Binary hydrocarbon-water

Kobayashi, R., Vapor-Liquid Equilibrium in Binary Hydrocarbon-Water Systems, Ph.D. Dissertation, University of Michigan, University Microfilms No. 3521, Ann Arbor, MI (1951). 

Figure 28 Critical p T) curves of binary hydrocarbon + water systems (1 = benzene + HjO 2 = benzene + DjO 3 = methylbenzene + 4 = 2-dimethyl-...

Mackay, D., Shiu, W.Y., Wolkoff, A.W. (1975) Gas chromatographic determination of low concentrations of hydrocarbons in water by vapor phase extraction. ASTM STP 573, pp. 251-258, Am. Soc. Testing and Materials, Philadelphia, Pennsylvania. Macknick, A.B., Prausnitz, J.M. (1979) Vapor pressures of high-molecular-weight hydrocarbons.. /. Chem. Eng. Data 24, 175-178. Mac/ynski. A., Wioeniewska-Goclowska, B., Goral, M. (2004) Recommended liquid-liquid equilibrium data. Part 1. Binary alkane-water systems. J. Phys. Chem. Ref. Data 33, 549-577. 

The API Subcommittee for Technical Data is sponsoring phase equilibria work by Grant Wilson (Wilco Co.) on water non-hydrocarbon/ hydrocarbon systems. The first system will be n-octane, ethylbenzene, and ethyl cyclohexane as binaries with water and as ternaries with hydrogen sulfide as the third component. 

Of the many possible non-hydrocarbon - water binary systems which are related to substitute gas processes, the data on only the water binaries containing H2S, C02, N2, and NH3 were used in this study. The treatment of hydrogen, a quantum gas, is different from that of the other gases. A separate paper will deal with the correlation of the data on hydrogen mixtures. 

Five binary-hydrocarbon mixtures of ethane or ethylene with heavier hydrocarbons were studied (Table III). The only substrate used in these studies was water. If an RPT did not occur, ice always formed rapidly. When n-butane or n-pentane was the heavier component, RPTs were 100% reproducible over a particular composition range. This was not, however, true if the heavier component were propane. 

During the past few years, the determination of the interfacial properties of binary mixtures of surfactants has been an area in which there has been considerable activity on the part of a number of investigators, both in industry and in academia. The Interest in this area stems from the fact that mixtures of two different types of surfactants often have interfacial properties that are better than those of the individual surfactants by themselves. For example, mixtures of two different surface-active components sometimes reduce the interfacial tension at the hydrocarbon/water interface to values far lower than that obtained with the individual surfactants, and certain mixtures of surfactants are better foaming agents than the individual components. For the purpose of this discussion we define synergism as existing in a system when a given property of the mixture can reach a more desirable value than that attainable by either surface-active component of the mixture by itself. 

To evaluate the phase equilibria of binary gas mixtures in contact with water, consider phase diagrams showing pressure versus pseudo-binary hydrocarbon composition. Water is present in excess throughout the phase diagrams and so the compositions of each phase is relative only to the hydrocarbon content. This type of analysis is particularly useful for hydrate phase equilibria since the distribution of the guests is of most importance. This section will discuss one diagram of each binary hydrate mixture of methane, ethane, and propane at a temperature of 277.6 K. 

As in binary surfactant-water systems considered previously, two constraints on the geometry of the surfactant interface are active a local constraint, which is due to the surfactant molecular architecture, and a global constraint, set by the composition. These constraints alone are sufficient to determine the microstructure of the microemulsion. They imply that the expected microstructure must vary continuously as a function of the composition of tile microemulsion. Calculations show - and small-angle X-ray and neutron scattering studies confirm - that the DDAB/water/alkane microemulsions consist of a complex network of water tubes within the hydrocarbon matrix. As water is added to the mixture, the Gaussian curvature - and topology -decreases [41]. Thus the connectivity of the water networks drops (Fig. 4.20). 

Example 4.27 Comparison of lie by SAFE, Peng-Robinson, and UNIFAC You and Chen [13] have compared these three eos s for calculating lie. They employed data for 5 binary mixtures of methanol + an aliphatic hydrocarbon, 6 binaries of phenol + an aliphatic hydrocarbon, 12 binaries of water + an aliphatic or a hydrocarbon, 7 binaries of water + an ester, 5 binaries of acetic acid + an aliphatic or a naphthenic hydrocarbon, and 6 binaries of aniline + an aliphatic or a naphthenic hydrocarbon. Temperature was in the range of 273-343°K, with one exception at 236°K. 

