Sciencemadness Discussion Board

L Lysine hydrochloride to lysine

Radium212 - 16-12-2017 at 05:02

Anyone know how one might convert L lysine hydrochloride to lysine? Perhaps reacting with sodium hydroxide to produce sodium chloride and lysine?
Might this work?

Melgar - 16-12-2017 at 09:14

Water solubility is 1.5 kg per liter, which makes that plan prohibitive. Ion exchange resin columns are often used to separate amino acids like this, but I don't have any experience doing it myself.

EilOr - 17-12-2017 at 05:23

Lysine*HCl is 1.5kg/l, isoelectric lysine 300g/L so in water should work if you're working in concentrated solutions, I don't see why it shouldn't work using equimolar amounts of NaOH to saturated lysine*HCl solution, though it's not the route I would recommend, as it's lossy unless you're doing many hours of workup&recristalliation

EtOH or better MeOH might be a much better alternative to water as NaOH is solouble, Lysine*HCl should be well solouble (741g/l in MeOH, 180g/l in 99% EtOH), Lysine should be quite well solouble aswell, while NaCl isnt (~1.3% in pure MeOH, in EtOH even much less)
So using equimolar masses of NaOH and Lysine*HCl should yield prcp. of NaCl and keep lysine in the alcohol



[Edited on 17-12-2017 by EilOr]

Radium212 - 17-12-2017 at 07:34

Quote: Originally posted by EilOr  
Lysine*HCl is 1.5kg/l, isoelectric lysine 300g/L so in water should work if you're working in concentrated solutions, I don't see why it shouldn't work using equimolar amounts of NaOH to saturated lysine*HCl solution, though it's not the route I would recommend, as it's lossy unless you're doing many hours of workup&recristalliation

EtOH or better MeOH might be a much better alternative to water as NaOH is solouble, Lysine*HCl should be well solouble (741g/l in MeOH, 180g/l in 99% EtOH), Lysine should be quite well solouble aswell, while NaCl isnt (~1.3% in pure MeOH, in EtOH even much less)

So using equimolar masses of NaOH and Lysine*HCl should yield prcp. of NaCl and keep lysine in the alcohol



[Edited on 17-12-2017 by EilOr]

I was thinking along those lines, thanks!