Activity Coefficients Of Benzene Research Articles

Activity Coefficients of the Components of the Binary Systems Consisting of Benzene, Diphenyl, and n-Alkanes

Theoretical calculations are compared to data from an experimental study of the position of eutectics in two-component systems consisting of benzene, diphenyl, and n-alkanes with 12 to 17 carbon atoms. Data on diphenyl–n-alkane (n = 12–17) and benzene–n-alkane (n = 12–17) systems are given for the composition of eutectics, their melting points, and activity coefficients of each component. The theoretical study is based on the Schroder–Le Chatelier approach and the original UNIFAC system; the experimental study is performed via DTA. Deviations of the experimental data from ones calculated for the studied systems are presented. The change in the activity coefficients of benzene and n-hexadecane is illustrated graphically according to UNIFAC and the experimental data.

Separation of benzene from mixtures with water, methanol, ethanol, and acetone: highlighting hydrogen bonding and molecular clustering influences in CuBTC.

Configurational-bias Monte Carlo (CBMC) simulations are used to establish the potential of CuBTC for separation of water/benzene, methanol/benzene, ethanol/benzene, and acetone/benzene mixtures. For operations under pore saturation conditions, the separations are in favor of molecules that partner benzene; this is due to molecular packing effects that disfavor benzene. CBMC simulations for adsorption of quaternary water/methanol/ethanol/benzene mixtures show that water can be selectively adsorbed at pore saturation, making CuBTC effective in drying applications. Ideal Adsorbed Solution Theory (IAST) calculations anticipate the right hierarchy of component loadings but the quantitative agreement with CBMC mixture simulations is poor for all investigated mixtures. The failure of the IAST to provide reasonable quantitative predictions of mixture adsorption is attributable to molecular clustering effects that are induced by hydrogen bonding between water-water, methanol-methanol, and ethanol-ethanol molecule pairs. There is, however, no detectable hydrogen bonding between benzene and partner molecules in the investigated mixtures. As a consequence of molecular clustering, the activity coefficients of benzene in the mixtures is lowered below unity by one to three orders of magnitude at pore saturation; such drastic reductions cannot be adequately captured by the Wilson model, that does not explicitly account for molecular clustering. Molecular clustering effects are also shown to influence the loading dependence of the diffusivities of guest molecules.

A new continuous dilution vapor liquid equilibrium apparatus: The activity coefficients of benzene and water in cyclohexane at 50°C

A semi-automated apparatus to measure vapor pressure differences between a reference solvent and dilute solutions as a function of concentration at constant temperature is described. Application to the benzene-cyclohexane and benzene-cyclohexane-water systems at high cyclohexane concentrations and low water concentrations is reported. At 50°C in the two component mixture we find lnγB=ln(f B/X B f B 0 )=0.408−0.89XB for 10−3<X B <3×10−2 and in the three component system, lnγW=6.79±0.04 for 10−6<X W <2×10−5 and 10−3<X B <3×10−2.

Rotation Ebulliometer, Part 2. Thermodynamic Investigation on Dilute Solutions of Diphenyl and Benzil in Benzene

AbstractA new pressure controlled twin‐ebulliometer without Cottrell‐pump is described. The boiling temperature can be chosen by setting the pressure by means of a pressure regulator in the range of 100 – 760 Torr. Measurements of polystyrene and other polymers show that in this rotation ebulliometer foaming is no more effective. This fact and the agreement of the experimental ideal ebullioscopic constant with those calculated mean that thermodynamic equilibrium between vapour and liquid may be established in the rotation ebulliometer. ‐ The systems diphenyl + benzene and benzil + benzene were investigated in a solute mole fraction between 0.01 and 0.04 at various temperatures (30–80 °C). The activity coefficients of benzene in the diphenyl + benzene system at 65 °C were compared with those obtained from vapour pressure measurements in more concentrated solutions. The experimental data can all be fitted by the Guggenheim's equation with r = 2, z = 6, and zw/k = 76°. The data in the benzil + benzene system at 65°C can be represented by the same equation with zw/k = 200°, which agrees with the value obtained by calorimetric determinations of the heats of dilution.

Thermodynamics of solutions of liquid crystals III. Vapour pressure of benzene + mbba (N- p-methoxybenzylidene- p-n-butylaniline)

The vapour pressure of mbba + benzene has been determined in a static apparatus at six temperatures between 298.176 and 323.233 K. The liquid-liquid phase-equilibrium diagram has been determined. Activity coefficients of benzene and partial molar excess enthalpies have been calculated and estimated, respectively.

