I really appreciate all the input and ideas people have provided to me on this topic. Thank you!!!

 

 

 

Hi Craig,

Thank you very much! This is an excellent idea to run a MS of the residue of the spilled material. It will greatly help to identify the reaction-side products.

https://www.sciencedirect.com/science/article/pii/S1004954119300333?via%3Dihub

2.3. Analysis methods

The reaction solution sample was analyzed by gas chromatography–mass spectrometry (Agilent 5973, GC–MS) firstly. The rest reaction solution sample was evaporated to dryness under reduced pressure to get the crude product, the crude product was purified by recrystallization using ethanol. And the purified product was obtained after filtration. ¹H NMR spectra were recorded using Bruker DRX-400 spectrometer using solvent peaks as CDCl₃ solutions after purification by recrystallization using ethanol.

 

Tilak

 

 

 

Alex,

 

A simple possibility is an aminolysis reaction. Since the solution was 44% ethyl acetate that is a huge amount of ester for reaction with amines to form amides. Anilines are usually less reactive than alkyl amines, but since there were p-phenylenediamines they are way more reactive. Aminolysis of simple esters is usually slow, but this waste bottle could have also contained traces of acidic or basic catalysts. That is not unlikely since phenylenediamines are so prone to decomposition.

 

This is simple to confirm or not – just do mass spec on the waste and look for acetamides of the p-phenylenediamines. No polymer as you wrote, just small molecules.

 

If this is correct, your suggestion to fill waste bottles to only 80% will not work. The reaction will still occur and since methanol has a low boiling point, reaction heat will cause pressure to build up. Hence, a venting cap might be appropriate here.

 

Best,

Craig

 

Craig A. Merlic

 

 

 

Good morning,

 

We had a small hazardous waste incident in one of our labs recently, and I am trying to help the lab gather information on potential causes. A four-liter amber glass bottle of chemical waste containing 50% methanol, 44% ethyl acetate, and an assortment of six p-phenylenediamine antioxidants (PPDs) pressurized and broke open. The bottle was tightly capped and very full, it only had about 1.5 inches of space left at the top. The bottle broke open at the bottom of the bottle in a jagged formation. No polymerization of the contents was observed, but some speculated an event like that could have led to the pressurization of the container. I have already informed the lab that they should not fill waste containers more than 80%.

 

I have not been able to find information on similar events involving PPDs. Any input or information this group could provide about what may have led to this event is greatly appreciated.

 

Regards,

ALEX HAGEN, CCHO

Laboratory Safety Inspection Program Manager

Environmental Health & Safety Department

Research & Occupational Safety, Laboratory Safety Inspection Program

 

Hall Health  /  Box 354400  /  Seattle, WA 98195-4400

206.221.2339 / mobile 206.713.5267 / fax 206.616.3360

fischera**At_Symbol_Here**uw.edu / www.ehs.washington.edu

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