eli5: why does oil deteriorate at lower pH?

Question

I heard that oils deteriorate at pH below 9 or so. How does this work and is it the same for all oils?

edit: i’m talking about anti dusting oil which you add to coat powders while they are in a solution

In: 1

Answer 1

Are you asking about motor oil or vegetable oil? Because the answer will be really different.

Vegetable oil is reasonably stable at low pH, but gets hydrolyzed at high pH. That’s literally how soap is made: treat a triglyceride (bio-based oil or fat) with high pH water.

Petroleum oils don’t have any significant pH catalyzed chemistry.

In either case, it’s not meaningful to talk about pH unless there’s water present.