Author Topic: p-toluenesulfonic acid  (Read 19122 times)

0 Members and 1 Guest are viewing this topic.

Chromic

  • Guest
Re: p-toluenesulfonic acid
« Reply #20 on: February 25, 2002, 07:10:00 PM »
SO3 isn't needed. The synthesis gave me a wet brown sludge, but it's definitely the sulfuric-acid-free tosic acid that I needed to use an a catalyst! The synth is very easy once everything is spelled out.

Summary:
3 equiv toluene, 1 equiv acid, stir bar. Slowly refluxed (<<1 drop/sec) for a few hours, the biphasic solution turned brown, and towards the end I decided to distill off about 1 equiv of toluene thinking that I might distill it to dryness (but decided against it). Instead of completing the distillation to dryness the solution was filtered (using saran wrap to press down the solids). There remained a bunch of brown sludge comprised of mostly tosic acid crystals.

Lovely!

PrimoPyro

  • Guest
Re: p-toluenesulfonic acid
« Reply #21 on: February 25, 2002, 07:12:00 PM »
We look forward to a future formal writeup with yields.  :)

Congratulations, Chromic!  8)

                                                   PrimoPyro

The Water Will Be Your Only Mirror

GlaseIs

  • Guest
Re: p-toluenesulfonic acid
« Reply #22 on: March 11, 2002, 07:44:00 PM »
This would be the dehydration of the diol to form MDP2P in the Oxone method right? Hopefully this works a lot better than H2SO4. Looking forward to a writeup :)

On the 6th day God created man. On the 7th day, man returned the favor.

psychokitty

  • Guest
Re: p-toluenesulfonic acid
« Reply #23 on: March 12, 2002, 12:52:00 PM »
You might want to try to saturate the aqueous layer with sodium bisulfate or something to salt out the tosic acid.  If it has any solubility in any of the common extraction solvents, it should go to the organic layer with ease.

Chromic

  • Guest
Well, there's a few problems I've run into and I ...
« Reply #24 on: April 16, 2002, 02:55:00 PM »
The above method works, but the brown sludge comprised of mostly tosic acid doesn't dissolve into toluene (perhaps it's wet with water?)

The crystals do seem to dissolve OK into methanol. I was wondering if I could take the impure tosic acid and do the pinacol rearrangement by refluxing the glycol in methanol? Is this a good idea, or should I just give up and order lab grade tosic acid?

Rhodium

  • Guest
tosic
« Reply #25 on: April 16, 2002, 06:25:00 PM »
The impure tosic acid probably will work as rearrangement catalyst, but to get those desired high yields, I believe you need some fresh acid from a chem supplier.

Chromic

  • Guest
tosic in methanol
« Reply #26 on: April 16, 2002, 08:29:00 PM »
Rhod, do you think the tosic acid rearrangement will work in methanol? (or is there something critical about benzene?)

I could distill off some of the methanol and then add water and extract with DCM. Should be easy, but will it work?

Chromic

  • Guest
Some searches please?
« Reply #27 on: April 17, 2002, 09:24:00 AM »
Foxy2, could you do a little searching on Pinacol rearrangements in alcohol? Is it possible?

foxy2

  • Guest
pinacol rearrangment
« Reply #28 on: April 17, 2002, 03:13:00 PM »
Check this out
Facile and fast pinacol rearrangement by AlCl3 in the solid state.
Abstract
A facile and efficient synthetic procedure for effecting the pinacol rearrangement catalyzed by AlCl3 in the absence of solvent is developed.  The rearrangement product is obtained at room temp. in a few minutes and in almost quant. yield.  Benzylic pinacols rearrange under these conditions, while aliph. pinacols do not react. 

http://www.mdpi.org/molecules/papers/60500442.pdf



I can't tell if it will yeild the desired ketone or propiophenone?  I think it will bee the right one.  Damn why didn't they do one more experiment. 

Will AlCl3 tear apart the MDO ring?

Here is something also worth looking into for ketone preparation possibilities.  Maybee even a whole new route to MDP2P from the dihalide,  if the dihalide of safrole rearranges to the ketone it would bee even better!!!

