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BackgroundA growing literature has reported associations between traffic-related air pollution and breast cancer, however there are fewer investigations into specific ambient agents and any putative risk of breast cancer development, particularly studies occurring in populations residing in higher pollution areas such as Los Angeles.ObjectivesTo estimate breast cancer risks related to ambient air toxics exposure at residential addresses.MethodsWe examined the relationships between ambient air toxics and breast cancer risk in the Multiethnic Cohort among 48,665 California female participants followed for cancer from 2003 through 2013. We obtained exposure data on chemicals acting as endocrine disruptors or mammary gland carcinogens from the National-Scale Air Toxics Assessment. Cox proportional hazards models were used to estimate breast cancer risk per one interquartile range (IQR) increase in air toxics exposure lagged by 5-years. Stratified analyses were conducted by race, ethnicity, and hormone receptor types.ResultsAmong all women, increased risks of invasive breast cancer were observed with toxicants related to industries [1,1,2,2-tetrachloroethane (hazard ratio [HR] = 4.22, 95% confidence interval [95% CI] 3.18-5.60), ethylene dichloride (HR = 2.81, 95% CI 2.20-3.59), and vinyl chloride (HR = 2.27, 95% CI 1.81, 2.85); these 3 agents were correlated (r2 = 0.45-0.77)]. Agents related to gasoline production or combustion were related to increased breast cancer risk [benzene (HR = 1.32, 95% CI 1.24, 1.41), ethylbenzene (HR = 1.20, 95% CI 1.13-1.28), toluene (HR = 1.29, 95% CI 1.20-1.38), naphthalene (HR = 1.11, 95% CI 1.02-2.22), acrolein (HR = 2.26, 95% CI 1.92, 2.65)]. Higher hazard ratios were observed in African Americans and Whites compared to other racial and ethnic groups (p-heterogeneity

Zeolites are widely used for removing volatile organic compounds (VOCs) in industrial processes. However, the understanding of the competitive adsorption behavior of multicomponent VOCs on zeolites remains insufficient. This study employed grand canonical Monte Carlo simulation to investigate the adsorption behaviors of nonpolar benzene and polar ethyl acetate in both pure and mixed forms on FAU, LTA and MFI zeolites. The effects of zeolite topology, Si/Al ratio, and compensating cations on competitive adsorption were explored. The results revealed that the adsorption capacities of benzene and ethyl acetate on FAU and LTA zeolites gradually increased with increasing Si/Al ratio, consistent with the increasing trends in their specific surface areas and pore volumes. However, the MFI zeolite shows no significant change in these properties with varying Si/Al ratios. Zeolites modified with Ca2+ significantly improved the benzene and ethyl acetate adsorption capacities, while impact on ethyl acetate adsorption is minimal. Zeolites modified with K+ reduced the adsorption capacities for both benzene and ethyl acetate. For binary mixtures, Na-FAU-1, Na-LTA-1, and Na-MFI-15 exhibited high selectivity for ethyl acetate. Increasing the Si/Al ratio and K+-modification reduced the adsorption selectivity of these zeolites for ethyl acetate. Ca2+-modification reduces the selectivity of LTA-1 toward ethyl acetate, with minimal impact on FAU-1 and MFI-15. Dynamic adsorption experiments with commercial zeolites confirm the reliability of the simulation results in predicting benzene and ethyl acetate adsorption performance. This study is expected to provide guidance for selecting appropriate zeolites for VOCs mixtures in practical applications. [ABSTRACT FROM AUTHOR]

Gracilaria sp. is a red macro-alga isolated from the marine environment of the Red Sea in Egypt. Unfortunately, this alga has not been well exploited yet in Egypt, thus the author preferred to highlight the economic importance of this alga. In this study, the chemical composition of the edible red seaweed Gracilaria sp. was evaluated via quantitative and qualitative tests using distilled water and two solvents (ethyl acetate and benzene) different in their polarity. The results showed that Gracilaria sp. contains a protein content of 22.75 %, fat of 1.01%, carbohydrate of 37.58% on dry weight basis, as well as pigments such as phycoerythrin, phycocyanin, allophycocyanin, β-carotene and chlorophyll a with yields of 3.8± 1.3, 1.8± 0.7, 0.9± 0.6, 7.7± 1.4, 1.6± 1.5mg/ ml D.W., respectively. Moroever, polysaccharide agar had a yield of 23.93% and total phenolic compounds of 54.5mg GAE/ g extract. Tests of the chemical composition of this alga showed the availability of many chemical compounds that have great economic importance in the field of medicine, pharmaceuticals, cosmetics, and food industries as an antioxidant IC50 27 ± 1.68mg/ ml, a bactericidal and fungicidal agent and as a bio pesticide in the field of agriculture. Egypt should also benefit from polysaccharide agar from Gracilaria sp. in biotechnology laboratories as growth media for bacteria, yeast, and fungi as well as the use of Gracilaria sp. pigments in the food and cosmetic industries as good natural colors. [ABSTRACT FROM AUTHOR]

Context: In the present work, we examined the sensing behavior of monolayer beta antimonide phosphorus (β-SbP) sheets towards toxic volatile organic compounds (VOCs) namely, 1,2-diethylbenzene and 2-ethyltoluene using density functional theory (DFT) method. At first, using cohesive energy structural stability of the monolayer β-SbP is confirmed. The calculated energy band gap value of monolayer β-SbP is 2.168 eV, which is a semiconductor. Furthermore, the adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP are studied through key factors, such as adsorption energy, Mulliken charge transfer, and relative band gap variation. The adsorption energy clearly shows (− 0.335 to − 0.903 eV) that both 1,2-diethylbenzene and 2-ethyltoluene are physisorbed on β-SbP monolayer. Besides, Mulliken charge transfer falls in the range of − 0.465 to 0.933 e; this information clearly shows that the β-SbP monolayer is a potential candidate for sensing 1,2-diethylbenzene and 2-ethyltoluene molecules. Methods: The structural firmness including electronic and adsorption properties of 1,2-diethylbenzene and 2-ethyltoluene on β-SbP monolayer are investigated with the support of the DFT method. Particularly, the hybrid generalized gradient approximation (hybrid GGA) along with Beck's three-parameter + Lee–Yang–Parr (B3LYP) exchange–correlation functional is utilized for relaxing the β-SbP monolayer. In the present work, all calculations are performed using the Quantum Atomistic Tool Kit (ATK) simulation package. In the present work, we utilized β-SbP monolayer as a chief sensing element to detect 1,2-diethylbenzene and 2-ethyltoluene to safeguard humans from toxic environments. [ABSTRACT FROM AUTHOR]

