How to determine Total Anhydrous Soap in Hand Liquid soap?
1 Answer
Dec 17, 2017
Here's one method I would try.
Explanation:
- Dissolve a sample in hot (60 °C) ethanol
- Add a slight excess of sulfuric acid
- Continue heating at 60 °C until the fatty acids separate as a clear layer.
- Transfer the mixture to a separatory funnel
- Draw off the acid layer into a second separatory funnel
- Extract the acid layer with ether
- Add the ether washings to the fatty acids
- Wash the ether solution with water until it is neutral to methyl orange
- Transfer the ether solution to a tared flask
- Add ethanol and titrate with sodium hydroxide.
- Evaporate the ether and alcohol on a steam bath
- Dry to constant weight at 105 °C
Finally, calculate the percentage of soda soap in the sample.
