Author Topic: gassing mdma freebase  (Read 3560 times)

0 Members and 1 Guest are viewing this topic.

bbeeasheets

  • Guest
gassing mdma freebase
« on: September 27, 2004, 04:37:00 PM »
when does a bee stop gassing the freebase/toluene solution? do you just keep gassing until no more precipitate comes out? or is there a certain ph that should be reached? the reason i ask is in my first (and only) mdma.hcl synth, i did it 4 times (the writeup called for 4). but the 4th gas didn't appear to have much less precipitate than the others, so i am wondering if i threw out a bunch of product.

indole_amine

  • Guest
pH and gassing
« Reply #1 on: September 27, 2004, 10:32:00 PM »
If you gas small portions, then filter and then gas again, you should repeat the process until nothing is formed anymore. DON'T THROW AWAY ANYTHING before gassing produces no more crystals!

If you gas all your freebase MDMA at once (and not with small portions of HCL gas), you should do so until pH 5 is reached. To measure this, you can use a electronic pH meter with glass electrode, or you can put a drop of your gassed toluene/freebase solution on a pre-wetted indicator strip (imprecise, but works too).

And sometimes the gassed solution only becomes cloudy at pH 5, no crystals appear immediately: then cool your toluene/freebase for several hours, maybe add some dry acetone - the crystalline amine hydrochloride will slowly precipitate on the walls and bottom of the flask.
Maybe you should try adding acetone/cooling with your already gassed solution, too - who knows, maybe there is still something in there!?

indole_amine

hypo

  • Guest
incredible
« Reply #2 on: September 27, 2004, 10:50:00 PM »
> i did it 4 times (the writeup called for 4). but the 4th gas didn't appear to have
> much less precipitate than the others, so i am wondering if i threw out a bunch of product.

and if the writeup called for jumping out of the window?
*shakes head in disbelief*

oh, and for fucks sake reuse your solvents!!


hypo

  • Guest
wah?
« Reply #3 on: September 27, 2004, 10:56:00 PM »
> To measure this, you can use a electronic pH meter with glass electrode

a pH-meter in anhydrous toluene? sorry, but i dont buy this.
what's so hard about gassing until the solution is very thick or no more salt is crashing
out? stop making a drama about something as trivial.


indole_amine

  • Guest
??
« Reply #4 on: September 28, 2004, 01:17:00 AM »

indole_amine

  • Guest
questions
« Reply #5 on: September 28, 2004, 01:43:00 AM »
Since this is the "Newbee" forum, I feel free to ask:

The talked-about pH meter (brand is OrionResearch, not even a newer one!) is capable of measuring accurately in nonpolar solutions, as long as the probe is rinsed properly (and not dry of course!).
At least, nonpolars have a pH with it (depends on what is dissolved in it of course).
The probe has a ceramic diaphragm and Ag/AgCl electrolyte (nothing special).

I don't see why a nonpolar solvent with a small percentage of H2O shouldn't be able to carry enough ions to allow for proper pH measurements?

And what is the phenomena called "overgassing", since it was just pointed out that "too much" doesn't exist when gassing amine/nonpolar solutions with HCl?

Last one: I always thought that for crystal formation, the molecules would need a possibility to move to their destined place in the crystal matrix, and this needs some solubility and some time (we all know this). But if the solvent is absolutely anhydrous (i.e. absolutely non-polar), these two requirements are not met, and the result will be an amorphous mass, rather than crystalline - now what was wrong with this?

indole_amine

Rhodium

  • Guest
Overgassing etc.
« Reply #6 on: September 28, 2004, 02:48:00 AM »
what is the phenomena called "overgassing"

"Overgassing" is the phenomenon of red/brown/amber oil/wax forming in a non-polar solution when introducing more than one equivalent of HCl gas into a solution of an amine freebase. It is caused by impurities polymerizing (acid-catalyzed condensation) and oiling out of these compounds (due to the solvent becoming more polar from dissolved HCl) due to lessened solubility.

