Ethanol in Soap
Date: July 2007
While preparing soap in lab ethanol is added. What is the
role of ethanol in soap?
I am assuming this is the soap preparation process that uses a
fatty acid oil and sodium hydroxide in water. Since the oil and
water do not mix, some solvent (the ethanol) that is able to
dissolve partially in both the oil and the water helps to facilitate
the reaction of sodium hydroxide with the fatty acid (to produce the
fatty acid salt - soap, and water). The ethanol essentially allows
better contact between the oil and the water.
Greg (Roberto Gregorius)
Ethanol is a wide spectrum anti-microbial agent. It is add to liquid
(not solid) soaps to function as a germicide. It would be insoluble
in solid soaps. I am not aware of the test data that shows its
efficacy under various use conditions.
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Update: June 2012