Author Topic: MM's Al/HG Condenser H2O Temperature  (Read 5328 times)

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Bubbleplate

  • Guest
MM's Al/HG Condenser H2O Temperature
« on: October 02, 2002, 05:58:00 AM »
SWIM has well water that is a constant 11 C. Is 11 C. cold enough to run through the Allihn Condenser for the MM Al/Hg Reduction?
SWIM has used this setup for other refluxes, etc. and water always seemed cold enough.

If they drive God from the earth, we shall shelter Him underground - Dostoevsky

pickler

  • Guest
You want your water as cold as possible, that's ...
« Reply #1 on: October 02, 2002, 06:30:00 AM »
You want your water as cold as possible, that's why it calls for ice. Once you run the synth, you'll understand why you need ice cold water.

I went into the business for the money, and the art grew out of it.-Charlie Chaplin


weedar

  • Guest
A bucket
« Reply #2 on: October 02, 2002, 07:20:00 AM »
A bucket filled with ice and then filled with water?
Throwing in more ice if needed.

Weedar

Save the Temporary Couch! And whales.

Chromic

  • Guest
Cold water is fine
« Reply #3 on: October 02, 2002, 08:05:00 AM »
Cold water is fine if you don't recirculate... the reason MM calls for ice is because he uses a bucket to recirculate water and it'll eventually heat up the water.

Diggity

  • Guest
I disagree chromic. YOU WANT THAT SHIT ICE ...
« Reply #4 on: October 02, 2002, 09:48:00 AM »
I disagree chromic. YOU WANT THAT SHIT ICE COLD!!! Trust that. Even with (2) .99c bags of ice, one may end up with a little reflux escaping.

The amount of ice needed will also reflect how fast the addition is done. Swim likes a fast addition, so he uses HUGE bags of ice, freezing fucking cold. Even then, on occasion, he has to stop/slow the addition as reflux is noted creeping up the condensor.  Cold water from your faucet will not cur it, unless you wanna spend a good hour and a half adding your goodies.

& I'm, somethin of a phenom, 1 puff of da cron, I'm un-stopable.   
 

Bubbleplate

  • Guest
Well, has anyone actually measured the temp
« Reply #5 on: October 02, 2002, 10:41:00 AM »
of H2O re-circulating through Ice Bucket? If it isn't in the 4 or 5 C. range, then I think 10 or 11 well water and an 8 Bulb Allihn may be OK....

If they drive God from the earth, we shall shelter Him underground - Dostoevsky

Osmium

  • Guest
If your reaction is running so hot that it stinks ...
« Reply #6 on: October 02, 2002, 10:59:00 AM »
If your reaction is running so hot that it stinks up your room then you should slow down somewhat. Can't hurt to cool the flask either in that case.

But you are missing the point, you guys should reduce the MeNH2 separately from the ketone, suddenly th reaction will be MUCH more controllable and yields will usually go up too.
Even if that way is somewhat wasteful on the nitromethane, which reagent is cheaper and easier to obtain? MDP2P or nitromethane???
So there. Maximise your yields dammit!

I'm not fat just horizontally disproportionate.

goiterjoe

  • Guest
ice isn't needed
« Reply #7 on: October 02, 2002, 03:54:00 PM »
you guys should really consider slowing down your addition rate.  Cold water with no ice works just fine if you use a lot of it for recirculation and use a reasonable addition rate.


All paths are the same: they lead nowhere

Bubbleplate

  • Guest
Osmium. What do you mean by " reduce the MeNH2"
« Reply #8 on: October 02, 2002, 05:30:00 PM »
separately from the ketone? Are you saying add the Nitro first, or actually do a separate reduction of the Nitro with Al/Hg, isolate and then use the Methylamine directly with Ketone???

