Ethylene glycol solubility parameter

The fluids have reasonably good chemical resistance but are attacked by concentrated mineral acids and alkalis. They are soluble in aliphatic, aromatic and chlorinated hydrocarbons, which is to be expected from the low solubility parameter of 14.9 MPa. They are insoluble in solvents of higher solubility parameter such as acetone, ethylene glycol and water. They are themselves very poor solvents. Some physical properties of the dimethylsilicone fluids are summarised in Table 29.2. 

Dioxane, ethylene glycol, water-soluble esters, and short-chain alcohols at high bulk phase concentrations may increase the CMC because they decrease the cohesive energy density, or solubility parameter, of the water, thus increasing the solubility of the monomeric form of the surfactant and hence the CMC (Schick, 1965). An alternative explanation for the action of these compounds in the case of ionic surfactants is based on the reduction of the dielectric constant of the aqueous phase that they produce (Herzfeld, 1950). This would cause increased mutual repulsion of the ionic heads in the micelle, thus opposing micellization and increasing the CMC. 

A variant on this theme is to attach a transition-metal complex of a smart polymer, the solubility of which can be dramatically influenced by a change in a physical parameter, e.g., temperature [23] (cf. Sections 4.6 and 4.7). Catalyst recovery can be achieved by simply lowering or raising the temperature. For example, block copolymers of ethylene oxide and propene oxide show an inverse dependence of solubility on temperature in water [24]. Karakhanov et al. [25] prepared water-soluble polymeric ligands comprising bipyridyl (bipy) or acetylacetonate (acac) moieties covalently attached to poly(ethylene glycol)s (PEGs) or ethylene oxide/propene oxide block copolymers 9 and 10. 

An investigation on the kinetic aspects of hydroformylation of 1-hexene using water soluble Rh-TPPTS complex catalyst in a biphasic medium using ethylene glycol as a cosolvent is presented. The effect of reaction parameters such as, partial pressure of CO, partial pressure of hydrogen and olefin concentration on the activity were studied at 353, K. A kinetic model has also been proposed to predict the observed rate data. Condensation of heptanals with ethylene glycol led to the formation of acetal derivatives, which were isolated and characterised. 

Of course, all the calculations here are approximate. In particular, we have used UNIFAC, which is not meant to be applicable to liquid-liquid equilibrium, and further, —25°C is below the temperature at which the UNIFAC parameters were obtained, so. the results we have obtained are not expected to be accurate. Therefore, all the conclusions should be checked against experimental data. As examples of the uncertainty of such predictions, from experimental data it is found that the amount of ethylene glycol required to result in a mixture freezing point of —25°C is closer to 45 wt % than the - 57 wt % estimated here, and that -pentanol is actually only soluble in water to about 2 j wt %, rather than the complete miscibility found here. This should serve as a warning concerning the use of any completely predictive method, even the UNIFAC model, which is currently the best. 

Solubility parameters Coalescing Agents Coupling Solvents, freeze thaw stabilisers. Propylene glycol benzyl alcohol glycol ethers ester alcohols ethylene glycol. 

In some cases the resolution of the solubility parameter into the three components p, and [14.31], [14.32], [14.34] is more suitable for explaining the experimental facts. For example, although the difference between the solubility parameters of the partially miscible solvent pair nitromethane-ethylene glycol is indeed small (A(5 = 3.5), both solvents differ greatly as regards their solubility parameter (5h (A(5h = 22.0). Many empirical results (e.g., the good miscibility of benzene and methanol) cannot, however, be explained by this approach. 

Solution ProportiGS. The amide group (—CONH2) in poly(acrylamide) provides for its solubility in water and in a few other polar solvents such as glycerol, ethylene glycol, and formamide. We can acquire a sense of poly(acrylamide) s affinity for water by examining a few characteristic parameters. Theta ( ) conditions for a polymer delineate a particular combination of solvent and temperature at which the polymer acts in an ideal manner (22), ie, the chains behave as random coils. The 0 temperature of poly(acrylamide) in water has been determined to be -8°C (23). Thus, water at 25°C is a solvent of intermediate quality for poly(acrylamide). Aqueous methanol (40 vol%), however, is a solvent for poly(acrylamide) at 25°C (24). The Flory / parameter, which is a measure of the relative affinity between the polymer segments with each other vs with the solvent, is 0.5 under conditions. The Flory / parameter of poly(acrylamide) has been determined to be 0.48 in water at 30°C (25). These and other properties of poly(acrylamide) in solution are collected in Table 2. 

Ozdemir, C., Giiner, A. (2007). Solubility profiles of poly(ethylene glycol)/solvent systems, I Qualitative comparison of solubility parameter approaches. European Polymer Journal, 43(1), 3068-3093. 

Table 1. Solubility parameter of poly(ethylene glycol). ...

Thus, for a typical case of van der Waals interactions, when the interaction parameter Kj(T) varies as 1/T, the critical temperature should be roughly proportional to the molecular weight. However, for water-soluble jpolymers, such as the dextran-poly(ethylene glycol)-water system ° currently used in purification of biological macromolecules, the monomer-morwmer interaction parameter Ki depends on T in a more complex way > and Tk should not be simply proportional to Af and Eq. (50) may be then used to find the mass dependence of... 

Treybal (1963, p. 108) has illustrated ways of estimating i2 by estimating the different activity coefficients y2i, yi2> yii Mtd 722- the system consists of alkyl benzene (i = 1), paraffin (i = 2), ethylene glycol or furfrual (solvent) and n-heptane (feed phase). The solubility-parameter-based approach using relation (4.1.34f) may also be employed. 

---