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Background: Bladder cancer has been linked to several occupations that involve the use of solvents, including those used in the dry-cleaning industry., Objectives: We evaluated exposure to solvents and risk of bladder cancer in 1182 incident cases and 1408 controls from a population-based study., Methods: Exposure to solvents was quantitatively assessed using a job-exposure matrix (CANJEM). Exposure to benzene, toluene and xylene often co-occur. Therefore, we created two additional sets of metrics for combined benzene, toluene and xylene (BTX) exposure: (1) CANJEM-based BTX metrics and (2) hybrid BTX metrics, using an approach that integrates the CANJEM-based BTX metrics together with lifetime occupational histories and exposure-oriented modules that captured within-job, respondent-specific details about tasks and chemicals. Adjusted odds ratios (ORs) and 95% confidence intervals (95% CI) were estimated using logistic regression., Results: Bladder cancer risks were increased among those ever exposed to benzene (OR = 1.63, 95% CI: 1.14-2.32), toluene (OR = 1.60, 95% CI: 1.06-2.43), and xylene (OR = 1.67, 95% CI: 1.13-2.48) individually. We further observed a statistically significant exposure-response relationship for cumulative BTX exposure, with a stronger association using the hybrid BTX metrics (OR Q1vsUnexposed  = 1.26, 95% CI: 0.83-1.90; OR Q2vsUnexposed  = 1.52, 95% CI: 1.00-2.31; OR Q3vsUnexposed  = 1.88, 95% CI: 1.24-2.85; and OR Q4vsUnexposed  = 2.23, 95% CI: 1.35-3.69) (p-trend=0.001) than using CANJEM-based metrics (p-trend=0.02)., Impact: There is limited evidence about the role of exposure to specific organic solvents, alone or in combination on the risk of developing bladder cancer. In this study, workers with increasing exposure to benzene, toluene, and xylene as a group (BTX) had a statistically significant exposure-response relationship with bladder cancer. Future evaluation of the carcinogenicity of BTX and other organic solvents, particularly concurrent exposure, on bladder cancer development is needed., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Objectives. The present study aimed to assess whether occupational exposure to low concentrations of benzene, toluene, ethylbenzene and xylene (BTEX) is associated with color vision impairment. Methods. We queried PubMed, Scopus, Embase, Web of Science and ProQuest as the main databases, as well as gray literature such as Google Scholar. A random-effects model was used to assess relative risk. A funnel plot was created to assess publication bias. Meta-regression analysis was applied to identify variables that explain the between-study variation in the reported risk estimate. Results. An overall standardized mean difference of 0.529 (95% confidence interval [0.269, 0.788]; p  < 0.0001) was obtained in the random-effects model, which corresponded to a medium-size effect. Duration and the levels of exposure to benzene, toluene and xylene were the significant predictors of the magnitude of the combined risk estimate. Chronic exposure to low levels of BTEX was associated with dyschromatopsia determined by the color confusion index. Conclusions . The impairments can occur even at exposures lower than the occupational exposure limits of BTEX. However, there are several flaws in the determination of workers' exposure, which did not allow to establish how low a level of these chemicals can cause color vision impairment.

Excitation–emission matrix (EEM) fluorescence spectroscopy of unmodified (pristine) fullerenes C60 and C70 in benzene, toluene, and n-hexane at room temperature was used for their quantification by their solvent-dependent EEM bands specific to each fullerene. The intensity and parameters of fluorescence depend on both the fullerene and solvent and provide the conditions for the quantification of both fullerenes in their mixtures without separation. The detection limits for C60 in n-hexane and C70 in benzene under the selected conditions are 7 and 2 nmol/L, respectively. The approach was tested for model and real mixtures of fullerenes C60 and C70. [ABSTRACT FROM AUTHOR]

Benzene proved to be a more effective eluent compared to chlorinated organic solvents traditionally used for chromatographic recovery of vanadyl petroporphyrins from the dimethylformamide (DMF) extract of asphaltenes on a column packed with mesoporous silica gel. Low eluting power of benzene can be compensated by moistening of the silica gel adsorbent. An increase in the silica gel moisture content from 0 to 7.7% does not lead to a decrease in the efficiency of the separation of vanadyl porphyrins from nonporphyrin components but leads to a tenfold decrease in the eluent consumption. A decrease in the eluent flow rate from 0.8 to 0.12 mL min–1 (per gram of the adsorbent) leads to a 1.5-fold increase in the yield of vanadyl porphyrins of required purity. An increase in the adsorbate : adsorbent weight ratio from 1 : 833 to 1 : 83 does not lead to a decrease in the efficiency of the vanadyl porphyrin recovery. Elution with benzene under optimum conditions (adsorbent moisture content, eluent flow rate, adsorbate : adsorbent ratio) allows the recovery of 3 times larger amount of petroleum vanadyl porphyrins from the DMF extract of asphaltenes than when using chloroform and dried silica gel under equal other conditions. [ABSTRACT FROM AUTHOR]

