Weight solubilization rate

Selective solubilization can also occur in mixtures of polar and nonpolar oils. Using their oil drop method described previously, Chen et al. measured solubilization rates of mixtures of triolein and oleic acid in solutions of pure nonionic surfactants. As Figure 9.9 shows for a drop initially containing 85/15 triolein/oleic acid by weight injected into 2 wt% Tergitol 15-S-7 at 35°C, they observed that the solubilization process consisted of two stages. In the first stage, the drop radius... 

Experiments with various surfactant systems [166,170,178] showed that the solubilization rates for solutions of ionic surfactants are generally much lower than those for nonionic surfactants. This can be attributed to the electrostatic repulsion between the micelles and the similarly charged surfactant adsorption monolayer at the oil-water interface. On the other hand, copolymers have been found to form micelles, which solubilize various hydrophobic compounds well, even in the absence of low-molecular-weight surfactants [179-187]. Moreover, appropriately chosen copolymers can act as very efficient promoters of solubilization [160,168-170]. 

The effect of surfactant structures and properties on emulsion polymerization have been investigated by numerous authors [82-89]. Efforts were made to study the effects of surfactants with different molecular weights on the rate of polymerization [82], swelling and solubilization effects [83], effects of alkyl chain length of homologous series on the rate of polymerization, particle size... 

The solubilized substrate MA is the analog of the complex ES in Reaction (E), and the product P is formed in the micelle with the rate constant km. The product can also form from the substrate without involving the micelle A 0 is the rate constant for the last process. The experimental (subscript exp) rate constant for Reaction (G) is then a weighted sum of the two constants km and k0 ... 

Transfer solubilized and completely reduced inclusion bodies into a dialysis bag with molecular weight cut-off pore size of 3500 and dialyze it against 10 volumes of refolding buffer for 24-36 h at 4°C. Once dialysis bag with protein is placed in dialysis beaker, stirring should be stopped to slow down the dialysis rate at this stage. 

For the solubilization of highly insoluble hydrocarbons by POE nonionics into water, the rate of solubilization has been found (Carroll, 1981, 1982) to be directly proportional to the surfactant concentration above the CMC, and to increase with the polarity and decrease with the molecular weight of the oil. The rate is also strongly temperature dependent in the region of the cloud point (Section IIIB below), increasing rapidly as that temperature is approached. The mechanism suggested involves diffusion of the micelles to the hydrocarbon-water interface, where they dissociate and adsorb as monomers. This adsorption produces concerted desorption from the interface of an equivalent amount of monomeric surfactant, but in the form of micelles containing a quantity of solubilizate. 

Polymer-solvent mixtures can be separated and the polymer recovered from solution at the lower critical solution temperature (LCST). This is the temperature at which the miscible polymer-solvent mixture separates into a polymer-rich phase and a solvent-rich phase. LCST phenomena are related to the chemical nature of the mixture components, the molecular weight of the mixture components, especially the polymer, and the critical temperature and critical pressure of the solvent (Allen and Baker, 1965). As the single-phase polymer solution is isobarically heated to conditions near the critical point of the solvent, the polymer and solvent thermally expand at different rates. This means their free volumes change at different rates (Patterson, 1969). The thermal expansion of the solvent is much greater than that of the polymer. Near its critical point, the solvent has expanded so much that it is no longer able to solubilize the polymer. Hence, the polymer falls out of solution. If the molecular weight of the polymer is on the order of 10 a polymer-solvent LCST can occur within about 20-30°C of the solvent s critical temperature. If the molecular weight of the polymer is closer to 10, the LCST phase... 

---