Kakis Rearrangement: A series of organic laboratory experiments.
Field, Kurt W.; Moroz, Judith S.   
Abstracts of Papers, 222nd ACS National Meeting, Chicago, IL, United States, August 26-30, 2001  (2001), CHED-426.  Publisher: ACS
Abstract
We have developed a microscale org. lab. expt. which illustrates the Kakis rearrangement and related reactions.  The Kakis reaction, which is comparable to the pinacol rearrangement, involves the silver ion promoted rearrangement of vic-dihalides to aldehydes or ketones.  For example, the reaction of 1,2-dichloro-1,1,2,2-tetraphenylethane, 1, with silver ion and water is solvent dependent.  In aq. (.apprx.1%) methanol, 1 gives 2,2,2-triphenylacetophenone almost exclusively.  However, in aq. (.apprx.11%) acetone, 1 affords near quant. yields of tetraphenylethylene oxide.  An efficient prepn. of 1 from tetraphenylethylene was also developed which eliminates the use of cylinders of chlorine and chloroform solvent.  These transformations illustrate a no. of important mechanistic processes; details of the expts. will be presented.

Those who give up essential liberties for temporary safety deserve neither liberty nor safety

Chromic

  • Guest
Not just that...
« Reply #29 on: April 17, 2002, 04:59:00 PM »
from that paper, "Toda found that the reaction proceeds faster and more selectively in the solid state by using organic acids like CCl3CO2H and p-TsOH [6]."

Toda, F. and Shigemasa, T. "Pinacol rearrangements in the solid state". J Chem Soc. Perkin Trans, 1, 1989, 209-211

That article sounds like it's worth reading. The more I think about it though, the more likely it seems that the rearrangement would work in methanol as it works with H2SO4/MeOH/H2O and in p-tosic/Benzene, so thoughts are that it should work in p-tosic/MeOH. I'm going to go ahead and give it a try anyways.

Antoncho

  • Guest
We are waiting impatiently!
« Reply #30 on: April 17, 2002, 05:22:00 PM »
[drooling]...

/thought you'd enjoy some feeedback,

Antoncho

foxy2

  • Guest
got it
« Reply #31 on: April 17, 2002, 11:38:00 PM »
Ok i was going to the library anyways and i picked up.

Toda, F. and Shigemasa, T. "Pinacol rearrangements in the solid state". J Chem Soc. Perkin Trans, 1, 1989, 209-211

Abstract
The rearrangement of PhCH(OH)C(OH)PhR1 (R1 = Ph, tolyl, anisyl, ClC6H4) to mixts. of PhCOCHPhR1 and R1CPh2CHO was catalyzed by HCl, p-toluenesulfonic acid, and CCl3CO2H.  The HCl-catalyzed rearrangement of MeCH(OH)C(OH)MePh, in a complex with a 2,2'-biphenyldicarboxamide deriv. host compd., gave MeCOCHMePh. 


They were looking at these substituted reactions in this article --> PhCH(OH)C(OH)PhR1 (R1 = Ph, tolyl, anisyl, ClC6H4). This paper is really short and doesn't really apply to pur case, except for a few short statements at the end which reference the following paper which might bee more interesting.
F. Toda, A. Kati, Y. Tagami, and T.C. Mak, Chem. Lett., 1987, 1393.

But this paper does have one very interesting thing.  They say the (dilute H2SO4 33wt% i think, under reflux at 112C)-catalyzed rearrangement of MeCH(OH)C(OH)MePh, yeilds MeCOCHMePh 48%,  (Me)2CHCOPh 29%, OCHC(Me)2Ph 5%.  Then they say that the same selectivity was observed by treating the above with p-TsOH in the solid state. 

I wonder if this same effect is occuring in the isosassy diol rearrangement to give an alpha-methylphenylacetaldehyde contaminant?

Oh yes, one other thing.  They got good rearramngement yeilds using dry HCl gas on the solids mentioned in the abstract.
Foxy


Those who give up essential liberties for temporary safety deserve neither liberty nor safety

Chromic

  • Guest
tosic acid
« Reply #32 on: April 18, 2002, 08:20:00 PM »
>so thoughts are that it should work in tosic/MeOH. I'm going to go ahead and give it a try anyways.

I ran a 29.6g anethole run with 300ml DCM, 13.1g NaHCO3. Added 152.1g peracetic acid (made from h2o2 and GAA that was left to sit 4 days), with 3.8g NaOAc. (heat evolved, and the smell changed to the typical glycol smell) I washed with 10% NaOH two times, went ahead with the impure tosic made from 2.4g toluene and 6.9 H2SO4 with 0.3g H2O (I figure about 4.5g tosic acid, 4.3g unreacted h2so4) in 200mL MeOH. Well, I refluxed for 30 mins, neutralized the acid, distilled off some of the methanol, flooded with water, and washed two times with 10% NaOH. The washes were clear each time. Anyways, it's sitting right now in DCM ready to be distilled and tested.