The structures of pentaphenylantimony (I), its solvates with benzene (II) and dioxane (III), and penta(p-tolyl)antimony (IV) are solved by X-ray diffraction (XRD) (CIF files CCDC nos. 2124594, 2121835, 2124972, and 2124962, respectively). The following parameters are determined from the XRD data: crystals of Ph5Sb (I): a = 10.286(3), b = 10.510(4), c = 13.590(4) Å; α = 68.29(2)°, β = 79.364(14)°, γ = 61.272(12)°; V = 1196.9(7) Å3; Z = 2; solvate Ph5Sb∙0.5PhH (II): a = 13.165(11), b = 14.394(16), c = 15.193(13) Å; α = 90.22(3)°, β = 113.71(2)°, γ = 94.23(5)°; V = 2627(4) Å3; Z = 2; solvate Ph5Sb∙0.5С4H8O2 (III): a = 10.451(5), b = 10.462(4), c = 13.323(5) Å; α = 75.647(11)°, β = 69.648(19)°, γ = 86.300(19)°; V = 1322.8(9) Å3; Z = 2; and p-Tol5Sb (IV): b = 12.084(7), c = 17.009(6) Å; β = 102.934(14)°; V = 2899(2) Å3; Z = 4. The antimony atoms in solvates II and III have a distorted trigonal bipyramidal coordination. [ABSTRACT FROM AUTHOR]

For the first time, membranes based on poly(1-trimethylsilyl-1-propyne) (PTMSP) with 5–50 wt% loading of hyper-crosslinked polystyrene sorbent particles (HCPS) were obtained; the membranes were investigated for the problem of effective removal of volatile organic compounds from aqueous solutions using vacuum pervaporation. The industrial HCPS sorbent Purolite Macronet™ MN200 was chosen due to its high sorption capacity for organic solvents. It has been found that the membranes are asymmetric when HCPS content is higher than 30 wt%; scanning electron microscopy of the cross-sections the membranes demonstrate that they have a clearly defined thin layer, consisting mainly of PTMSP, and a thick porous layer, consisting mainly of HCPS. The transport and separation characteristics of PTMSP membranes with different HCPS loading were studied during the pervaporation separation of binary and multicomponent mixtures of water with benzene, toluene and xylene. It was shown that the addition of HCPS up to 30 wt% not only increases the permeate fluxes by 4–7 times, but at the same time leads to 1.5–2 fold increase in the separation factor. It was possible to obtain separation factors exceeding 1000 for all studied mixtures at high permeate fluxes (0.5–1 kg/m2∙h) in pervaporation separation of binary solutions. [ABSTRACT FROM AUTHOR]

1,3,5-Tris(2-diphenylphosphoryl-4-ethylphenoxymethyl)benzene (L′), a phosphorylcontaining tripodand, was synthesized for the first time in order to find extraction systems for efficient recovery of lanthanides. The main regularities of extraction of lanthanide(III) ions with mixtures of L′ and 4-benzoyl-5-methyl-2-phenyl-3-pyrazolone (HL) into CHCl3, 1,2-dichloroethane, toluene, and carbon tetrachloride from chloride solutions were elucidated. A significant synergistic effect, associated with the formation of hydrophobic mixed-ligand complexes of lanthanides(III), was found. The stoichiometry of the extracted complexes was determined by the equilibrium shift method. The equilibrium constants and values of the synergistic effect in the LnIII—L′—HL—dichloroethane system were calculated. The influence of the nature of the organic solvent and the composition of the aqueous phase on the efficiency of lanthanide(III) ion extraction into the organic phase was considered. [ABSTRACT FROM AUTHOR]

Benzene is a highly toxic aromatic hydrocarbon. Inhaling benzene can cause dizziness, vertigo, headaches, aplasia, mutations and, in the most extreme cases, cancer. Trans,trans‐muconic acid (t,t‐MA) is one of the metabolization products of benzene. Although different analytical methods have been reported for the determination of t,t‐MA, these are often expensive, require trained personnel, are not suitable for on‐site measurements, and use hazardous organic solvents. For these reasons, the development of reliable, selective and sensitive methods for rapid and in situ detection of t,t‐MA are of importance. Addressing this challenge, a nanodevice for the selective and sensitive quantification of t,t‐MA in urine is reported. The nanodevice used is achieved using mesoporous silica nanoparticles loaded with a dye reporter and capped with a dicopper(II) azacryptand. Pore opening and payload release is induced rapidly (10 min) and selectively with t,t‐MA in urine, using a simple fluorimeter without sample pretreatment. [ABSTRACT FROM AUTHOR]

