[reflux]

A few colleagues and I have found that mixing commercial bleach and acetone gives a warm orange solution that is excellent for cleaning the exceptionally hard to clean glassware (often it is better than a base bath or aqua regia!) I was curious to know if anybody actually knew what the reaction between the aqueous sodium hypochlorite and acetone is. Maybe some type of haloform reaction?  I can't seem to find this simple reaction in the literature.

[sjb]

http://en.wikipedia.org/w/index.php?title=Chloroform&oldid=208121364 suggests possibly chloroform, and http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/chloroform.html suggests possibly phosgene, if you're not careful.

Doesn't really explain the orange colour though - is this your organic tar dissolving up?

S

[reflux]

Wow that is very interesting!  The orange color appears in clean glassware as well.  I was told that a basic solution can polymerize acetone creating a yellow/orange color.  The haloform reaction could provide the base and of course the chloroform (RCOCH3 + 3NaClO -> RCOONa + CHCl3 + 2NaOH)... but acetone is a "dimethyl ketone" so I'm not sure that equation is completely right.

I don't think it gets quite hot enough to create phosgene (at least I hope not)!  But I always do this in the fume hood and would suggest the same to anyone else who wants to clean their dirty glassware by this method (works great on Al-salts from AlMe3, DIBAL-H, etc.)!

[sjb]

Well, there is that as well, self-aldol condensation and the like - didn't think hypochlorite was strong enough a base for this, personally, but could be wrong.

You can get mesityl oxide ( http://en.wikipedia.org/w/index.php?title=Mesityl_oxide&oldid=207275195 ), or isophorone ( http://en.wikipedia.org/w/index.php?title=Isophorone&oldid=198625825 )

Maybe you have some NaOH floating around in your bleach, what sort of pH is it?

[Arkcon]

Maybe you have some NaOH floating around in your bleach, what sort of pH is it?

Well, chlorine bleach is a saturated solution of chlorine gas in an NaOH solution of a fixed concentration, so yes, NaOH is present.

Glad I had a chance to jump in, this is a great thread.  A little dangerous maybe, but a nice tip for cleaning labware.  Have one on me, both of you.

[reflux]

The pH of the bleach is about 12-13 according to my always accurate pH paper.  It's about the same as the bleach/acetone solution although the pH paper dipped in the latter does not go white within 1 minute... hmm...

I noticed the isophorene can be yellow in color and is used as a solvent (as is chloroform and mesityl oxide - both reasonable byproducts).  And it is found in cranberrys!  I wonder if NaOH/cranberry juice works just as well.... haha.  Well I think we're on to something at least.

So it is definitely VERY basic.  It's possible I am just creating a "hot" base bath in the flask and that is why it dissolves various organic tar or salts so well.  It stays warm for about an hour which is usually all it takes.  I rarely have to scrub afterwards just rinse with water then acetone.  Intrestingly if you wash with acetone first you get a white ppt. Another mystery for now...  but I should probably focus more on my thesis work!

Thanks for all the great ideas!