Toluene Research Articles

The Effect of Thermochemical Sulphate Reduction on the Carbon Isotope Ratio of Individual Light Hydrocarbons Associated With Natural Gas

To understand the effect of thermochemical sulphate reduction (TSR) on the stable carbon isotopes of light hydrocarbons (LHs) associated with natural gas, 15 gases with varying H2S content from Ordovician reservoir of the Tazhong gas field (TZ-I) in Tarim Basin and Triassic Leikoupo reservoir of the Zhongba gas field (ZB) in Sichuan Basin were collected. Based on the data from molecular components and stable carbon isotope ratios of the C1-C4 alongside the individual LHs (C6-C7) in these gases, the origin of natural gas and the effect of TSR on the stable carbon isotope ratio of individual LHs were studied. The δ13C in ethane (<−28‰), LHs (<−26‰) and the composition distribution characteristic of C6-C7 indicated that the gases were oil-associated gases. Moreover, the gas sourness index, defined as H2S/(H2S+∑Cn) demonstrated that the gases from the TZ-I and ZB gas fields were in the early liquid-hydrocarbon-involved and heavy-hydrocarbon-gas-dominated TSR stages, respectively. The comparison of stable carbon isotope ratios of the LHs between the two gas fields revealed that TSR exhibited a complex effect on the carbon isotope values of LHs, but only little effect on 2-methylpentane (2-MP) and 3-methylpentane (3-MP). The δ13C values of benzene (BEN) and toluene (TOL) were -28.3‰ and -29.4‰ in the TZ-I and -27.7‰ and -28.1‰ in the ZB gas field. The stable carbon isotope ratios of BEN and TOL in ZB gas field exhibited more enriched 13C than those in TZ-I gas field, likely driven by TSR. Meanwhile, cycloalkanes, such as methyl cyclopentane (MCP), cyclohexane (CH), and methylcyclohexane (MCH), enriched 13C with TSR process and displayed a greater trend than aromatic compounds, about 2‰. Therefore, the influence of TSR on the carbon isotopes of individual LHs should be considered while using the stable carbon isotope ratio of cycloalkanes, BEN, and TOL to identify the genetic type and source of marine natural gas, especially at the cross plot (δ13C = −24‰) of coal-derived gas and oil-associated gas.

Mixed Solvents Assisted Post-Treatment Enables High-Efficiency Single-Junction Perovskite and 4T Perovskite/CIGS Tandem Solar Cells.

The interface between the perovskite layer and the hole transport layer (HTL) plays a vital role in hole extraction and electron blocking in perovskite solar cells (PSCs), and it is particularly susceptible to harmful defects. Surface passivation is an effective strategy for addressing the above concerns. However, because of its strong polarity, isopropyl alcohol (IPA) is used as a solvent in all of the surface treatment materials reported thus far, and it frequently damages the surface of perovskite. In this paper, a method is proposed for dissolving the passivation materials, for example, guanidine bromide (GABr), in mixed solvents (1:1) of IPA and toluene (TL), which can efficiently passivate interface and grain boundary defects by minimizing the IPA solubility of the perovskite surface. As a result, all the performance parameters Voc, Jsc, and FF are improved, and the power conversion efficiency (PCE) increased from 20.1 to 22.7%. Moreover, combining the PSCs with GABr post‐treatment in mixed solvents with copper indium gallium selenide (CIGS) solar cells, a 4‐terminal (4T) perovskite/CIGS tandem device is realized and a PCE of 25.5% is achieved. The mixed solvent passivation strategy demonstrated here, hopefully, will open new avenues for improving PSCs’ efficiency and stability.

