problem with performic yields

[madprosr]

swim dreamed his first successful performic oxidation of safrole last night.
18.3g safrole was distilled at 140-144C, +KOH, 15.1g isosafrole at 150-158C.

swim used labtop's modified performic from the sticky thread...
he reduced the amount of bicarb proportionally, but used the slight excess of performic intended for 16.3g iso. mixed 1h, added to 46ml dcm, iso, buffer which did reflux nicely after 1/3 the performic was in.

seperated dcm, extracted with 10ml more, directly stripped as much dcm as possible first at atmospheric then aspirator vacuum yielding 21.8g glycol/monoformyl glycol. looks good so far...

heated with 30ml methanol, added hot 15% h2so4, refluxed slightly for 2h.
dark heavy oil falls out   , tapped, extracted with 2x 20ml 1x 10ml dcm.

well, labtop doesn't mention washing, but bees say to neutralize after h2so4-
so swim washed 3x 20ml dH2O, 3x 30ml 5% NaOH. the first NaOH wash was very dark, the next 2 were brownish, though they would help.
washed 2x 20ml saturated NaCl solution. dried over (too much) 12.9g MgSO4.

thing is, after gravity filtering the MgSO4 (who knows why), swim only had 25ml DCM left of the 50ml + ketone before washing. there were really no emulsions to speak of, the NaCl wash seperated slowest so swim cursed, and washed the MgSO4 with some more fresh DCM.

he distilled it with an un-packed claisen as a column, got a nice little iso forerun, and just ba-a-arely pulled 5g suspected ketone at 180C.

so swim wants to know, where's that other 5-10g ketone hiding at?
in the washes with dcm, or did that evaporate? eh? where is 'dat shit at?

swim supposes he should weigh the shit that didn't distill... feels like a newbee   . too bad 1oz of sassy is gone so quick. coming up... Leuckart!

[GC_MS]

If you want to check if one of your extractions contains a certain amount of ketone, you can try to make the bisulphite adduct.

https://www.thevespiary.org/rhodium/Rhodium/chemistry/eleusis/bisulfite.html

geh in die knie. wackle mit den hueften. klatsch in die haende. und tanz den mussolini.

[ClearLight]

 The tlc reagents are so sensitive, that you don't need to run a plate or slide.. just put a few drops in a white porcelin plate or cup and then put a few drops of the reagent on it... it will turn colors if the compound is there.. you probably want the gallic acid / hs2o4 one.. it does a nice job of locating your stuff... if it's everywhere, then you need to run a plate/slide and you can tell by spot size, where most of it is...


Infinite Radiant Light - THKRA

[lab_bitch]

I would almost guarantee that the missing ketone is in the distillation flask.  Especially if you distilled at 180 (too hot!!!).  What size distillation flask did you use?  Either get a better vacuum source, use a smaller flask, or both.

[abacus]

heres some tips.

1.  Scale up.

2.  Post hydrolysis with 15% H2SO4, don't wash with NaOH, wash once with saturated bicarb solution, once is all you need.

3.  The amount of raw ketone should be around the same as the amount of starting isosafrole. That is you should have  gotten around 15g raw ketone which will reduce to 70%-75% of that amount once you vacuum distill.

4  Strip of the residual water with vacuum and heat rather than drying over magnesium sulphate. 

4.  If you follow labtop write up, yields are always 70-75% unless your peroxide is old.  SWIM always gets 82% w/w (or 75% molar) yields with good peroxide when following this advice.

5.  Your scale is so low I suspect you have lost significant percentages of your product in the washes, drying with mag sulphate, stillhead, condenser etc.  If you do this at a bigger scale, you should get better yeilds.

Abacus

The problem is what you don't know you don't know.

[Sunlight]

A friend reproted me low yields, 40-50 %, with this rxn. Finally he told me that he got the expected yields stirring 24 hours and hydrolizing 3 hours.

[madprosr]

swim found the crap in the distillation flask is 5.5g
so thats where some of the ketone went, the other 1/3 must have washed out.
he did so many washes only because he didn't want it to burn too easily...

the performic reaction was stirred 9h, and distillation used small flasks (50ml, 25ml) with a 19/22 rig.

swim tried a sodium iodide + acetone trial-
1g NaI + a little more than 1.16g = 1.5ml acetone (3x molar equivalent)
stirred at room temp, cooled on an icebath, everything crystallizes.
the crystals set in 1h, and are weighed at 1.3g. they are insoluble in toluene.
wtf, where is the 2.16g, swim wonders if so much acetone could evaporate that quickly to throw off the yield.

swim cannot find good details on the NaI purification, just hellman and blaztoff's 'suggestions'. anybody have YIELDS for already distilled ketone?

his ketone smells bad, like burntness, only maybe a touch of sweetness... looks light yellow/clear.
he really wants to know what would come of a leukart with it, or if NaI is really a good idea (with .5g ketone first) to purify it.

and is the (limited) consensus here really that acetic + formamide is a 70% yielding leuckart and formic + formamide is more like 50% for mda?

