What are the Oxidation States of Carbon in Sebacic Acid and Propylene Glycol?

[Justin LaRose]

Hello,

I am a physics major and my friend is on a research vessel in the Arctic and can only operate email from the limited internet access there. I do not know organic chemistry so I was hoping someone could tell me if this was right (it is for homework when she returns; not in relation to her research).

She needs to know the oxidation state for the carbon atom in sebacic acid and propylene glycol.

For sebacic acid she got +3 for the oxidation state of the carbon atom.

For propylene glycol she got +2 for the oxidation state of the carbon atom.

Could someone please help me to confirm that these are correct or incorrect, and if they are incorrect help me to figure out what the right oxidation numbers on the carbon atoms are (keeping in mind I do not know organic chemistry)? I did an extensive search on Google and could not find anything relevant.

Thank you very much!
Justin

 

[Borek]

Definitely wrong, as different carbon atoms in the molecule can have different oxidation numbers.

In general assigning oxidation numbers is a kids playground, it doesn't matter much in chemistry - it is a nice tool when you start learning about redox processes, but has no relation to any real world properties of atoms.

 

[Justin LaRose]

I am wondering within the purposes of a geochemistry homework assignment. There is a definite number. If I wanted to theorize I would just say the carbon is in a superposition state of being a wave and a particle, or something like that, which is what I like to do, and why I'm a physics major, but this isn't for me.

There are definite rules to assigning oxidation numbers to Carbon atoms within molecules. Any help would be greatly appreciated.

 

[Justin LaRose]

I think I may be in the wrong place.

 

[Bystander]

There are definite rules "(Editorial modification) vague conventions" to assigning oxidation numbers to Carbon atoms within molecules.

Carbon dioxide: +4
Carboxylic acids, esters, anhydrides: +3
Aldehydes, ketones: +2
Alcohols, ethers: +1

And, basically, as Borek has said, a "game" to teach/illustrate electron counting.

 

[Justin LaRose]

Yeah that there pretty much confirms that she had the right numbers, because looking online I saw that those molecules fit that criteria.

Thanks a lot for the help there. Like I said, this is for a friend who is on a research vessel in the arctic and she said her email is slower than any dialup that can be imagined and she couldn't even load a webpage to check things out for herself. So she asked me thinking I know anything about organic chemistry; I dropped organic chemistry after the first week and that was when I became a physics major.

Much appreciated Bystander and Borek. I find it much more interesting to examine things from a physical perspective. I am very intrigued by this site here, she had mentioned it existed and I look forward to utilizing the knowledge base as I work through quantum and Lagrangian mechanics this semester.