Sciencemadness Discussion Board

Para Nitrophenol Isolation-New Video

Bmoore55 - 10-5-2022 at 03:52

Hello all! I have just uploaded a new video on the isolation of Para-Nitrophenol to my youtube page. This is a follow up to the phenol nitration video I previously did. Here I show how to isolate the para product from the remaining organic material in the distillation pot and then I analyzed the end product. I also analyzed all the different waste fractions form this synthesis to show what is remaining in them using gas chromatography with mass spectrometry (GCMS). I hope you all enjoy!

https://youtu.be/Q18jSxmcoSw

j_sum1 - 10-5-2022 at 14:47

Saved to my watch later. Looking forward to this one.

Keras - 11-5-2022 at 00:09

I took only a perfunctory look at it, but I hardly see the point of the last ¾ of the video. I mean, the video is technically great, no doubts about it. But it’s not really useful, given that 99.999% of us don’t have access to the analysis apparatuses you use.

If you want, I can parallel this with amateur radio: I can shoot a video showing how to tune whatever Yagi antenna using a 60k$+ network analyser I have in the lab at work. But that wouldn't help no one, because either they are part of the 99.99999% of hams who don’t have access to such an equipment, and the lucky 0.00001% left who have know how to use it. Instead, I can decide to show how to do it using a self-made SWR-meter, and that would be much more useful. As a last step, I would confirm the usefulness of that method by using the expensive tool.

Now what I would've done is recrystallise the p-nitrophenol you got, check his purity with a TLC using a suitable solvent (semi-polar, probably), and finally confirm the purity using GCMS. While I legit understand your curiosity as to what the tarry products are, I think most of us are just going to dispose of them by whatever responsible means (last time I diluted them in ethanol and burnt the mix).

I don’t want to come across as rude or whatever. I think it’s very cool that you have access to high-performance analysis tools, and that you could use it to vouch for the usefulness of a lot of elementary procedures the amateur chemist uses. After all, as someone else quoted on another thread, chemists were able to identify and purify compounds well before the days of dear electronic equipment, but those can assess products with a precision no other everyday manipulation could come close to.

[Edited on 11-5-2022 by Keras]

Fery - 11-5-2022 at 02:38

Bmoore55 well done and thanks for sharing your knowledge and skills! For me the video is very interesting. I did the synthesis and also the challenging separation of isomers. In my experiment the para isomer oiled out during crystallization from 2% HCl so I had to repeatedly extract it from the tarry mass reusing mother liquor and then crystallize from not too much hot solution as when the T and thus saturation was above some limit the product always oiled out from the beginning and only later the desired crystals started to form. I was able to simply scrap the crystals and mechanically separate them from the solidified tar at the bottom adhering to glass. Later I tried to purify the lowest quality crop by recrystallization from 0,5% sodium bisulfite solution with pH=5,4-6,4 which removed the discoloration completely and produced white crystals.
https://www.sciencemadness.org/whisper/viewthread.php?tid=15...

Oxy - 11-5-2022 at 11:31

Quote: Originally posted by Keras  
I took only a perfunctory look at it, but I hardly see the point of the last ¾ of the video. I mean, the video is technically great, no doubts about it. But it’s not really useful, given that 99.999% of us don’t have access to the analysis apparatuses you use.
[Edited on 11-5-2022 by Keras]


This is what makes Bmoore55's unique.

Well done Bmorre55!

[Edited on 12-5-2022 by Oxy]

Tsjerk - 11-5-2022 at 11:55

Quote: Originally posted by Keras  
I took only a perfunctory look at it, but I hardly see the point of the last ¾.
[Edited on 11-5-2022 by Keras]


Who cares for knowledge right? I like watching YouTube videos because I can watch stuff I would never be able to do at home

[Edited on 11-5-2022 by Tsjerk]

Keras - 11-5-2022 at 23:40

Quote: Originally posted by Tsjerk  

Who cares for knowledge right? I like watching YouTube videos because I can watch stuff I would never be able to do at home
[Edited on 11-5-2022 by Tsjerk]

Don’t get me wrong. The video is great. But it is a misnomer. It should’ve been called something like "Introduction to GCMS with an example: p-nitrophenol" and that would've been perfectly fine with me. But advertised as it is r.n., I was expecting a lot more about p-nitrophenol purification and analysis, and much less about anything else. Now, to each their own.

draculic acid69 - 12-5-2022 at 01:55

Excellent video. 10/10 plz keep making them as YouTube may have other videos on p,nitrophenol and on the analytical machines you use but they are rather dry and boring by comparison, don't go into detail, or are just online content for University classes.
You mix both analysis and amateur experimenting well into high quality interesting content

[Edited on 12-5-2022 by draculic acid69]

Bmoore55 - 12-5-2022 at 14:14

Quote: Originally posted by Keras  
Quote: Originally posted by Tsjerk  

Who cares for knowledge right? I like watching YouTube videos because I can watch stuff I would never be able to do at home
[Edited on 11-5-2022 by Tsjerk]

Don’t get me wrong. The video is great. But it is a misnomer. It should’ve been called something like "Introduction to GCMS with an example: p-nitrophenol" and that would've been perfectly fine with me. But advertised as it is r.n., I was expecting a lot more about p-nitrophenol purification and analysis, and much less about anything else. Now, to each their own.


