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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: syunchow on June 28, 2011, 12:20:19 AM

Title: Synthesis of p-cyanobenzoic acid
Post by: syunchow on June 28, 2011, 12:20:19 AM
Hi,

I'm having problem with the synthesis of p-cyanobenzoic acid. I started with p-tolunitrile, dissolved in sulfuric acid and added potassium dichromate with temperature maintained at 0 degree,  and then continue stirring at r.t for 48 h. The methyl group was oxidized to carboxylic acid group successfully but unfortunately the nitrile group has also been hydrolyzed into carboxylic acid. Is there a way to prevent this?
Title: Re: Synthesis of p-cyanobenzoic acid
Post by: OC pro on June 28, 2011, 02:03:04 AM
According to this reference with Ruthenium trichloride: J. Org. Chem. 1986, p.2880.
Title: Re: Synthesis of p-cyanobenzoic acid
Post by: Åke on June 28, 2011, 10:57:33 AM
Try: Levine, M.; Sedlecky, R. Preparation of p- and m-Aminomethylcyclohexylcarboxylic Acid. J. Org. Chem. 1959, 24, 115. http://pubs.acs.org/doi/abs/10.1021/jo01083a608
Title: Re: Synthesis of p-cyanobenzoic acid
Post by: syunchow on July 05, 2011, 09:13:13 PM
Yayyy! I have solved this issues. Using the same condition, I kept the sulfuric solution at 0 degree, and instead of long reaction time, I shorted it to 5h - got my compound without nitrile hydrolysis  ;D
Title: Re: Synthesis of p-cyanobenzoic acid
Post by: Vidya on July 05, 2011, 11:36:58 PM
That's really great