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  • Dehydroxyacetate turning yellow?

    Posted by BathroomChemist on September 2, 2023 at 12:32 pm

    I have a preservative from Inolex called Spectrastat that consists of caprylhydroxamic acid (CHA), caprylyl glycol, and glycerin. Yesterday, I added some sodium dehydroxyacetate (Na-DHA) to a small vial of pure Spectrastat. I knew that Na-DHA wouldn’t dissolve very well. I just wanted to see if anything interesting would happen.

    Well, a solution of 60 mg Na-DHA in 3 mL Spectrastat turned a transparent and very intense yellow, starting right above the powder that collected at the bottom. The Na-DHA mostly dissolved after a day or two, and the yellow color spread throughout. I didn’t see a color change with Na-DHA in caprylyl glycol, nor with Na-DHA and CHA both completely dissolved in water / dimethyl isosorbide.

    My chemistry isn’t good enough to predict reactions in different solvent systems, and that’s probably the same for most of the people here. However, I AM interested in knowing if anyone has had a solution with Na-DHA turn yellow before, and if that meant something bad for your formula (e.g. unexpected fungal growth). This is more of a fun question resulting from me puttering around in my home lab, not something for which I urgently need an answer. I’m working with several cosmetic scientists to make sure the preservative system for my unique product is effective.

    Shadowfitzy replied 4 months, 2 weeks ago 2 Members · 1 Reply
  • 1 Reply
  • Shadowfitzy

    Member
    December 6, 2023 at 2:25 am

    DHA is known to not “play nice” with acids - the best way to see if it has degraded or not would most likely to try it as a tanning solution vs the non yellowed version. CHA is also known to be incompatible with some materials such as lecithin and cause yellowing or a bad odour.

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