This study examined the artificial neural network (ANN) modeling of simultaneous biofiltration of methane (CH4) with two volatile organic compounds (VOCs): xylene and ethylbenzene, using an inorganic packed bed biofilter at an empty bed residence time (EBRT) of 4.5 min. Results showed that the removal efficiency (RE) of CH4 was in the range of 50 to 60% for concentrations of 1000 to 10,000 ppmv (0.6 to 6.5 g m−3), while the VOCs-REs were between 70 and 90% for X and EB concentrations in the range of 200 to 500 ppmv (0.9 to 2.2 g m−3). Artificial neural networks were used to predict and simulate the performances of the biofilter, based on a database containing previous biofiltration works. The ANN1 (architecture of 3 (input layer)-18 (hidden layer)-1 (output layer)) accurately predicted CH4 conversion at the pseudo-steadystate condition, while the ANN2 (4 (input layer)-18 (hidden layer)-2 (output layer)) predicted the simultaneous conversion of CH4 and VOCs with slightly lower accuracy than ANN1. The ANN3 (4 (input layer)-30 (hidden layer)-1 (output layer)) successfully predicted the acclimation period and final phase (CH4 concentration of 10,000 ppmv) of the biofilter but could not accurately predict the transient phases and showed differences (up to 20%) from experimental results once the CH4 concentration was changed. This study developed a decision support and prediction tool to anticipate the performance of biofilters in treating residual gases containing CH4 and VOCs, avoiding costs and delays associated with experimentation. [ABSTRACT FROM AUTHOR]

In this work, the precursors and intermediates of catalytic dehydrogenation of toluene, ethylbenzene, and styrene (TES) stream were detected, quantified, and classified at 750–800 °C. The classification approach for tracing the structural changes of the produced precursors was designed based on different residence times of intermediates, leading to the presentation of a morphology prediction model for precipitated coke according to the restriction of stream pass. The results revealed that the coke structure of encapsulating is formed by heavier precursors produced at a restricted direction of flow. On the other hand, the filamentous coke made from lighter precursors is formed at smooth streams with no restricted areas. [ABSTRACT FROM AUTHOR]

In this article, the concentration of some volatile organic compounds (VOCs) in the hot oil sample of the Pars petrochemical ethylbenzene unit is presented. Pars Petrochemical is one of the largest producers of ethylbenzene in the Middle East. The hot oil impurities that were analyzed were benzene and toluene (BT). The hot oil sample was taken in May 2023 at a special sampling station on the site. The presence of BT is related to its intensity in the hot oil sample. The Multiple Headspace Extraction (MHE) method was used for the extraction and quantitative analysis of BT followed by gas chromatography (GC) analysis. A GC with flame ionization detector (FID) instrument was used for the analysis of BT. This method offers advantages for the analysis of volatile pollutants because it eliminates the use of organic solvents and various sample purification steps that often lead to erroneous results. The MHE method is independent of standard concentration and could be used in a wide range of BT in Hot Oil without calibration for different ranges. Also, linearity, detection limits, and accuracy were looked into as part of the validation process. The limit of detection (LOD) and limit of quantification (LOQ), respectively, were between 0.05 - 0.56, and 0.17 - 1.9 mg/kg. Less than 13.95 percent (n= 15) was the relative standard deviation statistically. A quick and easy method for detecting BT in hot oil samples was used for the first time. This work will be a step forward for the detection of other aromatic and cyclic hydrocarbons in hot oil samples.

The purpose of this study was to assess the concentrations of persistent organic pollutants in the White Drin River, Kosovo region. The study focused on organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes. The White Drin River originates from Peja, Kosovo, and extends to the Albanian border near Kukesi, making it a significant water body. It is potentially affected by anthropogenic pollution due to its passage through Kosovo’s urban areas, villages, farms, and industries. Sampling was conducted at 15 stations along the river, from the river waterfall to the Albanian border, during two distinct periods in 2023 (January – February and August – September). Organochlorine pollutants were concurrently extracted using liquid-liquid extraction followed by analysis using capillary gas chromatography equipped with an electron capture detector. Polycyclic aromatic hydrocarbons were isolated through a two-step liquid-liquid extraction, with dichloromethane and hexane. Benzene, toluene, ethylbenzene, and xylenes were isolated using headspace solid – phase microextraction assisted by polydimethylsiloxane fibre. Qualitative and quantitative analyses of polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes, were conducted via gas chromatography with a flame ionization detector. The analyses showed the presence of persistent organic pollutants in the river water samples during both sampling periods. Elevated concentrations of volatile polychlorinated biphenyls, benzene, toluene, ethylbenzene, and xylenes, and polycyclic aromatic hydrocarbons, were observed in the water samples during both periods. This study underscores the significance of investigating organic pollutants in Kosovo’s water systems, considering both local geographic concerns and the broader global issue of environmental pollution

A series of mesoporous ceria-supported vanadium oxide catalysts were prepared and explored for aerobic oxidation of ethylbenzene to acetophenone without the involvement of any solvent or additive. Catalysts with varying contents of V2O5 (3, 6, and 10 wt%) on a mesoporous CeO2 support were prepared by the wet-impregnation method. Catalysts were characterized using techniques namely, XRD, Raman spectroscopy, BET surface area analysis, ICP-OES, FE-SEM, HR-TEM, XPS, and H2-TPR to establish a correlation between the physicochemical properties and catalytic performance. Among the investigated catalysts, the catalyst with 6 wt% of V2O5 on mesoporous ceria showed better activity with 69% ethylbenzene conversion and 88% acetophenone selectivity. The superior activity of this catalyst was ascribed to a strong synergetic interaction between ceria and vanadia as well as the formation of a CeVO4 phase, and a high specific surface area. The reaction parameters like temperature, pressure, and the amount of catalyst were optimized for possible commercial utilization. The stability of the catalyst was also investigated by the reusability test and was found to be stable and active up to five cycles. [ABSTRACT FROM AUTHOR]

In recent years, there has been a growing interest in developing portable and personal devices for measuring air quality and surrounding pollutants, partly due to the need for ventilation in the aftermath of COVID-19 situation. Moreover, the monitoring of hazardous chemical agents is a focus for ensuring compliance with safety standards and is an indispensable component in safeguarding human welfare. Air quality measurement is conducted by public institutions with high precision but costly equipment, which requires constant calibration and maintenance by highly qualified personnel for its proper operation. Such devices, used as reference stations, have a low spatial resolution since, due to their high cost, they are usually located in a few fixed places in the city or region to be studied. However, they also have a low temporal resolution, providing few samples per hour. To overcome these drawbacks and to provide people with personalized and up-to-date air quality information, a personal device (smartwatch) based on MEMS gas sensors has been developed. The methodology followed to validate the performance of the prototype was as follows: firstly, the detection capability was tested by measuring carbon dioxide and methane at different concentrations, resulting in low detection limits; secondly, several experiments were performed to test the discrimination capability against gases such as toluene, xylene, and ethylbenzene. principal component analysis of the data showed good separation and discrimination between the gases measured. [ABSTRACT FROM AUTHOR]

