Sciencemadness Discussion Board

Iodoform (Haloform Reaction) Complete Video

LifeisElemental - 19-12-2014 at 15:13

Hi guys! You may remember that awhile back I had posted a really silly skit on lead (II) iodide. There was a lot of good feedback there and from that I created the first episode in what I hope to become series of videos on chemistry.

I am really excited to hear your feedback on this first episode of the series. Do you like the structure - is there anything you might like changed?

Most of all does anyone have any suggestions for some visually-stunning reactions that I should cover?

CiC - Iodoform Synthesis (Haloform Reaction) [YOUTUBE LINK]

Thanks guys!

Justin Blaise - 20-12-2014 at 22:26

I definitely like the video. I have a few comments about the mechanism. First, you're missing the arrow that shows the iodine-iodine bond breaking. Second, when you get to your tetrahedral intermediate, you show triiodide as your leaving group instead of the -CI3 moiety. Nice video though. For a pretty nice visual, you could do one of the clock reactions. Lots of interesting chemistry there.

LifeisElemental - 21-12-2014 at 07:12

Quote: Originally posted by Justin Blaise  
I definitely like the video. I have a few comments about the mechanism. First, you're missing the arrow that shows the iodine-iodine bond breaking. Second, when you get to your tetrahedral intermediate, you show triiodide as your leaving group instead of the -CI3 moiety. Nice video though. For a pretty nice visual, you could do one of the clock reactions. Lots of interesting chemistry there.


Good idea on the clock reactions! I tried to correct those errors by annotations - noticed by of those after post unfortunately!

I was told this was a poor crystallization could anyone elaborate on why? I don't doubt it but feedback would help for next time.

chemrox - 21-12-2014 at 17:54

You didn't talk about tautomerism. I know that "plastic music" is popular on youtubes but it's not very professional and contrasted sharply with the other aspects of your presentation which were very good. I found the pace a little hyper and I think your crystallization could be more crisp. I'd run through it a few more times, playing with stoichiometry and temperature and see if I couldn't get a more uniform, snappier precipitation. It's worth working on a bit more. Thanks for asking. BTW I don't know where the comment page goes when I try to comment online. After you perfect it you may want some approbation from here. Please consider changing the music or leaving it altogether; in any case slow down the pace a bit so I don't feel like I might be missing steps. Check your arrows and bring up keto enol tautomerism whatever the equilibrium is doing.

Justin Blaise - 21-12-2014 at 19:25

It looks like after you let the solution cool and form crystals you also add some anti-solvent (water?) to precipitate the rest of the product. If this is what you did, then that is a poor recrystallization. The anti-solvent just reprecipitates any impurities you remove by crystallization. If you had instead just filtered and washed the initial crystals, then that would be a proper recrystallization. That may be what you received criticism for. Then again, I'm not sure exactly what you did, so I may be off base. If so, please post what you did exactly and I can give it another go.

Again though, I did like the video and it seems like you have a pretty solid grasp on the chemistry and safety aspects which is refreshing to see on YouTube.

LifeisElemental - 21-12-2014 at 20:44

Quote: Originally posted by Justin Blaise  
It looks like after you let the solution cool and form crystals you also add some anti-solvent (water?) to precipitate the rest of the product. If this is what you did, then that is a poor recrystallization. The anti-solvent just reprecipitates any impurities you remove by crystallization. If you had instead just filtered and washed the initial crystals, then that would be a proper recrystallization. That may be what you received criticism for. Then again, I'm not sure exactly what you did, so I may be off base. If so, please post what you did exactly and I can give it another go.

Again though, I did like the video and it seems like you have a pretty solid grasp on the chemistry and safety aspects which is refreshing to see on YouTube.


That was it! I added D.I. water. Thanks for pointing that out - I saw it mentioned online to do that and didn't think much of it. I will add an annotation to make a note of this and be careful of this in the future.