with antibacterial activity against multidrug-resistant bacteria. However, the bioavailability of IBG is not optimal due to its finite aqueous solubility, thus hampering its potential therapeutic exploitation. In this study, we prepared IBG/hydroxypropyl-ß-CD (IBG/HP-ß-CD) complex, and characterized it by differential scanning calorimetry, Fourier transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopy. Physicochemical characterization indicated that the crystal morphology of IBG transformed into an amorphous state, thus forming IBG/HP-ß-CD inclusion complexes. Complexation with HP-ß-CD significantly improve the aqueous solubility, pharmaceutical properties, absorption, and bioavailability of IBG. [ABSTRACT FROM AUTHOR]

The aim of this study was to assess the level of exposure to and contamination by smoke within a population of firefighter instructors. We performed a prospective observational study from September 17 to September 26, 2018, using environmental samples and urinary biomarker analysis. Occupational exposure limits (OELs) were never exceeded, except for carbon monoxide for the fire attack training chamber and formaldehyde and carbon monoxide for the fire box. As regards to urinary biomarkers, we observed that 1OHP and 1-naphtol did accumulate. The pre-post analysis showed an acute exposure exceeding the BRVs of benzene, 1-hydroxypyrene and naphtol, except for 3-benzo[a]pyrene which was undetectable in half of the cases. Even if values were reassuring, an effort could be made to improve the working conditions and reduce contamination by rethinking the respiratory protection and improving PPE quality. [ABSTRACT FROM AUTHOR]

Benzene exposure results in bone marrow suppression, leading to a decrease in the number of circulating white blood cells, an increased risk of chronic lymphocytic leukemia, acute myeloid leukemia and aplastic anemia. Since the mechanism of induction of benzene toxicity is due to active metabolites through cytochrome p450 enzymes and production of reactive oxygen species (ROS), we hypothesized that natural compound such linalool with anti-inflammatory/antioxidant properties could be effective in reducing its toxicity. Lymphocytes isolated from healthy individuals were simultaneously cotreated with different concentrations of LIN (10, 25 and 50 µM) and benzene (50 µM) for 4 h at 37 °C. After incubation, the toxicity parameters such cytotoxicity, ROS formation, lysosomal membrane integrity, mitochondria membrane potential (ΔΨm) collapse, oxidized/reduced glutathione (GSH/GSSG) and malondialdehyde (MDA) were analyzed using biochemical and flow cytometry evaluations. Our data showed that benzene (50 µM) induced a significant increase in cytotoxicity, ROS formation, mitochondrial membrane potential (MMP) collapse, lipid peroxidation and oxidative stress while LIN with antioxidant potential reversed the toxic effects of benzene on isolated human lymphocytes. Our results suggest that LIN reduces and reverses benzene-induced cytotoxicity, oxidative stress and lysosomal/mitochondrial damages in human lymphocyte. This study demonstrated that cotreatment of LIN with benzene can reduce several parameters indicative of oxidative stress. As such, LIN could represent a potential therapeutic agent in reducing certain aspects of benzene-induced toxicity. [ABSTRACT FROM AUTHOR]

Historically, benzene has been widely used in a large variety of applications. Occupational exposure limits (OELs) were set for benzene as it was found to be acutely toxic, causing central nervous system depression at high exposures. OELs were lowered when it was discovered that chronic exposure to benzene could cause haematotoxicity. After confirmation that benzene is a human carcinogen causing acute myeloid leukaemia and possibly other blood malignancies, OEL were further lowered. The industrial application of benzene as solvent is almost completely discontinued but it is still used as feedstock for the production of other materials, such as styrene. Occupational exposure to benzene may also occur since it is present in crude oil, natural gas condensate and a variety of petroleum products and because benzene can be formed in combustion of organic material. In the past few years, lower OELs for benzene in the range of 0.05–0.25 ppm have been proposed or were already established to protect workers from benzene-induced cancer. The skin is an important potential route of exposure and relatively more important at lower OELs. Consequently, human biomonitoring – which integrates all exposure routes – is routinely applied to control overall exposure to benzene. Several potential biomarkers have been proposed and investigated. For compliance check of the current low OELs, urinary S-phenylmercapturic acid (S-PMA), urinary benzene and blood benzene are feasible biomarkers. S-PMA appears to be the most promising biomarker but proper validation of biomarker levels corresponding to airborne benzene concentrations below 0.25 ppm are needed. [ABSTRACT FROM AUTHOR]