Motor dysfunction in Drosophila melanogaster as a biomarker for developmental neurotoxicity

SummaryAdequate alternatives to conventional animal testing are needed to study developmental neurotoxicity (DNT). Here, we used kinematic analysis to assess DNT of known (toluene (TOL) and chlorpyrifos (CPS)) and putative (β-N-methylamino-L-alanine (BMAA)) neurotoxic compounds. Drosophila melanogaster was exposed to these compounds during development and evaluated for survival and adult kinematic parameters using the FlyWalker system, a kinematics evaluation method. At concentrations that do not induce general toxicity, the solvent DMSO had a significant effect on kinematic parameters. Moreover, while TOL did not significantly induce lethality or kinematic dysfunction, CPS not only induced developmental lethality but also significantly impaired coordination in comparison to DMSO. Interestingly, BMAA, which was not lethal during development, induced motor decay in young adult animals, phenotypically resembling aged flies, an effect later attenuated upon aging. Furthermore, BMAA induced abnormal development of leg motor neuron projections. Our results suggest that our kinematic approach can assess potential DNT of chemical compounds.

A simple sampling method for quantification of hazardous volatile organic compounds in mainstream cigarette smoke: Method development and prestudy validation

Cigarette smoke can be fatal to human health, as it contains a plethora of hazardous compounds such as volatile organic compounds (VOCs). To assess the toxic effects of cigarette smoke, both qualitative and quantitative information about the VOCs in cigarette smoke are essential. However, sampling and analysis of cigarette smoke are not simple tasks and require complicated validation procedures. Here, we develop and verify a simple sampling method for the quantification of VOCs in mainstream cigarette smoke using three steps: direct collection of the mainstream cigarette smoke sample by gas-tight syringe, injection of the sample into a bag sampler for dilution, and extraction of VOCs into an adsorption-tube sampler for quantitation by thermal desorption-gas chromatography-mass spectrometry. This method has been employed successfully to quantify seven target VOCs (isoprene, methyl ethyl ketone, benzene, acrylonitrile, toluene, m-xylene, and styrene) in cigarette smoke from 3R4F reference cigarettes. The quantities of these major five VOCs (isoprene, methyl ethyl ketone, benzene, acrylonitrile, and toluene: average of 459 ± 646 ng mL−1), when measured from 3R4F samples based on our method, were comparable to or moderately higher than those measured based on the established standard methods (e.g., Health Canada Intense (462 ± 557 ng mL−1) and International Standardization Organization (356 ± 438 ng mL−1)). As such, we succeeded in reliably collecting and quantifying VOCs in cigarette smoke using a simple sampling method proposed in this research. The proposed method is thus recommended as an alternative to complicated and costly representative methods based on international guidelines.

Transition‐Metal‐Free Radical Cyclization of 2‐Arylbenzoimidazoles with Unactivated AlkanesviaC(sp3)−H Functionalizations in Aqueous Media

AbstractHere we present a transition‐metal‐free radical cyclization of 2‐arylbenzoimidazoles with unactivated alkanes. By using di‐tert‐butyl peroxide (DTBP) to promote the C(sp3)−H bond functionalization, this approach enables assembly of various benzimidazo[2,1‐a]isoquinolin‐6(5H)‐ones in aqueous media. This strategy can not only well tolerate a wide range of cyclic alkanes, straight‐chain alkanes, toluene derivatives, as well as pharmaceutical molecule eudesmol, but also provides an approach for the functionalization of unactivated C(sp3)−H bonds in aqueous media under transition‐metal‐free systems.magnified image

Production of furfural and 5-hydroxymethyl furfural from Camellia oleifera fruit shell in [Bmim]HSO4/H2O/1,4-dioxane biphasic medium