Conclusions on Polar—Nonpolar Mixtures. The recommendations given in Ref. 1 for polar-hydrocarbon binaries are generally still valid. With the new k s reported here for alcohol-nonpolar binaries, however, it is possible to develop a correlation for the nonpolar binaries of water as well as for alcohols. This tentative correlation, which relates ki to VCj (7 is the nonpolar component), is presented in Figure 5. 

B. Hydrocarbon + Water Systems.—In Figure 28 the critical phase behaviour of binary aqueous solutions of several hydrocarbons and fluorobenzene is shown according to data taken from the literature. The dashed curve is the vapour pressure curve of pure water and the solid lines are the branches of the critical curves of the binary systems that start from the critical point of pure water CP(H20). Except for naphthalene -I- H2O and biphenyl + H2O the critical... 

The application of the AEOS to hydrocarbon-water mixtures requires temperature-dependent binary interaction coefficients. These data can be obtained from binary water-hydrocarbon data. Once such data are available, then the AEOS can be used to predict the phase behavior of H2 0-crude oil systems. Figure 3.22 shows the binary interaction coefficients between Cj and heavier hydrocarbons from Shinta and Firoozabadi (1997). Binary interaction coefficients of... 

Two areas listed in Table 1 were not discussed—hydrocarbon-water binaries and petroleum fractions. For the former systems only eight systems of experimental VLE data (ethylene, propylene, 1-butene, 1-hexene, n-hexane, cyclohexane, benzene, and n-nonane) were available. Use of solubility data and calculated VLE data added only five more systems (propane, propyne, cyclopropane, n-butane, and 1,3-butadiene). For petroleum fraction systems only three sources and seven systems have been characterized well enough to use in analytical correlations to be tested. These systems Include three naphtha-fuel oil systems, two hydrogen-hydrocrackate fractions, and two hydrogen-hydrogen sulfide-hydrocrackate fractions. No reasonable work can be done without additional data. 

An adequate prediction of multicomponent vapor-liquid equilibria requires an accurate description of the phase equilibria for the binary systems. We have reduced a large body of binary data including a variety of systems containing, for example, alcohols, ethers, ketones, organic acids, water, and hydrocarbons with the UNIQUAC equation. Experience has shown it to do as well as any of the other common models. V7hen all types of mixtures are considered, including partially miscible systems, the... 

Another important class of materials which can be successfiilly described by mesoscopic and contimiiim models are amphiphilic systems. Amphiphilic molecules consist of two distinct entities that like different enviromnents. Lipid molecules, for instance, comprise a polar head that likes an aqueous enviromnent and one or two hydrocarbon tails that are strongly hydrophobic. Since the two entities are chemically joined together they cannot separate into macroscopically large phases. If these amphiphiles are added to a binary mixture (say, water and oil) they greatly promote the dispersion of one component into the other. At low amphiphile... 

Isoprene [78-79-5] (2-methyl-1,3-butadiene) is a colorless, volatile Hquid that is soluble in most hydrocarbons but is practically insoluble in water. Isoprene forms binary azeotropes with water, methanol, methylamine, acetonitrile, methyl formate, bromoethane, ethyl alcohol, methyl sulfide, acetone, propylene oxide, ethyl formate, isopropyl nitrate, methyla1 (dimethoxymethane), ethyl ether, and / -pentane. Ternary azeotropes form with water—acetone, water—acetonitrile, and methyl formate—ethyl bromide (8). Typical properties of isoprene are Hsted in Table 1. 

Principal component analysis has been used in combination with spectroscopy in other types of multicomponent analyses. For example, compatible and incompatible blends of polyphenzlene oxides and polystyrene were distinguished using Fourier-transform-infrared spectra (59). Raman spectra of sulfuric acid/water mixtures were used in conjunction with principal component analysis to identify different ions, compositions, and hydrates (60). The identity and number of species present in binary and tertiary mixtures of polycycHc aromatic hydrocarbons were deterrnined using fluorescence spectra (61). 

Esters of low volatility are accesible via several types of esterification. In the case of esters of butyl and amyl alcohols, water is removed as a binary azeotropic mixture with the alcohol. To produce esters of the lower alcohols (methyl, ethyl, propyl), it may be necessary to add a hydrocarbon such as benzene or toluene to increase the amount of distilled water. With high boiling alcohols, ie, benzyl, furfuryl, and P-phenylethyl, an accessory azeotroping Hquid is useful to eliminate the water by distillation. 

