• Formulating

  stearic acid and pH of emulsion

  Posted by Shams on May 4, 2021 at 12:32 am

  Hi everyone

  Seeking advice. If I am using stearic acid in a lotion formula (with other emulsifiers not alone) do I have to have the pH above 7 to ensure that it is doing it’s job as an emulsifier . Or can I still adjust my lotion to around 5.8 pH?
  Any good sources to read more on stearic acid woul;d be highly appreciated. I have been looking for a while but couldn’t find any.
  Thanks in advance

  Shams replied 3 years ago 3 Members · 3 Replies
• 3 Replies

• 

  singhc10

  Member

  May 7, 2021 at 11:36 am

  @Shams For In Situ emulsion with stearic acid, you would need to to go between pH 6.5-7.5 for complete saponification, Saponification is irreversible reaction, so you could re adjust the pH with Citric acid of your emulsion. Still advise to look at the stability

• 

  chemicalmatt

  Member

  May 7, 2021 at 9:00 pm

  I would suggest otherwise: saponify with tromethamine (the best now that TEA is out) to pH 6.2 - 6.8, leaving some free acid, both as builder and to prevent pearlescence on aging.

• 

  Shams

  Member

  May 11, 2021 at 6:12 am

  Thanks @singhc10 and @chemicalmatt

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