Background: Benzene, an important component of organic solvents, is commonly used in industry. Meanwhile, benzene is a human carcinogen leading to leukemia. Although the links between benzene and various types of genetic damage indicators have been evaluated in several studies, but their results remain inconsistent. So we conducted a meta-analysis, and to explore the influence of low concentration benzene exposure on workers' genetic damage indicators using 3.25 mg/m3 as the boundary value, in order to provide a basis for improved prevention and control of the harm from benzene exposure to the occupational population.Methods: We conducted a search of five databases, including Pub Med, Web of Science, China National Knowledge Infrastructure (CNKI), Wan Fang Data and Chongqing VIP, to identify relevant articles up to December 25, 2018. Two researchers independently extracted and evaluated the data according to the inclusion and exclusion criteria of the literature. The imported articles were managed by Endnote X7, and the data were extracted and sorted by Excel 2013. We utilized Stata 12.0 software to perform the meta-analysis in the present study.Results: A total of 68 eligible articles were finally included for the synthetic analyses. The meta-analysis results showed that occupational benzene exposure led to significantly increased Micronucleus (MN) frequency, Sister chromatid exchange (SCE) frequency, Chromosome aberration (CA) frequency, Olive Tail moment (OTM), Tail moment (TM), Tail length (TL), and Tail DNA% (T DNA%) compared to the control group (P < 0.05), and the pooled effect value estimates were 1.36, 0.98, 0.76, 1.06, 0.96, 1.78, and 1.42, respectively. Subsequent analysis of the effect of low concentration benzene exposure on genetic damage found significantly increased MN frequency increased compared with the control group (P < 0.05).Conclusions: Occupational benzene exposure can affect multiple genetic damage indicators. Even at an exposure concentration lower than 3.25 mg/m3, benzene exposure has genotoxicity. These data provide an important scientific basis for the further revision of occupational disease prevention strategies. At the same time, increased attention should be focused on the health monitoring of the occupational population exposed to benzene, and health management should be strengthened to improve the health of the occupational population. [ABSTRACT FROM AUTHOR]

Background: Benzene is a volatile organic solvent. Benzene has been designated as a carcinogen in humans or a cause of cancer by the International Agency for Research on Cancer. The entry of organic solvent vapors into the body can cause various main reactions in the respiratory tract. The purpose of this study was to determine the relationship between benzene exposure intake and respiratory symptoms. Displace to method, here in abstract. Method: This type of research used cross-sectional design and risk assessment approach. It is conducted in four footwear workshops in Bogor, West Java, during September 2017. This study involved 96 footwear workers. Results: The most symptoms experienced were cough 50% they were quickly tired or tightness during activity 39.6%, sore throat 33.3%, runny nose 31.3%, issued phlegm or reak 18.8%, shortness of breath 14.6%, snorting nouse 6.3%. The result of the risk assessment was 11.5% of workers had real time noncancer risk as well as 21.9% of workers who had cancer risk. Conclusion: There was no correlation between non-carcinogen intakes, carcinogen intakes and respiratory symptoms (p value> 0.05). The findings suggest vigilance against the risk of continuous benzene exposure because it can trigger symptoms of carcinogens or non carcinogens. [ABSTRACT FROM AUTHOR]

A combination of the polarizable continuum model (PCM) and the hybrid quantum mechanics/molecular mechanics (QM/MM) methodology, PCM-MM/QM, is used to include the solute electronic polarization and then study the solvent effects on the low-lying n→π* excitation energy and the 15N nuclear magnetic shielding of pyrazine and pyridazine in aqueous environment. The results obtained with PCM-MM/QM are compared with two other procedures, i.e., the conventional PCM and the iterative and sequential QM/MM (I-QM/MM). The QM calculations are made using density functional theory in the three procedures. For the excitation energies, the time-dependent B3LYP/6-311+G(d) model is used. For the magnetic shielding, the B3LYP/aug-pcS2(N)/pcS2(C,O,H) is used with the gauge-including atomic orbitals. In both cases, i.e., PCM-MM/QM and I-QM/MM, that use a discrete model of the solvent, the solute is surrounded by a first shell of explicit water molecules embedded by an electrostatic field of point charges for the outer shells. The best results are obtained including 28 explicit water molecules for the spectral calculations and 9 explicit water molecules for the magnetic shielding. Using the PCM-MM/QM methodology the results for the n→π* excitation energies of pyridazine and pyrazine are 32 070 ± 80 cm-1 and 32 675 ± 60 cm-1, respectively, in good agreement with the corresponding I-MM/QM results of 32 540 ± 80 cm-1 and 32 710 ± 60 cm-1 and the experimental results of 33 450-33 580 cm-1 and 32 700-33 300 cm-1. For the 15N magnetic shielding, the corresponding numbers for the gas-water shifts obtained with PCM-MM/QM are 47.4 ± 1.3 ppm for pyridazine and 19.7 ± 1.1 ppm for pyrazine, compared with the I-QM/MM values of 53.4 ± 1.3 ppm and 19.5 ± 1.2 ppm and the experimental results of 42-54 ppm and 17-22 ppm, respectively. The agreement between the two procedures is found to be very good and both are in agreement with the experimental values. PCM-MM/QM approach gives a good solute polarization and could be considered in obtaining reliable results within the expected QM/MM accuracy. With this electronic polarization, the solvent effects on the electronic absorption spectra and the 15N magnetic shielding of the diazines in water are well described by using only an electrostatic approximation. Finally, it is remarked that the experimental and theoretical results suggest that the 15N nuclear magnetic shielding of any diazine has a clear dependence with the solvent polarity but not directly with the solute-solvent hydrogen bonds. [ABSTRACT FROM AUTHOR]

