[cthotapalli]

the fischer indole synthesis which i am doing has phenylhydrazine and 4-piperidone as  starting materials and the acid catalyst used was gas dry hcl gas. 
the final product is amine salt at the same time it contains 1 equivalent of nh4cl as by product 
i dont want to change the catalyst. can anyone tell me how to prevent the nh4cl formation during the reaction or getting the free amine as final product with out nh4cl 
recrystallization methods to NH4Cl will also be good

[macman104]

NH4Cl is a byproduct of the reaction.  It is part of the mechanism of the reaction, so I'm not sure you can avoid it's formation