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  • Demulsifying

    Posted by Anonymous on November 12, 2018 at 1:29 pm

    Hello everyone,

    I was wondering if you have every demulsified an oil-in-water emulsion stabilized by anionic surfactant? We are looking to break the emulsion which is stabilized by stearic acid. The pH is 6.5 at which some of the stearic acid is deprotonated and converted to stearate/emulsifier. To use stearic acid as emulsifier you need to convert it to the stearate, usually in the range of pH 6.5-8.5. The problem is we cannot lower the pH as much to completely protonate the stearate. My initial thought was that fully protonated stearic acid wouldn’t act as a soap anymore.

    Looking forward to hearing your thoughts

    jeremien replied 6 years, 4 months ago 3 Members · 5 Replies
  • 5 Replies
  • OldPerry

    Professional Chemist / Formulator
    November 12, 2018 at 2:22 pm

    Salt (NaCl) will usually break an emulsion.

  • Anonymous

    Guest
    November 12, 2018 at 3:37 pm

    Thanks, Perry
    I forgot to mention that we cannot add any ions to the system. 

  • OldPerry

    Professional Chemist / Formulator
    November 12, 2018 at 4:58 pm

    Hmm. I suppose you could add more oil to the system to overwhelm the emulsifying ability of the emulsifier.

  • zaidjeber

    Member
    November 13, 2018 at 5:36 am
    out of curiosity, why do you want to demulsified an oil-in-water emulsion?
  • jeremien

    Member
    November 13, 2018 at 9:38 am

    ultracentrifugation, temperature cycles..

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