Question about performic

[raffike]

I posted some diagrams(if it's the right word for that) some time ago,oh here they are...

Post 385218

(raffike: "Also make sure your H2O2 is actually 35%.", Methods Discourse)
Measuring density @ room temp would be more accurate,it worked fine for me.My 5 year old H2O2 was still 35%,it was stored in cold and dark.

[madprosr]

swim just can't seem to get it right.

he distilled the still-orange over-hydrolized ketone through a 30mm column packed fairly tightly with steel wool. from 65g iso swim gets 8.1g ketone starting at 90C, peaking at 102C, then slowly climbing up to 105C. he was trying to use a lower vacuum, but was having a hard time (3 hours wasted) trying to get the column to heat up without having to boil the ketone too vigorously. so swim pushed slightly distended o-ring on his pump he uses to reduce vacuum back into place, and in seconds the ketone starts coming at 100C.

swim knew something was wrong when the temp didn't hold at 102C, but he kept collecting until he saw that new drops of ketone were leaving a snakey translucent 'string' in the oil which dissolved slowly.

he has seen this before as an early indicator of glycol contamination.
fortunately he cut the fraction after just a few sticky drops and the ketone does not become viscous when cold. maybe it will actually aminate well!

so swim distilled the next fraction coming at 114C, it's about 7-8g of orange oil. gotta be glycol. the rest is apparently burnt/polymerized crud.

at this point swim can't understand how there is glycol left after a 6h hydrolysis. please can someone explain this? this is swim's 3rd bad performic in a row.

it worked textbook-style once, all the glycol turned from orange to light red after 3 hours hydrolysis. swim distilled the tone with no column from 120-122C exactly, leaving only burnt stuff in the distillation flask, 75% m/m yield.

now swim can't duplicate this reaction. he tried another 3h glycol hydrolysis  using MeOH, but then distilled the ketone through a column at 100C instead of no column at 120. he got sticky shit.

the only thing different is the h2o2 has sat 3 more months at room temp.
could this somehow influenece the ratio of glycol to monoformyl glycol making the hydrolysis more difficult? swim thinks it should only result in more unconverted iso, but he'll check the h2o2 density eventually anyway...

he can't keep fucking up this reaction- thinking about trying some straight epoxide made with oxone at neutral pH. but the performic has the (potentially) high yields and the small volumes, it's so sexy...

one other thing, swim had more powerful stirring when he did the good hydrolysis. then he burned out the heating element, so now he has another hotplate with less powerful stirring. it still creates a vortex, but could this be IT? the reason for these problems?

[madprosr]

the 8.1g ketone distilled from 90-106C was dripped into a directly-scaled Osmium MeNH2/al/hg utilizing small square MeNH2 crystals extracted from nh4cl with IPA, crystalized, then dcm-washed. swim used 4g Al, 9g MeNH2.hcl freebased with NaOH solution before addition. solution was homogenous and at pH 9 (bit of extra NaOH) after 6 hours, basified to pH 12, extracted 3x 50ml toluene. washed 3x 50ml brine, dried over 7g MgSO4.1h2o, and gassed 3.6g mdma.hcl

after the ketone was distilled, 8.9g of slightly sticky when cold yellowish oil was collected peaking at 114C.

the rest of his 65g batch of iso turned into super-sticky brown sludge. eww...

swim is thinking it has to be insufficient stirring. his 75% m/m performic was done on an IKA Labortechnik hotplate/stirrer which no longer heats. the last three bad performics were hydrolized with a Marec Thermodyne 3.
to the glycol from 65g iso in a 500ml rb flask, swim added 360g 15% h2so4, and stirred with the Marec on max with a 1/2" octagonal stir bar, creating a vortex 3/4" across and perhaps 1" deep.

it was held at 60C for 6h, until swim realized that the orange color was never going away completely, turning a sweet red-brown, it was just going to stay orange as it burned.

any advise on this hydrolysis would be enormously appreciated.
how can swim have glycol contamination after such an excessive hydrolysis?

swim is going to try an oxone epoxidation followed by hydrolizing on the IKA stirrer, pulling the waterbath out occasionally to heat it up.
that or he could try to rig a mechanical stirrer for hydrolysis, he has a small AC motor rated at 2000 rpm, is this about right? where to find a sheet of teflon?

"one way or another, sooner or later, this darkness has got to give" -the dead

[abacus]

Am I the only one so far to realise you are not using enough 15% H2SO4, double the amount you are using and forget the remark that you can use half IMHO

Abacus

[madprosr]

many bees have had success with 90g 15% h2so4 per 100mmol isosafrole used in the performic. swim shared this success. then he switched stirrers.

if using 180g 15% h2so4 and 60ml MeOH can make up for slow stirring speed, that would be wonderful.

can anyone confirm or deny this conjecture?

swim is going to use his IKA stirrer for an oxone run, then 'hydrolize' with 120g 15% h2so4 per 100mmol iso and 45ml MeOH just as chromic wrote. hopefully he will have good new data soon for his bee brothers.

you tell me, how deep is your vortex when you convert epoxide/glycol?

