Question about Methylamine 40% aq. solution

[Ksalos]

What exactly does 40% stand for?
I believe 40% wt./wt. should be 664g MeNH2 in 1L of H2O. (997g/mol (H2O) / 60% * 40%)
This would mean that 1 liter would contain ~21 mols of methylamine. (664g / 31.1g/mol)

The following listing shows that it only should have 12 mol/l.

Methylamine Solution, (ca. 40 Percent in Water, ca. 12mol/L) (DEA List I Chemical)

Methylamine Solution, (ca. 40 Percent in Water, ca. 12mol/L) (DEA List I Chemical)

www.spectrumchemical.com

12 moles per liter would correspond to about 400g, instead of my calculated 664g.
Is "40%" not refering to weight percent or am I missing somethink else?

 

[island]

More like approx
600gr H2O +
400gr methlamin = total waight of solusion should be 1000gr
60%H2o + 40% methylamine

 

[Ksalos]

Ok, thank you for your quick response.

 

[rampage]

do you not have to add naoh?

 

[rampage]

How do you make aqueous methylamine?
is this how to do it?
Take methylamine hydrochloride salt then dissolve it in an appropriate amount of water, then cool the solution to around 5* C and you add enough (pre-cooled) dilute NaOH(aq) to create aqueous methylamine freebase in solution with NaCl
how do you calculate the amount of methylamine hcl and water used? how much dilute naoh is required?
can somebody post an example for a 200ml 40% solution of aqueuos methylamine,