acidity/basicity values of the same functional group

[minutemen11]

trying to rank the acidity/basicity of an OH or amine or substitution effects on EAS:

the more akyl groups, the more basic because alkyl groups are E donors? So a tertiary OH would act more like a base, than a proton donor, and abstract an H, leading to a H20 leaving group and an alkene (zaitsev)?? And for amines, NH4+ is the most acidic because it does not have any donating groups?

In EAS then, an E donor like an OH or NH2 when substituted on a clean benzene would make the benzene MORE basic and E withdrawing groups like NO2 or COOH would make the compound MORE acidic?

please tell me if these predictions are correct, also all of these effects are attributed to E density right? whenever you increase the E denesity you make the molecule more basic? are there any exceptions to this/ this is the same as resonance stabilization- when something is more stable it becomes more acidic?

---

Members don't see this ad.

 

[minutemen11]

selfish bump..

 

[inaccensa]

trying to rank the acidity/basicity of an OH or amine or substitution effects on EAS:

the more akyl groups, the more basic because alkyl groups are E donors? So a tertiary OH would act more like a base, than a proton donor, and abstract an H, leading to a H20 leaving group and an alkene (zaitsev)?? And for amines, NH4+ is the most acidic because it does not have any donating groups?

In EAS then, an E donor like an OH or NH2 when substituted on a clean benzene would make the benzene MORE basic and E withdrawing groups like NO2 or COOH would make the compound MORE acidic?

please tell me if these predictions are correct, also all of these effects are attributed to E density right? whenever you increase the E denesity you make the molecule more basic? are there any exceptions to this/ this is the same as resonance stabilization- when something is more stable it becomes more acidic?

You have to know the e- donating and withdrawing groups. You are pretty much on the right track. Think about t-butyl alcohol. We know that alchols are less acidic than water, but why. The presence of 3 alkyl groups makes the base highly unstable, due to the e-donating properties. T-alchol doesn't act as a BASE. it is a very weak acid, the conjugate base of t-alchol will act as a strong base. Btw what is the base of t-alchol? OR3- which is a very strong base.

I'm not very sure, I understand the EAS analogy with basicity, perhaps someone else can shed some light. I think i knw what you are asking. Since you have electron donating groups, it will donate electron density to benzene and thus decrease the acidity. We always think of groups on benzene as activating and deactivating. I hope someone does address that q. Benzene doesn't donate electrons, inshort it doesn't undergo addition rxn.