Effect of electrolytes on formulation and stability of water/di-ethyl oxalate/tween micro-emulsions

The formulated micro-emulsions was mainly composed of distilled water as the aqueous phase, diethyl oxalate as the oil phase, and Tween 80 as the surface-active agent (surfactant). Iso-propylene glycol was evaluated as the co-surfactant, thus both (water/diethyl oxalate/Tween-80) and (water/diethyl oxalate/Tween 80/isopropylene glycol) microemulsions were formulated. The effect of different electrolytes on the micro-emulsification of the oil phase was studied. Phase diagrams that represent the formulated micro-emulsions were constructed. The area within the phase diagram where the micro-emulsion is stable could be broadened using a set of strong or weak electrolytes, as additives or co-surfactants, which will result in thin, Newtonian behaving fluids. The use of weak electrolytes, e.g., acetic or propanoic acid, gave better characteristics in terms of a broader marginal stability and longer shelf-life under high-temperature, ambient, and cold conditions. This is an abstract of a paper presented at the CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference on Process Integration, Modelling and Optimisation for Energy Saving and Pollution Reduction (Prague, Czech Republic 8/25-29/2012).