[lindsayfs]

Hi Chem Folks,

I'm new to this forum and not a chemist at all, but I have an unusual job where I sometimes deal with chemistry in a very on-the surface kind of way.  This is why I'm on this forum, to get help from real chemists.

Let me describe my job:  I am the technical director for a small company that reviews products to ensure compliance with the National Organic Program.  So the majority of ingredients that are allowed in organic production or what we call nonsynthetic, or naturally occurring.  Only occasionally and explicitly are what we call "synthetics" allowed to be used.  This is why I only deal with chemistry every once in a while, not too many synthetic materials are allowed for use in organic agriculture and so we don't see them very often.

Anyway, "soap" is an allowed synthetic under the regulations.  So  my question is this:

What is the chemical defintion of soap? I understand how I saponify my fats with an acid, but is there more to it than that?  And specifically, does ethoxylated castor oil qualify as a soap in your chemistry minds?

Thanks in advance!  I'll probably stop by from time to time to ask questions!

[stewie griffin]

Soap chemically is a surfactant (obviously). I would say that part of the definition of soap is that it has both a polar head and nonpolar tail such that it can get nonpolar molecules to enter polar solvents via miscelles. I suppose you could also have a surfactant that would bring polar molecules into nonpolar solvents... however I would argue that this should not be included in the definition of soap, as I would believe soap is understood to be operating in water.
BTW, what is the "National Organic Program"??

[Melody]

Hi Chem Folks,

I'm new to this forum and not a chemist at all, but I have an unusual job where I sometimes deal with chemistry in a very on-the surface kind of way.  This is why I'm on this forum, to get help from real chemists.

Let me describe my job:  I am the technical director for a small company that reviews products to ensure compliance with the National Organic Program.  So the majority of ingredients that are allowed in organic production or what we call nonsynthetic, or naturally occurring.  Only occasionally and explicitly are what we call "synthetics" allowed to be used.  This is why I only deal with chemistry every once in a while, not too many synthetic materials are allowed for use in organic agriculture and so we don't see them very often.

Anyway, "soap" is an allowed synthetic under the regulations.  So  my question is this:

What is the chemical defintion of soap? I understand how I saponify my fats with an acid, but is there more to it than that?  And specifically, does ethoxylated castor oil qualify as a soap in your chemistry minds?

Thanks in advance!  I'll probably stop by from time to time to ask questions!

Hi

I think that in public imagination a "soap" is a synthetic substance that mixed in water produces foam, and often this definition is give to the branch of surfactants or surface-active agents having this characteristic.
It is also true that there are surfactants not developing foam, but they are able to stabilize or to make easier however to  the formation of an emulsion, and this power is described by their hydrophilic-lipophilic balance (you can look at this: http://en.wikipedia.org/wiki/Hydrophilic-lipophilic_balance)
Ethoxylated castor oil is a surfactant (you can look at this: http://www.mfc.co.jp/english/gif/gruf.gif or to this: http://www.galenotech.org/eccipienti/hlb.gif) with low HLB, used for water-in-oil emulsion, so chemically it is a surfactant but it developes no foam, so it is not what is commoly said a soap... So, it is all in what law comprises in this cathegory when saying "soap".

[baboom]

To understand soap, you need to understand the phrase "like dissolves like". This basically means that a polar substance dissolves in a polar substance and a non-polar substance dissolves in a non-polar substance.

Soap is a chemical which dissolves both water soluble (polar) substances and grease (non-polar). To do this, the soap molecule must have a water soluble (polar) end -basically a charged end, and a carbohydrate end which can dissolve oils (since oils are basically long carbohydrate chains).