Understanding Amino Acid Acidity and Basicity in Reactions

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Discussion Overview

The discussion revolves around the acidity and basicity of amino acids in the context of specific chemical reactions. Participants explore how these reactions can be interpreted as demonstrating acidic or basic behavior, particularly in relation to esterification and the definitions of acids and bases.

Discussion Character

  • Homework-related
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant states that an acid donates a proton and a base accepts a proton, expressing confusion over the classification of the reactions as acidic or basic.
  • Another participant suggests thinking outside the standard Bronsted acid definition and questions the nature of esters.
  • There is a discussion about the definition of an ester, with one participant asserting that an ester is a product of a reaction, not a type of reaction.
  • Some participants debate the mechanism of ester formation, with one noting that an acid loses OH, not just H, during the reaction.
  • Another participant claims that the definition provided by an external source is incorrect when considering the reaction mechanism, but acceptable when focusing on the product structure.
  • One participant expresses skepticism about the second reaction demonstrating basic behavior and indicates a lack of appreciation for the question posed.

Areas of Agreement / Disagreement

Participants express differing views on the classification of the reactions as demonstrating acidic or basic behavior, and there is no consensus on the definitions or interpretations of esters and the reactions involved.

Contextual Notes

There are unresolved assumptions regarding the definitions of acids and bases, as well as the mechanisms of the reactions discussed. The discussion also reflects varying interpretations of the reactions' classifications.

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Homework Statement



How does the following reaction demonstrate an amino acid as an acid:
H2NCH2COOH + CH3OH → H2NCH2COOCH3 + H2O

How does the following reaction demonstrate an amino acid as a base:
H2NCH2COOH + CH3COCl → CH3CONHCH2COOH + HCl

Homework Equations





The Attempt at a Solution


An acid is a species that DONATES a proton and a base is a species that ACCEPTS a proton

In both situations it seems more like an esterfication reaction than an acid / base reaction.

Also in the second reaction the H2N loses an H+ for water (I would call that acidic behaviour but it is actually basic behaviour) and the first example COOH loses OH (basic behaviour but is classified as acidic)

I am confused :S
 
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This is not about a standard Bronsted acid definition. Think outside of the box. What is an ester?

That's what they ask about, doesn't mean I like the question.
 
Borek said:
This is not about a standard Bronsted acid definition. Think outside of the box. What is an ester?

That's what they ask about, doesn't mean I like the question.

well an ester is a type of condensation reaction in which a small molecule is eliminated?
 
No, ester is not a type of a reaction. It is a product of a reaction. Reaction of what with what?
 
Borek said:
No, ester is not a type of a reaction. It is a product of a reaction. Reaction of what with what?

a carbonyl carbon (e.g: COOH or COCl) and a hydrogen attached to an electronegative atom (e.g: OH, H2N)
 
In fact another site says its when the hydrogen of an organic acid is replaced by an organic group (e.g: alkyl)

BUT the acid LOSES OH not just the H?
 
The other site is wrong. That is, it is wrong when you look at the mechanism, but it is OK when you look just at the product structure.

Ester is produced by a reaction of an acid (even doesn't have to be organic - think sulfuric, phosphoric) with an alcohol.
 
Borek said:
The other site is wrong. That is, it is wrong when you look at the mechanism, but it is OK when you look just at the product structure.

Ester is produced by a reaction of an acid (even doesn't have to be organic - think sulfuric, phosphoric) with an alcohol.

ok so I get the first one but how does the second rxn demonstrate basic behaviour?
 
To be honest - I don't see how. I told you I don't like the question.
 
  • #10
Borek said:
To be honest - I don't see how. I told you I don't like the question.

nm
thanks for your help :)
 

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