Oil-continuous microemulsions composed of hexane, water, and 2-propanol

On the basis of conductivity and centrifugation data and visual examination, ternary phase diagrams were prepared for systems composed of hexane, water, and 2-propanol. Certain ternary compositions were shown to be oil-continuous microemulsions, even though a soap or detergent was not present. Of a number of short-chain alcohols tested, only 2-propanol and 1-propanol could stabilize a microemulsified ternary solution. Addition of a small amount of hexadecyltrimethylammonium perchlorate to the ternary solutions produced only modest changes in the ternary phase diagram. However, in the presence of hexadecyltrimethylammonium salts, most short-chain alcohols containing less than eight carbons could stabilize an oil-continuous microemulsion.