The self-diffusion coefficients D for water, benzene, and cyclohexane are determined by using the pulsed-field-gradient spin echo method in high-temperature conditions along the liquid branch of the coexistence curve: 30–350 °C (1.0–0.58 g cm-3), 30–250 °C (0.87–0.56 g cm-3), and 30–250 °C (0.77–0.48 g cm-3) for water, benzene, and cyclohexane, respectively. The temperature and density effects are separated and their origins are discussed by examining the diffusion data over a wide range of thermodynamic states. The temperature dependence of the self-diffusion coefficient for water is larger than that for organic solvents due to the large contribution of the attractive hydrogen-bonding interaction in water. The density dependence is larger for organic solvents than for water. The difference is explained in terms of the van der Waals picture that the structure of nonpolar organic solvents is determined by the packing effect due to the repulsion or exclusion volumes. The dynamic solvation shell scheme [K. Yoshida et al., J. Chem. Phys. 127, 174509 (2007)] is applied for the molecular interpretation of the translational dynamics with the aid of molecular dynamics simulation. In water at high temperatures, the velocity relaxation is not completed before the relaxation of the solvation shell (mobile-shell type) as a result of the breakdown of the hydrogen-bonding network. In contrast, the velocity relaxation of benzene is rather confined within the solvation shell (in-shell type). [ABSTRACT FROM AUTHOR]

Spherical fractal aggregates of ∼10 μm were formed from a π-electronic amphiphile, C60-didodecyloxybenzene dyad when extracted from THF into water, necessitating a critical dielectric constant ε>=30 in binary THF-water mixtures. Molecular dynamics simulations revealed the unit cluster to such a form involves an aggregation number ∼90 with predominant soft associative molecular interactions which corroborated the octadecahedral model proposed for the cluster growth. [ABSTRACT FROM AUTHOR]

The separation of benzene and cyclohexane is a challenging process in petrochemical industry due to their close boiling points. Solvent mixing is a useful technique to enhance the extraction performance of liquid–liquid extraction process. In this work, the performance of solvent mixtures involving two organic solvents (N , N -dimethylformamide and ethylene glycol) and four ionic liquids (ILs), namely, 1-ethyl-3-methylimidazolium thiocyanate (C 2 mimSCN), 1-ethyl-3-methylimidazolium dicyanamide (C 2 mimN(CN) 2), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (C 2 mimTf 2 N) and 1-ethyl-3-methylimidazolium acetate (C 2 mimAc) was investigated for the extractive separation of benzene and cyclohexane. The mixing ratios of the binary solvents were optimized using the ideal mixing calculation and validated experimentally through liquid–liquid extraction process. Six new quaternary liquid–liquid equilibria for the mixed solvents with benzene and cyclohexane were investigated at 25 °C and 1 atm, with feed concentrations of benzene ranging from 10 to 50 wt%. Ethylene glycol was discovered a good solvent pair with C 2 mimTf 2 N that could lead to potential cost savings. At the optimized mixing fraction, the {C 2 mimTf 2 N + C 2 mimSCN} mixture demonstrated the highest extraction performance, which was superior to that of sulfolane. Additionally, the {C 2 mimSCN + C 2 mimN(CN) 2 } and {C 2 mimN(CN) 2 + C 2 mimAc} mixtures were found to increase the selectivity while maintaining the benzene distribution ratio in relation to sulfolane. The ILs were not present in the raffinate layer of any of the systems, indicating the reliable performance of the ILs in terms of avoiding solvent cross-contamination. This work demonstrated the use of binary solvent mixtures as a new efficient and versatile method to enhance extraction performance. Unlabelled Image • ILs and organic solvents mixtures were used to separate benzene from cyclohexane. • C 2 mimTf 2 N and C 2 mimSCN mixture produced the highest extraction performance. • Minimum cross-contamination was observed between the extract and raffinate layers. • Mixing solvents is a versatile method to optimize the extraction performance. [ABSTRACT FROM AUTHOR]

A search of the published chemical and engineering literature found enthalpy of solution data for an additional 104 and 49 organic compounds dissolved in benzene and acetonitrile, respectively. Standard thermodynamic relationships were used to convert the experimental enthalpy of solution data, ΔHsolv, to enthalpies of solvation, ΔHsolv. Updated Abraham model correlations were derived for describing gas-to-benzene and gas-to-acetonitrile enthalpies of solvation by combining the 104 and 49 additional values to existing benzene and acetonitrile ΔHsolv databases. The updated Abraham model correlations for benzene and acetonitrile described the observed ΔHsolv values to within overall standard deviations of less than 3.4 kJ mol−1. [ABSTRACT FROM AUTHOR]

Monodispersed core-shell silica spheres with fibrous shell structure and tunable pore size were prepared by using a one-pot oil-water biphase method. The pore size could be tuned from 7 nm to 37 nm by using organic solvents with different polarities as oil phase. The spheres synthesized by using benzene as organic solvent had the maximum pore size of 37 nm and possessed a surface area of 61 m 2  g −1 . The obtained wide pore core-shell silica spheres were applied for rapidly separating small molecules, peptides, small proteins, and large proteins with molecular weight up to 200 kDa. Since the pore size of the core-shell silica spheres was sufficiently large for the free access of all the solutes, sharp and symmetric peaks were obtained. The separation performance was as high as 264,531 plates m −1 for fluorene. The great efficient separation demonstrates that the wide pore core-shell silica spheres have a great potential for rapid analysis of both small and large solutes with high performance liquid chromatography. [ABSTRACT FROM AUTHOR]