[noj]

9 hrs is not enough time, try at least 18hrs. Also make sure your H2O2 is actually 35%. It degrades rapidly, especially after being opened.

Below LabTop's account in the sticky thread, are Baalchemist's amounts. Try those next time.
there's a big difference between criticizing your government and criticizing your country

[madprosr]

ok, swim's going to try letting the reaction run 18+ hours. and only one bicarb wash after hydrolysis. hooray for local sassy!

he wonders if it is actually beneficial to add water to his 35% h2o2 and 90% formic to make the solution exactly equal to labtop's values? he recalls bees with 60% formic having a problem with too much water... maybe he should just assume the h2o2 has degraded to 30% already (after being opened 5x) and just add the right amount of formic without dilution...

anybee care to comment? (another 100mmol is isomerizing right now   )

[ClearLight]

If the h202 is stored under argon, after being opened, will that prevent degradation?

Infinite Radiant Light - THKRA

[madprosr]

swim's isomerization sucked this time. the first isomerization was
18.3g safrole (once-distilled with stirring, no column) + .35g KOH, 7.5h vac reflux at about 140C => 15.1g iso
18.6g safrole (same) + .3g KOH, 12h vac reflux => 13.85g iso

the first time it didn't turn black until vacuum was disconnected, this time it turned black while heating up. obviously the KOH is wetter now...
so are 95%+ yields only attainable with large batches or what???
oh, swim has been sucking the water out through a vertical, uncooled condensor because he didn't want to setup for distillation and then switch (if that matters).

anyway he couldn't find ritter's origional performic synth, and he wanted to use Na2CO3, so he just used 1/2 the molar amount of bicarbonate labtop advises.
added 12.9g H2O2 (assumed 35% degraded to 30%), 21.4g 86% formic (1h premixed), to 13.85g iso and 2.7g Na2CO3 in 44ml dcm. refluxed nicely, stirred for 30 hours. yielded 21.1g glycol. this is still more than 100% monoformyl glycol weight...

so he hydrolyized 2h with 25ml MeOH, 78ml 15% h2so4, washed once with 20ml 10% NaHCO3, and distilled at 45mmHg, yielding-
4.8g ketone and 9.2g brown viscous crap left in the flask. more crap this time!

so all the washing before was excessive, its not necessary to prevent the ketone from burning, swim just needs a good pump to get good yields of ketone  

[El_Zorro]

try tossing your KOH in a short beaker and heating the shit out of it 'till the water boils off.  That'll get the water out, no prob.
Who is that masked man?

[Protium]

is the way to go without a doubt.  There are a lot of factors that come into play when reporting your results, but based upon the principles behind the reaction.. run the whole thing under vacuum at a lower temperature for minimal reflux over a much longer period of time.  By lowering the temperature you can significantly reduce the amount of polymers which develop at higher heating. In addition to removing any h2o present, running it all under vac just generally enhances the yeilds many times over.  When finished, vacuum distill it straight out of the reaction flask, discard the small amount of forerun, freeze crystalize if you are obsessive, and you're all set to worry about the oxidation which is the topic of the thread.
Pr(+)tium

[madprosr]

after putting 2.4g ketone in a failed leukart (hcl hydrolysis) and .6g into a failed NaI test (would not crystallize) a bee buzzed in swim's ear and said to see if the ketone eats a plastic CD case.

it DID, so swim decided to run the nitro/al/hg on his last 1.8g of mdp2p. he scaled it down directly from MM- 2g Al (extra heavy duty foil), 25ml 8% w/w MeNO2 in MeOH. about half of the .25g Hg he combined with .33g elemental I2 a week or so before had reacted. he added 10ml MeOH to the red chunks, which dissolved leaving unreacted Hg which was hidden inside them. he pulled the MeOH up with an eyedropper, gloved hands shaking and started the amalgamation. stirred briefly every 1-2 minutes, it took 15min to start bubbling, 30min for a few pieces to start floating, 45min to really look dull gray. he added the nitro over 20min trying to get it hot, and the ketone over 50min after which time there was no more than 1/5 of the Al left floating in solution. it did reflux slightly (1 drop/3 s) after 1/2 of the ketone was added.
edit: swim let it stir for 12h and sit at room temp for 12h at this point.

