strange PH effect

[suchtdruck24]

I observed a phenomenon when salting out a-oil in the past. I was working with methanol. For example, after setting the pH to 7 and letting the product stand for a while, it rose to 8, which seems to be normal. When I then lowered it back to 7, it went back to 8 after a few hours. I was able to repeat this several times.
The feedback from customers wasn't so good as i can remember. So I learned for myself that maybe you should set the pH correctly the first time.

Has anyone had a similar experience?

 

[GhostChemist]

What did you use to measure pH?

 

[Osmosis Vanderwaal]

what you are using to adjust your ph could be reacting with something in you RM or was it hot to start and cooled as you kept measuring? HCL is a gas that evaporates and when it does, the ph goes up. 3 of 100 possibilities

 

[suchtdruck24]

Thanks for the reply. I used a digital pH meter. Not a cheap one, but one without temperature compensation i guess. From what I read now, that's probably not normal, and the effect was probably due to temperature fluctuations. I never considered that before.

 

[GhostChemist]

The temperature affects the reaction rate and accordingly on the pH

The volume (You didn't write it) of your RM and effective mixing also affect pH