Phenylacetic acid from alkaline hydrolysis of benzyl cyanide

[markhor]

Hello everyone.

I am trying to prepare phenylacetic acid from the alkaline hydrolysis of benzyl cyanide, but I have not succeeded, I hope you can guide me in the process.
I've been doing research but haven't found much practical information.

I have based on this article and in this thread, I did the following test (small scale):

• 100 g Benzyl cyanide
• 220 ml Water
• 25 g Sodium hydroxide

Procedure:

• Dissolve the sodium hydroxide in the water
• I kept the dilute sodium hydroxide solution and the benzyl cyanide at reflux for 3 hours with stirring
• After that time a homogeneous mixture was made
• Let the solution cool and a kind of dough was made

It is assumed that up to this point the reaction mass is a salt, Sodium Phenylacetate; and to release the acid you have to add some strong acid, this is where I have the question: How much acid do you have to add?

I added 30% hydrochloric acid until reaching pH 2 (approximately 100 ml), but the reaction mass separated into two layers, one oily and one liquid. I was hoping to get a mixture that could be filtered, since in the thread that I took as a reference it says that it has to be put in the centrifuge.

Maybe I had to perform exactly the procedure as mentioned in the thread.

I hope you can help me please.

 

[G.Patton]

Why did you reflux 3h instead of 9? Did you add additional 25 ml water?
In theory, you need to add equimolar amount of H2SO4. For 100g benzyl cianide it is 83.7g (45.7ml).
Did you cool the reaction mixture as shown in the linked William's tutorial?