The high-value utilization of Camellia oleifera fruit shell (CFS), which is an important waste in edible tea oil processing, is of great significance for the sustainable development of Camellia oleifera industry. In this study, the CFS after being simply pretreated (PCFS) to remove crude fat, pigment, et al., was used as material to produce furfural (FF) and 5-hydroxymethyl furfural (5-HMF) catalyzed by 1-butyl-3-methylimidazole hydrogen sulfate ([Bmim]HSO4). On the basis of comparing the superiority of microwave heating and traditional oil bath heating, on the basis of comparing the in-situ extraction of FF and HMF with four common solvents including 1,4-dioxane, methyl isobutyl ketone (MIBK), benzene, and cyclohexane, the [Bmim]HSO4/H2O/1,4-dioxane biphasic catalytic reaction system assisted by microwave irradiation was established. In this reaction system, FF was the chief product and 5-HMF was the chief by-product. The highest yields of FF and 5-HMF were 67.54 mol% and 20.97 mol%, respectively. The yield of FF was much higher than that of 5-HMF under the same reaction conditions. The kinetic analysis indicated that the hemicellulose hydrolysis to xylose catalyzed by [Bmim]HSO4 was the rate-limiting step in the production of FF. The cellulose hydrolysis to glucose and the subsequent isomerization of glucose to fructose were the rate-limiting steps in the production of 5-HMF. The rapid formation of other by-products was also one of the reasons for low yield of 5-HMF. [Bmim]HSO4 still performed excellent stability and catalytic activity after three times of cycles. FF with a purity of 95.26% could be obtained from the 1,4-dioxane phase under vacuum distillation. The relative contents of hemicellulose and cellulose and the crystallinity index of cellulose in PCFS residues decreased with the enhancement of reaction temperature and retention time. The biphasic medium used in this study was efficient for the production of FF from CFS.

AIE mechanism of 2-(2-hydroxyphenyl) benzothiazole derivatives: CASPT2 and spin-flip study

Wang et al. synthesized phenylacetylene modified HBT derivative (HBT-s-Ph) and diphenylacetylene modified HBT derivative (HBT-d-Ph) with aggregation-induced emission (AIE) phenomenon. In this work, we have theoretically compared the photochemical and photophysical processes of HBT-s-Ph and HBT-d-Ph in the gas phase, toluene and solid phase using several theoretical methods. The ground-state, excited-state equilibrium structures, the potential energy curves and the excited-state properties were comparatively calculated for a better understanding of the AIE mechanism. The excited-state intramolecular proton transfer (ESIPT) process within HBT derivatives is very fast in both gas phase, toluene, and solid phase due to the small energy barrier, inducing the formation of Keto tautomer which is responsible for emission peaks observed in experiment in both gas phase, toluene and solid phase. But, the reaction paths are very different from there. In toluene, the non-radiative path via HBT intramolecular rotation along the C–C bond is favorable to occur, leading to low Φf of HBT-s-Ph and HBT-d-Ph in toluene. In contrast, the non-radiative path of HBT intramolecular rotation is strongly suppressed in solid phase due to the high energy barriers, which is responsible for high Φf of HBT-s-Ph and HBT-d-Ph in solid phase. The substitution effect on AIE and the large difference of Φf in HBT-s-Ph and HBT-d-Ph in solid phase have been revealed. The presents results contribute to a better understanding of the different photophysical properties of HBT derivatives in toluene and solid phase, and unveil the AIE mechanism in HBT derivatives, which provides deep insight into molecular design of organic photoelectric materials with high Φf.

Comparison of urinary biomarkers concentrations in exposed and non-exposed petrol station workers in the Eastern Economic Corridor (EEC), Thailand.

