Methanol molar volume

Fig. 4.24 Heat of immersion of a carbon (prepared by pyrolysis of Saran Polymer A) in different liquids at 300 K. The liquids for points 1-6 were (I) methanol (2) benzene (3) n-hexane (4) 3-methyl benzene (5) 2,2-dimethyl butane (6) 2,2,4-trimethyl pentane. The abscissae represent the molar volumes of the liquids. (Redrawn from the original diagram of Barton, Beswick and Harrison. " )...

Because the synthesis reactions are exothermic with a net decrease in molar volume, equiUbrium conversions of the carbon oxides to methanol by reactions 1 and 2 are favored by high pressure and low temperature, as shown for the indicated reformed natural gas composition in Figure 1. The mechanism of methanol synthesis on the copper—zinc—alumina catalyst was elucidated as recentiy as 1990 (7). For a pure H2—CO mixture, carbon monoxide is adsorbed on the copper surface where it is hydrogenated to methanol. When CO2 is added to the reacting mixture, the copper surface becomes partially covered by adsorbed oxygen by the reaction C02 CO + O (ads). This results in a change in mechanism where CO reacts with the adsorbed oxygen to form CO2, which becomes the primary source of carbon for methanol. 

If the volume fraction of methanol in the original mixture was (a), then the volume fraction of water would be (1-a). The molar volume of a substance is the ratio of the molecular weight to the density and thus the molar concentration of methanol and... 

For iodine in methanol solution, the partial molar volume of the solute is essentially constant, independent of concentration, and is equal to 62.3 cm ... 

Comelli, F. and Francesconi, R. Isothermal vapor-liquid equilibria measurements, excess molar enthalpies, and excess molar volumes of dimethyl carbonate + methanol. + ethanol, and propan-l -ol at 313.15 K. J. Chem. Eng. Data, 42(4) 705-709, 1997. 

Partial molar volumes have been determined for [Fe(phen)3] +, [Fe(bmi)3] +, and [Fe(cmi)3] + (emi = (10 ) in water and in methanol-water mixtures, and for [Fe(bipy)3] + and [Fe(Me2bsb)3] + in water. Caleulations of these partial molar volumes have been compared with the experimentally derived values. ... 

Comparison of dipole moments shows only small differences in polarity. From these data, it can be reasoned that micellization in methanol is feasible. Dielectric constants and effective polarities (dipole moment/molar volume) support this premise with more divergent values. It is noted that bis(2-ethyIhexyI) sodium sulfosuccinate forms micelles readily in water and 2-octanol which have the highest and lowest dielectric constants, respectively, but micelles are formed only at low concentrations in methanol whose dielectric constant is intermediate in value. 

The influence of temperature and pressure on the excess molar volume is not very well known. For ILs the values were observed more negative at higher temperature [60,63]. Increasing the pressure from 0.1 to 20 MPa at the same temperature, less negative values of were observed [63]. The influence of temperature on the values at the pressure 15 MPa for [CiCiIm][CiS04] -t methanol is presented in Figure 1.4. 

Zafarani-Moattar, M.T. and Shekaari, H. Volumetric and speed of sound of ionic liquid, l-butyl-3-methylimidazolium hexafluorophosphate with acetonitrile and methanol at T = (298.15 to 318.15) K, /. Chem., Eng. Data, 50,1694,2005. Wang, J. et al.. Excess molar volumes and excess logarithm viscosities for binary mixtures of the ionic liquid l-butyl-3-methylimidazolium hexafluorophosphate with some organic solvents, /. Solution Chem., 34, 585, 2005. 

The excess molar volumes of 10-40 mol % methanol/C02 mixtures at 26°C as a function of pressure has been determined. The excess molar volumes varied with composition and pressure significant interaction between CO2 and methanol was noted from the observed excess molar volumes. To better characterize the interaction and its effect on analyte solubility, the partial molar volume of naphthalene at infinite dilution in liquid 10 and 40 mol % methanol/C02 mixtures was determined. The variation of the partial molar volume at infinite dilution with pressure correlated well with isothermal compressibility of the methanol/C02 mixtures (Souvignet and Olesik, 1995). 