The purpose of this study was to assess the concentrations of persistent organic pollutants in the White Drin River, Kosovo region. The study focused on organochlorine pesticides, polychlorinated biphenyls, polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes. The White Drin River originates from Peja, Kosovo, and extends to the Albanian border near Kukesi, making it a significant water body. It is potentially affected by anthropogenic pollution due to its passage through Kosovo's urban areas, villages, farms, and industries. Sampling was conducted at 15 stations along the river, from the river waterfall to the Albanian border, during two distinct periods in 2023 (January - February and August - September). Organochlorine pollutants were concurrently extracted using liquid-liquid extraction followed by analysis using capillary gas chromatography equipped with an electron capture detector. Polycyclic aromatic hydrocarbons were isolated through a two-step liquid-liquid extraction, with dichloromethane and hexane. Benzene, toluene, ethylbenzene, and xylenes were isolated using headspace solid - phase microextraction assisted by polydimethylsiloxane fibre. Qualitative and quantitative analyses of polycyclic aromatic hydrocarbons, and benzene, toluene, ethylbenzene, and xylenes, were conducted via gas chromatography with a flame ionization detector. The analyses showed the presence of persistent organic pollutants in the river water samples during both sampling periods. Elevated concentrations of volatile polychlorinated biphenyls, benzene, toluene, ethylbenzene, and xylenes, and polycyclic aromatic hydrocarbons, were observed in the water samples during both periods. This study underscores the significance of investigating organic pollutants in Kosovo's water systems, considering both local geographic concerns and the broader global issue of environmental pollution. [ABSTRACT FROM AUTHOR]

Cyclooctene and alkylbenzenes are subjected to co-oxidation in oxygen and a system of two catalysts. Radical catalyst Fe(acac)3/NHPI mediates the formation of alkylbenzene hydroperoxides, which are consumed in situ during the MoO3/SiO2-catalyzed epoxidation of cyclooctene. The chain oxidation rate is limited in cyclooctene and MoO3/SiO2, but radical catalyst Fe(acac)3/NHPI retains fairly high activity in the oxidation of alkylbenzene in hydroperoxide. It is found that isopropylbenzene is a better co-reducing agent than ethylbenzene because it ensures more vigorous and selective formation of epoxycyclooctane. At optimized amounts of components and a temperature of 80°C, selectivity toward epoxycyclooctane reaches 92 and 96% in ethylbenzene or isopropylbenzene, respectively, with more than 70% conversion of cyclooctene. [ABSTRACT FROM AUTHOR]

Density and viscosity values of the binary mixture of ethylbenzene and aniline have been experimentally measured in different mole fractions at temperatures of 293.15 to 313.15 K and at an absolute pressure of 86.7 kPa. Based on the obtained experimental data, the excess molar volume and viscosity deviations have been reported, which can interpret the interactions in this mixture. The obtained data were fitted with the Redlich‐Kister equation. In addition, the viscosity results are discussed using the equation proposed by Gruenberg‐Nissan. After experimental studies, in order to investigate the interactions of these two components and their mixture, quantum mechanical calculations and molecular dynamics simulation have been used. In this way, the structures of the desired molecules have been optimized. Then Atoms in Molecules (AIM) and frontier molecular orbital (FMO) techniques have been used for a more detailed investigation. Finally, by plotting radial distribution functions (RDFs) obtained from molecular dynamics, these interactions have been investigated in a more comprehensive way. In addition, the simulated densities at 298.15 K have been reported. At the end, clear pictures of the interactions of molecules in mixtures were obtained by comparing the achievements of experimental measurements, quantum chemical and calculations MD simulation. [ABSTRACT FROM AUTHOR]

A rapid and mild coating strategy was applied on the millimeter scale calcium alginate capsules (Ca‐SA caps) by in situ interfacial polymerization of ethyl cyanoacrylate (ECA). The generated poly(ethyl cyanoacrylate) (PECA) coating was initiated by trace water in the surface of the Ca‐SA caps. The effects of ECA content, reaction time, and type of aromatic solvent on the morphology and control‐release property of the resulting PECA‐coated Ca‐SA caps (Ca‐SA caps@PECA) were investigated. The results demonstrated a white PECA layer successfully coated on the surface of Ca‐SA caps. Notably, the Ca‐SA caps@PECA remained consistently pleasing spherical shape as prepared in methylbenzene and ethylbenzene. When the ECA was 6 mL, the thickness of PECA layer of the Ca‐SA caps@PECA was 43.52 μm. Compared with the Ca‐SA caps, the weight retention ratio of water in the Ca‐SA caps@PECA increased by 254.61%, indicating the effective delay of water diffusion from core of the Ca‐SA caps@PECA. Moreover, the PECA coating improved the stability of the Ca‐SA caps@PECA, which achieved release‐controlling of dye at different pH. This method provides solution for surface modification of fragile hydrogel capsules to effectively control the releasing of liquid core, which is highly valuable in the field of food, cosmetic, and medical delivery. [ABSTRACT FROM AUTHOR]

Utilizing carbon dioxide as a carbon source for the synthesis of olefins and aromatics has emerged as one of the most practical methods for CO2 reduction. In this study, an improved selectivity of 85% for targeting products (ethylbenzene and propylbenzene) is achieved with a benzene conversion of 16.8% by coupling the hydrogenation of carbon dioxide to olefins over the bifunctional catalyst "Oxide-Zeolite" (OX-ZEO) and the alkylation of benzene with olefins over ZSM-5. In addition to investigating the influence of SAPO-34 and ZSM-5 zeolite acidity on product distribution, catalyst deactivation due to coke formation is addressed by modifying both molecular sieves to be hierarchical to extend the catalyst lifespan. Even after 100 h of operation at 400 °C, the catalysts maintained over 80% selectivity towards the target products, with benzene conversion over 14.2%. Furthermore, the pathway of propylbenzene formation is demonstrated through simple experimental design, revealing that the surface Brønsted acid sites of SAPO-34 serve as its primary formation sites. This provides a novel perspective for further investigation of the reaction network. [ABSTRACT FROM AUTHOR]

The densities (ρ), and ultrasonic speeds (u) of pure ethyl benzene, 1-butanol, 1-pentanol, and those of their binary mixtures, with ethyl benzene as a common component, covering the whole composition range have been measured at 298.15, 303.15, 308.15, 313.15, 318.15 and 323.15 K. From the experimental data the excess molar volume (VmE), deviations in isentropic compressibility (ΔKs) and deviations in ultrasonic speed (Δu) have been determined. The sign and magnitude of these parameters were found to be sensitive towards interactions prevailing in the studied systems. The excess or deviation properties (VmE, Δu, or ΔKs) have been correlated using a Redlich-Kister type equation to obtain their coefficients and standard deviations. The variations of derived parameters mentioned above with composition offer a convenient method to study the nature and extent of interactions between the component molecules of the liquid mixtures, which are not easily obtained by other means. [ABSTRACT FROM AUTHOR]

The development of highly active and selective photocatalytic systems for the oxidation of benzylic C(sp3)–H and C(sp3)–OH to C＝O bonds under solvent-free conditions with molecular oxygen as an oxidant is attractive and challenging. In this study, a carbon- and PdO-doped Nb2O5-based catalyst (PdO/C–Nb2O5) was designed and synthesized. This photocatalyst showed excellent solvent-free aerobic photocatalytic performances for two typical oxidation reactions of benzylic C(sp3)–H and C(sp3)–OH to C＝O compounds. It was found that the doping of carbon and PdO in Nb2O5 can modify its surface electrons, increase oxygen vacancies, and change the positions of its valence band and conduction band. Besides, the kinetic study showed that the oxidation of C–H in ethylbenzene to C–OH is the rate-limiting step in the two-step oxidation of ethylbenzene to acetophenone. Moreover, a photocatalytic reaction mechanism was proposed based on these experiments. In addition, the solvent-free aerobic photocatalytic oxidation system showed a good substrate tolerance for benzylic C(sp3)–H and C(sp3)–OH compounds with different substituents to the corresponding ketones and aldehydes. [ABSTRACT FROM AUTHOR]

