I am having some trouble trying to neutralize ethylene glycol with NaOH. I made a test in the laboratory and I got the volume to raise the pH from 5 to 8. Everthing was alright and the sample is stable after a month.
After the lab test, I made another test with 20L. Everything worked fine. pH stable, the numbers calculated worked very well.
Then I followed to a tank, 22000 L. Used the same number calculated before and ... Nothing. The pH does not change.
I tried to add more NaOH and nothing. The pH is stable on 5.
So I was wondering if the low water content plays a role. I tried with a mixed tank 50% EG/Water and nothing. Same ''buffering effect''.
After adding more than 15 times the NaOH volume tested on laboratory, I was able to raise the pH to 6.
Does anyone knows this effect of ethylene glycol volume buffer ?
Details: I have used ethylene glycol and recicled ethylene glycol (destilation method). They are pure (GC 99.9%) and don't have metals or others contaminants. But maybe it has additives, I cannot be sure as I don't have equipments to test it.
Thank you !