Can someone with a good knowledge of chemistry explain this to me?

This is a product I found in my house:

Now, according to the back of the bottle, it contains “No Sodium Lauryl Sulphate”, which, as the product is marketed as a “natural body wash” made with “100% pure oils and certified organic herbs”, I’m assuming the manufacturers don’t like very much as a chemical.

However, it DOES contain this “Sodium Salt of Sulphonated Laureth2″ – a fancy way of saying Sodium Laureth Sulphate, a close chemical relative to the (supposedly) dreaded Sodium Lauryl Sulphate. But what’s the main differences between the two? Aren’t they practically exactly the same in terms of chemical and dermatological effect?

All the surface information I could find online (that wasn’t from woo-filled websites like this one) doesn’t put one as more dangerous than the other in terms of irritation ability and allergen status… Weird.

Are there any chemists that could shed some light on this situation? Or is this product just being misleading, capitalising on the public’s fear of one chemical, while replacing it with another that is practically the same? I wouldn’t be surprised if it were the latter.

2010
02/21
CATEGORY
Chemistry
TAGS


1 comment

  1. Hahaha, how dodgy is that?

    Now… check this out: http://www.accc.gov.au/content/index.phtml/itemId/868614

    http://www.news.com.au/aussie-cosmetics-busted-for-chemicals/story-e6frf00r-1225699702180

    http://www.accc.gov.au/content/index.phtml/itemId/868764

    “Sodium Salt of Sulphonated Laureth” is almost certainly, without a doubt, sodium laureth sulfate, exactly the same thing.

    Since sodium laureth sulfate is not the same thing as sodium lauryl sulfate but it is a very similar but slightly different compound, if their product really does contain sodium laureth sulfate, it’s still legitimate for them to accurately claim that it contains “no sodium lauryl sulfate”, I suppose.

    Sodium laureth sulfate is the same thing as sodium lauryl ether sulfate… note that “laureth” is a contraction of “lauryl ether”.

    When these compounds are synthesised, we start with coconut oil or palm kernel oil, and that oil is hydrolysed, releasing a mixture of the fatty acids liberated from the triglycerides in the oil.

    This results in a mixture of fatty acids with different molecular weights, which is mainly lauric acid (aka. dodecanoic acid). The fatty acids can then be reduced to their corresponding alcohols (eg. dodecanol or lauryl alcohol). The “fatty alcohols” are then sulfonated by reacting them with sulfuric acid, forming hydrogen lauryl sulfate or analogous compounds. This is then neutralised with sodium carbonate to form sodium lauryl sulfate.

    In the case of sodium laureth sulfate, the lauryl alcohol is ethoxylated with ethylene oxide before sulfonation.

    So even though they describe the “Sodium Salt of Sulphonated Laureth” as a “Coconut/ Palm derivative”, the same is really always true of any sodium lauryl sulfate or sodium laureth sulfate.

    In terms of real, good science, I have yet to see much in the way of any convincing evidence that either compound is particularly harmful – other than, you know, soap is irritating if you get it in your eyes, or something like that. Lots of woo merchants seem to insist that these compounds are pure evil that will give you cancer or autism or whatever, though.

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