P2P via Tosic acid. Results

Friendlycat · Thu Apr 14, 2005 11:52 am

65g Trans Beta-Methylstyrene, 330g DCM and 8.3g Na2CO3 was placed in a 1L RBF and stirred. 137.3g 86% Formic acid and 82.9g 35% H2O2 was mixed, left for 1 hour then placed in the freezer till 0 deg.

The Performix was dropped in over 3 hrs keeping temp 39-40 deg. 22hrs later it was separated, washed with 100ml 10% NaHCO3 and Na2CO3 (by mistake) then 2x 100ml dH2O, dried, filtered and fractionally distilled. 9.4g Propenylbenzene and something else was recovered. Then at 133 - 137 deg @ approx 4mm was collected 59.3g of very clear viscous whatever the hell it is. 1,2-Phenylpropandiol? 12.3g was left in the reaction flask just because I didn't feel like finishing.

So! 30.1g of this glycol, 90ml toluene and 1.7g p-toluenesolphonic acid was placed in a 250ml RBF and set up with a dean stark trap and heated the oil bath to 140-150 deg C for 90 minutes. In that time 3.5ml water was collected.

Cooled, neutralized with 60ml 10% NaHCO3, washed with 60ml Brine and dried with MgSO4. Colour was golden honey. I felt good here! Filtered into a 250ml RBF and set up for simple distillation. Removed most of the toluene then transfered to a 100ml RBF and set up for vacuum fractional distillation with a packed claison adaptor. With bath at 120 deg @8mbar, no sign of P2P. No problem. So far was running as planned. 0.4g Tosic acid was added so with bath at 140 deg @9mbar came light yellow P2P. For a while, then stopped. Shit!! Not like before! 0.5 g extra was added and when vacuum was applied P2P came gushing over, for a while. Added another 0.4g and distilled to the end.

21.3g raw P2P was collected and 5.5g black residue.

I ran this same amount twice before with less problems and better yield. For instance, during the final distillation only about 0.4g was added and P2P came over nonstop till the end. I used both Toluene and Xylene with the same outcome.The only difference was how I got the Glycol.

The first two times I tried to run a full modified performic with the 15%H2SO4 @80 deg thing. Failed. The glycol residue from this was used for a very sucussful rearrangment with Tosic. I've run many other Performic nightmares and have never been successful at rearranging with H2SO4.

The thing I want to know is why don't I get a full load P2P when refluxing in toluene with 6%w/w tosic. There is some P2P formed but only a drop or two. I've even used twice that amount with the same results. I tried Xylene because I thought the reaction temp might be higher. I was actually more confident this time because I collected more water in the trap, 3.5ml as apposed to 2.7ml as in previous runs. So does anyone have a clue cause I frigging don't! I know there are other ways to P2P, but I want to conquere the Performic like the MDP2P guys.

Here’s what I did with the rest of the glycol.

42g Glycol with 1.8g Tosic acid and 90ml toluene was refluxed with a dean stark again.After 2 hours I realised the tosic and toluene values were wrong so I added an extra 0.7g tosic and 40ml toluene. After a total of 3 and ½ hrs, 3.4ml water was collected. Colour was much darker then before.

Neutralized, washed, dried, filtered, removed toluene with vacuum, transferred to smaller flask then fractionally distilled. With bath @128 deg C, @7.5mbar, P2P came over at 80 deg. About 10ml came over very very slowly, then there was a sudden loss of vacuum then regained slowly and P2P stopped. Added 0.5g tosic and P2P started coming over again until a higher fraction started coming. Stopped and added another 0.5g tosic and P2P started coming over again almost clear. Towards the end there was a dramatic loss of vacuum up to 25mbar which then started climbing back but that was the end of P2P. Bath was up to 176 deg. What was that? Did something blow up? The tosic? That’s what the flask looked like. The and a portion of the rashig rings

22.8g raw P2P was collected and 5.3g residue in reaction flask.

IndoleAmine · Dreamreader Deluxe

Good work!

(if you like performic, you could try to oxidize methyl-phenylbutenone with it, and hydrolyze with aequ.HCl to arrive at where you want, like here https://synthetikal.com/synthforum/viewtopic.php?t=19 - no explosions were reported until now... Wink

)

i_a

Friendlycat · Sat Apr 16, 2005 1:40 pm

Thanks indole.

I have that original post from the hive and that is definitly my next project. But at the moment I'm really unhappy with my results with the performic. The yield should be better and the proceedure should be easier. I also don't understand the step by step mechanics of my proceedure. I'd love it if some could explain what is actually happening. I would also really like to know if someone could verify that they have made P2P in good yield with the modified buffered performic with 15%H2SO4.

Kind regards,
FC.

IndoleAmine · Dreamreader Deluxe

around 60% yield of vac distilled p2p with unbuffered(!) performic without H2SO4 (since it decomposes the performic too fast!) and aequ.HCl rearrangement are waiting for being verified by a willing tester... Wink

For better performic, cool reagents to zero, then mix by swirling gently, and place in fridge for at most 10 minutes prior to use. Also, I would advise to drip reagent into performic, not other way round.

Friendlycat · Mon Apr 25, 2005 1:37 pm

I'll be the willing tester! Was Dal Carson bullshitting about his claimed 93% yield which includes H2SO4 hydrolysis?

Anyway here's what I did next; P2P via TsOH without solvent.

