Solubility Of Benzene Research Articles

Experimental Determination of the Oxygen Solubility in Benzene

Oxygen solubility in benzene was measured at pressures up to 0.4 MPa in the temperature range between 302.85 K and 332.63 K using a static synthetic method. The P,x data were correlated with the Soave−Redlich−Kwong equation of state and the Huron−Vidal mixing rule combined with the UNIQUAC model. From this correlation the Henry coefficients were derived and compared to data from literature. The experimental results were used together with literature data for fitting the interaction parameters between oxygen and the aromatic CH group of the predictive Soave−Redlich−Kwong (PSRK) model.

Liquid−Liquid Equilibria of the Benzene + Water + Acetic Acid Ternary System and Solubility of Benzene in Water: Effect of Calcium Chloride

The aqueous solubility of benzene in the presence of calcium chloride at different concentrations was measured at 303.15 K. Also, experimental liquid−liquid equilibrium data were obtained at 303.15 K for the ternary system benzene + water + acetic acid as a function of calcium chloride concentration. The solubility of benzene in water is 1910 ppm at 303.15 K and decreases to 502 ppm with the addition of 20 mass % calcium chloride. The solubility data of benzene in calcium chloride solutions were correlated with the Setschenow equation, and the Setschenow constant, ks, is 0.33 ± 0.002. From the liquid−liquid equilibrium studies it is observed that the amount of acetic acid extracted to the organic phase increases with the amount of added calcium chloride. It is suggested that the salt effect should be explored further to develop or improve processes to treat waste streams contaminated with organic compounds.

Electrochemical control of solubilization using a ferrocene-modified nonionic surfactant

An investigation was conducted on the control of solubilization making use of changes in the surface properties caused by the electrochemical redox reaction of 11-ferrocenylundecyl polyoxyethylene ether (FPEG), a ferrocene-modified nonionic surfactant, in aqueous solutions. Examinations through surface tension measurement of the effect of the redox reaction of the ferrocenyl group on the critical micelle concentration (cmc) of FPEG showed that the oxidation produces an increase in the cmc from 6×10 −6 to 5×10 −5 mol l −1 and the re-reduction causes the cmc to decrease from 5×10 −5 to 9×10 −6 mol l −1. The effect of the redox reaction of the ferrocenyl group was then examined on the solubilization equilibrium constant, K, for solubilization of benzene, ethylbenzene and 2-phenylethylalcohol in FPEG micelles. The equilibrium constant was found for all solubilizates to decrease when the ferrocenyl group is oxidized and increase again if the group is re-reduced, indicating that oxidation of the ferrocenyl group releases portions of the solubilizate from the micelles into the bulk and the re-reduction gives rise to re-solubilization of the released solubilizate.

PRELIMINARY CHARACTERIZATION OF RAW OIL PRODUCTS FROM THE THERMOCHEMICAL CONVERSION OF SWINE MANURE

In this study, the raw oil products from a thermochemical conversion process of swine manure were characterizedbased on elemental composition, benzene solubles, heating value, and water content. The analytical results of 78 samplesshowed that the raw TCC oil products had an average elemental composition of 71.1% carbon, 8.97% hydrogen, 4.12%nitrogen, 0.2% sulfur, and 3.44% ash. The water content of the raw oil varied from 11.3% to 15.8% by weight. The averagehigh heating value of the oil products was 34,760 kJ/kg. These properties of the oil products are similar to those of oil productsfrom the liquefaction of wood sludge and other biomass. The water content of the raw oil was less dependent on the operatingparameters of the process. However, the viscosity and benzene solubles of the raw oil were greatly influenced by the TCCoperating temperature and types of process gases. Further investigation on chemical composition is necessary before the fullutilization of the oil products can be achieved.

