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Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: ZidaneTribal on November 20, 2017, 05:20:48 AM

Title: Purifying an compound containing a tosylate nad a tosylate side product
Post by: ZidaneTribal on November 20, 2017, 05:20:48 AM
Greetings,

I've synthezized a functionalized polymer with tosylate groups. Due to excess ethanol formed during the the reaction, my tosylate chloride reagent reacted with that ethanol forming a side product. Purification was done by precipitation but the side product couldn't be removed. Is recommended to run a column over Al2O3 to remove the side product? I'm not sure if the tosylate will tolerate purification by column chromatography. What are your suggestions?
Title: Re: Purifying an compound containing a tosylate nad a tosylate side product
Post by: Babcock_Hall on November 20, 2017, 08:02:21 AM
I am not sure of the answer to your question.  Do you think that your material would tolerate some type of size exclusion chromatography?
Title: Re: Purifying an compound containing a tosylate nad a tosylate side product
Post by: ZidaneTribal on November 20, 2017, 11:27:08 AM
I am not sure of the answer to your question.  Do you think that your material would tolerate some type of size exclusion chromatography?

That's a good suggestion. But I'd like to run it as simple as possible. I fear that my tosylate groups will gone after column chromatography. Did ever purify a tosylate compound with column?
Title: Re: Purifying an compound containing a tosylate nad a tosylate side product
Post by: wildfyr on November 20, 2017, 12:34:36 PM
Yes, tosylates can handle a column just fine. I've never tried a alumina column with it, just a standard silica column.

However, polymers usually smear all over the column, so pay close attention to your TLC.

You should try precipitating or redissolving in various solvents and see if you can't get purification that way. For instance, tosyl ethanol is probably soluble in diethyl ether, but polymers tend to have terrible ether solubility.
Title: Re: Purifying an compound containing a tosylate nad a tosylate side product
Post by: phth on November 21, 2017, 04:49:49 PM
Run a 2D TLC plate to assess if it will decompose on alumina or silica.  Like Wildfyr said it will only be minor decomposition if any i.e. 10-20% loss.