How much stearic is in your stearic?

[bodhi]

Im getting ready to place an order and in looking for stearic and options for sourcing it from non palm sources, I read that most commercially available stearic acid contains stearic and palmitic but purified stearic is available. So, i started looking around and lo and behold, it seems that most stearic is only about 50% stearic. huh? Man does it bug me that you cant take anything at face value anymore. Here is part of a spec sheet from an importer:

Report Full GC
(C14- 16- 16:1- 18 -
18:1- 18:2- 18:3- C20)
% - Determine and record
Typical Values Approximate (%)
C14 2%
C16 45%
C18 52%

So I'm wondering, do you use pure stearic or the regular 50% stuff and just SAP it as stearic anyway?

 

[Robert]

That spec sheet looks like triple pressed, which is the the usual grade of cosmetic stearic acid. There's also a broader cut and a narrower cut as commercial standards according to Merck.

There are (though I'm not sure in the latest edition) in INCI some ingredients derived from triple pressed that are designated "cetearyl" in recognition of containing about equal amounts of cetyl (palmityl, C16) and stearyl (C18) chains.

I don't know what saponification numbers for stearic the programs are programmed for, i.e. whether they assume pure C18 or triple pressed or what. Only way to tell would be to calculate based on the avg. mol. wt.

Darn, "see eighteen" is coming out as a smiley!

 

[bodhi]

Yup, it did say tripple press. Do you think would i be correct in assuming that any stearic i purchased from general supply houses or that didnt specifically say 100% stearic is this stuff? I know, you cant say 100% but in general? Im not sure about the calcs either and this spec sheet doesnt list the sap value so I will call them if i can find the link and compare it with some calcs. Thanks for the info Robert and here is my try at the stearic smiey: (C18:0)

****, mine didnt work.

 

[Robert]

Yup, it did say tripple press. Do you think would i be correct in assuming that any stearic i purchased from general supply houses or that didnt specifically say 100% stearic is this stuff? I know, you cant say 100% but in general?

Yes.

 

[bodhi]

Thanks Robert.