To expand the market capacity of p‐diethylbenzene (PDEB), core‐shell zeolite (TS‐1@MCM‐48) is designed as a catalyst for PDEB oxidation. TS‐1@MCM‐48 catalyst is synthesized by in‐situ crystallization method and characterized by X‐ray diffraction (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM), X‐ray photoelectron spectroscopy (XPS), N2 adsorption‐desorption, in‐situ electron paramagnetic resonance (EPR) and 29Si nuclear magnetic resonance (29Si MAS‐NMR). Oxidation of PDEB by H2O2 was investigated systematically in liquid phase. The conversion of PDEB over TS‐1@MCM‐48 was 28.1 % and the total selectivity was 72.6 %, where the selectivity of EAP (p‐ethylacetophenone) and EPEA (4‐ethyl‐α‐methylbenzyl alcohol) was 28.6 % and 44.0 %, respectively. Compared with TS‐1 and MCM‐48 zeolite, the conversion rate of reactants and the selectivity of products have been significantly improved. The catalytic performance of TS‐1@MCM‐48 is derived from its well‐crystallized microporous core and mesoporous shell with regular channels, which make active sites of TS‐1 zeolite in the catalyst be fully utilized and mass transfer resistance be largely reduced. Further through theoretical calculation, we propose that the oxidation of PDEB is the result of the combination and mutual transformation of free radical process and carbocation process. Core‐shell structure ensures the conversion rate of raw materials and improves the selectivity of products. [ABSTRACT FROM AUTHOR]

Occupational health risk assessments of exposure to VOCs still need to be extensively studied to improve the safety standards in the industry. Based on the monitoring of organic pollutants at various workstations in a truck tire factory in Jiangsu Province, both semi-quantitative and quantitative health risk assessment methods were employed to assess health risk levels. The findings indicated that VOCs were categorized into five classes, which included alkanes, aromatics, halocarbons, carbon disulfide, and oxygenated volatile organic compounds (OVOCs). The highest concentration of total volatile organic compounds (TVOCs) was found in shaping workshop; alkanes were the most abundant class (74.2%), followed by aromatics (24.02%) and OVOCs (1.96%). Although the results of the semi-quantitative risk assessment showed that most of the organic compounds had low R values, various kinds of VOCs were detected; particularly, many harmful organic compounds (such as toluene, ethyl benzene) were detected in all the sampling sites. The quantitative risk in the calendering and vulcanizing workshop exceeded the acceptable level; both the carcinogenic risk of ethylbenzene in the tire-strip storage room, and trichloroethylene and perchloroethylene in the calendering workshop were unacceptable. Thus, the calendering and vulcanizing processes in rubber tire manufacturing should be priority-controlled processes. [ABSTRACT FROM AUTHOR]

A rapid increase in viscosity during the polymerization process impacts the polymerization rate. To address this issue, ethylbenzene is often introduced into the polymerization system in order to reduce viscosity. The thermal characteristics of styrene–ethylbenzene polymerization have been identified using differential scanning calorimetry. The rate of heat generation significantly decreases as the proportion of ethylbenzene increases. The polymerization product mixtures were analyzed using gel permeation chromatography. Polymerization at low viscosity yields a higher proportion of low molecular mass polymers and a more uniform distribution of product chain lengths compared to polymerization at high viscosities. The glass transition temperature and the activation energy for viscous flow of the products were also determined. The apparent kinetics of styrene polymerization may be described using the "autocatalytic + Nth-order" model. Two stages of monomer conversion are apparent: polymerization reactions initiated by AIBN and thermally induced polymerization. Valuable insights into the polymerization process which can contribute to the optimization of industrial polymerization reactions have been obtained. [ABSTRACT FROM AUTHOR]

Herein, it is aimed to investigate the effect of zeolite catalyst on the co‐pyrolysis process of waste tyre and poplar wood. A laboratory‐sized reactor is used to pyrolyze 15 g of sample at 500 °C under atmospheric pressure. In the results, it is indicated that co‐pyrolysis affects the properties of the products. Comparing to single feedstock, the co‐pyrolysis enhances the yields of bio‐oil, while reducing the formation of char. The pyrolysis of poplar wood produces 23.3 wt% of bio‐oil, while the pyrolysis of tyre yields 25 wt% of bio‐oil. However, it is 31.29 wt% for the co‐pyrolysis process. Higher content of valuable compounds are formed in the bio‐oil, which improve the fuel properties of the bio‐oil. The zeolite catalyst alters the characteristics of the products obtained from the co‐pyrolysis process. The gaseous products show a decrease in the concentrations of carbon monoxide and carbon dioxide when the catalyst is present. The liquid product analysis reveals the presence of light aromatics such as ethyl benzene and light linear compounds such as alkanes including octane, hexane, etc. The analysis of the catalysts suggests that a very small amount of coke deposits on the catalyst due to the slight increase in carbon content. [ABSTRACT FROM AUTHOR]

A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin, Beibuwan Basin, and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GCTOFMS). By analyzing the distribution characteristics of C0eC5 alkylbenzenes, it is found that the content of some alkylbenzenes varies greatly in crude oils. Based on the distribution characteristics of 1,2,4,5- tetramethylbenzene (TeMB) and 1,2,3,4-TeMB, the ratio of 1,2,4,5-TeMB to 1,2,3,4-TeMB is proposed to indicate the organic matter origin and depositional environment of ancient sediments. Oil samples originated mainly from lower hydrobiont, algae, bacteria and source rocks deposited under reducing/ anoxic conditions have low 1,2,4,5-/1,2,3,4-TeMB values (less than 0.6), while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-TeMB values (greater than 1.0). The significant difference of 1,2,4,5-/1,2,3,4-TeMB values is controlled by 1,2,4,5-TeMB content. 1,2,4,5-TeMB content in oils derived from source rocks deposited in oxidized sedimentary environment (greater than 1.0 mg/g whole oil) is higher than that in oils from source rocks deposited in reduced sedimentary environment (less than 1.0 mg/g whole oil). 1,2,4,5-/1,2,3,4-TeMB ratio might not or slightly be affected by evaporative fractionation, biodegradation and thermal maturity. 1,2,4,5-/1,2,3,4-TeMB ratio and 1,2,4,5-TeMB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input. It should be noted that compared to the identification of organic matter sources, the 1,2,4,5-/1,2,3,4-TeMB parameter is more effective in identifying sedimentary environments. [ABSTRACT FROM AUTHOR]

