The Vespiary

The Hive => Methods Discourse => Topic started by: wacko_reaco on May 18, 2001, 12:29:00 AM

Title: major Al/Hg failure-please help
Post by: wacko_reaco on May 18, 2001, 12:29:00 AM
Had some ketone made from the modified performic, the final vac distill was done without saff oil and started coming over at 115 and i turned it off at 170, when it was getting really brown, the cuts at lower temp where a nice light yellow.
Anyway so far i have tried to animate it five times, using MM's nitro route to the letter (have had success with this method before using benzo ketone), anyway in every case the reaction has not gotten to reflux temperature, not even close  (highest about 50C). Is this symptom typical of impure ketone and if so at what point does one turn off the distill.
I find it strange though that it is not getting to temperature, because isn't the nitro reduction very exothermic or does one really need the nitro reduction plus the imine reduction to generate the reflux temperatures?
All imput would be appreciated, also the final run was done with 10micron thick foil, so if anything was ever going to run hot it should have but it still only got to 50C and this was after adding some caustic because it had stalled at 45C,

wacka wacka wacka
Title: Re: major Al/Hg failure-please help
Post by: Osmium on May 18, 2001, 01:59:00 AM
Well first of all the purpose of distilling is to separate components, by taking a cut over a 55°C temperature range you are merely thermically refilling the contents of one flask into another. The boiling point of the ketone depends on your vacuum strength. You also have to observe the thermometer during distillation, sudden temp changes mean that a different compound with a different boiling point is coming over. That yellow stuff was your ketone, but there's no way of telling how much of your distillate was ketone with the numbers you provided.

The Al/Hg with foil definitely should reach reflux temperatures even with shitty ketone. The nitro reduction itself is highly exothermic and will be sufficient to heat it up quite a bit more.
You sure you did everything right? Used real nitro, real Hg salt? What did the Al look like before you added the lye?
Title: Re: major Al/Hg failure-please help
Post by: Vibrating_Lights on May 18, 2001, 02:14:00 AM
Swim Has also had this problem using hg salt made from Hg And H2SO4 It was white crystaline.  The alumnium turned grey instead of metallic and the supernat turned a green color. Some one who knows please answer this mans question.
Title: Re: major Al/Hg failure-please help
Post by: wacko_reaco on May 18, 2001, 02:44:00 AM
The mercuric acetate i used was from the bottle, i used slightly more because it has a higher molar mass than the chloride. The nitro I used i am assuming is good for two reasons
1) The label and the nice man in the hobby shop assurred me it was100%
2) It blew the socks off a larger batch I attempted using thick foil, basically what happened was I mixed some foil (2kg, 0.3mm)(used a drill press to stir it) and methanol (14L) and mercuric (4g) salt, then added 700mL of the same nitro, well about 30secs later all the methanol was vapour and i had a headache. So I assume it can react (luckily i had not added any ketone).
OK more  questions, do aluminum alloys exsist that can poison the amalagum, i have now tried two types with ordinary results, when i was having my succeses I was using a different kind of 100micron sheet, just stabbing in the dark really.
Also Osmium to better clarify my vac distill, I took the first cut from 115-120 (about 5% vol), then the temperature steady rose to 130 and sat there for quite some time (60-70%total vol) it then began to climb steadily again however the colour did not really appear to drastically darken, nor smell different, until about 155-160 so that's why I combined all the cuts from this period. I will now use different mercury, also i might try to distill the nitro, can one distill the nitro safely? will adequate seperation occur with vacuun to reduce the explosion risk?
The reason I am so perplexed is that I have checked everything, so the ketone is my only scapegoat.
No, now that i think about it has to be the nitro because if it was right the thing should still reflux. Any tests for nitro purity?

Thanks for your help.

wacka wacka wacka
Title: Re: major Al/Hg failure-please help
Post by: terbium on May 18, 2001, 10:30:00 AM
I would think that most of the heat is produced by the reaction of the nitro with the aluminum amalgam. So, if you didn't get a strong reflux, I would first suspect everything but the ketone - aluminum, nitro and amalgamation.

Perhaps you could experiment without using your precious ketone. Do everything else the same and see if you can get a good reflux and convert the nitro to methylamine.
Title: Re: major Al/Hg failure-please help
Post by: baalchemist on May 19, 2001, 03:43:00 AM
Mecuric acetate stinks, yes it will react with coaxing, but chloride is the way to go. Sounds like you didnt add any
outside heat at any point, maybe thats what it needed. I just say that because of the metal turning grey.Thats a sign of amalgamation, but at a much slower rate than what the chloride salt produces. There was a bee a couple years back that screwed around with the acetate before the Nitro route was around, he concluded that it created inconistent reaction conditions. More babysitting the reaction and longer amamlgamation times. However he was using a Osmium/Shulgin hybrid reaction if I remeber right, so I dont know if that would apply to the Nitro route at all.

Title: Re: major Al/Hg failure-please help
Post by: wacko_reaco on May 19, 2001, 04:17:00 AM
It's funny sometimes you think you are OK at what you do (like chemistry) and then something happens that doesn't go to plan and you have to examine things and then you realise how much it actually is that you don't know
The acetate comment (from Baal) is interesting, even though the observation goes a long way to explaining my results it makes you think why would something be inconsistent? My only guess is that if the acetate salt is not that soluble then this would cause problems. i am in the southern hemisphere, in summer when this reaction was working a breeze (using the same acetate) the methanol was probably at 25C or more (it's hot here), when another failed the other day I tested the temp of my methanol and it was 15C (it's winter, almost), if the salt is reluctant to go into solution anyway this minor temp drop could be enough to discourage it to the point that it won' t react. More speculation but definetly worth a quick try with no ketone, heat methanol to 30C, add and thoroughly stir in mercruric acetate, then do a nitro addition after amalgamation has begun to see if it gets to temp.
Will post with results for all to learn from.

What can i say but thanks so much for everyones imput.

wacka wacka wacka
Title: Re: major Al/Hg failure-please help
Post by: Osmium on May 19, 2001, 02:18:00 PM
I've used all kinds of Hg salts successfully in this reaction, including the acetate and Hg2Cl2, which is almost insoluble. Still worked.
Title: Re: major Al/Hg failure-please help
Post by: refluxx on May 19, 2001, 03:26:00 PM
SWIM did this reaction several times and had many problems, but getting this thing to heat up was never one of them.  He followed MM's amalgamation.  The nitro is apparently enough to heat it up big time because the last one SWIM did was with ketone that he wasn't even sure was ketone and it boiled like a motherfucker anyway.  His nitro is very pure (its clear) and he used the chloride salt.   SWIM will post his memoirs of screw ups and fuck ups in the near future for others to benefit, as he leaves the field for good since he apparently doesn't have the time and knack for it.  Good luck.

did I say that?
Title: Overstirring?
Post by: wacko_reaco on May 19, 2001, 06:26:00 PM
With my setup stirring is not a problem, in fact if this reaction can be kiiled with overstirring  this may be the problem, any comments?

wacka wacka wacka
Title: the solution
Post by: wacko_reaco on May 22, 2001, 03:30:00 PM
the foil
it was the damm foil, after flicking around all the other variables I went back to my thick foil (100micron) that had worked previously, bang it went like a charm.
Thanks for everyones help, also all those people that PM me, it seems that quite al lot of people have had problems using what they thought was al foil but wasa ctually some alduteration (a foil or annealed or something)
bye bye

wacka wacka wacka