acetonitrile-waste disposal

[kamila]

Hello,
I am a student from The Czech Republic and I would like to ask if any of you have ever heard about liquidation of acetonitrile (in waste bottle where mobile phase from detector (HPLC) constantly flows in) using 5% sodium hypochlorite? Could you write me how to do it, please? I mean the volume of 5% sodium hypochlorite with respect to the volume of waste bottle and so on..especially in case of daily routine use.
Thank you very much and please, excuse my bad English.

[Chris Pohl]

Kamila,

While I have not tried this approach, you will need to use a lot of 5% NaOCl to accomplish this since this reagent will need to be present in stoichiometric excess (I would guess at least a 50 mole % excess would be required). This would necessitate 54g of 5% NaOCl per gram of acetonitrile! If you want to pusue this, I would suggest base hydrolysis instead. With sodium hydroxide you can achieve quantitatively hydrolyse the acetonitrile to acetate and ammonia (this would only require about 1.5 g of NaOH per gram of acetonitrile with a 50% molar excess).

[pipettemonkey]

Bleach is typically used with cyanide salts such as NaCN, KCN. I have no experience using bleach to decompose acetonitrile but as mentioned, hydrolysis (by heating with NaOH or H2SO4) is easier, more reliable and safer.

PM

[Veronika R. Meyer]

Dear Kamila, there are two papers of mine about the disposal of acetonitrile / water mixtures:
K. Gilomen, H.P. Stauffer, V.R. Meyer, Detoxification of acetonitrile-water wastes from liquid chromatography, Chromatographia 41 (1995) 488-491.
K. Gilomen, H.P. Stauffer, V.R. Meyer, Management and detoxification of acetontrile wastes from liquid chromatography, LC GC Int. 14 (1996) 56-58.
These publications describe the detoxification with sodium hydroxide. I can send you the reprints if you are interested. In this case, please contact me directly by e-mail: veronika.meyer@empa.ch .

Yours sincerely, Veronika

[pipettemonkey]

Have one for TFA?