Sciencemadness Discussion Board

hmtd catalyst

prometheus1970 - 29-6-2010 at 11:29

Does anyone know if it's possible to use 98% h2so4 in hmtd synth as the acid catalyst? It may sound totally retarded, but here is my thinking: h2so4 can be used in place of hcl as the catalyst in the synthesis of tatp. Hmtd synths generally call for citric acid, but generally hcl can be substituted for the citric acid and bot tatp and hmtd are organic peroxides. I know enough to know that this analogy may not be ironclad, but it makes enough sense (I think) that I may pose the question without being flamed. However if my query IS so far-fetched as to deserve pointed answers, I welcome them, as being called a "dumbass" is better than being called "lefty" ('cause there ain't much left of him)

-=HeX=- - 29-6-2010 at 14:34

IIRC, it works. But with H2SO4, you can make HCl.

hissingnoise - 30-6-2010 at 03:01

HMTD may be acid-sensitive so that using citric acid (a weak acid, easily obtained OTC) to consume the NH3 formed may produce better yields. . .

Justin - 30-6-2010 at 03:25

citric acid is the only way that i got a yeild, i used HCl once and i ended up with methylamine HCl, when i went to neutralize it with bicarb i unknowingly freebased it and it all bubbled away. i was using the synthesis off Mr. Cools site btw, anyway just use citric acid, and keep a eye on that stuff!! i had it in my fridge in my shop and forgot to check on it periodically and i ended up with a whole fridge full of black smelly polymerized crap and a freaking black chunk as hard as asphalt in my beaker, it must have spewed like a fountain or something, try the one patent synthesis i think its in the library here, well after the stirring at 0C they let it sit out to warm up to RT for two hours, at about an hour and a half i see bubbles forming in the bottom of the beaker, this stuff seems really picky about reaction conditons, so keep a close eye on it, oh and if you do end up with a hell of a black stinky mess, its water soluble atleast!

hissingnoise - 30-6-2010 at 04:15

Use the HMTD synthesis in COPAE (in the forum library) if you want reproducible yields and wash the precipitate repeatedly with water (no bicarb!) and dry at RT..




quicksilver - 30-6-2010 at 05:59

As w/ most energetic peroxides, you have to work your lab in a consistent cold temp. Problems arise from both warmer temperatures & fluctuations. The David lab is another example of the care needed when scaling up a defined synthesis by multiplication alone. Move that 14gr to 140 and watch it fail.

pjig - 30-6-2010 at 10:21

Quote: Originally posted by quicksilver  
As w/ most energetic peroxides, you have to work your lab in a consistent cold temp. Problems arise from both warmer temperatures & fluctuations. The David lab is another example of the care needed when scaling up a defined synthesis by multiplication alone. Move that 14gr to 140 and watch it fail.


It is best to make a few smaller batches to obtain a good yield, not a bigger one( as quicksilver said). Scaling up on several synthesis yields poorly. "Cold" is the key for stability and yields, and not drying at temps above RT.

quicksilver - 1-7-2010 at 08:20

It's a bummer when you can't edit something you see a day later. I meant "the DAVIS lab" like in Tenny DAVIS (but most would guess that I suppose).

There are very few ways to tell (off the cuff) if you can't scale up by simple multiples of reagents. What I've found is that in very simple "big Bertha" nitrations; the classic nitric esters can be scaled unless you have a finicky solid alcohol like mannitol*. The other issue is making a mixed acid in situ with a solid nitrate. When a solid nitrate is used (for a mixed acid) the ratio of HNO3 is altered by levels of water & contaminants [of course] that jump up as you use more sulfuric acid. This is one reason why the whole "OTC lab" using a drain cleaner has challenges that sometimes are inexplicable. The reagent is not consistent. The sulfuric is generally a surplus used material from another industry (like pickling steel or anodizing or whatever). The notation of "93%" is not written in stone. That's a good reason for boiling off the water and raising the % of acid in that reagent; especially if inconsistencies are noted from one lab to the next & you have been careful to follow your notes, the process is simple, the major issues like temp have been covered & yet you still get a variation in yield or even the final product is "off".


* Actually mannitol is a classic for that example. What would be appropriate at a 5 gr level simply won't work at 25gr. I have a very workable synthesis of stephnic acid that works very well, up to a certain point. THAT issue is much more complex: I believe that many benzene ring nitrations have greater sensitivity to more issues than esters.