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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: tiff8968 on November 29, 2008, 06:09:26 PM

Title: Dehydration of Cyclohexanol
Post by: tiff8968 on November 29, 2008, 06:09:26 PM
I'm doing this in lab class. I wanted to know what happens when cyclohexanol is dehydrated. I know that water is eliminated, but how is the double formed? Another thing why is IR spectroscopy used? I know it detects different functional groups but after distilling the alcohol and the acid shouldn't you already assume the product will be an alkene???
Title: Re: Dehydration of Cyclohexanol
Post by: macman104 on November 29, 2008, 08:32:43 PM
The attached document has the mechanism for the dehydration (I assume that is what you meant by how).

As for why you use IR, it is just for verification.  Yes, you could assume that it is cyclohexene, but it's a lab, you're meant to gain experience with different instrumentation.
Title: Re: Dehydration of Cyclohexanol
Post by: g-bones on November 29, 2008, 10:52:19 PM
For the IR you are looking for two obvious peaks.  If your reaction is complete than you shouldn't see the very obvious peak for the O-H (really broad and strong) but you should see the presence of the C=C bond (also decently obvious).  you will also sp2 (=C-H) bands above 3000 cm-1 (these may be less obvious but should still appear).  you can check any text for the typical wavenumbers of the stretches. 

And your reaction will go, no worries

Hope this helps