Two series of benzoates containing 1,2,3-triazole heterocyclic were prepared. The molecules containing alkyl chains of 12 ∼ 14 carbon atoms and with benzene ring as the central core show liquid crystal behaviors. After replacing benzene ring with cyclohexane, the compounds with short or long alkyl chains or ferrocene terminal group have no mesomorphic behavior. However, the compounds with medium length alkyl chain have lower melting point and wider mesomorphic domain than those with benzene ring as the central core containing the same length alkyl chain. This study adds new members to liquid crystal whose central core is a flexible ring. [ABSTRACT FROM AUTHOR]

In this paper, we discuss the degree based topological properties of the novel planar metal-organic networks TM – TCNB. Interestingly, the TM – TCNB systems are metallic in any event in one turn heading and show long-run ferromagnetic coupling on the off chance that for attractive structures, which speak to perfect applicants and a fascinating possibility of uncommon applications in spintronics. Chemical graph theory plays an important role in modeling and designing any chemical structure. The topological indices are the numerical invariants of a molecular graph and are very useful for predicting their physical properties. We have computed the degree based topological indices for this metal-organic networks TM – TCNB. [ABSTRACT FROM AUTHOR]

A new type of photocatalysts, nanocrystalline titanium dioxide (TiO2) doped with Co and I, were synthesized and modified via the sol-gel method to enhance the utilization of visible light. Herein, mono- and co-doped TiO2 (i.e. Co-TiO2, I-TiO2, Co-I-TiO2) were employed as the photocatalysts to investigate the photocatalytic performance on gaseous benzene removal. The prepared photocatalysts were characterized by X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET)-specific surface areas, Raman spectroscopy, UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and electrochemical impedance spectroscopy (EIS). Results indicated that both particle sizes and band gaps of TiO2 were significantly reduced by doping with Co/I. Also, the lattice defects and the specific surface areas of TiO2 were substantially augmented by adding Co/I because of the increase of oxygen vacancies, especially for Co-I-TiO2. Meanwhile, Co and I were distributed on the titanium base with the existence of multivalent states. The benzene treatment capacity of Co-I-TiO2, Co-TiO2, I-TiO2 and Pure TiO2 is 441.46, 424.36, 388.06, and 51.25 μgC6H6/(g·h), respectively. To sum up, photocatalytic degradation of gaseous benzene could be improved by doping with Co/I because of the extension of catalyst lifetime and light response range covering visible light. [ABSTRACT FROM AUTHOR]

The representation of chemical compounds and chemical networks with the ve-degree and ev-degree is a new idea, and it gives nice and good results of the topological descriptors. These results are utilized to relate the chemical compounds and chemical networks with their chemical properties and bioactivities. Also, the ve-degree and ev-degree topological descriptors are useful in calculation of π-electron energy, decision-making, Kovats constants, boiling point and stability alkanes. In this article, particular attention will be put on the derivation of ve-degree and ev-degree for the benzene ring embedded in the P-type surface network in 2D BR(p, q). In the end, the graphical representation and comparison of the ve-degree and ev-degree topological descriptors for BR(p, q) are discussed. [ABSTRACT FROM AUTHOR]