The Thai government has been developing its Eastern Economic Corridor (EEC), which spans three provinces, with the aim of improving connections with other Asian nations. Since this strategic development, the number of trucks, private car, and passenger car registrations have continued to grow, with a corresponding increase in related to benzene, toluene, ethylbenzene, and xylene (BTEX). This study aims to compare the levels of trans, trans-muconic acid (t, t MA); toluene (TU); mandelic acid (MA); and methyl hippuric acid (MHA) in the urine of gas station employees, considering demographic and occupational factors. These employees worked either near or away from the fuel dispenser, and there 100 people in each group. Data were collected using interviews and testing environmental air and urine samples for benzene, toluene, ethyl benzene, and xylene (BTEX). The results showed that BTEX concentrations were just detectable in all 200 cases (100%). The mean (±SD) urine level of t, t MA was 449.28 (±213.32) μg/g creatinine, while the median (min-max) was 428.23 (95.58-1202.56) μg/g creatinine. The mean TU was 0.011 (0.001) mg/L, while the median (min-max) was 0.011 (0.010-0.013) mg/L. MA levels were higher inside the pollution control zone than they were outside the zone (p=.009). Employees who practiced poor personal hygiene had relatively high urinary toluene and MHA levels (p=.009) and those who did not wear personal protective equipment (PPE) had relatively high MA levels (p=.040). The results of this study revealed statistically significant biomarkers influencing the levels of t, t MA; TU; MA; and MHA in urine. The recommendations of this study are that employers should provide their employees with suitable PPE, check regularly to ensure that it is worn, and strongly encourage employees to take care of their sanitation. Employees should take appropriate breaks and days off to minimize their exposure to BTEX.

Investigation of kidney function changes in sea salt workers during harvest season in Thailand.

Occupational factors have previously been mentioned as contributing to decreased kidney function and the development of chronic kidney disease of unknown cause. Sea salt workers are one of the occupations facing high outdoor temperatures and a highly, intensive workload. The purpose of the study was to examine whether the kidney function of sea salt workers at the beginning of the harvest season differs from kidney function at the end of the harvest season and to identify factors that can predict the change of kidney function. Data were collected from salt workers (n=50) who were between 18–60 years of age without hypertension, diabetes, and kidney disease in Samut Sakhon province, Thailand. Urine specific gravity (USG) was used for hydration status and the estimated glomerular filter rate (eGFR) was used to measure kidney function. The mixed model was used to find differences over the harvest season and prediction of factors. On average, the eGFR was estimated to decrease by 15.2 ml/min/1.73 m2 over the harvest season. The decline in eGFR of sea salt workers with moderate and heavy workloads were significantly faster than their light workload counterparts after controlling for other covariates. Similarly, dehydration (USG ≥ 1.030) significantly accelerated the rate of kidney function loss. Our study confirmed exposure to heat over the harvest season leads to decreased eGFR in sea salt workers. The rate of change of eGFR could be predicted by workload and hydration status. Workers with dehydration who performed medium to heavy workloads in farms showed faster kidney function decline than those who performed light workload.

Physical engineering of anti‐solvents in perovskite precipitation for enhanced photosensitive affinity

For the development of the perovskite formation process, it is necessary to explore the principle of fabricating the photosensitive layer. Herein, a novel perspective on the physical properties of anti-solvents is proposed, which is related to perovskite crystallization. Specifically, we focus on aromatic solvents with different functional groups as anti-solvents (methylbenzene (MB) and chlorobenzene (CB)). This is because the precursor solubility depends on the interactions with each solvent, which is closely observed via FT-IR. In this context, the interfacial affinity of thin perovskite layer induced uniform morphology of electron transport layer (ETL). This phenomenon is characterized by FE-SEM, AFM, and XRD in detail. Based on these data, CB-treated perovskite photodetector exhibits superior detectivity and fast response speed owing to better interfacial affinity between perovskite and ETL. Also, improved charge dynamic behavior (dark current and impedance analysis) was observed in CB-treated condition. Therefore, it is demonstrated that the selection of anti-solvent is important to optimize morphological affinity between perovskite and interlayer in fabricating thin photosensitive layer, which contributes to realization of fast and highly sensitive photodetector.