That is a perfectly fair critique. I don't expect all replies to be glowing praise and I see this as nothing but constructive criticism. Hopefully the video was a little fun at times, that is all I am striving for is to be a little entertaining and informative. Hopefully you will still come back to watch what I make in the future. Thanks again for the feedback!

Tsjerk - 12-5-2022 at 14:25

I think this video was very interesting because now at least I know a little bit more about where my yield is going.

Bmoore55 - 12-5-2022 at 16:56

Quote: Originally posted by Tsjerk  
I think this video was very interesting because now at least I know a little bit more about where my yield is going.


That was partly what I was going for. For example when I watch an Explosions and Fire video and he jokes about low yield or the dreaded tar, well I can look into those sorts of things and mane show if something is polymerizing, degrading, or if maybe the product has gone into a phase/fraction we did not expect. I just thought a deep dive into the other stuff aside from just the end product would be interesting.

Fery - 12-5-2022 at 21:26

Low yield of para nitrophenol is due to its solubility in water as well in 2% HCl. From too much concentrated solution I observed always oiling out. Crystals formed when ratio about 2 g in solution from which 1 g of crystals and 1 g stayed in mother liquor. You have to crystallize from not too much hot and not too much concentrated solution. I improved yield by repeatedly reusing mother liquor but at the cost of purity.

Keras - 12-5-2022 at 21:46

I’m still wondering why people keep insisting on nitration while nitrosation by nitrous acid generated in situ produces almost pure p-nitrosophenol. Okay, I’m still groping in the dark for the proper recipe, despite everything written here and there, but if the goal is ultimately to get p-aminophenol by reduction, then the p-nitrosophenol intermediate is likely to be much more interesting.

Fery - 13-5-2022 at 01:25

because by nitration you obtain also o-nitrophenol

Keras - 13-5-2022 at 04:59

Quote: Originally posted by Fery  
because by nitration you obtain also o-nitrophenol


I totally agree if your goal is to get o-nitrophenol!

Texium - 13-5-2022 at 08:43

Quote: Originally posted by Bmoore55  
Quote: Originally posted by Keras  
Quote: Originally posted by Tsjerk  

Who cares for knowledge right? I like watching YouTube videos because I can watch stuff I would never be able to do at home
[Edited on 11-5-2022 by Tsjerk]

Don’t get me wrong. The video is great. But it is a misnomer. It should’ve been called something like "Introduction to GCMS with an example: p-nitrophenol" and that would've been perfectly fine with me. But advertised as it is r.n., I was expecting a lot more about p-nitrophenol purification and analysis, and much less about anything else. Now, to each their own.


That is a perfectly fair critique. I don't expect all replies to be glowing praise and I see this as nothing but constructive criticism. Hopefully the video was a little fun at times, that is all I am striving for is to be a little entertaining and informative. Hopefully you will still come back to watch what I make in the future. Thanks again for the feedback!
Can't win them all I guess. I watched it last night and thought it was fantastic! I especially liked to see the analysis of the aqueous layers, because I always wonder how much material I'm losing during workups. Cool to see the 2,4- and 2,6-dinitrophenols in the aqueous phase as well. Also, the 4-hydroxy-4-methyl-2-pentanone that you see in a few of those runs is definitely from the acetone. It's the first product of acetone self-aldol condensation and is actually also known as "diacetone alcohol."

I would suggest that you keep being yourself and doing what you're doing, as these first couple videos have been great. No need to force it to be more "fun" just to pander to people who don't appreciate the content.

Keras - 13-5-2022 at 10:49

Quote: Originally posted by Texium  

Quote: Originally posted by Bmoore55  

Quote: Originally posted by Keras  
…

That is a perfectly fair critique. I don't expect all replies to be glowing praise and I see this as nothing but constructive criticism. Hopefully the video was a little fun at times, that is all I am striving for is to be a little entertaining and informative. Hopefully you will still come back to watch what I make in the future. Thanks again for the feedback!



I will! It’s nice to see what a modern chemistry lab looks like and what you can do with the various devices there! I thought it was filmed in an uni lab, but apparently this is all yours. I’m flabbergasted! :p Also please also do continue. There are not enough good chemistry videos out there, so every new one is warmly welcome, especially when they’re technically outstanding!
Quote: Originally posted by Texium  

I would suggest that you keep being yourself and doing what you're doing, as these first couple videos have been great. No need to force it to be more "fun" just to pander to people who don't appreciate the content.


I strongly agree with that. Try to not fall into the same trap as NileRed, for example. Sounds like his channel has become a dog and pony show, and that’s a shame.