If you are like me and hate having to generate HCl gas on your bench, waste large amounts of expensive organic solvents to claim small amounts of hydrochloride, and/or titrate with concentrated aqueous HCl, here’s a very neat trick that my good friend Xtaldoc was kind enough to share with me. I haven’t seen him post here lately but I wanted to report great success with his technique and give him the props that he deserve. Most probably some of you already use it but interestingly enough I don’t see it that often being mentioned.

It involves generating in situ HCl gas in anhydrous acetone, ether or any solvent of choice. I prefer acetone by far. Basically appropriate amounts of NaCl and H2SO4 are mixed in the appropriate amount of dry solvent in order to saturate it with dry HCl. Once the addition is complete, the solvent is simply decanted and used as is. The freebase is simply dissolved in a mimimum of non-acidified solvent and the fraction is dripped into the HCl/solvent mixture to make the hydrochloride salt crash right away. The latter is filtered and wash with cold acetone.

Swix has created anhydrous HCl solutions in Et2O, MeOH, EtOH, i-pr-OH and acetone without bubbling HCl gas into the solvent or worrying whether his solvent(s) or HCl gas was dry enough for use. When employing any of the solvents listed, pre-charge the flask with sodium chloride and slowly add 92% H2SO4 dropwise while stirring in an ice/salt bath. The H2SO4 can be diluted in the solvent (if miscible) prior to addition, for a more gentle evolution. Use the stoichiometric amounts of the salt and acid calculated to yield sodium suphate. This substance is a dessicant and will absorb most all water in the solvent. Take care to look up how much HCl your solvent will hold at room temp and use solvent in an excess of what is required to dissolve the amount of HCl yoou'll generate in your set-up. Keep everything chilled throughout the whole process, then decant carefully off of the solids in the flask. Can filter if necessary. Keep well sealed or stoppered and chilled prior to use. To determine strength; titrate against a known base, etc. Just thought I'd toss this in the mix of "Tips & Tricks" for this thread: Peace

HCl gas
Solubility in methanol (g/100 g soln):  54.6 (-10°); 51.3 (0°); 47.0 (20°); 43.0 (30°); in ethanol:  45.4 (0°); 42.7 (10°); 41.0 (20°); 38.1 (30°); in ether:  37.52 (-10°); 35.6 (0°); 24.9 (20°); 19.47 (30°).


127 mL Acetone, 53 grams pure NaCl, and 45 grams (24.5 mL) 98 % H2SO4 will roughly create a 33 g HCl/ 100g Acetone.

It is best to use it right away and keep it chilled. You are right.

Aldol condensation of acetone can be easily controlled with temperature.

Sounds good, but does the sulfuric acid in the acetone present a problem when you try to recrystallize the salt?

i like organic salts

it depends on the pka of the base and the acid when considering the stoichoimetry you employ you can always do 1-1 stochiometry in any case.
basically like this;
 you weigh the base determime the amount of acid to use and the dissollve the acid in ethanol or isopropanol using the minmum that wil disollve the salt at elevated teperatures.
mix together and precip by adding 5 volumes of ether or acetone in the cold.

something like dmt is a stronger base so if you had say citric acid i could probably get away with 2/1 stoichoimetry citric to dmt.
mda on the other hand is'nt strong enough of a base to deprotonate citric acid's 2nd and 3rd proton.

This is the only thread where "fumaric" shows up, but I read elsewhere that DMT fumarate was FDA approved for injection (for research). I don't know where I would find fumaric acid, but it seems like other organic salts should work well too.

you have to rinse the excess oxalic with acetone i even used ethylacetate, ethyllactacte or recrystallize it two recrystallizations cleans it up i just don't like federal fuck me in the ass reaction soup sitting in the freeze for days.

Thanks for the links - especially the second one about the FASA tek for DMT - I had no idea that was posted.

one thing that is very rarely discussed is picorates. I belive these are not soluble in water so all one has to
do is add picoric acid to a solution of freebase to percipate a pure salt. this may not be so good for consumption
but at least it gets the stuff out pure and storable.

Hmm  you must mean picric acid, picrates are indeed insolubles but gotta remember that picric acid is a powerful explosive.

Hmm  you must mean picric acid, picrates are indeed insolubles but gotta remember that picric acid is a powerful explosive.

Picric acid itself is insensitive to shock and does not DDT, but certain picrates are very sensitive to shock and heat.