Which is More Polar: Ethyl Acetate or Nitrobutane?

  • Thread starter Thread starter freedom856
  • Start date Start date
  • Tags Tags
    Organic Polarity
Click For Summary

Discussion Overview

The discussion revolves around the polarity of ethyl acetate and nitrobutane, particularly in the context of liquid chromatography techniques, including normal phase and reverse phase. Participants are exploring how to determine which compound is more polar and its implications for elution order in chromatography.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Experimental/applied

Main Points Raised

  • One participant questions which compound is more polar, seeking clarity for test scenarios involving chromatography.
  • Some participants propose that nitrobutane is more polar due to its ability to form an aci type structure.
  • Another participant suggests that ethyl acetate can also form a similar structure, indicating that the polarity comparison may not be straightforward.
  • A participant mentions the importance of solvent polarity in determining elution order and suggests using thin-layer chromatography (TLC) as a method to gauge polarity, despite acknowledging the context of high-performance liquid chromatography (HPLC).
  • One participant argues that nitrobutane's dual ionic nature contributes to its polarity, while ethyl acetate's structure may be less polar due to having fewer charged atoms.
  • Another participant emphasizes that the nitro group (NO2) is a strong electron-withdrawing group, which may enhance the polarity of nitrobutane.

Areas of Agreement / Disagreement

Participants express differing views on which compound is more polar, with no consensus reached. Multiple competing perspectives regarding the factors influencing polarity are presented.

Contextual Notes

Participants note the lack of information regarding the solvent used in the chromatography question, which may affect the determination of polarity. There is also uncertainty regarding the application of TLC versus HPLC in assessing polarity.

freedom856
Messages
11
Reaction score
0
i was wondering the polarity of ethyl acetate and nitrobutane, which one is more polar?
As i face this question in test(liquid chromatography using normal phase and reverse phase)
Asking for the elution order, i am not sure which one is more polar? Can anyone answer my question? Also, if i face this kind of question again, what can i do? Thank you
 
Chemistry news on Phys.org
I would say that the nitroalkane is more polar as it can form an aci type structure.

R-CH2-NO2 <-------> R-CH=NO2H
 
chemisttree said:
I would say that the nitroalkane is more polar as it can form an aci type structure.

R-CH2-NO2 <-------> R-CH=NO2H

Well, so can the ester CH3CO2Et <-> CH2=C(OH)OEt, so I doubt that's the full story. Perhaps take a reasonably polar compound and see what kind of an Rf you get on TLC with pure ester and nitroalkane each as solvent, as a first approximation?
 
Sorry.It is not TLC. It is HPLC. i do remember the question does not state what solvent is used
 
I appreciate what you're saying, but you can get a measure of solvent polarity from Rfs on TLC (I know it's a different stationary phase). Imagine running a TLC in pure hexane, your compound will hardly move as the interaction with the silica (or other phase, e.g. alumina) and your compound is much greater than between compound and solvent. Now, if you run the same compound in EtOAc, or DCM, or similar, then the Rf would be greater as the polarity is greater..? (Or am I totally confused here?)
 
your answer is correct if i run TLC once and i can find the answer, but the problem is i only sit in the classroom and answer this question. How can i run TLC to determine their polarity? i really request a way to solve this kind of problem.
 
My guess would be nitrobutane as it's actually two ions (notwithstanding resonance structures). Ethyl acetate might have one less carbon moiety, but the hydrophilicity of two charged atoms outweighs the hydrophobicity of one methyl group.
 
sjb-2812 said:
Well, so can the ester CH3CO2Et <-> CH2=C(OH)OEt, so I doubt that's the full story. Perhaps take a reasonably polar compound and see what kind of an Rf you get on TLC with pure ester and nitroalkane each as solvent, as a first approximation?

Trust me. It's enough of the story to get the question right. TLC will give you the same ranking but how will you visualize the spot?

http://books.google.com/books?id=HN...AA#v=onepage&q=nitroalkanes polarity&f=false" Some things you just have to remember.
 
Last edited by a moderator:
I would say the nitro compound is more polar because NO2 is a very strong electron drawing group.
 

Similar threads

Non polar molecule with polar bonds?
  • · Replies 34 ·
2
Replies
34
Views
5K
Ordering Rf of Aspirin with Polar Eluents
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Why do orthogonal polarizers at slits eliminate interference pattern?
  • · Replies 28 ·
Replies
28
Views
2K
Undergrad How To Experimentally Confirm the Wigner-Von Neumann Interpretation
  • · Replies 52 ·
2
Replies
52
Views
7K
Protocol and solvent help needed for gel-permeation chromatography
  • · Replies 11 ·
Replies
11
Views
7K
Theoretical ξr of a molecule from the absolute configuration
  • · Replies 2 ·
Replies
2
Views
6K
Graduate How Does MWI explain Type I PDC Photon Polarization Entanglement?
  • · Replies 19 ·
Replies
19
Views
1K
Salting out and organic solvents
  • · Replies 4 ·
Replies
4
Views
6K
Separation using acids and bases
  • · Replies 1 ·
Replies
1
Views
10K
Undergrad Hidden phase in polarization tests of Bell's inequality?
  • · Replies 49 ·
2
Replies
49
Views
6K