This work presents the first example of the utilization of polar ester group functionalized pillar[6]arene (P6A-C10-OAc) as a stationary phase for capillary gas chromatographic (GC) separations. The statically coated P6A-C10-OAc column showed a high column efficiency of 5393 plates/m and moderate polar nature. Its resolving capability and retention behaviors were investigated for a mixture of 20 analytes and more than a dozen isomers from apolar to polar in nature. As evidenced, the P6A-C10-OAc column achieved high-resolution separations of all the analytes and good inertness. Importantly, it exhibited distinctly advantageous performance for high resolution of the challenging isomers of xylenes, diethylbenzenes, ethyltoluenes, and halobenzenes over the commercial HP-5 (5% phenyl dimethyl polysiloxane), HP-35 (25% phenyl dimethyl polysiloxane), and PEG-20M (polyethylene glycol) columns. [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]

Mandatory use of low-sulfur fuel according to global sulfur limit regulation has reduced the emissions of SO2 and PM significantly on ships, while it also leads to very large uncertainty on VOCs emission. Therefore, on-board test of VOCs from 9 typical cargo ships with low-sulfur fuels in China were carried out in this study. Results showed that emission factor of VOCs (EFVOCs) varied largely from 0.09 to 3.01 g kg-1 fuel, with domestic coastal cargo ships (CCSs) had the highest levels and ocean-going vessels (OGVs) the lowest. The switch of fuels from heavy fuel oil (HFO) to diesel increased EFVOCs by 48 % on average, which enhanced both O3 and secondary organic aerosol (SOA) formation potentials, especially for OGVs. Besides, the use of low-sulfur fuels for OGVs also lead to significant increase of naphthalene emission. These indicated the implementation of globally ultra-low-sulfur oil policy in the near future needs to be optimized. Moreover, aromatics were the most important common contributors to O3 and SOA in ship exhausts, which need to be controlled with priority. It was also found that benzene, toluene, and ethylbenzene ratio of 0.5:0.3:0.2 on average could be considered as a diagnostic characteristic to distinguish ship emission from other emission sources. [ABSTRACT FROM AUTHOR]

Introduction: Considering the adverse carcinogenic and non-carcinogenic health effects of Volatile Organic Compounds (VOC) and specially Benzene, Toluene, Ethylbenzene and Xylenes (BTEX) which are widely used in vehicle manufacturing industry, it is clear that monitoring and control of occupational exposure to these substances is of utmost significance. More often than not the studies on occupational exposure to VOCs in vehicle manufacturing industry—specifically BTEX—have been carried out exclusively in paint shop units. The purpose of this study was to assess occupational BTEX exposure & health risk in different units of a vehicle manufacturing industry. Material and methods: Foam injection unit (FIU), gluing unit (GU), repair shop unit (RSU), molding unit (MU) as well as paint shop units (PSU) were selected for this study. Sampling and analysis were conducted based on National Institute for Occupational Safety and Health (NIOSH) 1501 guidelines by utilizing MSA personal sampling pumps set to 0.2 l/m and Gas Chromatography equipped with Flame Ionization Detector (GC-FID). Risk characterization and assessment was performed using Environmental Protection Agency Risk Assessment Information System (EPA RAIS). Results and conclusion: The results revealed that the concentration of benzene in gluing and paint shop units was above occupational exposure limits. Carcinogenic risk levels in 8 out of 10 units registered in the 1E-2 to 1E-4 range, and only two units registered a risk level below EPA's acceptable risk level (10–6). The highest risk levels were measured in gluing, paint shop and repair shop units. Furthermore, the total non-carcinogenic hazard quotient was measured higher than 1 in 8 out of 10 studied units. Considering the abundance and wide use of VOCs -most notably BTEX- and the adverse carcinogenic and non-carcinogenic health effects of these compounds, it is advised to: change the type of paint used in paint shops, improve the existing ventilation systems, develop new and more efficient ventilation systems and conduct consistent training. Highlights: In this paper, we report on the levels of occupational exposure workers encounter on a daily basis to a specific group of Volatile Organic Compounds (VOC): Benzene, Toluene, Ethylbenzene and Xylene(s) (BTEX) in various sections of a vehicle manufacturing industry and the resulting health risks. Reviewing previous studies revealed that as a result of low occupational exposure to BTEX in vehicle manufacturing industry, more often than not the studies on said compounds and the ensuing health effects were exclusively carried out in paint shop units, ignoring health risks in other units & creating the assumption that health risks in other units are negligible. The purpose of this study was to assess occupational BTEX exposure and its associated health risk in different units of a vehicle manufacturing industry, including foam injection unit (FIU), gluing unit (GU), repair shop unit (RSU), molding unit (MU) as well as paint shop units (PSU). Revealing the possibility of exposure to BTEX not only in paint shop units but also other previously disregarded units, the health risk calculated in some units such as gluing unit was higher than the EPA acceptable risk range (10-4). Moreover, cancer risk levels of molding (Unit No 6) and repair shop (Unit No 7) units registered in the 10-4 to 10-2 range despite meeting the TLV-TWA (0.174 PPM and 0.449 PPM respectively), suggesting the need for implementation of a health risk assessment in conjunction with exposure assessment. [ABSTRACT FROM AUTHOR]

Production of commodity chemicals, such as benzene, toluene, ethylbenzene, and xylenes (BTEX), from renewable resources is key for a sustainable society. Biocatalysis enables one‐pot multistep transformation of bioresources under mild conditions, yet it is often limited to biochemicals. Herein, we developed a non‐natural three‐enzyme cascade for one‐pot conversion of biobased l‐phenylalanine into ethylbenzene. The key rate‐limiting photodecarboxylase was subjected to structure‐guided semirational engineering, and a triple mutant CvFAP(Y466T/P460A/G462I) was obtained with a 6.3‐fold higher productivity. With this improved photodecarboxylase, an optimized two‐cell sequential process was developed to convert l‐phenylalanine into ethylbenzene with 82 % conversion. The cascade reaction was integrated with fermentation to achieve the one‐pot bioproduction of ethylbenzene from biobased glycerol, demonstrating the potential of cascade biocatalysis plus enzyme engineering for the production of biobased commodity chemicals. [ABSTRACT FROM AUTHOR]

This study aimed to examine the impacts of single and multiple air pollutants (AP) on the severity of breast cancer (BC). Data of 1148 diagnosed BC cases (2008–2016) were obtained from the Cancer Research Center and private oncologist offices in Tehran, Iran. Ambient PM10, SO2, NO, NO2, NOX, benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, and BTEX data were obtained from previously developed land use regression models. Associations between pollutants and stage of BC were assessed by multinomial logistic regression models. An increase of 10 μg/m3 in ethylbenzene, o-xylene, m-xylene, and 10 ppb of NO corresponded to 10.41 (95% CI 1.32–82.41), 4.07 (1.46–11.33), 2.89 (1.08–7.73) and 1.08 (1.00–1.15) increase in the odds of stage I versus non-invasive BC, respectively. Benzene (OR, odds ratio = 1.16, 95% CI 1.01–1.33) and o-xylene (OR = 1.18, 1.02–1.38) were associated with increased odds of incidence of BC stages III & IV versus non-invasive stages. BC stage I and stage III&IV in women living in low SES areas was associated with significantly higher levels of benzene, ethylbenzene, o-xylene, and m-xylene. The highest multiple-air-pollutants quartile was associated with a higher odds of stage I BC (OR = 3.16) in patients under 50 years old. This study provides evidence that exposure to AP is associated with increased BC stage at diagnosis, especially under premenopause age. [ABSTRACT FROM AUTHOR]

