Organic Chemistry - Synthesis of Lidocaine

[Sylvia]

In lab we had to synthesize lidocaine, and one of the steps involved reacting a-chloro-2,6-dimethylacetanilide with diethylamine to form lidocaine. My professor told us that diethylamine-HCl crystals would form and these would help us determine the lidocaine yield (since they form at a 1:1 mole ratio). However, I did not get any of these crystals but I was able to form lidocaine.

So my question, how is this possible? Please help.

 

[Bystander]

diethylamine-HCl crystals would form

I did not get any of these crystals

The by-product didn't precipitate. "Why?" Without information regarding temperature, concentration, and other such details, there's no telling what kept the diethylamine hydrochloride from precipitating.

 

[Sylvia]

Diethylamine was in excess (4 equivs to 1 equiv a-chloro-2,6-dimethylacetanilide), refluxed reaction for about an hour