Reducing Photovoltaic Property Loss of Organic Solar Cells in Blade‐Coating by Optimizing Micro‐Nanomorphology via Nonhalogenated Solvent

AbstractBlade‐coating which is compatible with roll‐to‐roll (R2R) fabrication has been considered a promising technology for the large‐scale production of organic solar cells (OSCs). Despite the rapid increase in power conversion efficiency (PCE) of the devices, most processing solvents are still halogenated, which is a key issue that needs to be addressed urgently in commercialized manufacturing. In this work, targeted strategies are explored for the preparation of efficient OSCs via combining the nonhalogenated solvent toluene (TL) with blade‐coating. Based on the in situ UV–vis absorption, grazing‐incidence wide‐angle X‐ray scattering, and device performance measurements, the subtle relationship between processing solvents, film morphology, and properties is successfully established. The PM6:BTP‐eC9 blend film prepared by this strategy demonstrates higher crystallinity and smaller phase separation morphology, resulting in an outstanding PCE of 16.58% with low energy loss and high fill factor, which is higher than the CF‐based device (15.08%). Finally, the 1.00 cm2 device exhibits a high PCE of 14.82%, which is one of the highest values for OSCs prepared by blade‐coating based on TL solvent. This specific strategy combines blade‐coating with nonhalogenated solvent processing shows outstanding synergy in optimization of morphology, demonstrating excellent potential for the preparation of highly efficient large area OSCs.

Metal-Free Aerobic C–H Oxidation of Methylarenes to Aromatic Aldehydes by Sulfur-Containing Tetracyclic Compounds as Visible-Light Photocatalysts

Abstract Oxidation of benzylic sp3 C–H bonds smoothly proceeded at ambient temperature under blue LED (465 nm) photo-irradiation using sulfur-containing tetracyclic compounds as photocatalysts. The use of 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) as a co-solvent was the key to success: various toluene derivatives were selectively oxidized to substituted benzaldehydes without over-oxidation. Preliminary mechanism studies were undertaken, including electron spin resonance (ESR) spectroscopy analyses.

Health risk assessment of volatile organic compounds exposure among nail salon workers in Vietnam

Purpose The objective of this study is to assess the carcinogen and non-carcinogen risks due to exposure to volatile organic compounds including methyl methacrylate (MMA), benzene, toluene, and xylene among Vietnamese nail salon workers, using probabilistic health risk assessment. Methods This study applied the probabilistic health risk assessment framework to assess the health risk due to exposure to four types of volatile organic compounds among nail salon workers. Forty-two passive personal samples of full-shift female nail workers from 15 salons in Da Nang city were monitored and analyzed by GC-FID in the Thammasat laboratory. Exposure parameters were collected by interviewing nail salon workers. Monte Carlo simulation was used to characterize the risk and its uncertainty. Results The mean of concentrations of MMA, benzene, toluene, and xylene were 20.62, 0.21, 2.49, and 0.58 mg m−3, respectively. The 95th percentile hazard quotients calculated for MMA, benzene, toluene, and xylene were 33.14, 7.49, 0.54, and 2.07, respectively. The 95th percentile lifetime cancer risk for benzene was 198 times higher than the EPA recommendation for cancer risk (10−6). Conclusions Non-cancer risks from exposure to MMA, benzene, and xylene were many times higher than the acceptable limit, which indicated a possible risk of adverse health effects among nail salon workers. Nail salon workers may also be at risk of leukemia or cancer of the blood-forming organs because the cancer risk due to exposure to benzene is higher than the recommended level.

NaN(SiMe3)2/CsTFA Copromoted Aminobenzylation/Cyclization of 2-Isocyanobenzaldehydes with Toluene Derivatives or Benzyl Compounds: One-Pot Access to Dihydroquinazolines and Quinazolines.

A NaN(SiMe3)2/CsTFA copromoted aminobenzylation/cyclization reaction of 2-isocyanobenzaldehydes with toluene derivatives or benzyl compounds has been developed. The reaction works with a broad range of toluene derivatives and benzyl compounds, and provides a simple and efficient strategy for the synthesis of 4-benzyl-substitued dihydroquinazoline and quinazoline derivatives from easily available acyclic starting materials in a single step. Further applications, including synthesis of quinazoline, dihydroindolo[1,2-c]quinazoline, and dihydro-8H-isoquinolino[2,3-c]quinazoline, demonstrated the tremendous potential of the tandem reaction.

