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Topic: Did I find the correct functional groups?  (Read 21671 times)

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Offline krista07

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Did I find the correct functional groups?
« on: October 28, 2008, 05:49:02 PM »
In my lab (separating the components of spearmint oil), we have to list the functional groups of the 3 main components of spearmint oil.

I would greatly appreciate if someone could check my work. Unfortunately, I don't know how to draw the molecules, so I can only give you the name and hope you know from that what the functional groups are.

I'm not very good at this, so they might all be wrong :(.

First, (L)-(-)-carvone:

Looks like methyl, ethyl, and a ketone.

(+)-limonene:

methyl, ethyl?

(1R, 2R, 4R)-dihydrocarveol

methyl, ethyl, alcohol??

I don't even know if I'm picking the right carbon chain, but I am pretty sure since they are all hexagons with groups coming off of them that the hexagon counts as the chain, and I shouldn't for example start with the ethyl group.


**Edit: Oh, by the way...I said that dihydrocarveol was the most polar. Am I right? Does the alcohol make it more polar than the double bond to an oxygen in the carvone? Obviously the limonene was the last polar.

Offline azmanam

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Re: Did I find the correct functional groups?
« Reply #1 on: October 28, 2008, 05:59:05 PM »
Methyl, ketone, and alcohol I'm ok with.

I'm not thrilled with ethyl.  It's not an ethyl group (ethyl groups are 2-carbon units).  There's a specific name for this functional group, C=C.  That's the functional group you need to identify.

Polarity trend is good.
Knowing why you got a question wrong is better than knowing that you got a question right.

Offline krista07

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Re: Did I find the correct functional groups?
« Reply #2 on: October 28, 2008, 06:08:33 PM »
Methyl, ketone, and alcohol I'm ok with.

I'm not thrilled with ethyl.  It's not an ethyl group (ethyl groups are 2-carbon units).  There's a specific name for this functional group, C=C.  That's the functional group you need to identify.

Polarity trend is good.

Thank you for the quick reply :).

I said ethyl because coming off of the bottom of each hexagon, I saw CH2CH3....Except now that I look at it, I see the double bond.

Actually, I don't think I've seen anything like that before. It's almost like an isopropyl, except with a double bond. There is a CH in the middle, and coming off of it is a CH3 and then a CH2 double bonded to it.

A C double bond C is an alkene, but is it called something different when it looks like that? I don't see anything that looks exactly like that in my list of functional groups....Again, closest was the isopropyl, just instead of both groups being CH3, one is CH2.

Thanks again for the help.


**Edit: Actually, no. I just looked again -- Is one group vinyl and the other methyl?

Offline azmanam

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Re: Did I find the correct functional groups?
« Reply #3 on: October 28, 2008, 06:17:29 PM »
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There is a CH in the middle

no there's not.

I'd give you credit for alkene (there are two alkenes in each of the molecules, except for the dihydrocarveol).  If you wanted to be more specific, the one in the ring is a cyclohexene.  The one off the ring is a propene.  Vinyl may be technically correct, but I don't think many organic chemists would look at that and say 'vinyl.'  Alkene is your best bet, imho.
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Offline azmanam

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Re: Did I find the correct functional groups?
« Reply #4 on: October 28, 2008, 06:18:41 PM »
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hexagon

(cringe).  Call it a cyclohexane.  Or a 6-membered ring.  Just not a hexagon :)

Otherwise, good work.
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Offline krista07

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Re: Did I find the correct functional groups?
« Reply #5 on: October 28, 2008, 06:35:40 PM »
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hexagon

(cringe).  Call it a cyclohexane.  Or a 6-membered ring.  Just not a hexagon :)

Otherwise, good work.

Ha yeah, cyclohexane. We recently had a quiz on naming molecules, too :P.

Thanks again for your help; I'm not doing well in the main course, so I am really trying not to screw up the lab section.

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