[shrikantvarma]

I have done reductive amination of aldehyde & amine compound,reduction performed by using sodium borohydride ,after reaction i workup with addition of water to quench NaBH4,but it gives some white foaming while addition of water,but after quenching reaction with dilute HCl i get no foaming is it correct to quench NaBH4 with HCl?

[Doc Oc]

The overall effect is the same, using aqueous conditions to quench NaBH4 creates hydrogen gas, which is why you see bubbling.  You should consider the sensitive functionalities on your molecule when deciding whether to use HCl or water to quench.

[shrikantvarma]

thanks,can u tell me what will be the by product of reaction after quenching with water & HCl,is there formation of boric acid ?

[Doc Oc]

Yes, boric acid is formed.

[g-bones]

the gas you see is H2.  if you are concerned about using HCl to quench the reaction AcOH will do the trick to.