[Woojin]

Hi I am not a chemist, but I found weird issue from my experiment, and I thought chemist know the answer.

I was cleaning my glass frit. I fused the glass frit to a glass capillary, and boiling it in acetone bath, while pull weak vacuum through the capillary to purge the frit with the hot acetone.

I occasionally found that part of my my glass frit near the glass capillary turn brown. Does this some kind of polymerization of acetone and building up near the glass capillary?

I'd like to attach a photo, but not sure how to do it.

Thank you in advance.

[Borek]

What is the purity of the acetone?

[Woojin]

What is the purity of the acetone?

Thank you for reply. I need to double check the purity tomorrow, but I think it is 99.5%. Do you suspect some impurity polymerize near the glass capillary of the frit?

[Borek]

For me that would be the most obvious thing. Acetone by itself is rather stable (it does condense, but in the presence of catalyst), but it easily dissolves many organic substances and gets contaminated.

[diwalpi1]

It was an object lesson in considering side reactions and not focusing on my primary reagents. I didn't consider the solvent as a possible reactant at the time.

[Hunter2]

Hi I am not a chemist, but I found weird issue from my experiment, and I thought chemist know the answer.

I was cleaning my glass frit. I fused the glass frit to a glass capillary, and boiling it in acetone bath, while pull weak vacuum through the capillary to purge the frit with the hot acetone.

I occasionally found that part of my my glass frit near the glass capillary turn brown. Does this some kind of polymerization of acetone and building up near the glass capillary?

I'd like to attach a photo, but not sure how to do it.

Thank you in advance.

I think it's some dirt residue in your frit.
Aceton doesn't have this behaviour.
Clean several times until colour less.

[marquis]

Is it acetone polymerization?  I worked with a PhD who had problems with acetone "polymerization".  They were at a plant and the longer the plant ran continuously, the more money the company made.  So the pressure was on to keep the plant running as long as possible. After three months of running, they found a white material.  Finally, it  was identified as triacetone peroxide. Not a polymer in the usual sense of the word.  Still, something that had to be handled very carefully.

[marquis]

Not polymer used because it was cyclical.  Three molecules in a ring. Also why it was also.not stable. 

[Hunter2]

What does the plant produce? Acetone used for cleaning or for a chemical reaction.
The Material found is a result of a reaction of peroxide and acetone. Acetone itself has nothing to do with it.
This compound is a dangerous explosive, so no further discussion on it.

[marquis]

The plant was using acetone as a solvent.  Its similar to warnings about distillation in organic lab.  If you go to far, bad by products will be produced. 

[Hunter2]

But no Peroxide, if H2O2 is not involved.

[marquis]

There are batch processes and continuous processes.  From a manufacturing point of view, a continuous process is much better.  However, there are down sides to the continuous process.

[marquis]

The continuous process usually (at least for polymers) requires catalysts(often rare metals) high pressure, and other unique conditions (at least they did,as of my retirement). Care is taken to make sure no peroxide are formed.  But there is a trade, often to be made.  The longer the plant is run between cleaning, the more profit.  The longer it is run, the more peroxide is formed.