Gelation behavior in mixtures has been investigated based on a gelator (BP8-A), containing three di-hydrazide units as the rigid core. It was demonstrated that BP8-A was soluble in many organic solvents, such as chloroform (CHL), benzene (Ben), toluene (Tol), and tetrahydrofuran (THF) but formed gels in alcohols, except methanol (MeOH) in which precipitate was observed. We developed a simple but effective method for preparation of BP8-A gel in different solvents at room temperature without heating-cooling process, that is, injection of certain amount of methanol (volume ratio between 8:2 and 7:3) into BP8-A solutions in CHL, Ben, Tol, and THF. Xerogels from MeOH/CHL, MeOH/Ben, MeOH/Tol, and MeOH/THF showed crystalline feature. The films from BP8-A xerogels in the mixtures are superhydrophobic with the contact angles (CAs) higher than 140°. [ABSTRACT FROM PUBLISHER]

Sulfonamides incorporating 1,3,5-triazine moieties can selectively and potently inhibit carbonic anhydrase transmembrane isoforms IX, XII, and XIV over cytosolic isoforms I and II. In the present work, a highly effective synthetic procedure was proposed for this group of potent cancerostatic drugs and compared with previously used methods. The synthesis of triazinyl-substituted benzene-sulfonamide conjugates with amino acids can be easily carried out using sodium carbonate-based water solution as a synthetic medium instead of N,N-Diisopropylethylamine/Dimethylformamide. The benefits of this synthetic procedure include: (i) high selectivity of the creation of disubstituted conjugates; (ii) several times higher yield (≥95%) than that achieved previously; (iii) elimination of organic solvents by the use of an environmental friendly water medium (green chemistry); (iv) simple and fast isolation of the product. The synthesis and resulting products were evaluated using TLC, IR, NMR, and MS methods. The present work demonstrates a significant advantage in providing shortened routes to target structures. [ABSTRACT FROM AUTHOR]

In this paper, the formation and ageing of C 60 colloids in acetonitrile and benzene–acetonitrile mixed solvents is considered. The peculiarities of these processes are studied using the UV- and visible spectroscopy, dynamic and static light scattering, transmission electron microscopy, electrophoretic measurements, electrospray spectroscopy, and monitoring of the particles size with time. The negative charge of the colloidal species is proved to be a result of formation of free radicals. [ABSTRACT FROM AUTHOR]

In this study, the cellulose nanocrystals (CNCs) were prepared by method of acid hydrolysis, while the polymeric ionic liquid (PIL) [PEP-MIM]DBS was synthesized by epichlorohydrin, o -phthalic anhydride as well as N -methylimidazole then anion exchanged by sodium dodecyl benzene sulfonate. It was demonstrated that [PEP-MIM]DBS could modify CNCs by non-covalent interaction to change its surface properties, such as amphiphilicity. The chemical structure of the composite CNCs/[PEP-MIM]DBS was characterized via FTIR, 13 C NMR, TGA, XRD, etc. Moreover, the properties and applications were characterized through a series of dispersion experiments, contact angle tests, FE-SEM, etc. This study showed that the PIL-modification improved the dispersion of CNCs in non-polar organic solvents with their chemical structure integrated. [ABSTRACT FROM AUTHOR]

Isotope fractionation between benzene-D 0 and benzene-D 6 caused by multi-step partitioning of the benzenes between water and two organic solvents, n-octane and 1-octanol, as well as between water and the gas phase, was measured. The obtained fractionation factors α H = K H / K D are α H = 1.080 ± 0.015 and α H = 1.074 ± 0.015 for extraction into n-octane and 1-octanol, respectively, and α H = 1.049 ± 0.010 for evaporation from aqueous solution. The comparison of solvent- and gas-phase partitioning reveals that about 2/3 of the driving force of fractionation is due to different interactions in the aqueous phase, whereas 1/3 is due to different interactions in the organic phase. The heavy benzene isotopologue behaves more ‘hydrophilically’ and the light one more ‘hydrophobically’. This synergistic alignment gives rise to relatively large fractionation effects in partitioning between water and non-polar organic matter. In contrast to a previous study, there is no indication of strong fractionation by specific interactions between benzene and octanol. Partitioning under non-equilibrium conditions yields smaller apparent fractionation effects due to opposite trends of thermodynamic and kinetic fractionation parameters, i.e. partition and diffusion coefficients of the isotopologues. This may have consequences which should be taken into account when considering isotope fractionation due to sorption in environmental compartments. [ABSTRACT FROM AUTHOR]