With really pure, fractionally distilled freebase in a pure, inert solvent the "overgassing" phenomenon seldom appear, unless enough acid is introduced to decompose the amine.

I don't see why a nonpolar solvent with a small percentage of H2O shouldn't be able to carry enough ions to allow for proper pH measurements?

Solubility of water in toluene, 0.033% at 25°C. Ref:

http://macro.lsu.edu/howto/solvents/toluene.htm



As far as I know, it hasn't got to do with the solubility of ions in the solvent, but rather that the definition of pH requires the measurement to be made in an aqueous solution. If you insert a wet pH electrode in a non-polar solution, you aren't measuring the pH of the non-polar solution, but rather the pH of the aqueous film on the electrode surface (and that isn't the same thing).

I always thought that for crystal formation, the molecules would need a possibility to move to their destined place in the crystal matrix, and this needs some solubility and some time (we all know this). But if the solvent is absolutely anhydrous (i.e. absolutely non-polar), these two requirements are not met, and the result will be an amorphous mass, rather than crystalline

For all practical purposes, you need to recrystallize the precipitate anyway to get proper crystals. Also, there are several steps inbetween "amorphous masses" and "crystalline solids", and a few reasons why follows here:

Reality vs. Ideal theoretical approximation
Anhydrous toluene isn't absolutely non-polar. Toluene is a non-polar solvent.
Amine salts doesn't have zero solubility in toluene. Salts aren't soluble in toluene.
100-10000 µs pass before formed salts crash out. Salts precipitate immediately when amines are gassed with HCl.


hypo

  • Guest
exactly
« Reply #7 on: September 28, 2004, 09:40:00 AM »
> If you insert a wet pH electrode in a non-polar solution, you aren't measuring
> the pH of the non-polar solution, but rather the pH of the aqueous film on the
> electrode surface (and that isn't the same thing).

exactly. the way i see it: the "effective activity" (i call it that way: the activity
if that was an aqueous solution) of protons in toluene is totally different from protons
in water. then having a water film makes this even worse, because you have phase transition
phenomenons. now the freebase is probably mainly solvated by toluene, so the activity
of the protons solvated by water isn't even interesting and finally the pKb of the freebase
in toluene is probably completely different from the (theoretical) pKb in water. so why
would you want to adjust it to a "pH" of 5? what you really want is to make it acidic,
and that is seen anyway when the salt crashes out. of course you did distill and weigh
the freebase, so you didn't use too much toluene.

> Reality vs. Ideal theoretical approximation

hehe... that made my day  ;D


hest

  • Guest
pH paper
« Reply #8 on: September 28, 2004, 09:47:00 AM »
Wondering wath's wrong with wet pH paper, the only way to mesure pH in a polar solvent.

indole_amine

  • Guest
why pH 5
« Reply #9 on: September 28, 2004, 05:50:00 PM »
"so why would you want to adjust it to a "pH" of 5? what you really want is to make it acidic,
and that is seen anyway when the salt crashes out. of course you did distill and weigh
the freebase, so you didn't use too much toluene."



The reason is that overacidification can happen, and results in the impurities crashing out as waxy/oily substances (if there are any). Which complicates proper purification. pH 5 is a slightly acidic environment, but not too acidic for the above to happen.
Someone asked about a specific pH, and I told him.

BTW "pH" just means reverse logarithm of the concentration of h+ in the medium. No matter if it is nonpolar or polar. Therefore all solvents that are able of dissolving acids do have a pH.

Hypo, maybe you have no problems determining the time when to stop gassing - but take into consideration that not all bees are as experienced as you are.

Did it really make your day to have confused a newbee about the pH he has to reach when gassing?

Better start explaining why Bbeeasheets could've used too much non-polar (I won't)  ;) !

indole_amine

hypo

  • Guest
no sense
« Reply #10 on: September 28, 2004, 06:40:00 PM »
> The reason is that overacidification can happen, and results in the
> impurities crashing out as waxy/oily substances (if there are any).

well, they shouldn't be there in the first place. i doubt that those impurities
crash out only on overacidification - i still believe that they're amines and
at least some of them will come out with your first gassing.

