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Salicylic acid powder
Hello,
I haven’t formulated with this acid before and would appreciate some advice. This would be a more advanced formulation technique than I’m used to.
The supplier recommended reacting the acid powder with sodium bicarbonate to neutralise it into sodium salicylate. What would be the ratio of sodium bicarbonate to water to acid please?Or could you suggest other ways to incorporate this acid into a product? Solubility in glycols seems low to me but I could be missing something completely. The supplier also mentioned using sodium citrate as a helper.thank you for any guidance.
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2 Replies
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If I am not mistaken the next formula is correct for the ratio:
138.121g of SA + 84.007 of baking soda = 160.11 Sodium Salicylate + other products of the reaction.I don’t think there is much profit in using sodium citrate if you gonna neutralize SA.
Solubility in glycols is IMHO quite high, it low in water+glycol mixture. According to research called “Solubility prediction of salicylic acid in water-ethanol-propylene glycol mixtures using the Jouyban-Acree model” you need a 50%50% mixture of water+propylene glycol to get 2% solubility of SA
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you need a 50%50% mixture of water+propylene glycol to get 2% solubility of SAThank you for your reply. would you say it’s 2g into 50g glycol then mixed with 50g water? Or 2g direct into a mixture of glycol and water?
Would you recommend heating to a certain temperature to aid the process?
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