What would be the good method and solvent to purify biphenyl?

  • Thread starter Thread starter Fairway
  • Start date Start date
  • Tags Tags
    Method Solvent
AI Thread Summary
To purify biphenyl contaminated with fluorene, crystallization is suggested as an effective method due to the significant difference in their melting points. Biphenyl and fluorene are both non-polar, but fluorene is more polar due to its acidic proton, making it more soluble in polar solvents. Using NaOH can deprotonate fluorene, allowing it to separate from biphenyl when mixed with a solvent like ether. In this scenario, biphenyl remains in the ether phase while fluorene moves to the aqueous phase. Understanding this separation process is crucial for achieving successful purification.
Fairway
Messages
8
Reaction score
0

Homework Statement



what would be the good method and solvent to purify biphenyl contaminated with fluorene?


Homework Equations







The Attempt at a Solution



The polarity of biphenyl (MP: 68.93°C) and fluorene (MP: 116-117°C ) are same which is non polar but their MP is hugh different. So, I'm not so sure which solvent is good to use. I think cryatallization would be the good method to purify. Could you help on this? Thank you so much.
 
Physics news on Phys.org
Fluorene has an acidic proton and the anion is stabilized by aromatic stabilization. NaOH is apparently a strong enough base to deprotonate it.

You could also use an alcohol like butanol or butanol + ether.
 
Thanks for help, It's kind of still confusing becaue the question is asking about to purify the biphenyl from fluorene.
 
Fluorene is somewhat acidic (NaOH can deprotonate it) and is therefore more polar than biphenyl. It would more soluble in a polar solvent like alcohol. What would happen if you were to shake a sample containing fluorene with NaOH and ether? Would you find the fluorene in the organic or the aqueous phase? Would the biphenyl stay in the ether phase or would it cross over into the aqueous phase as well?
 
Thank you so much. It makes sense NaOH and ether will sepearte biphenyl from Fluorene because biphenyl will stay in ether phase. If I understood this earlier, then I would have got the right answer for my lab. Well, Still I'm so happy that I know now. Thank you again!
 
Thread 'Confusion regarding a chemical kinetics problem'
TL;DR Summary: cannot find out error in solution proposed. [![question with rate laws][1]][1] Now the rate law for the reaction (i.e reaction rate) can be written as: $$ R= k[N_2O_5] $$ my main question is, WHAT is this reaction equal to? what I mean here is, whether $$k[N_2O_5]= -d[N_2O_5]/dt$$ or is it $$k[N_2O_5]= -1/2 \frac{d}{dt} [N_2O_5] $$ ? The latter seems to be more apt, as the reaction rate must be -1/2 (disappearance rate of N2O5), which adheres to the stoichiometry of the...
Back
Top