Screening of a Novel Solvent for Optimum Extraction of Anionic Surfactants in Water.

Anionic surfactants (AS) are detrimental aquatic pollutants due to their well-characterized toxicity to aquatic organisms. The concentration of AS in aquatic environments is increasing because of their extensive use in many industries and households. The standard reference method for AS analysis is to determine a methylene blue active substance (MBAS) complex formed between AS and the methylene blue (MB) cation by using chloroform. However, chloroform has a low AS extraction efficiency and other limiting properties, such as a high density and volatility, which make the conventional AS analytical method time-consuming and labor-intensive. In an effort to replace the use of chloroform, this study was carried out to screen novel solvents for their ability to extract AS in water samples. Criteria were based on AS extraction efficiency, physicochemical properties, and the stability of the solvent under different environmental conditions. Organic solvents, such as methyl isobutyl ketone (MIBK), 1,2-dichloroethane (DCE), dichloromethane, benzene, and n-hexane, were assessed. In extraction of the anionic surfactant sodium dodecyl sulfate (SDS), the mixture of MIBK-DCE (3:1) proved to be an optimum solvent as an alternative to chloroform. It not only enhanced SDS extractability but also improved properties, such as having a lower volatility, a lower density than water, and a quicker phase separation. Among solvents screened, no one single solvent in SDS extraction could meet such criteria. The performance of the MIBK-DCE (3:1) mixture in SDS extraction was stable, irrespective of pH and ionic strength of the SDS solution, washing process, and presence of cations. Anionic interference from halogen and polyatomic and organic anions in SDS extraction by MIBK-DCE (3:1) existed only at an elevated concentration, which is not occurring in the natural aquatic environment. Results demonstrated that a MIBK-DCE (3:1) mixture solvent could be used in AS analysis for a wide range of aquatic samples and it could be the basis for the development of a new analytical method to replace conventional chloroform.

Volatile organic compounds released in the mainstream smoke of flavor capsule cigarettes

In this study, the composition of mainstream smoke was investigated with an emphasis on a list of volatile organic compounds (VOCs: e.g., isoprene, acrylonitrile, methyl ethyl ketone, benzene, toluene, m-xylene and styrene) using the two types of flavor capsule cigarettes (FCCs, here coded as F1 and F2) in reference to one commercial, non-flavored (NF) and 3R4F cigarette. The concentrations of all the target compounds from FCCs were quantified under two contrasting conditions (i.e., with and without breaking the capsules). The effect of breaking the capsule was apparent in the FCC products with the enhancement of VOC levels, specifically between after and before breaking the capsules (e.g., 1.10–1.58 folds (benzene) and 1.30–1.53 folds (acetonitrile)). Such increases were apparent in both FCC samples if assessed in terms of the total amount of VOCs (TVOC): (1) F1 (from 2159 to 2530 μg cig−1 (p = 9.42 × 10−6)) and (2) F2 (from 1470 to 2014 μg cig−1 (p = 0.05)). In addition, these TVOC levels determined from the FCCs were 1.62- to 1.83- and 1.29- to 1.46-fold higher than those of the NF cigarette and the 3R4F cigarette, respectively. Thus, these FCC products are suspected to play a role as stronger sources of VOCs than the general cigarette products.

Photocatalyzed site-selective C(sp3)-H sulfonylation of toluene derivatives and cycloalkanes with inorganic sulfinates

The development of practical methods for the direct and selective C(sp3)-H functionalization of hydrocarbons is an attractive topic in synthetic chemistry. Although the radical-mediated hydrogen atom transfer (HAT) process has shown considerable potential in such reactions, it still faces fundamental problems associated with reactivity and selectivity. Herein, we report a convenient and economic approach to site-selective C(sp3)-H sulfonylation via photo-induced HAT catalysis. Employing a conjugated polycyclic quinone as a direct HAT photocatalyst, commercially available inorganic sulfinates as the sulfonylation source, copper triflate as an inexpensive oxidant, a variety of toluene derivatives and cycloalkanes were converted into biologically and synthetically interesting sulfone products under mild conditions. The mechanistic studies reveal that the reaction sequence involves direct HAT-induced radical formation and a subsequent copper-mediated organometallic process for the C-S bond formation. This method offers an appealing opportunity to furnish high value-added products from abundant hydrocarbon starting materials and inexpensive reagents.