A comprehensive density functional theory investigation has been presented towards the comparison of the C–H activation reactivity between high-valent iron-oxo and ruthenium-oxo complexes. A total of four compounds, e.g., [Ru(IV)O(tpy-dcbpy)] (1), [Fe(IV)O(tpy-dcbpy)] (1′), [Ru(IV)O(TMCS)] (2), and [Fe(IV)O(TMCS)] (2′), have been considered for this investigation. The macrocyclic ligand framework tpy(dcbpy) implies tpy = 2,2′:6′,2′′-terpyridine, dcbpy = 5,5′-dicarboxy-2,2′-bipyridine, and TMCS is TMC with an axially tethered –SCH2CH2 group. Compounds 1 and 2′ are experimentally synthesized standard complexes with Ru and Fe, whereas compounds 1′ and 2 were considered to keep the macrocycle intact when switching the central metal atom. Three reactants including benzyl alcohol, ethyl benzene, and dihydroanthracene were selected as substrates for C–H activation. It is noteworthy to mention that Fe(IV)O complexes exhibit higher reactivity than those of their Ru(IV)O counterparts. Furthermore, regardless of the central metal, the complex featuring a tpy-dcbpy macrocycle demonstrates higher reactivity than that of TMCS. Here, a thorough analysis of the reactivity-controlling characteristics—such as spin state, steric factor, distortion energy, energy of the electron acceptor orbital, and quantum mechanical tunneling—was conducted. Fe(IV)O exhibits the exchanged enhanced two-state-reactivity with the quintet reactive state, whereas Ru(IV)O has only a triplet reactive state. Both the distortion energy and acceptor orbital energy are low in the case of Fe(IV)O supporting its higher reactivity. All the investigated C–H activation processes involve a significant contribution from hydrogen tunneling, which is more pronounced in the case of Ru, although it cannot alter the reactivity pattern. Furthermore, it has also been found that, independent of the central metal, aliphatic hydroxylation is always preferable to aromatic hydroxylation. Overall, this work is successful in establishing and investigating the cause of enzymes' natural preference for Fe over Ru as a cofactor for C–H activation enzymes. [ABSTRACT FROM AUTHOR]

The efficient conversion of ethane has attracted more and more attention because of the shale gas revolution. The coupling of ethane dehydrogenation (EDH) and benzene alkylation over the 1.5Pt/HZSM-5 realize high activity close to the thermodynamic equilibrium of EDH at 500 ℃ and 0.9 bar ethane partial pressure. Meanwhile, the coupled reaction shows long-term stability during 22 h with a slightly decreased ethane conversion of 0.03% per hour and as high as 42% selectivity of ethylbenzene. Based on various characterization, including XRD, HR-TEM, NH3-TPD, Py-IR, TGA, it is confirmed that the coupling reaction could convert ethylene, formed by EDH over Pt sites, to ethylbenzene via benzene alkylation over Brönsted acidic sites (BAS) subsequently, and suppressing the sintering of Pt species and coke deposition induced by aromatization and deep dehydrogenation, resulting in high activity and long-time steady state. [ABSTRACT FROM AUTHOR]

Styrene polymerization is a strong exothermic reaction, where the reactants, initiators and diluents are flammable and explosive substances. Once the reaction is out of control, it is extremely easy to cause fire and explosion accidents. In order to analyze the thermal hazards of styrene polymerization reactions, the thermal behaviors of reactions at different reaction conditions are investigated in this paper. Differential scanning calorimeter (DSC) and adiabatic rate calorimeter (ARC) were used to study thermal behavior of styrene polymerization reactions initiated by dual initiators (azodiisobutyronitrile/tert-butyl peroxybenzoate) with different ratios. Reaction calorimetric experiments were performed via reaction calorimeter (RC1e) to analyze the process hazard and calculate thermal hazard parameters. Subsequently, the thermal decomposition properties of the polymerization products were studied by simultaneous thermal analyzer (TGA–DSC). Moreover, the apparent activation energy (Ea) during product decomposition was calculated by Starink and Friedman methods. The results show that the presence of initiators increases the risk of thermal runaway of the reaction. The thermal hazard of styrene polymerization can be reduced due to the addition of ethylbenzene. The most serious consequences of thermal runaway were caused at an early stage. It can be concluded that the reaction of the system containing AIBN initiator reacts at a lower temperature, while the reaction of the system with TBPB is relatively lagged. This study is valuable for the selection of initiator in the polymerization reaction process. [ABSTRACT FROM AUTHOR]

One of the steps in scaling the technology for the synthesis of zeolite-containing catalysts from the laboratory to commercial level is support forming. In this study, halloysite nanotubes and aluminum oxide were used as binders for preparing a support based on MFI (ZSM-5) zeolite. The Pt catalysts (Pt/ZSM-5/Al2O3 and Pt/ZSM-5/Hall) were tested in isomerization of the aromatic C8 fraction. The forming of supports influenced not only mechanical but also physicochemical properties of the catalysts. On introducing binders into the catalytic system, the fraction of mesopores in the total pore volume of the supports increased, the acidity of the samples decreased, and the ratio of the amounts of the weak and strong acid sites changed. The use of aluminum oxide and halloysite as binders leads to different pathways of the transformation of the aromatic feedstock. The main side reactions observed in the presence of Pt/ZSM-5/Al2O3 and Pt/ZSM-5/Hall catalysts are hydrocracking of alkylaromatic hydrocarbons and their transalkylation/disproportionation, respectively. The best results were obtained at 380°C and feed space velocity of 6 h–1 with Pt/ZSM-5/Hall: p-/о-xylene ratio 1.05, loss of xylenes 4.31%, and ethylbenzene conversion 34%. [ABSTRACT FROM AUTHOR]

The kinetically-derived maximal dose (KMD) is defined as the maximal external dose at which kinetics are unchanged relative to lower doses, e.g., doses at which kinetic processes are not saturated. Toxicity produced at doses above the KMD can be qualitatively different from toxicity produced at lower doses. Here, we test the hypothesis that neoplastic lesions reported in the National Toxicology Program's (NTP) rodent cancer bioassay with ethylbenzene are a high-dose phenomenon secondary to saturation of elimination kinetics. To test this, we applied Bayesian modeling on kinetic data for ethylbenzene from rats and humans to estimate the Vmax and Km for the Michaelis–Menten equation that governs the elimination kinetics. Analysis of the Michaelis–Menten elimination curve generated from those Vmax and Km values indicated KMD ranges for venous ethylbenzene of 8–17 mg/L in rats and 10–18 mg/L in humans. Those venous concentrations are produced by inhalation concentrations of around 200 ppm ethylbenzene, which is well above typical human exposures. These KMD estimates support the hypothesis that neoplastic lesions seen in the NTP rodent bioassay occur secondary to saturation of ethylbenzene elimination pathways and are not relevant for human risk assessment. Thus, ethylbenzene does not pose a credible cancer risk to humans under foreseeable exposure conditions. Cancer risk assessments focused on protecting human health should avoid endpoint data from rodents exposed to ethylbenzene above the KMD range and future toxicological testing should focus on doses below the KMD range. [ABSTRACT FROM AUTHOR]

