Polyoxyethylene compounds

Okahara, M., and Nakatsuji, Y. Active Transport of Ions Using Synthetic Ionophores Derived from Cyclic and Noncyclic Polyoxyethylene Compounds. 128, 37-59 (1985). 

QIM of Schiiurmann for Oxyethylated Surfactants Schiiurmann [63] studied Kow and its relation to aquatic toxicity for polyoxyethylene compounds of the type shown in Figure 13.5.4. The contribution of the -CH2-CH2-O- group is not a constant but depends on the length of the oxyethylene chain. For the insertion of a -CH2-CH2-O- group, Schiiurmann reports a variation from — 0.10 for long-chain molecules to —0.19 for short-chain molecules. 

Alternatively, the reaction may be carried out in a mixture of two immiscible solvents. The contact area between the phases may be increased by agitation. Phase transfer reagents, in particular quaternary ammonium compounds, are useful aids in many two-phase reactions. Also, crown ethers are very effective in overcoming phase contact problems however, their usefulness is limited by high price. (Open-chain polyoxyethylene compounds often give a crown ether effecf and may constitute practically interesting alternative phase transfer reagents.)... 

Polyhedral niosomes were found to be thermoresponsive Fig. 7 (a). Above 35 °C, there was an increase in the release of CF from these niosomes even though the polyhedral shape was preserved until these vesicles were heated to 50 °C. Solulan C24-free polyhedral niosomes do not exhibit this thermoresponsive behavior [160] due to a decrease in the interaction of the polyoxyethylene compound solulan C24 with water at this temperature (due to decreased hydrogen bonding) as identified by viscometry [161]. This observed thermoresponsive behavior was used to design a reversible thermoresponsive controlled release system Fig. 7 (b). Thermoresponsive liposomal systems which rely on the changing membrane permeability, when the system transfers from the gel state (La) to the liquid crystal state (L 3) [162], are not reversible. This is not unex-... 

Among commercial nonionic surfactants, those made from fatty alcohols with ethylene oxide are the most commonly used. Ethoxylation offers the production of a wide range of nonionic surfactants as the hydrophobic part, and the ethylene oxide number can be easily adjusted according to the desired properties. The chemical reaction to convert a fatty alcohol into a nonionic ethoxylated surfactant uses ethylene oxide under pressure (typically 2-8 bars) and heat (typically 120-200°C). Actually, fatty alcohols have a hydroxyl group that can react further with ethylene oxide providing polyoxyethylene compounds with a range of molecular weights. 

Burger, K., Surface-active polyoxyethylene compounds and PEG (in German), Fresenius Z. Anal. Chem., 1963,196, 251-259 ibid., 1964,199, 434-438. 

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