Little Chemistry Help?

Muse_Cubed · 28 Feb 2008 at 16:54

I saw there are a few chemists on here...got a little (quite specific conundrum). Trying to oxidise the methyl sidechain on toluene to an aldehyde. Can't think how to do it because potassium permanganate is a bit of a sledgehammer and will take it down to the carboxylic acid.

Any ideas?

Tefal · 28 Feb 2008 at 17:12

lol since I've started my degree I've developed a strong hatred for organic chemistry

Will have a look over my notes later, but It may take some time as i am incredibly lazy.

*am drunk and on pain pills at the mo so can't give a sane response at the mo*

Muse_Cubed · 28 Feb 2008 at 17:15

Well. I am predominantly into organic. I just can't stand aromatic chemistry. It's horrendously boring. Cheers! What year are you in?

Azza · 28 Feb 2008 at 17:16

I would help out but frankly Im not terribly good at chemistry.

But I shall have a think.

radderfire · 28 Feb 2008 at 17:22

Googled it for you:

Reaction with chromyl chloride leads to benzaldehyde (Étard reaction).

http://en.wikipedia.org/wiki/Étard_reaction

dave_a141 · 28 Feb 2008 at 17:23

From what i can remember of a level chemistry:

if you distill with a small amount of the permanganate you will get the aldehyde,
You have to reflux with excess to get the carboxhylic acid

This is assuming that the the benzene ring has no other effects anyway

Hope this helps

Muse_Cubed · 28 Feb 2008 at 17:31

Etard, that's the one, thank you very much! I'm not keen on the partial oxidation reactions because they're not particularly easy to do in the lab mind but there we go.

Tefal · 28 Feb 2008 at 17:35

Muse_Cubed said:
Well. I am predominantly into organic. I just can't stand aromatic chemistry. It's horrendously boring. Cheers! What year are you in?

only first year at the mo, but really hating organic chem can never remember reagents, although some of the little tricks to get around the problems, of other functional groups you don't want to change (like making protecting groups etc) is really interesting. You at oxford uni then?

for fun and lulz set a hotplate to 370 C and then once it's hot pour a little water on it, it doesn't boil, just flows around like mercury

Muse_Cubed · 28 Feb 2008 at 17:39

Tefal said:
only first year at the mo, but really hating organic chem can never remember reagents, although some of the little tricks to get around the problems, of other functional groups you don't want to change (like making protecting groups etc) is really interesting. You at oxford uni then?

Yep, I'm there. Yourself?

I'm a second year currently...I have to say by second year you should be quite finely tuned towards the types of reagents you have to use rather than specific ones. So I just think what I need (electrophile/nucleophile etc.) and pick it out of the class depending on reaction conditions etc. Just I sometimes hit the occasional blip when it's a bit of a grey area.

Tefal · 28 Feb 2008 at 18:30

Muse_Cubed said:
Yep, I'm there. Yourself?

I'm a second year currently...I have to say by second year you should be quite finely tuned towards the types of reagents you have to use rather than specific ones. So I just think what I need (electrophile/nucleophile etc.) and pick it out of the class depending on reaction conditions etc. Just I sometimes hit the occasional blip when it's a bit of a grey area.

I'm Manchester

blade007 · 28 Feb 2008 at 23:59

you need a special reagent to stop it oxidising further into the carboxylic acid. You also want it powerful enough to oxidise the O-H which tends to appear first.

someone mentioned chromyl chloride, and this is a common one to use.