Composition dependences of the thermodynamic functions of solvation in various aqueous-organic mixtures are studied. Limiting activity coefficients and solvation Gibbs free energies of benzene in the mixtures of water with acetone, 1,4-dioxane, dimethyl sulfoxide, and tert -butanol with different compositions at 298 K were determined. The results were combined with literature data for the enthalpies of solution in these mixtures and known values of thermodynamic functions of solvation of benzene in several other aqueous-organic solvents. We observed general tendencies of nonlinear enthalpy-entropy compensation, preferential solvation, and existence of a critical composition of the mixtures when the maximum of Δ solv H and the bend in Δ solv G vs Δ solv H plot are observed. The nature of both organic cosolvent and solute influences the concentration of water corresponding to this critical composition. For benzene, it lies between 0.75 and 0.95 mole percent of water in all considered systems. In the same range of compositions, extrema of many other properties of aqueous-organic mixtures were observed. It is concluded that at these compositions, solvation in the mixture is characterized with the highest enthalpy cost of reorganization of binary solvent upon insertion of solute molecules and diminishment of the hydrophobic effect. [ABSTRACT FROM AUTHOR]

[Display omitted] • The separation potential of [Opy]Br for benzene was evaluated by thermodynamic research. • Reliable NRTL model parameters were obtained by correlating binary VLE data. • Designed benzene/ethanol extractive distillation process with Aspen Plus software. The N -octylpyridinium bromide ([Opy]Br) ionic liquid was subjected to thermodynamic properties studies, including those of activity coefficients at infinite dilution (γ 12 ∞) and Flory–Huggins interaction parameters (χ 12 ∞), to evaluate the interaction and solubility of [Opy]Br and solvents. [Opy]Br showed different separation potentials for three inseparable systems (benzene/ethanol, benzene/isopropanol, and benzene/thiophene), but no phase separation was observed when it was used as an entrainer for extractive distillation. Through the analysis of relative volatility curve, [Opy]Br can effectively separate benzene from benzene/ethanol and benzene/isopropanol azeotropic mixture, but it had no evident enhancement effect on benzene/thiophene. The results of separation performance were consistent with the analysis of selectivity (S ij ∞) and capability (k j ∞). Furthermore, an extractive distillation process was designed with Aspen Plus software to evaluate the competitiveness of [Opy]Br entrainer in the separation of benzene/ethanol. The results showed that [Opy]Br can be fully recycled without loss, which is more in line with the concept of green development than organic solvent entrainers. [ABSTRACT FROM AUTHOR]

In this work, the suitability of the ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [BMpyr][NTf 2 ], as an extraction agent to replace the traditional organic solvents in the separation of aromatic/aliphatic hydrocarbons was evaluated. Following this aim, the (liquid + liquid) equilibrium (LLE) of the quaternary system { n -octane (1) + n -decane (2) + benzene (3) + [BMpyr][NTf 2 ] (4)} and its corresponding ternary systems { n -octane or n -decane (1) + benzene (2) + [BMpyr][NTf 2 ] (3)} was determined at T = 298.15 K and at 101.3 kPa. Solute distribution ratio and selectivity were calculated from the experimental LLE values in order to evaluate the capability of this ionic liquid to accomplish the separation of benzene from its mixtures with n -octane and n -decane. A comparison of the results obtained from the LLE results of the ternary and quaternary systems was carried out. Finally, the experimental tie-lines compositions were correlated using the NRTL thermodynamic model. [ABSTRACT FROM AUTHOR]

The paper has investigated the possibility of using preliminary treatment of polyurethane tablets by organic solvents for determination of anionic SAS. A technique has been developed of their sorption-photometric determination in waters with a detection limit 0.004-0.144 mg/dm depending on the wave length. [ABSTRACT FROM AUTHOR]

One-pot synthetic routes from furfurals to polysubstituted aromatic compounds have been developed in water, without the need for any organic solvents. The reaction proceeds via an uncatalysed, one-pot reaction cascade through formation of a hydrazone derivative, in situ cycloaddition with a dienophile, then aromatisation. A range of substituted phthalimides can be accessed with complete control over the substitution pattern. The reaction was also extended to other dienophiles and the diene 2-furylacrolein. The phthalimide products were further elaborated to produce a variety of polysubstituted benzenes including pharmaceutically relevant compounds. [ABSTRACT FROM AUTHOR]

An efficient, three-component, one-pot synthesis of highly functionalized tricyclic 4-spiro pyrano[2,3-c]pyrazoles incorporating medicinally privileged heterocyclic moieties has been developed, which also involves the tandem Knoevenagel/Michael addition reaction followed by dehydrative cyclization of pyrazolone derivatives, cyclic 1,3-diketones and cyclic ketones, catalyzed by dodecylbenzenesulphonic acid (DBSA) as a Brønsted acid–surfactant-combined catalyst in aqueous medium. The catalyst is found to be highly competent in accelerating this reaction that results in a considerable short reaction time, alleviating the need for high thermal energy. Wide substrate scope, high to excellent product yield, operational simplicity, absence of any hazardous organic solvent, mild reaction conditions, a simple work up procedure and easily available starting materials are the salient features of this protocol. [ABSTRACT FROM AUTHOR]