Figure 5.8 Ratio of the activity coefficient in water (y/w) and in methanol/water [20% (v v) and 40% (v v) methanol] as a function of the molar volume (Vix, see Box 5.1) of the solute log(y // ) = a Vix + b. The three compound classes include the following compounds ...

The mole fraction of methanol in a 30% methanol/70% water mixture is 0.16 (Eq. 5-34). The molar volume of methanol is 0.0406 L mol 1. Hence, the molar volume of the mixture can be calculated as (Eq. 3-43, note that we assume additivity) ... 

FIGURE 7.18 Experimental energy, entropy, and volume profiles for the oxidative addition of H2 to RhI(bpy)2+ in methanol and acetone (a) enthalpy, (b) entropy, and (c) partial molar volume. For details, see reference 345. For clarification, methanol (red), acetone (blue), see original Figure in Ref. 344. Reproduced by permission of the American Chemical Society. 

The actual molar volumes of the binary solution methanol(l)/water 2) at 2S°C and 1 bar are shown in Fig. 13.3. In addition the values of V, and V2 are plotted as functions of x,. The line drawn tangent to the V-vs.-x, curve at x, = 03 illustrates the procedure by which values of and V2 are obtained. The particular numerical values shown on the graph are those given with Example 11.2. 

Example 1U The need arises in a laboratory for 2,000 cm3 of an antifreeze solution consisting of a 30 mole percent solution of methanol in water. What volumes of pure methanol and of pure water at 25°C must be mixed to form the 2,000 cm3 of antifreeze, also at 2S°C Partial molar volumes for methanol and water in a 30 mole percent methanol solution at 25°C are ... 

Here Vi is the molar volume of the solute / incm3/(mol) at its normal boiling point (for some values of Vu see Tables 2.9a and b), p the viscosity of solvent in pP, i//. an association parameter for solvent, and T the absolute temperature in K. Recommended values of the association parameters are 2.6 for water, 1.9 for methanol, 1.5 for ethanol, and l.Ofor benzene, ether, heptane, and other unassociated solvents. Equation (2.82) should be used only for dilute nondissociating solutions. 

Chen-Chen [7] Their correlation was based on diffusion measurements of 50 combinations of conditions with 3 to 4 replicates each and exhibited an average error of 6 percent. In this correlation, Vr = VB/[0.9724 (Vrf, + 0.04765)] and V B = the liquid molar volume at the melting point, as discussed previously. Their association parameter P [which is different from the definition of that symbol in Eq. (5-229)] accounts for hydrogen bonding of the solvent. Values for acetonitrile and methanol are P = 1.58 ana 2.31, respectively. 

The present paper is devoted to the local composition of liquid mixtures calculated in the framework of the Kirkwood—Buff theory of solutions. A new method is suggested to calculate the excess (or deficit) number of various molecules around a selected (central) molecule in binary and multicomponent liquid mixtures in terms of measurable macroscopic thermodynamic quantities, such as the derivatives of the chemical potentials with respect to concentrations, the isothermal compressibility, and the partial molar volumes. This method accounts for an inaccessible volume due to the presence of a central molecule and is applied to binary and ternary mixtures. For the ideal binary mixture it is shown that because of the difference in the volumes of the pure components there is an excess (or deficit) number of different molecules around a central molecule. The excess (or deficit) becomes zero when the components of the ideal binary mixture have the same volume. The new method is also applied to methanol + water and 2-propanol -I- water mixtures. In the case of the 2-propanol + water mixture, the new method, in contrast to the other ones, indicates that clusters dominated by 2-propanol disappear at high alcohol mole fractions, in agreement with experimental observations. Finally, it is shown that the application of the new procedure to the ternary mixture water/protein/cosolvent at infinite dilution of the protein led to almost the same results as the methods involving a reference state. 

From the solubilities in the individual constituents of the solvent and their molar volumes. The molar volume of a ternary mixed solvent (W) in Equation 23 can be obtained from the molar volumes of water, methanol and 1-propanol as an ideal molar volume... 

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