> BTW "pH" just means reverse logarithm of the concentration of h+ in the medium.
> No matter if it is nonpolar or polar. Therefore all solvents that are able of
> dissolving acids do have a pH.

your pH-meter will definitely NOT show "the reverse logarithm of the concentration of h+
in the medium". and whatever it shows and whatever it really is is unrelated to the case
of an aqueous solution. ergo your number is completely meaningless. why would you make
someone buy a completely useless pH-meter for lots of money? as hest noted, a drop on a
wet pH-paper will be just as useful.

> Did it really make your day to have confused a newbee about the pH he has to
> reach when gassing?

no, i laughed about rhodium's sometimes hilarious (imho) writing style.


indole_amine

  • Guest
no sense - why?
« Reply #11 on: September 28, 2004, 07:06:00 PM »
You can doubt whatever you want - still overgassing can happen, and gassing to pH 5 (measured however you like) is the way around this.

About pH of solutions you should check

http://www.google.com/search?hl=en&lr=&ie=UTF-8&oi=defmore&q=define%3Aph



One definition of "pH" I found there, being rather concise:

"A logarithmic scale for expressing the acidity of a solution. pH is an abbreviation of "potential of hydrogen" and is in effect a measure of the amount of hydrogen ions, expressed on moles per cubic decimeter (10m x 10m x 10m, or 1000m3) The pH scale goes from 0 - 14. A value of 7 is neutral (i.e. neither acid or alkaline). Values below 7 indicate an acid solution, whilst values greater than 7 indicate an alkaline solution. For every increase in pH of 1.0, the alkalinity increases ten fold (and for every decrease of 1.0, the acidity increases ten fold. Therefore a solution at pH8.5 has ten times less acidity of a solution at pH7.5. Rapid changes in the pH of the water can stress fish (and also other organisms such as bacteria in biological filters). "

And another one, being more scientifically correct:
"(chemistry) p(otential of) H(ydrogen); the logarithm of the reciprocal of hydrogen-ion concentration in gram atoms per liter; provides a measure on a scale from 0 to 14 of the acidity or alkalinity of a solution (where 7 is neutral and greater than 7 is acidic and less than 7 is basic)."

And this one is from our beeloved US government:
"Represents the negative base-10 logarithm of hydrogen ion activity of a solution in moles per liter; a measure of the acidity (pH less than 7) or alkalinity (pH greater than 7) of a solution."

Please note the word "solution" is used in all definitions - not "water"!

Another one, also from a government institution:
"A measure to indicate an acid or alkaline condition; pH values can range from zero (extremely acidic) to 14 (extremely basic or alkaline). pH measurements are based on a log scale such that pH 6 is 10 times more acidic than pH 7 (neutral) and pH 5 is 100 times more acidic than pH 7."

(all those definitions can be found via the page I linked to)

(and if I had suggested the buy of a pH/mV-meter, I would not have mentioned that strips can be used too)


indole_amine

hypo

  • Guest
great!
« Reply #12 on: September 28, 2004, 08:16:00 PM »
now that you know what pH is, google for glass electrode and learn why
when your thinggy shows 5, there won't be 10^-5 mol/l protons. (btw: did you
notice how the definitions you quoted were contradictory?  :) )

> You can doubt whatever you want - still overgassing can happen

not if you do it right

> and gassing to pH 5 (measured however you like) is the way around this.

you can't gas to pH 5, because you can't easily measure pH in toluene.  ;)

the right thing to do is: distill, dissolve in not too much of toluene and then
gas until thick, filter, repeat until it doesn't get thick anymore. or save yourself
the hassle and user other methods.


indole_amine

  • Guest
no measurement doesn't mean no pH...
« Reply #13 on: September 28, 2004, 08:42:00 PM »
When my thinggy shows 5, there won't be 10^-5 mol/l protons; but rather exactly enough free protons to result in the number "5" when calculating the inverse reciproque logarithm of their overall number per liter.

