Author Topic: Crap. Newbee finds trouble with rxn  (Read 2316 times)

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Relux

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Crap. Newbee finds trouble with rxn
« on: March 26, 2004, 12:41:00 AM »
So yeah, let's say one was to mix up a rxn with reagents in the ratio 1.5:1.25:1.5 Mbrp:Pseu:I with and extra molar equivalent of iodine because the free base was used, along with .8mL of water per g pseu. So this one then slowly heating the rxn finds that a big black glob forms that barely dissolves with the upmost trouble and above all the reaction is so thick that the stirbar almost refuses to spin. Ok, this has got to be an easy one so here goes...
-What the fuck is the greasy insoluble black glob that almost seems to float in the center of the flask?
-How does one rid one's self of this glob?
-why the hell don't I hear about other people getting these, it happens every fucking time one tries.
-should this wet reaction be gassing off and fuming like the drier ones?

I'll leave it at that, then hopefully they may be answered...

geezmeister

  • Guest
black glob in water?
« Reply #1 on: March 26, 2004, 09:35:00 AM »
Do you have a black glob in water? Is that what it is "almost" floating in? You will sometimes see a black glob like you describe if you mix pseudo, I2 and dilute hypophosphorous acid; this glob will dissappear with swirling as the solution is heated and HI produced. You won't have time to see this glob if you use concentrated hypo acid.)

Your glob of I2 and rP mixed together is either reacting very slowly in the presence of the water and E, and needs more heat to kick it off, or your red phosphorous is not up to par. There is a good chance your mbrP is not clean enough (or not all red Phos) if no exothermic reaction is taking place with that much red phos in the mix.


midway

  • Guest
Question..did the flask feel warmer when rp...
« Reply #2 on: March 26, 2004, 02:42:00 PM »
Question..did the flask feel warmer when rp and i2 were added together? Was there any kind of reaction at all taking place? One should have to let the reaction slow down by itself some before having to add heat to keep it going at a stable pace...if there was barely any reaction to beging with, then youve got problems with your RP.
much like he said.

wareami

  • Guest
Ratio...
« Reply #3 on: March 27, 2004, 09:49:00 AM »
Let's get this str8.
How clean is suzy first off.
Secondly, the adjustment of I2 is understood, but why the excess MBRP.
Maybe I'm not reading this ratio right as it's written.
But there seems to bee a chemical imbalance here. ;)
The self diagnosed continual rxn dilemma would be easily fixed if you'd run the salt instead of the FB, thereby giving you no excuse for running ratio's that don't fit threw the suggested window of success.
If using FB,(greasyblob in aqueous solution??? ;D ) Ibee would definately drop back on the h2o to .5ml per g of E.
If AWE the reactants won't intimately combine, blame it on that hor-ratio :P


Relux

  • Guest
Crap reaction continued
« Reply #4 on: March 27, 2004, 02:10:00 PM »
Starting with a reply for geez:
Yeah, the blackish reflective glob was in the water but didn't seem miscible. It seemed to float in the middle of the reaction as if there were three phases. I added the iodine in two different allotments, the first created the glob, dissolved slowly, heated the reaction a bunch and produced a yellowish solution above the phos. The second addition locked it all up into that mass with only a dark brown (free iodine-like) aqueous layer floating on top, the mass not dissolving. I ended up cutting the reaction in half removing the majority of the glob and heating at 100C for 18 hours. When the flask was viewed after this time there was no black glob but the solution was deeply reddish brown.
    I truly believe this to be a problem with the phosphorus. The stuff had been through a reaction before (one that didn't end up working either, but I've definitely progressed a lot since then in knowing what I'm doing, which obviously I still don't). Not only that, but the previous reaction had unclean psue in it that was so waxy and nasty that I believe it to be the ill fate of the other reaction. That time the phosphorus and iodine reacted so vigorously though that my house filled with HI gas (ahhh joint didn't seal!), but that was a dry reaction. And with mbrp there is no telling when the phos is gone and only glass, MnO2, iron oxide and all the other crap remain. In other words I think my phosphorus must have been dirty from the previous reaction and mostly used up resulting in an incomplete formation of HI which caused the ending reaction mix to be so red.
    Also, I have never done a wet reaction before (well, not many reactions at all actually) and so there is a chance it needs more heat than the dry reaction to get the I gone. I never had the reaction get higher than 110 with the majority of the steaming not quite boiling reflux happening just around 100C.

Midway: Yeah the flask felt warmer with the initial addition of I2, but didn't seem to even care that I added the second allotment and did not heat any further.

Wareami: The psue is grade A pure as fuck, triple recrystallized, triple boiled, acid based and more. The melting point of both the salt and freebase are right on and the crystals are like glass.
    When I added more I2 to make up for the neutralization, I assumed that the addition of iodine would mean an addition of rp to change it to HI. (one thing I left out, that I only discovered later, is that I was using a ratio of psue to everything else based on it's weight as a salt, but I used freebase and therefore too much. Damn!) I hear you about using the salt instead of freebase. Freebase sucks and never again. The exothermic reaction of the first addition of iodine was stopped upon addition of the freebase and didn't continue after more I2 was added. I added the first allotment of I2, then the psue, then more I. (enough HI to form the acid salt of psue, then I dissolved psue in the acid, then created more acid (this was the thought anyway)). I don't think that the greasy blob was the freebase because after it's partial removal and the post wish-it-were-a reaction I obtained butt loads of crystals in return that I haven't worked up that much but appear to be only psue once again, unreacted. The blob was the color of what you would imagine liquid iodine would look like, and was semi reflective, almost metallic.

