ShadowWarrior4444 - 9-5-2008 at 00:15
I'm not certain whether this more belongs in Societal Issues, but it may pertain to the acquisition of chemicals, specifically knowing what you are
buying.
I have recently read the ingredients on a bottle of shampoo from Britain, assuming they are in order of prevalence within the product, the mid-to-last
most present ingredients were: "...Sodium Chloride, Sodium Hydroxide, Imidurea, Hydrochloric Acid..."
Hmmm. I naturally thought this was the most plausible thing I've seen all day. It wasn't as if these ingredients were tacked on last 'just in case
they might be there,' no, NaOH outranked Imidurea--a common antimicrobial preservative. Now, Imidurea *is* synthesized from formaldehyde and NaOH,
which is then neutralized by HCl...however...
My central question is, do EU product labels list everything that was ever remotely used in the synthesis of the product? (Unlikely.) Or everything
that may or may not be in the product in order of probability? Because NaOH and HCl in intimate contact within a shampoo is highly unlikely.
Especially when they are listed as being present in non-negligible amounts.
[Edited on 5-9-2008 by ShadowWarrior4444]
not_important - 9-5-2008 at 00:58
I believe what the label gives is a list of everything that went directly into making of the product. NaOH may have been added to help
dissolve/disperse something, later HCl added to adjust the pH. If it went into the pot you list it, even though it may have reacted.
garage chemist - 9-5-2008 at 01:58
Yes, I also think the HCl and NaOH on the label just says that they used this to adjust the pH of the final product to a skin-friendly value. The
ingredients may have traces of base or acid from their manufacture in them.
And imidurea is way, way more complicated to make that what you said. Just look at its structure:
http://chemicalland21.com/lifescience/foco/IMIDAZOLIDINYL%20...
"Imidurea" is an acronym for a complex molecule, N'-1-(hydroxy methyl)- 2,5-dioxo-4-imidazolidinyl urea.
ScienceGeek - 9-5-2008 at 02:10
Isn't it more likely that the NaOH was used in the saponification process?
garage chemist - 9-5-2008 at 02:19
No, they don't use NaOH in the saponification any more. They hydrolyse with superheated steam to get the free fatty acids directly.
Pulverulescent - 9-5-2008 at 08:18
I thought a high PH was still required, even for that!
P
ScienceGeek - 9-5-2008 at 08:57
Ooh! Very interesting! Makes sense!
P:
Why do you think a high pH is still needed?
Pulverulescent - 9-5-2008 at 09:12
Okay SG, sarcastic asides aside, I'm simply mistaken. 'No big deal!
P
Pulverulescent - 9-5-2008 at 09:44
What I meant was say, 7.5 anyway!
P