"you can't gas to pH 5, because you can't easily measure pH in toluene"

Are you saying that toluene cannot have a (reciproque logarithmic measured) concentration of H+-ions per liter??

(strange, HCl is soluble in toluene, and dissociates into Cl- and H+ upon dissolution. And you say that there are nevertheless no protons present in gassed toluene?)

Or do you mean that you are too retarded to measure the pH while gassing at the same time, and therefore YOU can't gas until a certain pH is reached??  ;D

What does a prewetted pH strip show when toluene is dripped onto it - the pH of the small water film that it is enclosed in, maybe?

Why should someone use wet pH strips at all - since you can't measure the pH of nonpolars and simply have to gas without checking? Hm?

Show me a link to somewhere where it is said that glass probes with Ag electrodes and potassium electrolyte aren't able of measuring in other media than water, and I will believe you.

If you do drive right, car crashes are impossible.
Still thousands of people die each year in traffic accidents, inside their own cars.
Would you say that driving carefully is not needed, because crashes are impossible under certain conditions??

I fail to see the motivation behind your posts, sorry.

hypo

  • Guest
the only retard here is you
« Reply #14 on: September 28, 2004, 08:59:00 PM »
what part of "the H+ concentration in the water film will have nothing to do
with the H+ concentration in your toluene and thus your pH meter will show a
meaningless value" do you not understand?

> I fail to see the motivation behind your posts, sorry.

prevent naive newbees from doing useless stuff.


indole_amine

  • Guest
but pH strips show a meaningful value, hm?
« Reply #15 on: September 28, 2004, 09:10:00 PM »
And the wetted pH strip paper has the magic ability of adjusting the concentration of its protons according to the liquid that is being dripped onto it?

Sorry, but I don't take that. Luckily I don't have to.

hypo

  • Guest
of course not!
« Reply #16 on: September 28, 2004, 10:10:00 PM »
actually a pH strip doesn't give you a value at all, it only tells you
neutral/slightly acidic/strongly acidic.

but the whole thing is useless anyway. (yeah, gassing with HCl gives an
acidic solution. d'oh.) if you do it like i tell you, then overgassing
(if that actually really exists) won't happen.


indole_amine

  • Guest
what about narrow range pH strips?
« Reply #17 on: September 28, 2004, 11:56:00 PM »
Now it starts getting funny...

There are so-called "narrow range pH strips" out there - they give you a value within 1/10th pH exactness...

And even normal litmus paper (which you seem to talk about) displays whether there is an excess of free protons or not.

Since it has to be prewetted: how can this measurement be reliable? According to what you just said, the pH of the water on the strip has got nothing to do with the pH of the nonpolar being dripped onto it...

Personally, I wouldn't gas at all BTW - better use pregassed solvent and add that to the amine/solvent soln., or check Bandil's new salt preparation method with molecular sieves (really rocks!).

indole_amine

Rhodium

  • Guest
Is it so hard to admit that you're wrong?
« Reply #18 on: September 29, 2004, 04:28:00 AM »
There are so-called "narrow range pH strips" out there - they give you a value within 1/10th pH exactness...

These will not give a reliable figure either, when wetted and put into a non-polar solution, only in water. The best value you can ever get is what's said in

Post 533616

(hypo: "of course not!", Newbee Forum)


Electronic pH meters are calibrated for use in aqueous solutions, and will give erroneous values in other solvent mixtures.

Show me a link to somewhere where it is said that glass probes with Ag electrodes and potassium electrolyte aren't able of measuring in other media than water, and I will believe you.

"Glass membrane pH probes rapidly dehydrate and lose response in non-aqueous solutions"

Source:

http://multitrator.com/downloads/Multitrator_Thermometric_Titration_Introduction.ppt



"...precludes titration in non-conducting environments, for instance, many non-aqueous solvents.
Probes such as pH electrodes perform very poorly under such circumstances."


Source:

http://multitrator.com/FAQs.htm