Absorption characteristics of methane and carbon dioxide on fluorinated LaNl 4.7Al 0.3 alloy hydride surface

The Brown Coal Liquefaction (BCL) process is a two-stage liquefaction (hydrogenation) process developed for Victorian brown coal in Australia. In the BCL process, the heavy product (vacuum residue) derived from the coal in the primary hydrogenation, which is named CLB (coal liquid bottom, boiling point > 420°C), is treated in a solvent (CLB/solvent ratio, 18–14, wt./wt.) under high temperature (200–290°C) and high pressure (4–5 MPa) to remove the ash and heavy preasphaltenes. This solvent de-ashing process uses toluene or coal-derived naphtha as a de-ashing solvent. After dissolving the CLB into the solvent, insoluble solid particles which consist of the ash and heavy preasphaltenes are settled in a settler by gravity and separated from the solution as an ash-concentrated slurry. The ash-concentrated slurry and the de-ashed solution are withdrawn from the settler as an underflow and overflow, respectively. The de-ashing solvent is recovered from both the overflow and underflow by distillation, and reused in the de-ashing process. The de-ashed heavy product recovered from the solution by eliminating the solvent is further hydrogenated in the secondary hydrogenation.This paper discusses the solubility of the CLB into toluene and settling velocity of the ash under the de-ashing conditions. The extraction experiments made clear that toluene dissolved ∼ 60 wt.% of preasphaltenes (benzene insoluble-pyridine solubles) in the CLB under the following conditions, temperature 100–300°C and CLB/toluene ratio (wt./wt.) of 13 or less. This solubility of CLB (ϵCLB) under the de-ashing conditions is expressed as ϵCLB = CBS + 0.6CBIorg, where CBS and CBIorg are the contents of benzene solubles and organic benzene insolubles, respectively, and organic CLB (ash-free CLB) = CBS + CBIorg. The de-ashing experiments confirmed that the insolubles including ash formed a boundary of concentration during the settling period, and the de-ashing efficiency was represented by the settling velocity of the boundary (V), V is expressed as V = ACLB(CSA/2.5)−0.91(T/573)9.5. Where, ACLB, CSAand T are parameters expressing the properties of organic CLB, ash content in the feed slurry (wt.%) and temperature (K), respectively. The ACLB is also expressed by using the analytical results of the organic insolubles in the CLB under the de-ashing conditions. The ash content of the de-ashed heavy product recovered from the upper zone of the boundary is less than 3000 ppm, which is low enough to feed as a mixture with two times of the middle distillate to the secondary hydrogenation over NiMo catalyst with fixed bed reactors.

EFFECTS OF FEEDSTOCK pH, INITIAL CO ADDITION, AND TOTAL SOLIDS CONTENT ON THE THERMOCHEMICAL CONVERSION PROCESS OF SWINE MANURE

The effects of feedstock pH, ratio of initial carbon monoxide to volatile solids (CO/VS), and total solids content of the feedstock on the thermochemical conversion process of swine manure were studied. The pH values of the feedstock ranged from 4 to 10. High pH values favored oil production in the biomass conversion process. When the feedstock pH was 10, the process yielded the highest oil production efficiency, but the benzene solubles of the oil product was 10% lower than those at pH 7, pH 4, and without pH control. The CO/VS ratio varied from 0.07 to 0.25, while the corresponding carbon monoxide initial pressure ranged from 0.69 to 2.76 MPa. The oil production efficiency increased from 55% to 70% as the CO/VS ratio increased from 0.07 to 0.25. The COD reduction, on the other hand, decreased to 50%, while the CO/VS ratio increased to 0.25. A CO/VS ratio higher than 0.1 is not recommended. Total solids of the feedstock were studied from 10% to 25%. The total solids content of the feedstock directly affected the effectiveness of the process. The higher the total solids content, the higher the oil production and COD reduction efficiencies, limited by the handling capability of the feedstock.

Electric field-induced mobilisation of multiphase solution systems based on the nitration of benzene in a micro reactor.

This paper describes the electric field-induced flow characteristics of multiphase solutions in a micro reactor device using the nitration of benzene as a model process. Photolithographic and wet etching techniques were used to fabricate the micro reactor (channels, 200 microns id, 100 microns deep) in a borosilicate glass substrate. The results focus specifically on the flow parameters of reagents/reactants (i.e., voltage, solution concentration and pH ranges and current-voltage relationships) used in this study. The benzene was introduced and mobilised by electroosmotic flow (EOF), as a microemulsion using an appropriate surfactant (sodium dodecyl sulfate), whilst the nitronium ions, produced in situ from mixed H2SO4-HNO3 (the nitrating agent), underwent electrophoretic-induced (electrokinetic) mobility. A co-surfactant, butan-1-ol, was used owing to (a) its relative solubility in the aqueous surfactant solution, (b) its ability to aid the solubilization of benzene, (c) the provision of a water-rich (oil-in-water) rather than oil-rich (water-in-oil) microemulsion system and (d) its lack of significant adverse effects on the EOF. The optimum conditions used for the nitration of benzene within the micro reactor were a run of the microemulsion as main reagent stream, then three 30 s segmented injections of mixed acid, with a 5 s push of the microemulsion into the system after each injection, and then a 60 s stopped-flow reaction time before driving reaction product segments to a collection reservoir.

