Chromatography Forum

Hello,
I have a mixture of 1-pentene, trans-2-pentene and cis-2-pentene. is it possible to separate them on a non polar column - 100% dimethylpolysiloxane phase (30 m x 0.25 mm, 0.25 µm)?

and my second qouestion....

on the same column, what are the parameters for the separation of 1-methylcyclohexene, 3-methylcyclohexene and methylenecyclohexane?

I'll be glad for a quick answer!
Thank you,

Edith

My gut feeling is that you're going to have a hard time with that separation on that column. It's not a very selective phase and those are some very similar materials.

I thought so, too. I wanted to be sure about that...
Thank you for your quick reply.

You have a good chance on an alumina column:

http://www.restek.com/chromatogram/view ... 7C109-66-0

For the cyclohexane's you might have a chance. Restek doesn't have an app note on that. If you have a standard, make it up and shoot it. Just don't make it too concentrated.

It's for a student lab, there is no budget for a new column...

but I will try the methylcyclohexene isomers.

thanks for the advise!

A good system for the 1 phase might be ethylbenzene, p-xylene, and o-xylene. All are isomers. You can't separate m- and p-xylene from each other on this phase but you can separate EB and o-XY from m- and p-.

I was planning a student project that compares product distribution of 1 and 2-pentanol elimination reaction.
Thank you, anyway...

Ah. I thought perhaps it was an analytical lab. The compounds I mentioned are contaminants (BTEX) that show up in ground water if a gasoline storage tank is leaking somewhere.

You might have success with the methylcyclohexanol system and the 1 phase. Generally, if the analyte is heavier, it gets easier to separate closely related compounds on that phase.

It is easier, I have just succeeded to separate them...

Very good! Good luck with the experiment in the hands of the rookies.

Thank you