[Rhodium]

It is not so much the depth of the vortex that is important, it is rather a question if you are stirring the solution hard enough to whip it into an emulsion, where no layers or even large droplets are visible. Make sure you evaporate off any DCM or other non-polars that may be left in your organics, or the layers will not mix as good.

Something I have always wondered is if the addition of 0.01-0.05% of a tetrabutylammonium bromide (or other relatively hydrophilic PTC) wouldn't increase the yields and/or shorten the reaction time in this step. It would be very nice if someone could try that out on a smaller (100 mmol) scale.

[raffike]

Rh:
What do you define as large(i mean droplets) when it comes to hydrolysis w/H2SO4?Raf used overhead to stir hydrolysis mix(made out of electric drill and variac) and did see small droplets or bubbles or whatever you call em.Rad also had some DCM in his mix.

[Rhodium]

I think I would define "large" as a few millimeters in this case. If your droplets are 1-2 mm you are fine. Mayber bigger is ok too, but 10 mm is definitely too much.

[raffike]

Oh,mine were 0,5-1 mm or so in dia.No problem in that case,thanx.

[SiLiCoN7]

The Oxone route works great and has been scaled to the size you are talking about. Works with about 70% yields and OTC!!!!

[hCiLdOdUeDn]

Swim has always consistenly gotten 50% yield from distilled isosafrole to distilled ketone with the oxone method.

[madprosr]

silicon, do you vacuum distill the epoxide? i think VL was talking about this.

in swim's last 3 h2so4 rearrangements, he set the Thermodyne 3 on high, using a 1/2" octagonal stirbar in either a 250ml or 500ml flask.
he saw no droplets bigger than .5mm, pretty much a uniform orange soup.

swim is going to give the oxone a whirl, just as soon he gets some dcm out of a paste-stripper with MeOH,toluene,acetone. the dang big orange store tricked him when they gave him an msds claiming 80% dcm, 10% MeOH, ethanolamine. it was from 1999; no longer correct. gotta h2o wash the dcm and redistil apparently...

[abacus]

Rhodiums correct re stirring.

Firstly, remove the condenser for a couple minutes to let any residual DCM boil away,

Then stirring should be strong enough so that there shouldn't be any layers forming on the bottom of the flask and you can notice small droplets swirling around the flask at about 1 revolution per second.

Normally such droplets are about 1mm or less with good stirring then after 2 hours at around 90DegC, stop stirring and a brown ketone layer will settle on the bottom of the flask.

[SiLiCoN7]

Err, what SWIM ment was 70% iso to epoxide...

55% from distiled iso to distilled ketone has been known and that was with H2SO4 rearragnment.
No real need to distill epoxide for 'purity' only for thermal rearrangment.

[wacko_reaco]

Rhodium,
My mother happens to have some of the PTC you mentioned but has no experience whatsoever with PTC's. What would be the workup after the hydrolysis to break the emulsion, is it simply extraction into non-polar? Also what proportion of PTC shall she use (as a w/w for glycol).

 

[madprosr]

swim got some fresh 35% peroxide, ran a Na2CO3 buffered performic, and got 99% yield of monoformyl glycol (stripped solvent under high vac, stopping when formic smell was noted), then 75% yield of ketone after a 3h rearrangement.

an MeNH2/al/hg yielded 80% w/w of the hcl salt.

is it possible that the monoformyl glycol rearranges more easily than the glycol? i know rhodium's faq shows the glycol as an intermediate, is it really?

[Rhodium]

Yes, that's true - see

Post 99146 (missing)

(Ritter: "isosafrole glycol less reactive than its formate", Chemistry Discourse).

The glycol need not to be a "true" intermediate in the rearrangement, even though at least part of the formylglycol is hydrolyzed to the free glycol in the course of the reaction. The reaction diagram in my Peracid Review is just a simplified schematic outline to illustrate that both the formyl glycol and the free glycol are rearranged by H₂SO₄ to MDP2P.

[Promethium]

GC_MS mentioned that indanes are natural substances found in plants. Actually, even the very desirable indan-5-carbaldehyde (I5A) can be found in a plant called Ammomum medium: Ind J Chem Sect B, 27, 1988, 660-661. The article reports the synthesis of I5A via Vilsmeier (POCl3/DMF) benzannulation from 1-allylcyclopentanol, which is easily accessible from cyclopentanone and allyl bromide via Grignard or Barbier reaction. The yield, however, is disappointing.