Carbides, which are binary compounds containing anionic carbon, occur as covalent and as salt-like compounds. The salt-like carbides are water-reactive and, upon hydrolysis, yield flammable hydrocarbons. Typical hydrolysis reactions include ... 

When comparable amounts of oil and water are mixed with surfactant a bicontinuous, isotropic phase is formed [6]. This bicontinuous phase, called a microemulsion, can coexist with oil- and water-rich phases [7,1]. The range of order in microemulsions is comparable to the typical length of the structure (domain size). When the strength of the surfactant (a length of the hydrocarbon chain, or a size of the polar head) and/or its concentration are large enough, the microemulsion undergoes a transition to ordered phases. One of them is the lamellar phase with a periodic stack of internal surfaces parallel to each other. In binary water-surfactant mixtures, or in... 

Prus and Kowalska [75] dealt with the optimization of separation quality in adsorption TLC with binary mobile phases of alcohol and hydrocarbons. They used the window diagrams to show the relationships between separation selectivity a and the mobile phase eomposition (volume fraction Xj of 2-propanol) that were caleulated on the basis of equations derived using Soezewiriski and Kowalska approaehes for three solute pairs. At the same time, they eompared the efficiency of the three different approaehes for the optimization of separation selectivity in reversed-phase TLC systems, using RP-2 stationary phase and methanol and water as the binary mobile phase. The window diagrams were performed presenting plots of a vs. volume fraetion Xj derived from the retention models of Snyder, Schoen-makers, and Kowalska [76]. 

For ternary and higher order mixtures, we have usually assumed that the interaction parameters for the non-water binary pairs in the water rich phase are identical to the vapor (hydrocarbon rich liquid phase) interaction parameters. Some work has been done on changing all water phase interaction parameters we concluded that predicted results were not improved enough to warrant the expenditure of time required to develop the additional parameters. A third interaction parameter for the hydrocarbon rich liquid could also be determined. Again, our work indicated that little improvement resulted from using this third parameter. Additional work is being done on both points. 

A similar strategy was used to develop the PFGC-MES equation of state parameters for describing the behavior of methanol hydrocarbon acid gas water systems. Multiple phase binary interaction parameters were used as required. Again, these second phase binary interaction parameters were usually not temperature dependent. 

Interaction parameter was also generated for the hydrocarbon -rich phases of the n-octane - water system. The data of Kalafati and Piir (37j were used. There were no data available for the water - rich liquid phase for this binary. 

Using a recent equation of state of the van der Waals type developed to describe non-polar components, a model is presented which considers water as a mixture of monomers and a limited number of polymers formed by association. The parameters of the model are determined so as to describe the pure-component properties (vapour pressure, saturated volumes of both phases) of water and the phase equilibria (vapour-liquid and/or liquid-liquid) for binary systems with water including selected hydrocarbons and inorganic gases. The results obtained are satisfactory for a considerable variety of different types of system over a wide range of pressure and temperature. 

Reversed-phase chromatography employs a nonpolar stationary phase and a polar aqueous-organic mobile phase. The stationary phase may be a nonpolar ligand, such as an alkyl hydrocarbon, bonded to a support matrix such as microparticulate silica, or it may be a microparticulate polymeric resin such as cross-linked polystyrene-divinylbenzene. The mobile phase is typically a binary mixture of a weak solvent, such as water or an aqueous buffer, and a strong solvent such as acetonitrile or a short-chain alcohol. Retention is modulated by changing the relative proportion of the weak and strong solvents. Additives may be incorporated into the mobile phase to modulate chromatographic selectivity, to suppress undesirable interactions of the analyte with the matrix, or to promote analyte solubility or stability. 

A number of tests were also carried out with liquefied ethane containing various amounts of heavier hydrocarbons. The compositions where RPTs were reported are given in Table VI. Also shown is the ratio TJT which, from previous tests, would be expected to be slightly greater than unity for an RPT to occur. The agreement is excellent. Note also that, for pure ethane, TJT i 1.09, yet no RPT results if this liquefied gas is simply poured into water. The value TJT 1.09 is close to the upper cutoff of the ethane binaries in Table VI. While theory would still indicate that RPTs are possible, they do not often occur when the water temperature is much above the superheat limit temperature of the liquefied gas. 

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