If they drive God from the earth, we shall shelter Him underground - Dostoevsky

wyndowlicker

  • Guest
Quick additions!
« Reply #9 on: October 03, 2002, 03:54:00 AM »
Swiw would like to add a few words here.!A 1 pound bag of ice cuts it for swiw.There should bee no reflux escaping at all if you dont do you addition in 4 minutes.Swiw makes sure his addition is no faster than 5/8th the rate of reflux returning to the flask.Thats about 2 drops per second.Startwith 1 till it gets going.Swiw finds if the addition is too fast Your sludge thickens and stirring is inhibited.Leading to a need for addition of MeOH.Perhaps with a 5-600MM reflux column can handel those quick additions,But swiw doesnt feel safe going that fast.Why rush it 30 minutes.Swiw never broke the rreflux rate during addition and had terrable yields.Wont bee doing that again. :P

Counting starts by candlelight all are dim ,but one is bright.-GD

Bubbleplate

  • Guest
Well, Here's The Lab Notes:
« Reply #10 on: October 03, 2002, 06:14:00 PM »
SWIM decided to try the Ice Bucket/Recirculation to "bee on the safe side". 8 lbs. ice in 5 gallon bucket. Halfway through the MM Al/Hg ketone addition, all the ice had melted. SWIM decided to switch over to straight well water from faucet, just as reaction started to really "take off". Turns out methanol vapors never got much past the 3rd bulb of an 8 bulb Condenser, and reflux was "pouring like rain" from bottom. Looks like 12 C. H2O is just fine with 2K ml Flask and 8 bulb Allihn.
BTW, the actual reaction temperature peaked at 71 C., and stood at 65 C. throughout most of reaction. Took a long time to come down to 50 C.


If they drive God from the earth, we shall shelter Him underground - Dostoevsky

lab_bitch

  • Guest
I was under the impression that adding your ...
« Reply #11 on: October 04, 2002, 11:05:00 PM »
I was under the impression that adding your reactants faster gave better yields.  Personally, I have run the reaction with PURE ketone and can never get close to Baalchemist's 30g MDMA/30g ketone.  Mabey my aluminum sucks.  I usually add the reactants in about 15 minutes and get 20g MDMA/30g ketone.

goiterjoe

  • Guest
don't mix them
« Reply #12 on: October 05, 2002, 12:14:00 AM »
you can get gram for gram yields by adding your nitro first as fast as you can, letting it settle back down some, and then dump your ketone in wholesale.  27g ketone in, 27g crystal out.

All paths are the same: they lead nowhere

lab_bitch

  • Guest
Damn! I'll give it a shot.
« Reply #13 on: October 05, 2002, 11:40:00 PM »
Damn!  I'll give it a shot.  How much HgCl2 to you use per gram aluminum?

Diggity

  • Guest
I was under the impression that adding your ...
« Reply #14 on: October 06, 2002, 01:21:00 AM »
I was under the impression that adding your reactants faster gave better yields.

I agree, it's true, although, joe has me very excited over here.. Gram for gram? Eye for eye? Joe? Say it again man!? Is it really so?

Swim has added 3/4 his nitro first before and hasn't been granted g/g access.. Im sure 3/4 or 4/4 wouldn't make a world of difference at that point, though he will try again. G/G on a a foil rxn would be very nice!  :)  

Shal swing all, then all.. interested..  :)  I also have a headache.

& I'm, somethin of a phenom, 1 puff of da cron, I'm un-stopable.   
 

goiterjoe

  • Guest
that's only 78% molar yeilds.
« Reply #15 on: October 06, 2002, 02:26:00 PM »
yes, gram for gram can be seen from a nitromethane reduction if the nitromethane is allowed to reduce first to methylamine.  The reaction should have a small amount of water added to it, and that will make it run a LOT hotter than if it is anhydrous.  it will also make a serious difference in yields.  Another yield inhibitor is ketone purity.  If you're not getting clean fractional separation when you distill your ketone, then your yeilds will suffer as well.  The last thing that will help is the basification process.  Don't basify the reaction wholesale, but instead filter out the aluminum sludge and back wash it with some methanol and basify the extracts.  It is a lot cleaner and easier, and can make it a lot easier to get good NP separation.