Benzene, toluene, ethyl benzene, and xylene (BTEX) are prevalent pollutants in shoe industry-related workplaces. The aim of this study was to assess exposure to BTEX and their carcinogenic and non-carcinogenic risks in shoe-industry-related workplaces. This study was carried out at different shoe manufactures, small shoe workshop units, shoe markets, and shoe stores in Tabriz, Iran in 2021. Personal inhalation exposure to BTEX was measured using the National Institute for Occupational Safety and Health (NIOSH) 1501 method. Carcinogenic and non-carcinogenic risks due to inhalation exposure to BTEX were estimated by United States Environmental Protection Agency (U.S. EPA) method based on Mont Carlo simulation. Results showed that the concentrations of benzene and toluene were higher than the threshold limit value (TLV) in both gluing and non-gluing units of shoe manufactures. The total carcinogenic risk (TCR) due to exposure to benzene and ethyl benzene was considerable in all shoe industry-related workplaces. Also, the hazard index (HI) as a non-carcinogenic index was higher than standard levels in all shoe industry-related workplaces. Therefore, shoe industry-related workers are at cancer and non-cancer risks due to exposure to BTEX. Prevention measures need to be implemented to reduce the concentration of BTEX in shoe industry-related workplaces. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Faculty of Pharmacy of Ankara University / Ankara Üniversitesi Eczacilik Fakültesi Dergisi is the property of Ankara University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This perspective paper aims to spark a fundamental debate on the key laws that would combine the nano- to micro-scale flow dynamics of resident contaminants in soil systems under supercritical phase-assisted transportation. The rank of supercritical solvents (SCFs) for hazardous polycyclic aromatic hydrocarbons, benzene, toluene, ethylbenzene, and xylenes is deeply discussed beside its confines to meet the current requests of in situ/ex situ fields. The scaling behaviors during soil–pollutants–SCFs interactions are highlighted to underline the hidden laws behind the basic transportation under flooding remediation. A new strategy based on artificial intelligence learning is emphasized with a demonstrative sample to predict the solubility behavior of this kind of contaminants during a spatiotemporal mechanism. This debate illustrates the conjugate experimental and numerical pathways to deal with the complex nano-remediation dynamics and sheds the light on the current trends and future outlook with techno-economic concerns to promote the faith of a clean and sustainable environment. [ABSTRACT FROM AUTHOR]

Copyright of Applied Chemical Industry is the property of Shaanxi Research Design Insitute of Petroleum & Chemical Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The reactions of two complexes [(RNHP)Mn(CO)4] (RNHP=N‐arylated N‐heterocyclic phosphenium) with H2 at elevated pressure (≈4 bar) were studied by NMR spectroscopy. Irradiation with UV light initialized in one case (5 a, R=Dipp) the unselective formation of (RNHP‐H)MnH(CO)4] (6 a) via cooperative addition of H2 across the Mn=P double bond. In the other case (5 b, R=Mes), addition of H2 was unobservable and the reaction proceeded via decarbonylation to a dimeric species [(RNHP)2Mn2(CO)7] (7 b) that was isolated and identified spectroscopically. Taking into account the outcome of further reaction studies under various conditions in the absence and presence of H2, both transformations can be explained in the context of a common mechanism involving decarbonylation to 7 a,b as the first step, and the different outcome is attributable to the fact that 7 b is unreactive towards both H2 and CO while 7 a is not. DFT studies relate this divergence to deviations in the molecular constitution and stability arising from a different level of steric congestion. Preliminary studies suggest further that 5 a/H2 as well as 6 a enable the photo‐induced hydrogenation of styrene to ethyl benzene, even if the mechanism and possibly catalytic nature of this process remain yet unknown. [ABSTRACT FROM AUTHOR]

Copyright of Applied Chemical Industry is the property of Shaanxi Research Design Insitute of Petroleum & Chemical Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Anodized TiO2 nanotube fibers using in-headspace solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS) have been exploited as an analytical method for volatile organic compounds such as benzene, toluene, ethylbenzene, and xylenes (BTEX) detection. The factors of anodizing time and annealing temperature for TiO2 nanotube production are studied and the adsorption factors (time, ionic strength, and temperature) and desorption factors (time and temperature) for BTEX analysis are optimized. The limit of detections (LODs) for benzene, toluene, ethylbenzene o-xylene, and m, p-xylene are 0.5, 0.1, 1.0, 1.0, and 2.0 µg L-1, respectively. The linear ranges for BTEX (0.5-15,000 µg L-1) and satisfactory linearity (R² ≥ 0.9954) are obtained. This method is successfully applied in real samples with the recoveries ranging from 92% to 97%. TiO2 nanotube fiber is a promising technique for BTEX analysis. [ABSTRACT FROM AUTHOR]

The main objective of this study is to enhance the valuable octane booster aromatics benzene, toluene, and ethylbenzene (BTE) and reduction of styrene in the fuel oil obtained from the pyrolysis of equally mixed waste expanded polystyrene (WEPS) and waste high density polyethylene (WHDPE). This research article, demonstrated the pyrolysis of equally mixed (50 wt.%:50 wt.%) waste expanded polystyrene (WEPS) and waste high-density polyethylene (WHDPE) followed by in situ-hydrogenation and aromatization in a small laboratory scale reactor for the production of value added commodity and gasoline octane boosters mainly benzene, toluene, and ethylbenzene (BTE). Three reactor arrangements i.e., liquid phase/L-type, vapour phase/V-type, and multiphase/M-type were used for conducting the catalytic pyrolysis of feedstock using ZSM-5, ammonium powder as a catalyst. The maximum liquid yield of 87.41 wt.% was obtained for thermal pyrolysis at a temperature of 650°C and at a heating rate of 15°C/min. Whereas, the maximum liquid yield of 82.65 wt.% was obtained for liquid phase/L-type catalytic pyrolysis at a temperature of 600°C, and at a heating rate of 15°C/min. On the other side, vapour phase/V-type and multiphase/M-type catalytic pyrolysis produced a maximum liquid yield of 78.62 wt.% and 74.07 wt.%, respectively at a reaction temperature of 550°C and at the same heating rate. The pyrolysis oil obtained from thermal pyrolysis contained lowest BTE content of 10.43 wt.% and highest styrene content of 66.25 wt.%. Whereas, the highest BTE content of 30.16 wt.% and lowest styrene content of 53.32 wt.% was found in pyrolysis oil obtained from multiphase/M-type catalytic pyrolysis. The quantitative measurement of BTE and styrene content in the pyrolysis oil was made by the gas chromatography (GC) in a flame ionization detector (FID) mode. Graphical Abstract [ABSTRACT FROM AUTHOR]