N, N′-bis(4-methoxysalicylide)benzene-1,4-diamine ( S1) was synthesized from 4-methoxysalicylaldehyde and p-phenylenediamine and it was found to exhibit interesting aggregation-induced emission enhancement (AIEE) characteristics. In aprotic solvent, S1 displayed very weak fluorescence, whilst strong emission was observed when in protic solvent. The morphology characteristics and luminescent properties of S1 were determined from the fluorescence and UV absorption spectra, SEM, fluorescence microscope and grading analysis. Analysis of the single crystal diffraction data infers that the intramolecular hydrogen bonding constitutes to a coplanar structure and orderly packing in aggregated state, which in turn hinders intramolecular C-N single bond rotation. Given that the three benzene rings formed a large plane conjugated structure, the fluorescence emission was significantly enhanced. The absolute fluorescence quantum yield and fluorescence lifetime also showed that radiation transition was effectively enhanced in the aggregated state. Moreover, the AIEE behavior of S1 suggests there is a potential application in the fluorescence sensing of some volatile organic solvents. [ABSTRACT FROM AUTHOR]

Candida antarctica lipase B proved to be a highly active biocatalyst for the direct acylation of phenolic hydroxy groups of substituted hydroquinones and resorcinols, which have rarely been reported so far. More importantly, the acylation reactions took place generally in a markedly regioselective manner: the hydroxy group remote from the substituent was preferentially acylated. In the case of substituted hydroquinones, the selectivity increased with the increase in the bulk of the substituent. Interestingly, the 1- O -monoacylated derivatives were obtained as the sole products in the case of 4-substituted resorcinols. [ABSTRACT FROM AUTHOR]

Reactions of aluminium isopropoxide with 2-(o-hydroxyphenyl)-benzoxazole (pbox H) and salicylidene-4-chloroaniline (spca H) in different molar ratios in benzene solution afforded the complexes of the types [(μ-OPri)2Al2(pbox)2(OPri)2] 1, [Al(OPri)(pbox)2] 2, [Al(pbox)3] 3, [(μ-OPri)2Al2(spca)2(OPri)2] 4, [Al(OPri)(spca)2] 5 and [Al(spca)3] 6. All these colored solid complexes are soluble in common organic solvents and were characterized by elemental (C, H, N and Al) analysis, spectroscopic [IR (1H, 13C and 27Al) NMR] and mass spectrometric studies. On the basis of these studies, plausible structures have been tentatively proposed for these complexes. [ABSTRACT FROM AUTHOR]

The study describes the possibility of application of self-organizing maps technique to assess the greenness of analytical methodologies. The metrological and "environmental impact" parameters of procedures for benzene and phenol determination in water samples were sets of input data for chemometric analysis. Totally 47 objects and 8 variables formed the data used for analysis. The major factors responsible for non-green character of the methodology are the amount of organic solvent and amount of solid wastes formed. The results of the assessment methods with NEMI symbols and Eco-scale are in good agreement. Greener procedures for benzene and phenol determination are those based on SPME. In case of phenol the methodologies based on GC separation are much greener than those based on LC. The results also show that it is easier to apply green methodologies for benzene, as a compound with lower polarity and hence with less affinity to, than for phenol. The SOM assessment methodology can be useful in choosing the proper analytical procedures. [ABSTRACT FROM AUTHOR]

This manuscript presents the preparation and catalytic application of highly ordered benzene bridged periodic mesoporous organosilicas (PMOs) functionalized with carboxylic acid (-COOH) group at varied density. The COOH-functionalized PMOs were synthesized by one-step condensation of 1,4-bis (triethoxysilyl) benzene and carboxylic group containing organosilane carboxyethylsilanetriol sodium salt using Brij-76 as the template. The obtained materials were characterized by a mean of methods including powder X-ray diffraction, nitrogen adsorption-desorption, scanning- and transmission electron microscopy, and 13C solid-state nuclear magnetic resonance measurements. The potentials of the obtained PMO materials with ordered mesopores were examined as solid catalysts for the chemical conversion of fructose to 5-hydroxymethylfurfural (HMF) in an organic solvent. The results showed that COOH-functionalized PMO with 10% COOH loading exhibited best results for the fructose to HMF conversion and selectivity. The high surface area, the adequate density acid functional group, and the strength of the PMO materials contributing to a promising catalytic ability were observed. [ABSTRACT FROM AUTHOR]

Highlights: [•] One-step, high efficiency Staphylococcus warneri EX17 lipase purification and immobilization. [•] Interfacial adsorption was carried out on 3 different hydrophobic supports. [•] Biocatalysts Octyl-SWL and MCI-SWL were stable in the presence of several solvents. [•] Octyl-SWL and MCI-SWL preparations presented very high specific activities. [Copyright &y& Elsevier]

A fluorousbiphasic system consists of a fluorinated solvent andan organic solvent. The mutual solubility data of fluorous biphasicsystems were analyzed for common organic solvents such as benzene,toluene, and xylene with perfluamine. Fluorous/organic amphiphilicether solvents such as HFE7300 and HFE7500 were added to the fluorousbiphasic system. The equilibrium tie lines for ternary systems weredetermined at two different temperatures, and the equilibrium datasets were correlated with the nonrandom two-liquid and universal quasichemicalmodels. [ABSTRACT FROM AUTHOR]

