Re: ORGLIST:Oleic acid and paraffin wax

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From: =?ISO-8859-2?Q?Jerzy Kr=F3l-Bogomilski Ph.D.?= (jerzy.krol$##$op.pl)
Date: Sun May 16 2004 - 09:39:27 EDT


Mr. Alan Walker

You ask if the oleic acid can oxidise?

> Can the oleic acid oxidise a little after a few days exposed to
>air?

And you probably are right.

According to L. F. Fieser and M. Fieser, they oxidise in air at rt, below 50 degree C. They show readiness to form free radicals. The products of this reactions contain -OOH or -OH groups in their molecules. These groups influence viscosity of the products.

Perform a blank test:

1) 2 weight percent oleic acid and 5 weight percent oleic acid,
2 - 5 days - the high oleic acid becomes stronger and tougher.

2) 2 weight percent oleic acid and 5 weight percent oleic acid,
2 - 5 days, but without air, under an inert atmosphere of nitrogen or argon.

If you are right, the high oleic acid sample will not become stronger and tougher in 2 - 5 days (in this last case).

Write about your results, please.

Yours sincerely,

Jerzy Król-Bogomilski Ph.D.
http://www.geocities.com/jerzor/absart06.html

walker$##$netcon.net.au napisał:
>I have been working with a mixture of oleic acid and paraffin wax as a
>binder. The oleic acid is in the mix as a rheology modifier. I have
>noticed something strange about the physical properties of the material and
>I hope someone can explain it to me. I am not an organic chemist.
>
>
>I use a low melting (around 50 deg C) paraffin wax which is a mixture of C20
>to C35 alkanes, mostly C23 - C26. I use lab grade (99.9%) oleic acid.
>
>I melt the wax at 100 deg C and mix in the oleic acid very thoroughly then
>cool it to solidify.
>
>I have tried 2 weight percent oleic acid and 5 weight percent oleic acid.
>
>The strange effect is that the physical properties of the resulting solid
>material changes over time. The low oleic acid mix becomes more brittle in
>2 - 5 days and the high oleic acid becomes stronger and tougher in 2 - 5
>days.
>
>Why is this? Is there some sort of cross-linking reacion with the double
>bond? Can the oleic acid oxidise a little after a few days exposed to air?
>
>Any comments?
>
>Thanks
>
>Alan Walker
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