A hybrid structured honey-comb photonic crystal fiber sensor is designed to detect the sensitivity of methyl salicylate (C8H8O3), arsenic trichloride (AsCl3), and ethylbenzene (C8H10) analytes. The cladding portion of the proposed structure consists of both circular and hexagonal holes in the form of a hexagon with a honeycomb arrangement. Moreover, the structure has a circular core with the chosen analyte. The design is investigated in the scope of wavelength ranging from 0.4 to 1.75 µm. The hybrid photonic crystal fiber sensor displays a sensitivity of 85.05%, 87.89%, 82.73% for methyl salicylate, arsenic trichloride, and ethylbenzene, respectively at 1.550 µm. [ABSTRACT FROM AUTHOR]

Ho Chi Minh City (HCMC) is one of the main socioeconomic and financial centers of Vietnam. The city also faces serious air pollution. However, the city polluted with benzene, toluene, ethylbenzene, and xylene (BTEX) has rarely been studied. We used positive matrix factorization (PMF) to analyze BTEX concentrations measured at two sampling locations to identify the main sources of BTEX in HCMC. The locations represented residential area (i.e., To Hien Thanh) and industrial area (i.e., Tan Binh Industrial Park). At the To Hien Thanh location, the average concentrations of benzene, ethylbenzene, toluene, and xylene were 6.9, 14.4, 4.9, and 12.7 µg/m3, respectively. At the Tan Binh location, the average concentrations of benzene, ethylbenzene, toluene, and xylene were 9.8, 22.6, 2.4, and 9.2 µg/m3, respectively. The results showed that PMF was a reliable model for source apportionment in HCMC. Traffic activities were the main sources of BTEX. Besides, industrial activities also contributed to BTEX emissions, especially the location near the industrial park. The majority of BTEXs at the To Hien Thanh sampling site come from traffic sources accounting for 56.2%. Activities from traffic and photochemical reactions (42.7%) and industrial sources (40.5%) were the main sources affecting BTEX emissions at the sampling site of Tan Binh Industrial Park. This study can be used as a reference for mitigation solutions to reduce the BTEX emission in HCMC. [ABSTRACT FROM AUTHOR]

The standard method to evaluate human exposure to volatile organic compounds (VOCs) is in general performed by sampling the air on sorbents followed by liquid extraction and detection using laboratory gas chromatograph (GC). The conventional method is time and labor intensive and employs a toxic solvent which adds a risk factor as well as waste. Hence, there have been increasing demands for portable GC instruments which allow near real-time, in-situ analysis. In this study, the potential use of a prototype, dual column portable GC (protoGC) with flame ionization detector (FID) was examined by comparing its performance with a conventional GC laboratory method. Four target concentration levels (1x, 2x, 4x, and 8x; x = 1.12 ± 0.01 ppm) of toluene, ethylbenzene, and o-, m-, and p-xylene were generated in an exposure chamber (24 ± 1 °C and 50 ± 5% RH). The challenge atmosphere was directly sampled and analyzed with protoGC while for the conventional method it was sampled on a sorbent tube and analyzed with a laboratory GC/FID. The results of protoGC correlated well with the conventional method (r = 0.991–0.999), indicating that protoGC has comparable performance with the conventional method within the test conditions. Although two-way ANOVA showed significant differences in mean concentrations between the methods, the differences were small. protoGC would be useful to monitor VOCs in air with high temporal resolution or to quickly determine the safety of the environment of interest due to the substantial time savings in sampling and analysis. Further examinations at various environmental conditions and other analytes will be necessary to thoroughly evaluate its performance. [ABSTRACT FROM AUTHOR]

In this research, the feasibility study of revamping of simulated moving bed for paraxylene separation in ELUXYL process to produce meta-xylene using industrial Ba-faujasite exchanged adsorbent by changing operating condition (temperature and pressure) were examined experimentally and theoretically. Two different mixed-xylene feed cases (with and without presence of para-xylene) were considered. Different sets of temperature and pressure were evaluated with the help of equilibrium and dynamic experiments to obtain optimum operating condition in a favor of separation of meta-xylene. Results confirm that in the presence of para-xylene in a feed, selectivity of the adsorbent could not change towards meta-xylene. But, in the absence of para in some pressure and temperature meta-xylene was more selective than ortho and ethylbenzene. Finally, by the means of statistical experimental design method the results of all experiments were compered and an optimum temperature and pressure were found. Breakthrough experiment in optimum condition showed MX/OX and MX/EB selectivity as 1.83 and 1.15, respectively. Furthermore, the design and simulation of the real industrial SMB plant was performed in Aspen Chromatography and HYSYS software to evaluate the real performance of MX separation. Simulation results showed the final purification in SMB plant can be reached to 83.91%. At the end, for the aim of promoting purity by considering extra distillation towers the purity of meta-xylene was achieved by 96%. The economical investigation showed that by considering 700$/ton for feed supplied, the process can be satisfactory from economical point of view. [ABSTRACT FROM AUTHOR]

Exfoliated graphitic carbon nitride (eg‐C3N4) material was applied as a support to load cobalt catalysts (CoOx/eg‐C3N4) through a simple impregnation method. The physical and chemical properties of the synthesized CoOx/eg‐C3N4 materials were characterized by a series of analytic techniques including XRD, SEM, FT‐IR, UV–vis, and XPS. The characterization results revealed that the introduction of Co2+ species had not altered the graphitic structure of eg‐C3N4. The Co2+ species probably coordinatively interact with the nitrogen‐containing group of eg‐C3N4. The catalytic performances of the CoOx/eg‐C3N4 were evaluated in the solvent‐free selective oxidation of ethylbenzene (EB) using molecular oxygen as an oxidant. Among the 3CoOx/eg‐C3N4 materials with various preparation temperatures, 3CoOx/eg‐C3N4‐400 exhibited the highest EB conversion, which was owing to its superior percentages of Co2+ and tertiary nitrogen species. [ABSTRACT FROM AUTHOR]

Copyright of Petroleum Refinery Engineering is the property of Petroleum Refinery Engineering Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The extractive distillation was used to separate ethylbenzene and m-xylene. After the solvent screening, 1,2,4-trichlorobenzene was chosen as the extractive solvent. The vapor–liquid equilibrium (VLE) of binary mixtures of m-xylene, ethylbenzene, and 1,2,4-trichlorobenzene was measured at 101.33 kPa. The measurements were taken with a modified Rose equilibrium still. The Wisniak's test was used to assess the thermodynamic consistency of the VLE experimental results. To obtain the binary interaction parameters, the binary VLE experimental data were correlated with the NRTL, Wilson, and UNIQUAC activity coefficient models. The results showed that three models all fit the experimental values of three binary systems well, and the ternary VLE data of m-xylene + ethylbenzene + 1,2,4-trichlorobenzene were estimated using Aspen Plus V11 based on these model parameters. The experimental data agree well with the estimation values generated from three models. Finally, the effect of 1,2,4-trichlorobenzene as an extractant was analyzed, and it is proved to have a good influence on the separation of ethylbenzene from mixed xylenes by extractive distillation. [ABSTRACT FROM AUTHOR]