Abstract: A series of well-defined star-shaped molecules have been synthesized by Pd-catalyzed Suzuki cross-coupling starting from very simple reactants with 1,3,5-trisubstituted benzene, 2,4,6-trisubstituted pyridine and trisubstituted phenylcarbazole as the backbones. These star-molecules are all soluble in common organic solvents and electrochemically stable with reversible cyclic voltammographs and high lying HOMOs. They exhibit excellent blue-fluorescence with quantum yield up to 0.87 and high glass transition temperatures. These molecules offer potential as pure blue-light emitting, hole-transport or host materials for optoelectronic applications. [Copyright &y& Elsevier]

Novel Y-type polyurethane 3 containing 4-(4-nitrophenylazo)resorcinoxy groups as nonlinear optical (NLO) chromophores, which constitute part of the polymer backbone, was prepared and characterized. Polyurethane 3 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. It shows thermal stabilities up to 270°C from thermogravimetric analysis with glass transition temperature obtained from differential scanning calorimetry of 102°C. The second harmonic generation (SHG) coefficient (d 33) of poled polymer film at 1064 nm fundamental wavelength is 4.92 × 10−9 esu. Polymer 3 exhibits a high thermal stability even at 8°C higher than T g, and no significant SHG decay is observed below 110°C, which is acceptable for nonlinear optical device applications. [ABSTRACT FROM AUTHOR]

To investigate the effect of spatial configuration on the gelation properties of low molecular mass gelators (LMMGs), four novel di-cholesteryl derivatives have been specially designed and synthesized by introducing the cis-/ trans-isomers of butene diacid and the optical isomers of D/ L-phenylalanine into the linker between two cholesteryl moieties. These isomers have been denoted as MaDC, FaDC, MaLC and FaLC, respectively. The gelation properties of the compounds were examined in 26 organic solvents, and it was found that the trans-configuration is more favorable for the gelation, but the chirality of the linker shows little effect to the gelation. FaDC has the strongest gelation ability among the four isomers. Interestingly, FaDC and FaLC display phase-selective gelation of benzene, toluene and xylene from their mixtures with water at room temperature, which establishes a foundation for the purification of water contaminated by oil or aromatic solvents. SEM and CD spectroscopy studies revealed that the spatial configuration of the linkers of the gelators affects significantly the aggregation mode, the morphologies and the chirality of the network of the gels. Moreover, the different aggregation behaviors also have an impact on mechanical properties of the gels, which are consistent with the results from rheological studies. Furthermore, temperature- and concentration-dependent H NMR and FTIR measurements demonstrated that intermolecular hydrogen bonding and π-π stacking are the main driving forces for the formation of the gels. [ABSTRACT FROM AUTHOR]

The influence of solvents in the crystallization of tris(p-halogen-phenyl) substituted benzene-1,3,5-tricarboxamides, 1, was studied by using the solvents capable of forming hydrogenbonds with amide N–H groups. All four halogen (I, Br, Cl andF) derivatives have shown a tendency to form triple helices viaamide-to-amide hydrogen bonds in the presence of THFmolecules. The crystallization of the fluoro derivative was foundto have no solvent influence as the same material was obtained repeatedlyfrom various solvents. The bromo analogue affords two solvates fromTHF and DMF, respectively, while seven solvated crystals were obtainedin the case of the iodo derivative when it was crystallized from acetone,acetaldehyde-THF, pyridine, γ-picoline cyclohexanone, DMF orTHF solvents. The solvates exhibited different molecular as well assupramolecular geometries to adjust with the solvent inclusion inthe crystal lattices. The I3trimer synthon was accomplishedin the cyclohexanone solvate of the iodo derivative where cyclohexanonewas able to block all the three amide groups. The Cambridge StructuralDatabase (CSD) analysis was performed on the X3synthon(X = Cl, Br and I) in order to understand their formation. Sorptionstudies on the THF included materials show that they are mesoporousand have a greater tendency to adsorb nitrogen over hydrogen. [ABSTRACT FROM AUTHOR]

Abstract: In this study, solution-processable carbazole-type host materials, 1,3-bis(3-(3,6-di-n-butylcarbazol-9-yl)phenyl)benzene (BCzPPh) and 4,6-bis(3-(3,6-di-n-butylcarbazol-9-yl)phenyl)pyrimidine (BCzPPm), were synthesized for use in phosphorescent organic light-emitting devices (OLEDs). Both host materials possess a high solubility in common organic solvents and high triplet energy to confine excitons to the phosphorescent emitter. The two nitrogen atoms in the central pyrimidine ring of BCzPPm have a profound effect on the photoluminescence properties and the electron-accepting capability. When doped with the green phosphorescent emitter tris(2-(4-tolyl)phenylpyridine)iridium (III), BCzPPh exhibited power efficiencies and external quantum efficiencies above 30lm/W and 13%, respectively, in a simple bilayer OLED. [Copyright &y& Elsevier]