Solubility of Alkylporphyrins

The solubility in benzene and ethanol of 2,8,12,18-tetramethyl-3,7,13,17-tetrabuthylporphyrin with various substituents in the5,15-positions of the molecule is investigated. A comparative analysis of the influence of alkyl substituents on porphyrin solubility is carried out.

Cosolvency Effects of Monoethanolamine and Triethanolamine: Implications for the Remediation of Benzene in Groundwater at Sour-Gas Plants

Studies were conducted to measure the cosolvency effect of monoethanolamine (MEA) and triethanolamine (TEA) on the aqueous solubility of benzene in support of the remediation of contaminated subsurface environments at gas plants in western Canada. Experiments utilized sodium chloride solutions of the amines in the concentration range of 0–0.065 volume fractions, and non-saline waters in the range 0–1 volume fractions. The measured values of the cosolvency power σ for MEA and TEA, based on the log-linear model, were 1.86 ± 0.05 and 2.21 ± 0.04, respectively. The corresponding values for the semi-cosolvency power σ0.5 were 1.22 ± 0.005 and 1.19 ± 0.005, respectively. It is postulated that the difference in the values of σ and σ0.5 may be linked to cosolvent polarity of the amines in water. In 0.2 Mol/L NaCl saline water, the solubility of benzene increased linearly from 1660 mg/L to 2170 mg/L and 1960 mg/L for cosolvents MEA and TEA (0–0.065 volume fractions), respectively. As evidenced by the measured 30% increase in the solubility of benzene, remediation strategies of groundwater at sour-gas plants should therefore take into account the levels of these amines and their effects on the transport of hydrocarbon contaminants.

THERMOCHEMICAL CONVERSION OF SWINE MANURE: AN ALTERNATIVE PROCESS FOR WASTE TREATMENT AND RENEWABLE ENERGY PRODUCTION

A thermochemical conversion (TCC) process was applied to the treatment of swine manure slurry for oilproduction and waste reduction. The objectives of the first stage study were to explore the feasibility of oil productionfrom swine manure and to determine the waste reduction rates through the TCC process. A bench TCC reactor wasdeveloped and tested at operating temperatures of 275C to 350C. The corresponding operating pressures ranged from5.5 to 18 MPa. Carbon monoxide was used as a reducing agent at pressures from 0.34 to 2.76 MPa. The oil product wasevaluated by element analysis, heating value, and benzene solubility. The waste reduction rate was evaluated in terms ofchemical oxygen demand (COD) before and after the TCC process. The highest oil yield was 76.2% of the total volatilesolids of the feedstock. The hydrogen to carbon molar ratio was 1.53. The TCC oil product had a similar quality as that ofpyrolysis oils from liquefaction of other biomass such as wood sludge and newspaper waste. The average heating value ofthe oil product was estimated at 34 940 kJ/kg. The COD in the post-processed water after the TCC process was reducedas much as 75.4%. Carbon dioxide was the sole detected gaseous by-product. The solid by-product of the TCC processwas only 3.3% of the total solids input by weight.

Role of Counterions in the Solubilization of Benzene by Cetyltrimethylammonium Aggregates. A Multinuclear NMR Investigation

This paper reports about the influence of counterions on the solubilization of benzene in aqueous solutions of cetyltrimethylammonium surfactants (CTAX, X = Br-, Cl-, NO3-, CH3SO3-, and (SO4)2-1/2, CTAB, CTAC, CTAN, CTAMs, and CTAS, respectively) investigated by 1H, 13C, and 14N NMR spectroscopy, at [CTAX] = 0.10 M. Benzene solubility and the size of the aggregates upon benzene addition depend strongly on the nature of counterion. Aqueous CTAC, CTAMs, and CTAS solutions reach benzene saturation up to [benzene]/[CTAX] ∼ 3 without showing any aggregate growth; on the other hand aqueous CTAB and CTAN solutions are able to solubilize a smaller amount of benzene up to [benzene]/[CTAX] ∼ 1 and the solute addition promotes a sphere to rod transition. 1H chemical shifts of the headgroup signals, namely, the trimethylammonium and four methylenes of the aliphatic chain, undergo a more relevant upfield shift upon benzene addition with respect to the hydrophobic chain signals. 1H NMR headgroup signals correlate to [benzene] through cubic equations, while the other signals do not show any simple correlation to [benzene]. A qualitative model in which benzene displaces water from the clefts which characterize the surface of the micellar aggregates is in agreement with all the experimental data.

