[gregrib]

ladies and gentelman of the chemistry world, i absolutely need some help. JUST FOR THE RECORD I AM NOT AN ENGINEER . HOWEVER i feel as though i should be after dealing with a certain dry cleaning co. who sold there machine as a machine that can clean white metals ,our biggest problem being titanium.this machine is designed as a clothes cleaning machine but they managed to sell it to my boss as a machine that can handle metal parts. and boy did it, the parts were beautiful.BUT IT DID NOT LAST LONG ,IM TALKING ONLY DAYS.so back to me , i served on a submarine for 5 yrs, i had to learn systems and how they operate to become a sub sailor .these guys thought they had us fooled but the more i learn about this system the more i realize what con atists they really are. so to the point , we use glycol ether dpnb as a solvent for heavy oil for titanium draw,we cannot filter the solvent because from what i have learned is that some where along the line glycol and co2 make carbon which leaves the solvent black. i have tried filtering it only to find out later that the carbon is at an atomic level which cant be filtered.RUN OUT OF SPACE NEED HELP

[Arkcon]

Wow.  Just for the fun of it, would you consider saying that again?  This time, drop the emotional appeal, the random ALL CAPS, and just say what you know, and ask clear questions of what you don't know.

[gregrib]

sorry. parts are cleaned with different types of oil, synthetic,halo carbon,and a heavy red oil designed for drawing titanium.This oil is removed in a chamber that is filled with glycol ether once that chamber is full ultrasonics's do there part.the chamber is drained and a series of pressurized co2 rinses begin (from gas to liquid ).At the end of the rinse,the chamber is depressurized.  the problem (there are many) is that some parts will have a light to heavy black film. the glycol is cleaned using a distill, but it is still very dark,i have tried filtering with charcoal ,.05 micron filters and any thing else that i thought might help, all this removes is particulates.I have many questions so i will start with this.    Is glycol ether dpnb the right chemical for the job? And is co2 a good rinse agent?

[Arkcon]

I don't know the specific properties of this particular solvent, and I hope some experts will come by soon to help.  Sonicating should help clean pieces, and we can assume this solvent is a good choice for your application.  Liquid CO₂ behaves like a non-polar solvent, so its great for rinsing other solvents away, and leaving no residue.  I don't know if there's an incompatibility like you've observed.  If you could understand your black contaminant better, maybe you could wash it away from your Dowanol, maybe even with water, before distilling?