"Improve the Photovoltaic Performing of Carbon-Form Perovskite Solar Cells "

A solvent-assisted approach was established to make CH3NH3PbI3 perovskite absorber layers. A mixture of CH3NH3I, PbI2, c-butyrolactone, and dimethyl sulfoxide (DMSO) was used, followed by the addition of chlorobenzene (CB). The approach produced ultra-flat and dense perovskite capping layers atop mesoporous films TiO2, allowing for a significant boost in the performance of carbon electrode-form perovskite solar cells using free whole transport material (HTM) (PSCs). As a comparative solvent, toluene (TO) was also investigated. The generated HTM-free PSCs form on drop-casting CB showed a power conversion efficiency (PCE) of 9.73 percent at an annealing temperature of 100 C, which is 36 and 71 percent greater than those fabricated from perovskite films using TO or without adding an additional solvent, respectively. The interaction between the intermediate phase of PbI2–DMSO–CH3NH3I and the extra solvent was discussed. The effect of annealing temperature on absorber film development, morphology, and crystalline structure was also examined, and the results were connected with photovoltaic performance. Highly efficient, simple, and stable HTM-free solar cells with a PCE of 11.44 percent were created using the best perovskite absorbers annealed at 120 C.

Frustrated Lewis pair catalyzed hydrodehalogenation of benzyl-halides.

10 mol% B(2,6-C6F2H3)3 in the presence of excess tetramethylpiperidine (TMP) and H2 (or D2) is shown to catalyze the hydrogenative dehalogenation of benzyl-halides to give corresponding toluene derivatives. These reactions proceed via an initial FLP activation of H2 yielding the ammonium hydridoborate [TMPH][HB(2,6-C6F2H3)3]. This species acts in analogy to a FLP to cooperatively activate C-X bond (X = Cl, Br, I) of benzyl-halides delivering hydride and generating the corresponding ammonium halide salts.

Adsorption of Volatile Organic Compounds and Microwave Regeneration on Self-prepared High-surface-area Beaded Activated Carbon

Self-prepared beaded activated carbons (SBAC) were derived from carbonized phenolic formaldehyde (PF) resins through an optimal activation procedure (900°C for 4 h) using CO2 and compared with a commercial BAC (termed KBAC) over physicochemical properties, adsorption performance against methyl ethyl ketone (MEK) and toluene (TOL), and their regenerability. Langmuir, Freundlich, and Dubinin‒Radushkevich (D‒R) isotherm models showed good fitting results. The isosteric heat of adsorption was calculated using the Clausius-Clapeyron equation; the parameters obtained from the D‒R isotherm indicate that the physisorption predominates the adsorption process. Microwave heating was applied to regenerate the saturated adsorbents to examine the effect of irradiation power and heating time on the desorption behavior. Within 12 min of microwave irradiation, excellent desorption efficiencies were shown, reaching 110 ± 14.4%, 104 ± 2.6%, 90.2 ± 2.3%, and 85.5 ± 5.7% for MEK-SBAC, MEK-KBAC, TOL-SBAC, and TOL-KBAC samples, respectively. Kinetic models were further employed to illustrate the desorption behavior, showing that intraparticle diffusion in SBAC and KBAC was the rate-limiting step during microwave heating. The core kinetic parameters could provide insights for lab-scale or practical engineering scale design. In conclusion, this study demonstrates the excellent adsorption performance of SBAC and the feasibility of microwave regeneration of BACs.