Solubility of Liquid Organics of Environmental Interest in Subcritical (Hot/Liquid) Water from 298 K to 473 K

The solubilities of benzene, toluene, m-xylene, p-cymene, octane, 2,2,4-trimethylpentane (isooctane), tetrachloroethylene, 1,2-dichlorobenzene, and tetraethyltin were determined at temperatures ranging from 298 K to 473 K. Increasing the temperature up to 473 K increased the solubilities by a factor of ∼10−250. For example, increasing the temperature from 298 K to 473 K increased the mole fraction solubility of tetraethyltin from (0.03 ± 0.002) × 10-7 to (8.8 ± 0.6) × 10-7 but only increased the solubility of benzene from (4.0 ± 0.1) × 10-4 to (41 ± 3) × 10-4. Pressure had a minimal effect; for example, increasing the pressure from 65 to 400 bar at either 298 K or 473 K reduced the solubility of benzene by only ∼20%.

Hydrophobicity of benzene

The present work tries to clarify the molecular origin of the poor solubility of benzene in water. The transfer of benzene from pure liquid phase into water is dissected in two processes: transfer from gas phase to pure liquid benzene; and transfer from gas phase to liquid water. The two solvation processes are analyzed in the temperature range 5–100°C according to Lee’s Theory. The solvation Gibbs energy change is determined by the balance between the work of cavity creation in the solvent, and the dispersive interactions of the inserted benzene molecule with the surrounding solvent molecules. The purely structural solvent reorganization upon solute insertion proves to be a compensating process. The analysis shows that the work of cavity creation is larger in water than in benzene, whereas the attractive energetic interactions are stronger in benzene than in water; this scenario is true at any temperature. Therefore, both terms act in the same direction, contrasting the transfer of benzene from pure liquid phase into water and determining its hydrophobicity.

Solubilities of benzene, toluene and diphenyl in the t-butyl alcohol+water mixtures and hydrophobic interaction

The solubilitices of benzene, toluene and diphenyl in mixed solvents of t-butyl alcohol (TBA) and water at 283.15, 288.15, 293.15 and 298.15 K have been determined by spectrophotometry. The mole fraction of TBA [x (TBA)] in the mixed solvent are 0.000, 0.010, 0.020, 0.030, 0.040, 0.045, 0.050, 0.060, 0.080 and 0.100, respectively. The standard Gibbs energies of solution of benzene, toluene and diphenyl in the mixed solvent have also been calculated based on the solubility data. The hydrophobic interactions (HI) for the pairs of benzene-benzene, methane-benzene and methane-methane in the mixed solvent were calculated and discussed.

Solubilization ofn-Alkylbenzenes into Lithium 1-Perfluoroundecanoate Micelles

The solubilization of benzene, toluene, ethylbenzene,n-propylbenzene,n-butylbenzene,n-pentylbenzene,n-hexylbenzene, and some arenes into lithium 1-perfluoroundecanoate micelles was measured with increasing the surfactant concentration. Concentrations of all the solubilizates in equilibrium were determined spectrophotometrically at 293.2, 298.2, 303.2, and 308.2 K. The concentration of benzene, toluene, naphthalene, anthracene, and pyrene was not found to increase under the same condition. The first stepwise association constants (K̄1) between solubilizate monomer and vacant micelle were evaluated from the equilibrium concentration of solubilizate and were found to increase with increasing hydrophobicity of the solubilizate molecules for the alkylbenzenes. The thermodynamic parameters in this system were compared with those for solubilization into 1-dodecanesulfonic acid micelles. These solubilizates were all solubilized on the surface region of the fluorocarbon micelles, which is different from the previous result that the solubilizates with longer alkyl chains were in the inner part of the above-mentioned hydrocarbon micelles.

