Magpie - 7-3-2005 at 20:49
In setting up my melting point apparatus I wanted to use silicone oil so went searching for this OTC. I found that DOT 5 brake fluid is silicone oil
so handed over my $10 for a pint (~ 500 mL). On the way home I thought damn I'll bet that fluid has some dye in it. Sure enough it was loaded
with purple dye. So I added some of my new favorite reagent, activated carbon, and some diatomaceous earth and filtered it clear. Then I remembered
that in organic class in one experiment we destroyed unamed dye contaminants by adding dithionite (sodium hydrosulfite, Na2S2O4). This was supposed
to reduce the dyes by acting on their double bonds. Now I'm wondering if this wouldn't have been easier than my carbon black routine. It
may be a generic way to remove those pesky dyes that seem to be added to many OTCs? Does anyone else have any experience or knowledge on dye removal?