Naming Citric Acid

[ChrisChrisau]

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Hi all,

For citric acid, I was wondering the reason behind it being named "2-hydroxypropane-1,2,3-tricarboxylic acid" as opposed to "1,2,3-tricarboxylic-2-hydroxypropane"

The reason I ask is that I was under the impression that when naming hydrocarbons, the segments are put in alphabetical order, without the prefixes.

Thanks!
Chris

[live.life]

My understanding is that it's in alphabetical order but you try to put the smaller numbers groups at the front. Thus the 2-hydroxy blah blah blah. But I could be wrong...In fact this is highly likely.

When you look at the structural formula, it makes more sense the way it is named. I think so anyway...

But also hydrocarbons consist of ONLY hydrogen and carbon. Citric Acid has oxygen too. Perhaps this is also an explanation.


My chemistry teacher told us "There's an exception to every rule in chemistry. And even that rule has an exception", so this could be chemistry doing what is does best and being confusing...

Hope it helps...

[ChrisChrisau]

All very likely answers... particularly the last haha

Thanks for the help

[chuboy]

For citric acid, I was wondering the reason behind it being named "2-hydroxypropane-1,2,3-tricarboxylic acid" as opposed to "1,2,3-tricarboxylic-2-hydroxypropane"

The reason I ask is that I was under the impression that when naming hydrocarbons, the segments are put in alphabetical order, without the prefixes.

You are correct, however carboxylic acid groups take precedence over the hydroxypropane, therefore it comes last. Link