Solubilization of Benzene and Several Benzene Derivatives in Dilute Aqueous Solution of 18-Crown-6

Solubilities of benzene, toluene, nitrobenzene, p-and o-nitrotoluene in dilute aqueous solutions of 18-crown-6 have been determined by UV-spectrometry at 15, 25, and 35°C. The saturation concentration of each aromatic solute depends linearly on the l8-crown-6 concentration. Experimental results show that 18-crown-6 molecules form host-guest complexes (with 1:1 stoichiometry) with the aromatic molecules, which supports the assumption that the force of combination between the crown ether and the aromatic molecules is a weak hydrophobic interaction.

Key Factors Affecting Subsurface Contamination of Natural Waters near Sour-gas Plants

Hydrocarbon contamination of lakes and rivers from subsurface discharge of ground-water is a common environmental problem in many countries. This source of contamination, particularly dissolved phase hydrocarbons, can significantly reduce the quality of natural waters. Laboratory results show that the aqueous solubility of benzene can be predicted by Raoul's Law for BTEX mixtures and for gas condensate. In contrast, the solubility of total xylenes was up to three times higher than the calculated results using Raoul's Law. A comparison of these finding with the composition of BTEX in groundwater at a sour-gas plant, indicated that the mole fraction and groundwater flow velocity were two principle factors affecting the discharge concentration of benzene and xylenes to natural waters.;Hydrocarbon contamination of lakes and rivers from subsurface discharge of ground-water is a common environmental problem in many countries. This source of contamination, particularly dissolved phase hydrocarbons, can significantly reduce the quality of natural waters. Laboratory results show that the aqueous solubility of benzene can be predicted by Raoul's Law for BTEX mixtures and for gas condensate. In contrast, the solubility of total xylenes was up to three times higher than the calculated results using Raoul's Law. A comparison of these finding with the composition of BTEX in groundwater at a sour-gas plant, indicated that the mole fraction and groundwater flow velocity were two principle factors affecting the discharge concentration of benzene and xylenes to natural waters.

Sorption of benzene, toluene and chloroform by poly(styrene) at 298.15 K and 323.15 K using a quartz crystal balance

An isopiestic apparatus using the quartz crystal balance principle has been constructed for vapor sorption measurements on polymers. Isothermal solubilities of benzene, toluene and chloroform in poly(styrene) were measured in the concentrated polymer regime. Benzene results were obtained at 323.15 K. Toluene and chloroform results were obtained at 298.15 K and at 323.15 K. Solvent activities were represented with a modified Flory-Huggins activity model and compared with available literature data with favorable results. Comparisons were also made with predictions of three free volume activity models described in the literature. Details of the applicability and reliability of the quartz crystal balance for these sorption measurements are considered and discussed.

Temperature, stability, and the hydrophobic interaction

Changes in free energy are normally used to track the effect of temperature on the stability of proteins and hydrophobic interactions. Use of this procedure on the aqueous solubility of hydrocarbons, a standard representation of the hydrophobic effect, leads to the conclusion that the hydrophobic effect increases in strength as the temperature is raised to approximately 140 degrees C. Acceptance of this interpretation leads to a number of far-reaching conclusions that are at variance with the original conception of the hydrophobic effect and add considerably to the complexity of interpretation. There are two legitimate thermodynamic functions that can be used to look at stability as a function of temperature: the standard Gibbs free energy change, deltaG degrees, and deltaG degrees/T. The latter is proportional to the log of the equilibrium constant and is sometimes called the Massieu-Planck function. Arguments are presented for using deltaG degrees/T rather than deltaG degrees for variations in stability with temperature. This makes a considerable difference in the interpretation of the hydrophobic interaction, but makes little change in the stability profile of proteins. Protein unfolding and the aqueous solubility of benzene are given as examples. The contrast between protein unfolding and the hydration of nonpolar molecules provides a rough estimate of the contribution of other factors that stabilize and destabilize protein structure.

Solubilities of benzene and diphenyl in (t-butyl alcohol + water) and hydrophobic interaction

The solubilities of benzene and diphenyl in mixed solvents oft-butyl alcohol (TBA) and water atT= (298.15, 303.15, 308.15, and 313.15) K have been determined by spectrophotometry. The mole fractions of TBA in the mixed solvent arex= (0, 0.010, 0.020, 0.030, 0.040, 0.045, 0.050, 0.060, 0.080, and 0.150), respectively. The standard Gibbs energies of solution of benzene and diphenyl have been calculated based on the solubility data. The hydrophobic interaction (HI) for the pair benzene–benzene in the mixed solvent has also been calculated and discussed.