Hi!
You say:
"1 mole hex, 140g, makes in theory 202g methylamine.hcl
37% of that is 75g.
100g hex in theory makes 144g methylamine.hcl, 37% yield gives 53g."Actually, I'm not completely satisfied with your calculation!
I think you refer to the post linked below when you wrote this:
Post 500578
(Bond_DoubleBond: "Nothin special, but here ya go . . .", Methods Discourse)So let's recalculate the molar proportions bouble bond used:
100g hexamine + 104.03g HCl + 77.12g H2O -> 152.62g NH4Cl + 128.53g HCHO
(The remaining water from the HCl amounts to 226.22g - 77.12g (used for hexamine hydrolysis) = 149.1g (or ml))
152.62g NH4Cl + additional 30g -> 182.62g NH4Cl
(if the concentration of the acid BDB used was w/w, he used in fact 103.76g HCl instead of 104.03g - but that's neglectible, let's simply say he had used the correct amount
)
So the ratio of reactands are:
3.41 mol NH4Cl
4.28 mol HCHO
2.11 mol EtOH (again not exactly 2x the molar amount of HCHO, but close enough)
The limiting reactand is obviously the NH4Cl.
Now I don't see how you came to your statement that 100g hexamine results in 144g MeAm*HCl theoretically - because the max. theoretical yield would be 3.41 mol * 67.52g/mol = 230.24g methylamine hydrochloride
He claimed having got 120g pure product (anhydr. IPA recrystallization). Therefore:
230.24 / 120 = 0.5212 ==> 52.12 percent of theory
There's nothing wrong with getting twice as much as with standard, well-known procedures if you use some new/unknown improvement. And the claimed yields seem achievable, at least seen from the mathematical point of view...
I got 45.11 percent of theory BTW, and that was after gassing - I think "BubbleBond"s (nice nick
) 52.12 percent correspond pretty well with that...
Greetz, A