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Benzyl Alcohol and Dehydroacetic Acid
Who has experience formulating with this preservative? I notice that it’s being used on many products to replace phenoxyethanol. I like that pH range is broad.
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10 Replies
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It’s a good preservative, but a bit weak on mold … beef it up by adding some Sodium Benzoate at 0.4% to 0.5% … so your preservative actually becomes:
Benzyl Alcohol, Sodium Benzoate, Dehydroacetic Acid.
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I thought that with sodium benzoate you have to formulate at a very low pH.
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With Na benzoate as per Chemac you have to be at PH 4-5 but have passed USP 51 with either BA or DHA alone.BA works well even at PH 9-used in OTC Antacids-
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DHA threw one of my ingredients out of solution and made a precipitate. Take care if you want to use it with salts.
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What is the pH of your final formulation? BA-DHA is good up to pH 7.0, but I would not use it alone at a pH above 6.0. I always beef it up with additional fungicide. The product is mostly BA (87%) and about 8% DHA … balance is water.
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I’m staying under 6. The question is what fungicide to supplement it with. From what I’ve seen sodium benzoate has minimal activity at this pH.
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You may try sodium salt of DHA-Lonza
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Does anyone know where to buy small (ie, 4-8 oz) quantities of DHA + Benzyl Alcohol stateside? I’ve only found suppliers in the UK.
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Strike that, Making Cosmetics carries it.
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From my experience BA has a tendency to yellowish when exposed to oxigen.
I suggest adding antioxidant such as Vit-E at 0.2% if color is important
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