Activity coefficients of benzene in n-alkane solutions A theoretical investigation

In this work, the Guggenheim-Miller-Flory-Huggins one-parameter equation is fitted to 23 sets of activity coefficients at non-zero mole fractions and the resultant χ values together with χ from infinite-dilution activity coefficients (21 points) are fitted to a simple lattice theory. The result is one equation for predicting activity coefficients (within 3 per cent) for benzene + n-alkanes in the range C 5 to C 32 over a large temperature range.

Activity coefficients of C5 to C8 hydrocarbons in squalane and dinonyl phthalate at 30°C determined by a vacuum micro-balance technique

The activity coefficients of benzene, cyclohexane, n-pentane, n-hexane, n-heptane and n-octane in the involatile solvents, dinonyl phthalate and squalane, have been determined over a solute mole fraction range 0.05 to 0.4 at 30°C using a vacuum microbalance. The results are analysed in terms of the Flory-Huggins equation by regarding the interaction parameter as an empirical quantity dependent on the composition of the solution. Values of the solute activity coefficient at infinite dilution in the solvent are derived from the analysis for comparison with values from gas-liquid-chromatographic determinations. The technique is relatively quick compared to classical methods of determining activity coefficients of such systems and shown to be capable of good precision.

Thermodynamics of the system benzene-biphenyl

Abstract The Maron theory of nonelectrolyte solutions has been applied to the system benzene-biphenyl in order to correlate the available thermal and vapor pressure data. Using the thermal data, the interaction parameter was evaluated as a function of concentration and temperature, and it was then used to predict the activity coefficients of benzene. The results obtained agree within 0.3% with the experimental measurements over the entire concentration range and at temperatures ranging from 15 to 80°C. The deduced equations were also used to calculate the fusion functions for biphenyl as a function of temperature as well as its melting point. The success of the Maron theory in correlating the thermodynamic behavior of this system is of particular interest, since various statistical mechanical approaches to this system have not been able to attain such a correlation.

Activity coefficients of benzene in solution of n-alkanes and the second virial coefficients of benzene + nitrogen mixtures. Gas-chromatographic investigation

The activity coefficients of benzene in a series of n-alkanes and the mixed second virial coefficients of benzene + carrier gas have been determined by gas chromatography. Nitrogen has been used as carrier gas in most cases. The experimental procedure and method of data analysis have been discussed in previous papers. The mixed second virial coefficients have been compared with values predicted by the principle of corresponding states. The activity coefficients of several of the benzene + n-alkane mixtures were studied over a temperature range and the excess partial molar enthalpies at infinite dilution have been calculated for these systems. These enthalpies have been compared with data obtained calorimetrically by other workers on the lower n-alkane + benzene mixtures. The activity coefficients, extrapolated to the same temperature, have been discussed in terms of the quasi-lattice theory. Both “segment” and “contact point” treatments, previously used for n-alkane mixtures, have been extended to binary mixtures of n-alkanes with substances having one type of contact point or segment. The experimental results are adequately explained in terms of constant “benzene-end” group, “benzene middle group” and “end-middle” group interchange energies.

Thermodynamics of liquid surfaces: Adsorption at the binary hydrocarbon liquid—vapor interface

The surface tension and density of n-dodecane- n-hexane mixtures were determined at 25°, 30°, 35°, and 40°C. The activity coefficients of benzene— n-dodecane mixtures were determined at 30°C. The composite and individual adsorption isotherms at the liquid—vapor interface were calculated by the Gibbs adsorption equation for mixtures of benzene with n-hexane, 2,2,4-trimethylpentane, and n-dodecane; cyclohexane with n-hexane and 2,2,4-trimethylpentane; and n-dodecane with n-hexane and 2,2,4-trimethylpentane. Results are discussed on the basis of activity and of position and orientation effects at the interface. The positive excess surface tension found in the n-dodecane— n-hexane and the n-dodecane—2,2,4-trimethylpentane systems is explained on the basis of position and orientation effects at the liquid—vapor interface; isotherms for the benzene— n-dodecane system indicate that a multilayer may be adsorbed at the interface.

Liquid phase adsorption

Adsorption equilibria of binary benzene + cyclohexane liquid mixtures on silica gel, and heats of immersion of silica gel in pure liquids and in binary liquid mixtures of the two components were determined at 25°C. Liquid activity coefficients of benzene and cyclohexane were evaluated at 25°C and employed for calculating activity coefficients of the components in the adsorbed phase. The thermodynamic treatment of adsorption from solution proposed by Everett was adopted in this investigation. The heats of mixing in the surface phase appear to be much greater than that in the bulk liquid.