My whole reason for using the freebase to begin with is that I've read in the past that it reacted with vigor and I was looking forward to that. I also figured that having a system with no Cl- would make cleaner product quicker. In the future I'm going to try the HI salt in the reaction with a slight alteration of the weight ratio to make up for the heavier iodine atom.

Last but not least, when adding base to the reaction mix in the end, there was an intense smell of the sought product. But, to my dismay, there was also a mass of... needles?? I got plates for psue freebase before... and meth freebase is an oil... what the fuck? anyway, I extracted some of the reaction with et2o, washed it with water, dried with Na2SO4, and attempted to gas the product out with HCL and received no precipitate (maybe I didn't do this for long enough because I ended up adding water, shaking, extracting water and the water was slightly alkaline). Acid water was then added for the fuck of it, which dropped all the brownish color that had transferred to the ether from the reaction into the acidic water. These extracts were dried to obtain an almost reddish black product that when recrystallized 3 times in acetone yielded off white crystals with a melting point 169-172.5 and the smell of honey. The only problem being that the huge mass of crystals found when basing the reaction did not dissolve easily or at all in et2o. I have not yet assayed this material, and don't plan on it either. Maybe if I had an IR spec...
Overall yield: probably about 1%. Fuck.

SHORTY

  • Guest
Definetly the rp
« Reply #5 on: March 27, 2004, 04:43:00 PM »
It sounds to me like your iodine was the blob and was not dissolving due to insufficient amount of phosphorous.  Judging by your description of the mbrp being used once in a dry rxn i would say most of what you had left of the mbrp was not rp and if there was rp left it was coated with the gaak from the dry rxn.


wareami

  • Guest
Nothing ventured, nothing gained.
« Reply #6 on: March 27, 2004, 09:44:00 PM »
Once UPon a Time
For several reasons, bees eventually come to realize that rarely do two rxns run identical. The main reason:
The variances are too numerous to handle a slight adjust an-E-ware without effecting one thing or another.
The most basic suggested guidelines are just that. Basic! 50 different write-ups or discussions addressing the various aspects and detailing unique variables introduced on a whim, cannot possibly list a solution for every problem created by the end user's trigger-happy slight-adjust hand.
Relux: Hindsight is 20/20 and without it we'd all bee blind.
Every determined bee has a little goofball on his shoulder that screams out "Don't Do It" at every questionable decision making fork in the road.
You shoulda listened to yours when it smacked ya upside the head with it's pitchfork and said that the RP might be questionable since it got gangbanged during the last rxn.
Always remember the saying:
"If there is the slightest iota of doubt concerning any of the reactants effectiveness/cleanliness, don't proceed until the visioncorrecting goofball stops pokin yer ass :P

Now...a few concerns.
What's UP with tweekin the ratio in order to snag the goodz sooner?
Two things determine complete reduction.
HI concentration, while it plays a large role,  isn't a first choice. Surely that little goofball chimed in at that thought-provoking junction...ehh? :)
Temp and hydration level can be tweeked in order to shorten cooktime at a price.
Three prices actually.
Purity, yield, and quality.
They all deal with the "degree of doneness" factor which can be deceptive and misleading if only considering the "Success versus Failure" scale of calculation.
All three are governed by cooktime and directly associated with reactant concentration, rxn rate/heat of rxn laws, collision theories, second order rxns...etc...etc.

•Purity, as in substituent impurity by-products initially created in-situ, in HI rxns, and found to be present in product considered to bee done by popular standard measures when pulled prematurely without allowing the rxn to fully run it's course.

•Yield, as in percentage of unreacted vs fully reduced....minus the weight of impurities.

•Quality, as in the sum of all factors considered and exactly where, when, and how many compromising tweeks were employed before the shoulder dwelling goofball threw down his pitchfork in frustration screaming "I GIVE UP!", just to see what kind of rxn he could get out of ya.... ;D  

And They AWE Lived Happily Ever After


geezmeister

  • Guest
Sounds like...
« Reply #7 on: March 27, 2004, 09:55:00 PM »
Sounds like the phosphorous was the culprit. The previous reaction left it gakked up and it could not react in the condition it was in at the temperatures you ran the reaction. Your description of what the second portion of I2 did in the reaction is a good description of what happens when you do not have enough active phosphorous compound present to make HI.

I've had that happen when I thought the rP was clean, and it was always a hard lesson to learn and relearn. You should clean your phosphorous before reusing it, and may want to test fire a little of it with iodine to see how they react together.

Don't be too shy about using freebase pseudo. It reacts well. Just remember that it converts in the reaction to pseudo HI and that is an exothermic reaction. Either slow the HI production down, or make the HI and then add the pseudo a little at a time until all is added before proceeding. Yields from freebase pseudo were usually higher than those with the salt form, because the freebase was almost always cleaner. Really clean pseudo HCl will react as well and yeild as well as freebase pseduo, in my experience.


lemuralia

  • Guest
how clean is your psuedo?
« Reply #8 on: March 28, 2004, 07:13:00 PM »
how clean is your psuedo?

sounds like PEG.I use to get black blobs in my hypo rxns when I didnt clean the pill mass properly.Soaking the mass in xylene gets rid of it.

SHORTY

  • Guest
You should read the whole thread
« Reply #9 on: March 28, 2004, 07:29:00 PM »

The psue is grade A pure as fuck, triple recrystallized, triple boiled, acid based and more. The melting point of both the salt and freebase are right on and the crystals are like glass.