swim worked it up as MM. basified and extracted w/ 40ml, 2x 10ml toluene. washed  1x 30ml saturated NaHCO3 which bound up about 5ml of toluene in a yucky emulsion which settled at the bottom of the water layer. stirring, addition of a little NaCl, then 10ml saturated NaCl solution did not break it. washed 2x 30ml saturated NaCl which separated instantaneously. dried over MgSO4, gassed through CaCl2 by dripping HCl onto H2SO4 with stirring and pressure to the top of the hcl addition funnel equalized. first nothing happens, then it gets a little cloudy, then it turns to white soup. after drying- .83g brillant white mdma.hcl    so light and fluffy that swim though he had twice as much. the toluene was gassed again and started to get cloudy when the generator sucked back like a motherfucker causing swim to add too much hcl trying to balance it out. it bubbled up hard but swim thinks the toluene wasn't contaminated because there are a few crystals undissolved in it.

bioassay pending, as a speck of it tasted has an hcl tang before the bitterness hits, and it smells slightly of methylamine in addition to a pleasant rootbeer aroma. so swim feels the only ethical (or healthy) thing to do is recrystallize. who knows the solubility of mdma.hcl in IPA at 80C?

this is where it gets good. with Halfapint's NH2OH from MeNO2 + HCl synth swim has alot of options.

[goiterjoe]

just because it will eat a hole in a CD case doesn't mean it's ketone.  safrole and isosafrole will do the same thing, but it will take them several hours to do so.  ketone will melt the plastic almost instantly.  It's a good thing to keep a rag nearby when weighing out ketone with a plastic topped scale just incase you spill a drop on it.
If at first you don't succeed, try, try again. Then give up. There's no use being a fool about it.

[raffike]

Also make sure your H2O2 is actually 35%. It degrades rapidly, especially after being opened.
I have about 1 liter of 35% H2O2.It's at least 5 years old but still in good condition(bp 107 which means around 30% H2O2 content and when some iron rust was added to H2O2 sample,it decomposed violently).When kept in dark cold place it's quite stable.For those who want to test H2O2 conc in water solution:

And by density:

For those about to synth,we salute you

[madprosr]

wow, those charts could bee useful in the peracids document.

but is it a bad idea to boil h2o2 stronger than 60%, or is 1ml heated in a test tube a minimal danger?

ah well, the freezing point test is totally sufficient for any h2o2 less than 57% concentration to begin with anyway.

that bp data seems most useful for concentrating h2o2...
i've read that bees (and rocket enthusiasts) have boiled half the volume off of 30% h2o2. but could one go so far as to concentrate 3% h2o2 to 35% by heating until distillate temperature hit 108C (at sealevel)?

[madprosr]

i hope you enjoy reading this as much as i enjoy writing it.

swim recrystallized about .83g mdma.hcl from about 2ml boiling IPA, after 1ml it was a cloudy solution but made IPA was added to clear it up. it recrystallized immediately on cooling.

swim dropped 100mg in some ch3ch2oh and orange juice, definite postive.
better go do a bump.

[raffike]

Stronger h2o2,more unstable it is.I imagine that when one had 1 liter of 90% H2O2 and threw in,let's say,about 100 grams of Fe2O3,he would be no longer among us.Other substances may act as catalyst too.If i remember correctly,somebody used conc. H2O2 as explosive too.I say don't make it,buy some from pool shop or chem supplier,it's not watched as performic acid manu isn't the only use of H2O2
For those about to synth,we salute you

[madprosr]

well, swim dreamed he got a nice new 1-stage 250micron 1.1cfm pump.

so he ran a NaHCO3 buffered performic ala labtop, 3h H2SO4 reflux (a bit long he thinks in retrospect) and distilled some ketone in 74% mol/mol yield at 120-123C. expected it at 75C, but oh well  

the ketone came as continuous fraction mixed with iso starting at 104C but it was only about 5% of the volume so he left it in. he was able to seal all the glass joints using ptfe paste on the outside (no leaking bubbles seen), but the system did not hold vacuum long. always there is room for improvement... ooh, a silvered vacuum-jacketed 100mm fractionating column and a straight vacuum adaptor to rig up a fraction cutter (thanks MadmAx) would be nice. and some dang vacuum grease. his otc (heh) pump came with oil but no silicone grease. bees who use automotive silicone grease, you're not talking about dielectric silicone grease for spark plugs, are you?