Orange shit while gasing

[methlab]

Hi! During my last HCL gasing, i saw some orange shit clumping on my gasing tube and on my beaker. What was this ?

[chilly_willy]

Its your freebase coming out as oil instead of crystals because you didnt dry the solvent properly.

[Rhodium]

...or you didn't purify the freebase before gassing, so that the impurities react with the acid forming a sticky goo, which sticks to your product.

This symptom is often (incorrectly) referred to as "overgassing", as it tends to manifest itself towards the end of the gassing procedure. The real problem was there all the time though, and should have been remedied by a/b washings and preferably distillation of the freebase before the gassing.

[methlab]

happend during first gasing. did dry the xylene with MgSO4, but maybe not enough. How much CaCl2 should i use to dry the HCl gas? I just used about 1-2g, was this too less?

[Rhodium]

Oh yes, that definitely too small an amount - either bubble the HCl gas through a few cm of conc. sulfuric acid instead, or use as much CaCl₂ as you plan to run HCl gas through it. It is not just about the water absorbant capacity of the CaCl₂, it is also about how fast you're running the gas through it. A small amount may have too small surface area to absorb the gas in the split second it takes for the gas to pass through the drying agent.

[methlab]

I think i blew too mush HCl gas into my xylene solution. First there where some cristalls forming but then it started to clump. It also turned dark orange after 2 seconds or so. This was my first try and i thought i fucked it up, that's why i have discarded (yes, down the toilette) the whole thing... (please don't hit me, now i know this was not a good idea). Next time i will wait for a response before discarding it. But no problem, i'm happy with your answer, because now i know i can make it. This weekend i will do it better. I think i will use my 50cm condenser as a drying tube, will fill it with CaCl2 and attach a hose on top. I will also be very careful with the amount of gas blowing into the solution. I am a newbee and you are a professional, bt i will learn how to o it better. Thank you guys for your help, greetings from europe,

[biffman]

Never discard something just because it didn't work right on the first try.  Usually (or often anyways) it can easily be recovered.  Especially in this case.  All you would have had to do was evaporate off your solvent and do another acid/base extraction then distill again.  Sometimes even just evaporating the solvent will make the crystals  form.
  Now you will have to start from the very beginning.
  You will learn not to immediately dump your failure until you are sure that it is absolutely recoverable.  This goes for saving all parts of an acid and base extraction until you are sure that you have extracted everything and are working with the right layers.  It is always an good idea to save all your washes with solvent separately so that you can late evaporate and recover the solvent.  Saves on cost and environmental damage.

[Bond_DoubleBond]

swim experienced the same thing his first try and has always had trouble gassing when he didn't a/b wash the freebase first.

a/b the freebase and use dry hcl gas and you will be rewarded with beautiful billowing clouds of crystals.

[Glasya]

I have seen this several times and really want to do this on my freebase and extract the freebase into DCM, distill of 90% of the DCM and gas in the DCM, since I am doing such small amounts I’m afraid of losing too much trying to distill the freebase over.

I was wondering is someone could provide a step by step for doing this A/B from the Xylene/Toluene, I can’t image that a 10% HCL would work correctly since 35% NaOH was used. Unfortunately I don’t have anything to check PH.

Any suggestions?

[MarleyBob]

Glasya -

3.5 mls of 10%HCL will neutralize 1 ml 35%NaOH, it's all proportionate.

[cublium]

3.5 mls of 10%HCL will neutralize 1 ml 35%NaOH, it's all proportionate.
Almost,MW of HCl is 36,5 or something and NaOH's is 40.One mole of one neutralizes 1 mole of another.