25g glycol and 1.8g TsOH was placed in a 100mm RBF and set up for simple distillation in an oil bath. With bath at 130 deg C, aqueous stuff was seen creeping up into the head then at 140 (bath) started coming over. Took bath up to 155 deg. 15 minutes passed between seeing distillate and removing bath.

Transfered to a 250ml sep with 75ml DCM, neutralised with 50ml 10% NaHCO3, then brine and dried with MgSO4 and set up for simple fractional distillation in a water bath. After DCM was removed, transfered to a 100ml RBF. removed rest of DCM with vacuum and distilled very clear P2P.

Collected 15g P2P with 4.5g golden stuff as residue, which I'm willing to bet, can be rearranged in another run.

I'm exited by this reaction but I think it might be difficult to time it perfectly when scaling up, even so, it was quick and clean.

Kind regards,
FF.

PS, Does anyone have BP info on the glycol?

Pemulwuy · Mon Apr 25, 2005 2:07 pm

left for 1 hour then placed in the freezer till 0 deg.

Any reason for this?

Is your Tosic home made? Did you test it for purity?

Some tips:

Test the purity of your other reagents.

Let the initial performic go a while longer, or better yet, use TLC.

Try a 15% HCL hydrolysis and let it go 4 hours.

Friendlycat · Mon Apr 25, 2005 2:28 pm

In the freezer till 0. Just following directions eg; Lab Top etc.
Tosic monohydrate was lab grade.
Let the initial performic go longer than 24 hours from start of addition? Why?
I will definately try a HCL hydrolysis.

Thanks.

Pemulwuy · Mon Apr 25, 2005 4:40 pm

Let the initial performic go longer than 24 hours from start of addition? Why?

Because, I would assume that the reason you had unreacted propenylbenzene left over, as described in your first post, is because you did not let the reaction go to completion.

The performic with MDP2P writeup states to let the reaction run 24 hours and P2P is generally considered to be a tougher compound to oxidise.

TLC will most likely take care of a lot of your problems.

IndoleAmine · Dreamreader Deluxe

24h is plenty, usually the oxidation is mainly finished within 12h.

Friendlycat · Tue Apr 26, 2005 6:20 am

Wow, thanks! Didn't realise the performic was so fragile. Swim will prepare performic as suggested.

A little confused about your suggestion to drip reagent into the performic. What about all the agitation that the performic will be subjected to before all the propenyl is driped in? We are talking about buffered performic aren't we? Keeping temp around 36 - 40 deg?

Yes, Dal Carson on Rhodiums site where he describes a standard performic with some "modifications" to achieve 93% yield of p2p with H2SO4 hyrolysis.

I remember reading some were that "Eleusis" deceided to neutralise the standard performic with NaOH instead of distilling all that formic acid and that he picked up this hint from reading Dal Carsons overview. I also remember reading that this might have been a mistake because the diol was formed before the H2SO4 hydrolisys resulting in lower yields. Is that right?

But yet what swim is trying to do is just that , get the diol and rearrange with TsOH.
I need a holiday.

Kind regards.
FC

IndoleAmine · Dreamreader Deluxe

SWIA would always use performic unbuffered in his dreams.

The order of adding reactands isn't really that important. Dripping propenylbenzene into performic has the advantage that you can cool the performic very nicely. Wink

Of course you should stir on low setting, as to just maintain proper mixing and homogenous rxn conditions. Temperature should be kept as low as possible, 40°C is the maximum allowed temp., but 20°C are favorable. OTOH, addition of the propenylbenzene shouldn't take too much time - since the formic decomposes whether propenylbenzene is present or not! Its not too difficult, as long as you don't work with huge quantities a simple ice/salt/water bath will suffice...

Idoubt that H2SO4 can produce that high yields in glycol rearrangement, but suspect that its possible with aequ. HCl, as said. The point of preliminary partial epoxide ring-opening is a good one, but I think it doesn't reduce yields dramatically if it all, since you want to do this anyway, and as long as you don't isolate epoxide and/or glycol, everything is still in there, awaiting further H+ treatment...

Do you think tosic acid rearrangement could also be done on the oxidation product of 2-acetylpropenylbenzene?

cheers

i_a

Friendlycat · Wed Jul 13, 2005 10:36 am

Don't know the answer to that, sorry.

Solventless rearrangment with TsOH.
Better yield, more detail.

28.7g Glycol and 2.1 Toluenesulphonic acid monohydrate was placed in a 250 ml RBF with a stir bar and set up for simple distillation in an oil bath without water in the condenser. Heat was applied and after a while a few droplets of water came over. Nothing else was expected. Max bath temp was 148 deg C.

When the oil bath was at 110 deg C, flask wall was frosty with water vapour and at 125 deg, water droplets were forming at the distillation head and at 130 deg, were running down into the flask. This took 24 minutes. Tempreture to 145 deg, time 40 minutes. Heat up to 148 deg. Total time from when water formed droplets till removal of bath was 50 min. Cooled to room temp with fan and water bath approx 10 - 15 min.

Added 90 ml DCM and neutralised with 90 ml 10% NaHCO3, washed with 40 ml brine. Colour at this point was golden like light beer. Dried with MgSO4, placed in a 250 ml RBF, removed DCM then vacuum fractionally distilled the suspected P2P which came over at 5.25 mbar at 75 deg all the way. Collected 18.1g with 4 g residue as a dark thick liquid, did not turn solid. Yield 71.5%. This has not been aminated yet, so god only knows if it's any good.

I don't think this is an ideal way to do it, because you can easily destroy the P2P if not timed well and I have doubts about scaling up, but any comments would be appreciated.

Regards,
FC