Density of Ethanol-Water Mixtures

New tables of practical laboratory data such as Flame and Bead tests. Flame Temperatures, and Density of Ethanol-Water Mixtures... 

Most frequently, volume data for solutions are tabulated as density p as a function of composition. The procedure for obtaining y i2 is illustrated by reference to the densities and weight percent concentrations of ethanol-water mixtures (Table 18.1, Columns 1 and 4 at 25°C). 

TABLE 18.1. Densities and Partial Volumes of Ethanol-Water Mixtures"... 

The density of the liquid mixture can be determined using a pyknometer or it can be derived from a previously determined calibration curve. For the determination of densities less than unity (e.g., polyethylene), ethanol/water mixtures are suitable for densities larger than unity one may use mixtures of water with aqueous salt solutions (40% CaCl2 solution = 1.40 g/ml 72% ZnCl2 solution = 1.95 g/ml). The density gradient method, which is an elegant var-... 

A test set of 6 to 13 aroma compound partition coefficients between different food contact polymers (low density polyethylene (LDPE), high density polyethylene (HDPE) polypropylene (PP), polyethylene terephthalate (PET), polyamide (PA)) and different food simulant phases (water, ethanol, aqueous ethanol/water mixtures, methanol, 1-propanol) were taken from the literature (Koszinowski and Piringer, 1989, Baner, 1992, Franz, 1990, Koszinowski, 1986, Franz, 1991, Baner, 1993, Piringer, 1992). Table 4-2 shows the test set of 13 different aroma compounds, with their properties and their structures. The experimental data were compared to estimations using different estimation methods of UNIFAC-FV, GCFLORY (1990), GCFLORY (1994) and ELBRO-FV. 

Adsorption onto activated charcoal (Norit A) has been used for small oligonucleotides, up to tetranucleotides (Crane and Lipman 1953 Mandeles and Kammen 1966). The method is quicker and more convenient than DEAE-cellulose chromatography. Mandeles and Kammen (1966) used Norit A suspended in 1 mM phosphate 1 mM pyrophosphate buffer at pH 6.0 at a concentration of 100 mg/ml. The nucleotide solution is adjusted to pH 3 and 5 mg Norit for every optical density unit ( 40 pg) of nucleotides is added. The charcoal is collected on a filter paper and washed with water. (A good quantitative measure of or radio-activity may be obtained by counting the dry filter paper in a Geiger-Muller thin window counter.) The nucleotide material is eluted with a small volume of a mixture of ethanol, water and ammonia (600 400 6.5 v/v/v) which is then removed by drying under reduced pressure at 40°C. 

Although density measurements of varying degrees of accuracy have been reported for ethanolic solutions, standard state partial molal volumes in ethanol have been evaluated for only a few electrolytes. Vosburgh, Connell and Butler reported for LiCl in water and a series of alcohols, including ethanol. They observed that the salt had a much smaller value of F in the alcohols than in water, and that for all the systems studied it was smallest in ethanol. Sobkowski and Mine have reported for HCl in water and the three lower alcohols and also observe F to be smaller in the alcohols than in water, but it is smallest in methanol rather than ethanol. Lee and Hyne have reported F° at 50.25°C for the tetraalkylammonium chlorides in ethanol-water mixtures up to 0.4 mol fraction of ethanol. With the tetramethyl and tetraethyl salts, the volumes are all very positive in water but decrease rapidly with an increase in alcohol content and appear to be at a minimum around 0.3 to 0.4 mol fraction of ethanol. The higher tetraalkyl salts are not entirely consistent with this pattern. 

Table 6.49 Densities of Pure Ethanol-Water Mixtures at Various Temperatures (19)...

Extractable di-(2-ethylhexyl) phthalate, DOP, is determined in plastic collapsible containers for human blood and blood components. A sample of plastic is extracted with ethanol-water mixture having a density of 0.937 at 37°C for 60 min. The resultant solution is measured for absorbance at 272 nm and concentration of plasticizer determined from calibration curve. 

The errors caused by this simplification are usually small The largest error has been reported for the ethanol-water mixture, where the contribution of the excess volume can arise up to 3.5% [17]. It is worth mentioning that Eq. (3.60) yields better results than a linear mixing rule for the density, which is often applied due to its simplicity, especially when the pure component densities are significantly different. 

Density Prediction of Ternary Mixtures of Ethanol + Water + Ionic Liquid Using Backpropagation Artificial Neural Networks... 

The aim of this chapter is to demonstrate the good predictive power of ANNs for determination of the density of ternary mixtures of ethanol + water + ionic liquid. 

DENSITY PREDICTION OF TERNARY MIXTURES OF ETHANOL + WATER + IONIC LIQUID... 

As quoted previously, densities of ternary mixtures of ethanol + water + ionic liquid were obtained using ANNs. The model that achieves better predictions consists in five input neurons, one middle layer with four neurons and one output neuron. This model presents RMSEs of 0.024g cm" (R =0.982) for the training set and 0.008g-cm (R = 0.977) for the vahdation set. The average percentage deviation for training and validation phase is 1.96%. 

Example 2.17 Estimation of diffusivity in a dilute liquid mixture Estimate the dilTusivity of ethanol in a dilute solution of ethanol-water at 25°C. The density of ethanol is 0.79 g/cm and the viscosity of water at 25°C is 0.95 cP. 

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