ptlt
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Getting rid of benzene smell
Hello everyone. This is my first post here, so I apologise if I posted in the wrong section.
Recently, I have carried out a synthesis of benzene via the decarboxylation of sodium benzoate. During the synthesis I had to filter out calcium
chloride from the dry benzene before the second distillation. I did a gravity filtration in a polypropylene (PP) funnel (sources suggest that PP
shouldn’t have a severe reaction with benzene, giving it a B in resistance). After filtering I focused on the distillation, forgetting to take out
the paper filter out of the funnel, and it ended up sitting in the PP funnel for about 1,5 h.
After the synthesis I rinsed the funnel with copious amounts of hot water, then with distilled water, and finally with acetone. It appeared clean.
However, when the funnel was drying I noticed a very strong benzene smell it had. So I rinsed it again the same way, it didn’t help at all. And
again. No improvement. For the fourth try I found a bottle of unscented, uncoloured dish soap (I understand that it’s a huge no-no to use dish soap
for cleaning lab glass(plastic)ware, but I don’t have proper detergent, so at the time I thought this was the best option). It seemed to help a bit
each time, and after four times the smell was gone!.. or so I thought, only to realize after drying - the smell was still there, though much less
intense.
I am not sure what to do anymore, as TFSE suggests to clean off benzene with hot water and acetone, but it doesn’t work for me. So, I figured, maybe
You would have some suggestions. Or am I just being paranoid?
Thank You in advance for Your answers. Have a nice day.
[Edited on 20-8-2019 by ptlt]
[Edited on 20-8-2019 by ptlt]
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Steam
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Try using Dawn soap followed by MeOH, and then a good washing with acetone. If you got a dedicated lab oven you can try to dry it off at elevated
temperature. You might have dissolved some of the PP which subsequently got precipitated out on the surface of your flask along with some benzene. IF
you are really having problems try some conc. sulfuric along with a splash or two of hydrogen peroxide. This stuff will 'eat' through just about
anything (including you so be careful) and should remove any trace organics from the surface of your glassware.
DISCLAIMER: The information in this post is provided for general informational purposes only and may not reflect the current law in your jurisdiction.
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counsel on any subject matter. No reader of this post should act or refrain from acting on the basis of any information included in, or accessible
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licensed in the recipient’s state, country or other appropriate licensing jurisdiction.
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Ubya
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Quote: Originally posted by Steam  | | Try using Dawn soap followed by MeOH, and then a good washing with acetone. If you got a dedicated lab oven you can try to dry it off at
elevated temperature. You might have dissolved some of the PP which subsequently got precipitated out on the surface of your flask
along with some benzene. IF you are really having problems try some conc. sulfuric along with a splash or two of hydrogen peroxide. This stuff
will 'eat' through just about anything (including you so be careful) and should remove any trace organics from the surface of your
glassware. |
plasticware, can't use heat, or piranha solution, did you read where he was talking about his PP funnel?
@ptlt maybe try letting your funnel soak in soapy water first for a few hours, and then maybe an alcohol soak
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Sulaiman
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Never used benzene myself but I'd expect that leaving the funnel somewhere outdoors in the shade for a few days would remove benzene as it should be
quite volatile.
CAUTION : Hobby Chemist, not Professional or even Amateur
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draculic acid69
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Rinsing with solvents instead of water would be a good start.oven dry it or leave it outside for a few days. Air it out would also work if benzene is
anything like toluene or xylene just air it out.
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ptlt
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Hello again.
I have decided to follow Ubya’s advice. I let my funnel soak in soapy warm water for an hour, then for 10 min in iPrOH. After that I rinsed it with
acetone and iPrOH, then finally with dist. water. After drying it, no smell was present.
I am very thankful to all of You for very friendly and quick responses.
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