All paths are the same: they lead nowhere

Protium

  • Guest
Not exactly
« Reply #16 on: October 06, 2002, 04:17:00 PM »
I was under the impression that adding your reactants faster gave better yields.

While in many cases this is do-able, just dumping in the ketone wholesale really is not the way to go, and will most often in larger reactions stink up your workspace.  The devil is in the timing, slower titration in the correct timeframe would be higher yeilding than a wholesale dump, as it is prefferable to have a large excess of the methylamine to the ketone, however many bee's who set their addition funnels to a slow drip rate and allow the addition to continue after the amalgum is spent, wind up with a lot of unreacted ketone in the mix and the yeild is shit.  It's all about the thickness of the aluminum and the timing of the amalgum, thicker aluminum and slow titration is ultimately higher yeilding.  However, slower drip rates are not always an option for those who opt to use aluminum foil.  This is balanced somewhat, however, by a pre-addition of the nitromethane to facilitate the excess, although I have found as a general rule slower additions when properly timed are considerably higher yeilding, and easier to control.

Moral to the story : timing is everthing

Pr(+)tium

lab_bitch

  • Guest
How to basify and filter a nitro
« Reply #17 on: October 06, 2002, 07:11:00 PM »
goiterjoe:  How much water is "a small amount"?  How much HgCl2 do you use per gram of aluminum?  What is the scale of your reaction?

Have you actually filtered off the sludge w/o basifying first?  It is a BITCH!  By basifying the reaction, you are converting the aluminum hydroxide/methoxide into NaAl(OH)4 which becomes a small black blob on the bottom of the flask.  Filtering takes about 5 minutes.  You must add the base correctly, though, or you will not get this awesome precipitation.  Here is how I do it:

After the rxn is done (it is not necessay to let is cool down first), add exactly 500g of 25% NaOH to the rxn while stirring the reaction at maximum speed.  This addition should take between one and two minutes.  You don't need to drip it in, but you don't want to dump it in all at once or your rxn mixture will become the consistancy of clay and will require lots of extra base/solvent to salvage.  After the rxn stirs for a few minutes, the fine particles of aluminum will begin to coagulate while a good deal of MeAm gas is evolved.  One the gas stops coming off and making the aluminum float, give the flask a good shake and all of the aluminum will sink to the bottom, leaving crystal clear solvent on top.  If you let is sit overnight at this point without stirring, the aluminum will collect into a golf ball sized black blob that is stuck to the bottom of the flask and you can simply decant the solvent without even having to filter it.  Then just strip off the methanol and perform an A/B, distill the freebase, and gas.  The above method is for 30g ketone, 24g MeNO2, and 33.5g Al.  If your numbers are different, you may require a different amount of base.

lab_bitch

  • Guest
Aluminum size
« Reply #18 on: October 06, 2002, 07:19:00 PM »
I know that Al thickness is very important in this rxn, but does it matter how small the Al squares are cut?  Because I have better things to do with my time than cut up aluminum, I bought a paper shredder that cuts the foil into pieces about 1x1/2 cm.  I then grind them in a paper cutter.  I use Reynold's Heavy Duty, by the way.  Would this make a difference as opposed to cutting the pieces bigger (1 inch squares)?  Also, does anyone have experience using aluminum pie pans or other thicker aluminum with this particular reaction?

Rhodium

  • Guest
*Filter* the Al hydroxides, do not try to A/B
« Reply #19 on: October 06, 2002, 07:29:00 PM »
If you perform the reaction as in Pihkal #109, but before filtering you add X milliliter 25% NaOH for every X gram of aluminum used from the beginning and then stir the reaction mixture for 30 minutes before you filter it all through Celite (common "dirt cheap" ;)  diatomaceous earth), then the filtering will take at most 5 min at the same scale as Shulgin's.