The study aimed to evaluated the relationship between BTEX (benzene, toluene, ethyl benzene and xylene) concentrations in the ambient air with human biomarkers in Assaluyeh city, Iran. According to the results, the average benzene concentration in the high pollution city was measured at 30.05 µg/m3, which is higher than the value recommended (0.03 mg/m3) by the U.S. Environmental Protection Agency (U.S. EPA). The mean spirometric parameters of the resident population in two high and low pollution areas were forced vital capacity (FVC) (high = 4.52; low = 4.78 L), forced expiratory volume in 1 second (FEV1) (high = 3.52; low = 3.88 L), FEV1/FVC (high = 77.9; low = 82.08%), peak expiratory flow (PEF) (high = 9.76; low = 27.85 L/min), and forced inspiratory flow 25–75% (FEF25-75) (high = 3.17; low = 3.95 L/s). Besides, no statistically significant difference was observed between the two groups by comparison of blood tests and the mean concentration of BTEX. BTEX concentration was measured at zero in low pollution areas due to lack of traffic and industries, but it was higher than the respiratory air standard and in the high-pollution area due to the being close to gas and petrochemical stations and industries in the surrounding. As a result, prolonged exposure to higher concentrations of BTEX increases the risks of respiratory dysfunction. [ABSTRACT FROM AUTHOR]

Two new metal-organic frameworks (MOFs) {[Cu3(timb)2(chtc)2]·14H2O}n, (I) and {[Co3(timb)2(chtc)2]·6H2O}n, (II) were hydrothermally synthesized by corresponding metal salt with mixed organic ligands of 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (timb) and cyclohexane-1,3,5-tricarboxylic acid (H3chtc). Crystal structural analysis reveals that they exhibit varied structures. In the MOFs (I), CuII adopts an four coordination geometry, timb and cyclohexane-1,3,5-tricarboxylate ligands bridge neighboring CuII centers to result in two different one-dimensional knotted chains along the [0 − 1 2] and [1 0 − 1] directions, respectively. The two kinds of chains intersect each other vis CuII centers, resulting in a two-dimensional layered structure running parallel to the (1 2 1) plane. Adjacent layers are further linked by water moleculars via classical O–H...O hydrogen-bonding interactions, giving rise to a three-dimensional supramolecular network structure in the solid state. While in MOFs (II), the cyclohexane-1,3,5-tricarboxylate anions link the CoII cations to generate a two-dimensional sheeted metal-organic structure running parallel to the bc plane. Adjacent sheets are further bridged by timb ligands, forming a porous three-dimensional metal-organic framework with a rare (3, 4)-connected (6.82)2(62.84)3(62.8)2 topology. The solvent water molecules guest in the micropores of porous framework via water-carboxylate O–H...O hydrogen bonds. In addition, their thermal stabilities have also been investigated. [ABSTRACT FROM AUTHOR]

The surface of low-rank coal has many oxygen functionalities, which leads to poor coal slime dehydration. To improve the effect of coal slime dewatering, sodium dodecyl benzene sulfonate (SDBS) was used as accelerator in the coal slime dehydration process. In addition, the mechanism of acceleration was studied using X-ray photoelectron spectroscopy (XPS) and molecular dynamics (MD) simulations. The results of dehydration experiments showed that adding a certain amount of SDBS into the slurry water was conducive to promoting the removal of water. When the concentration of the SDBS solution was 0.06 g/L, the water content of the filter cake decreased from an initial value of 59.98% to 54.55%. XPS measurements and MD simulations show that the polar groups (sulfonic acid) of SDBS are adsorbed on the oxygen-containing functional groups on the coal surface, thus, exposing the nonpolar groups (alkyl chains) of the molecule to the solution. The calculation of the self-diffusion coefficient (D) of water molecules in the simulated system indicate that the presence of SDBS improves the mobility of water at the coal surface, which is helpful in improving the loss of water from the coal surface, thus, improving its hydrophobicity. Crucially, the results of the MD simulations are consistent with those from experiment. Addition of a certain amount of SDBS helps to remove moisture from the coal slime. Oxygen-containing functional groups on the coal surface are effectively covered by SDBS. The interaction mechanism of SDBS at coal/water interface was studied by combining experiments and theoretical calculations. [ABSTRACT FROM AUTHOR]