I'm just curious about making dry methanol/methylamine solution for use in boro reduction? I read someone was adding lye to methanol with methylamine HCl but that doesn't seem right.
Easiest way to make methanol/methylamine solution
- Thread starter Gale
- Start date
BTCboss the legend posted about this, I was skeptical at first but it worked for me.
there is some variations however, you can’t put 500g methylamine hcl into 2-3L methanol and expect it to work for 1L of ketone just because the maths does, because a lot of the gas escapes
The solution.
As long as the methanol is chilled and in abundance (6-12L per L ketone) such that it can absorb as much freebase as possible when converted, about 1kg methylamine hcl will convert and retain at least the ~200g methylamine freebase needed for 1L P2P.
It’s still a poor yield for the freebase, as the rest escapes the solution but still it worked
For me and is convenient.
The reaction produces NaCl which doesn’t affect the reaction, as well as water, so you need to use a minimum amount of drying agent to soak up the water prior to reducing the imine with NaBH4.
there is some variations however, you can’t put 500g methylamine hcl into 2-3L methanol and expect it to work for 1L of ketone just because the maths does, because a lot of the gas escapes
The solution.
As long as the methanol is chilled and in abundance (6-12L per L ketone) such that it can absorb as much freebase as possible when converted, about 1kg methylamine hcl will convert and retain at least the ~200g methylamine freebase needed for 1L P2P.
It’s still a poor yield for the freebase, as the rest escapes the solution but still it worked
For me and is convenient.
The reaction produces NaCl which doesn’t affect the reaction, as well as water, so you need to use a minimum amount of drying agent to soak up the water prior to reducing the imine with NaBH4.
And of course, as you mentioned you convert it to the freebase by adding NaOH / caustic soda / lye, just as you would to convert it to gas normally.
The other caviat is
That Methylamine hcl is sparingly soluble in chill methanol. What I did was dissolve it at room temp under heavy stirring, then bring the temp down whilst maintaining the heavy stirring, Followed by the addition of NaOH
The other caviat is
That Methylamine hcl is sparingly soluble in chill methanol. What I did was dissolve it at room temp under heavy stirring, then bring the temp down whilst maintaining the heavy stirring, Followed by the addition of NaOH