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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: portugal on April 04, 2008, 09:03:49 AM

Title: racemic phenylbutanoic acid
Post by: portugal on April 04, 2008, 09:03:49 AM
how would one resolve a racemic mix of 2-phenylbutnanoci acid using pure(optically) using alpha-phenylethylamine?
Title: Re: racemic phenylbutanoic acid
Post by: Dan on April 04, 2008, 09:29:17 AM
Two possibilities immediately spring to mind:

1. When you mix the acid with the amine you will form a mixture of two diastereomeric salts, one of which may be possible to selectively crystallise out of the mixture.
Then you have to get back from the (seperated) salts to the acids, which you could do by washing/extraction methods or you could use ion exchange resins.

2. Convert your acid to, say, the acyl chloride, react with your amine. This gives you a mixture of diastereomeric amides which might be seperable by crystallisation or also chromatography.
Then hydrolyse the seperated amides back to acid + amine and isolate your acid. Again, you could use washing/extraction methods or ion exchange resins.