Dear fellow chemists...

When glycine reacts with methanol in excess sulfuric acid, does it simply produce ester (and water) or ester (with NH3+ ion) and water??

Glycerine AKA propan-1,2,3-triol + another alcohol (methanol) might struggle a bit to make an ester.

With methanoic acid, it'd make a triester with the release of water.

NH3+ - Whatcha talkin bout Willis?

Yes, a general esterification proceeds to give the methyl ester. The amine functionality will remain protonated until whatever work up removes them. It would need to be mildly basic.

So in excess acid catalyst, it wouldn't form NH3+ ion, just the ester and water?

Why would the NH3+ fall off? What possible reason would it have to do that?

The acid part of the ester has an NH2 group on it (glycine is an amino acid), in acid conditions it would be protonated to form the NH3+ group. The ester formed would therefore be an ion with an ammonium group, balanced out by SO42- ions.

I meant that it would only form nh2 (and rest) not NH3+ because I'm thinking that the acid catalyst (overall) doesn't (or at least should not) get consumed/used up in the reaction.

The formation of an ammonium ion isn't a part of the reaction in question.

It was, I was asking whether it forms ammonium ion (NH3+) or remains with nh2 (and obviously rest of molecule)

You misunderstand.

Esterification does proceed with acid catalysis, which means that, on net, protons are not used up in the process.

However, the protonation of the -NH2 to -NH3+ is not part of the esterification reaction, and the protonation of these is not catalytic; there is no requirement for there to be regeneration of the acid catalyst.

mil88 - you are confuzzled, the ammonium ion is NH4+, which is different from the ammonium functional group, -NH3+