溶液的超额摩尔体积测定实验

溶液的超额摩尔体积测定实验浙江大学王关勤化工热力学教材中，溶液的超额性质（函数）是一个非常重要的基本概念。其中，越额摩尔体积（Ｅ－ｃｏｅｓ。ＭｄａｒＶｄｕｍｅ）是一个常用的，而且可用实验测定的热力学性质。为此，作者设计制作了一种适用于教学实验用的稀释...

Excess Molar Volume, Viscosity and Heat Capacity for the Mixture of 1,2-Propanediol-Water at Different Temperatures

Experimental densities, viscosities and heat capacities at different temperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water. Density values were used in the determination of excess molar volumes, VE. At the same time, the excess viscosity was investigated. The values of VE and E were fitted to the Redlich-Kister equation. Good agreement was observed. The excess volumes are negative over the entire range of composition. They show an U-shaped-concentration dependence and decrease in absolute values with increase of temperature. Values of E are negative over the entire range of the composition, and has a trend very similar to that of VE . The analysis shows that at any temperature the specific heat of mixture is a linear function of the composition as x1 > 20%. All the extended lines intersect at one point. An empirical equation is obtained to calculate the specific heat to mixture at any composition and temperature in the experimental range.

Excess Molar Volume, Viscosity and Heat Capacity for the Binary Mixture of p-Xylene and Acetic Acid at Different Temperatures

Experimental densities, viscosities and heat capacities atdifferent temperatures were presented over the entire range of molefraction for the binary mixture of p-xylene and acetic acid. Densityvalues were used in the determination of excess molar volumes, V^E.At the same time, the excess viscosity and excess molar heatcapacities were calculated. The values of V^E, η~E and c^E_p werefitted to the Redlich-Kister equation. Good agreements were observed.The excess molar volumes are positive with a large maximum valuelocated in the central concentration range.

Density and Excess Molar Volume of Binary Mixtures ofp-Xylene＋Acetic Acid and o-Xylene＋Acetic Acid at Different Temperatures and Pressures

A new apparatus was designed with a thick-walled glass capillary, electric heater tube with red copper and heat preservation. The thick-walled glass capillary was used for its advantages of resistance to acid corrosion and pressure, and ease of observation. The experimental densities over the entire range of mole fraction for the binary mixture of p-xylene＋acetic acid and o-xylene＋acetic acid were measured using the new apparatus at temperatures ranging from 313.15K to 473.15K and pressure ranging from 0.20 to 2,0 MPa. The density values were used in the determination of excess molar volumes, W. The Redlich-Kister equation was used to fit the excess molar volume values, and the coefficients and estimate ot the standard error values were presented. The experimental resuits prove that the density measurement apparatus is successful.

Pressure-volume-temperature and excess molar volume prediction of amorphous and crystallizable polymer blends by equation of state

In this work the statistical mechanical equation of state was developed for volumetric properties of crystalline and amorphous polymer blends.The Ihm-Song-Mason equations of state(ISMEOS) based on temperature and density at melting point(T_m and ρ_m) as scaling constants were developed for crystalline polymers such as poly(propylene glycol) + poly(ethylene glycol)-200(PPG + PEG-200),poly(ethylene glycol) methyl ether-300(PEGME-350) + PEG-200 and PEGME-350 + PEG-600.Furthermore,for amorphous polymer blends containing poly(2,6-dimethyl-1,4-phenylene oxide)(PPO) + polystyrene(PS) and PS + poly(vinylmethylether)(PVME),the density and surface tension at glass transition(ρ_g and γ_g) were used for estimation of second Virial coefficient.The calculation of second Virial coefficients(B_2),effective van der Waals co-volume(b) and correction factor(α) was required for judgment about applicability of this model.The obtained results by ISMEOS for crystalline and amorphous polymer blends were in good agreement with the experimental data with absolute average deviations of 0.84%and 1.04%,respectively.

The physicochemical properties of some imidazolium-based ionic liquids and their binary mixtures

The density, viscosity and conductivity of ionic liquids （ILs）, 1-octyl-3-methylimidazolium tetrafluoroborate （[omim][BF4]）, 1-octyl-3-methylimidazolium chloride （[omim][C1]）, 1-hexyl-3-methylimidazolium tetrafluoroborate （[hmim] BF4]）, 1-hexyl- 3-methylimidazolium chloride （[hmim][C1]）, 1-hexyl-3-methylimidazolium hexafluorophosphate （[hmim][PF6]）, and the [omim][BF4] ＋ [omim][Cl], [hmim][BF4] ＋ [hmim][C1], and [hmim][PF6] ＋ [hmim][C1] binary mixtures were studied at dif- ferent temperatures. It was demonstrated that the densities of both the neat ILs and their mixtures varied linearly with temper- ature. The density sensitivity of a binary mixture is between those of the two components. The excess molar volumes （l/e） of [hmim][BF4] ＋ [hmim][C1] and [hmim][PF6] ＋ [hmim][C1] mixtures are positive in the whole composition range. For [omim][BF4] ＋ [omim][C1], the VE is also positive in the [omirn][C1]-rich region, but is negative in the [omim][BF4]-rich re- gion. The viscosity or conductivity of a mixture is in the intermediate of those of the two neat ILs. For all the neat ILs and the binary mixtures studied, the order of conductivity is opposite to that of the viscosity. The Vogel-Tammann-Fulcher （VTF） equations can be used to fit the viscosity and conductivity of all the neat ILs and the binary mixtures. The neat ILs and their mixtures obey the Fractional Walden Rule very well, and the values of the Walden slopes are all smaller than unit, indicating obvious ion associations in the neat ILs and the binary mixtures.