Hello!
About E2 elimination mechanism, there is the Hofmann elimination is based on the base promoted elimination of NH3 ions. What would be the explanation for a positive "p"? And why do they have to be plotted against Sigma Z (Z substituents)?

Question

Hello!
About E2 elimination mechanism, there is the Hofmann elimination is based on the base promoted elimination of NH3 ions. What would be the explanation for a positive "p"? And why do they have to be plotted against Sigma Z (Z substituents)?

aaronq · Answer

positive "p"? what has to be plotted?

please write your question more clearly and, ideally, provide an example.

liliakarina · Answer

P is the proportionality constant , which relates de substituent constant (electron donating or withdrawing) with the substituent's effect on rate. It is determined by plotting the log of kz (rate constant for a compound with a meta or para substituent) versus the substituent constant.
I don't understant very well what the electron donating or withdrawing has to do with the effect on rate in the formation of products :/
I'm attaching an example, along with some tables for the constant.