[beheada]

When bubbling something with HCl gas, how do you figure out how much HCl to use and how long to do it? (Stoichiometric?)

[hmx9123]

A lot of that probably depends on the reaction.  Can you use an excess of HCl?  Does the HCl induce an insoluble salt to form and thus you can tell if the reaction is done by precipitate no longer forming?  Does the HCl need to be anhydrous or can you use aqueous HCl?

You can generate a measured amount of HCl or leave a reaction under a flow of it, it all depends on what you need.

[beheada]

This was in use of precipitating an alkaloid from a nonpolar solvent and the reason the precipitation did not occur is because the HCl used was aqueous (more specifically muriatic 31%) and formed an aqueous layer which the alkaloid migrated to.

In this instance, I think I have two ways of dealing with this. Mix nonpolar solent with muriatic (stir) and evaporate the resultant aqueous layer which would leave the .HCl salt?

Or repeat the same experiment and utilize a drying agent in the gassing setup, possibly using a dry tube with calcium chloride between the gassing and the reaction flask?

[pantone159]

Could this work?

Bubble the dry HCl gas into a dry alcohol solvent (e.g. iPrOH).  You can then titrate this to see how much HCl is in that solution, then add this to your organic layer with base.

[hmx9123]

Precipitating an alkaloid, i.e., making drugs.