If this is ketone, it's the most unbelievably clear stuff I've seen after rearrangement. I'll keep my fingers crossed.

Chromic

  • Guest
The results are in!
« Reply #33 on: April 19, 2002, 05:05:00 PM »
Well, I distilled off the DCM and tested with bisulfite. Negative. I tested by trying to form the oxime. Negative.

So I distilled the oil. At 120-200C I got 5.1g forerun (more dense than water), at about 272-278C I got 22.6g. I pulled it off the heat, and maybe 3g was left in the flask. I tested the main fraction with bisulfite. Negative.

Conclusion: the main fraction is not ketone, I don't think it's the acetyl glycol as that normally smells of acetic acid after distillation, so it's most likely glycol. This fits because anethole's BP is 235, the anethole ketone is 268C, so it makes sense for the glycol to be 278C.

This means a couple things:

1) dilute tosic acid in methanol doesn't work to rearrange the glycol

2) distilling glycol does not rearrange it to ketone


This is not to say the technique doesn't work with the epoxide. Who knows? This is not to say that distilling formyl glycols does not rearrange them. Twodogs said in

Post 229901

(twodogs: "Re: Ketones from Propenylbenzenes via the di-bromides", Novel Discourse)
that it works. Remember the reason Horing wanted to check out the epoxide rearrangement by boiling? It wanted to prove that the rearrangement was an intramolecular transformation (not one catalyzed by minute amounts of acid). Perhaps a small amount of H2SO4, p-tosic, or even formic acid from the formyl glycol could be used to catalyze the rearrangement.

PS. When attempting the oxime, I got some white precipitate that definitely wasn't the oxime... what is that stuff? I talked of it in other threads, perhaps some sodium sulfate or something?

PPS. The glycol withstands heat alright, it showed only a very mild discoloration after heating to ~280C for 20 minutes.

For further study: I also wonder if adding just a couple drops of sulfuric acid would bring about the rearrangement of the 20.0g. I'll have to try that!

foxy2

  • Guest
solventless
« Reply #34 on: April 19, 2002, 06:09:00 PM »
Do it solventless!
The diol is liquid right?
Just add the tosic acid right to it.

Those who give up essential liberties for temporary safety deserve neither liberty nor safety

Chromic

  • Guest
sulfuric acid - solventless
« Reply #35 on: April 19, 2002, 06:12:00 PM »
I wonder if adding just a couple drops of sulfuric acid would bring about the rearrangement of the glycol

Well, no that doesn't work either!!! Bisulfite gave some nice white jagged crystals (hey, it's good to be reaffirmed that the bisulfite test actually works!)... but there's obviously oil not reacting. 65% recovered of the ~20g was recovered. Distillate came across at about the same temperature range (~260-~280). Still most of it is the glycol. Damn.

OK... ONE LAST TIME... as foxy2 said, we're going to do it solventless!  8)

Chromic

  • Guest
Welp.
« Reply #36 on: April 20, 2002, 02:11:00 PM »
Well, that was a waste of time... didn't work... it seemed that the p-tosic acid was breaking down at the high temperatures, and the distillate was murky. I guess there's good reason to stick to the references...

Chromic

  • Guest
Another idea on the rearrangement
« Reply #37 on: August 04, 2002, 02:13:00 PM »
Well, I finally am ready for another idea... how does this sound to people?

I was thinking about doing a 100mmol batch of the peracetic (glycol from 16.2g isosafrole) in 100ml toluene using 1.0g tosic (same 1% acid solution, but reduced volume than the reference in

Post 264135

(Scooby_Doo: "Ref on Isosafrole to diol via electro", Novel Discourse)
).

I plan to make the tosic acid in situ as needed, by slowly refluxing 0.57g of 90% sulfuric acid in 100ml of toluene using a dean stark, when that's done, then to add the glycol and continue the reflux for 20mins. I know toluene refluxes at a higher temp but I hope everything will be OK. Then wash with 10% NaOH and distill the ketone.

Does this sound alright to everyone? Would using that huge excess of toluene stop the sulfuric acid from reacting? If so, this seems like a nice easy way OTC way to do the rearrangement. (minus the unusual piece of glass...)

Ritter

  • Guest
tosic acid rearrangement
« Reply #38 on: August 04, 2002, 05:51:00 PM »
Chromic,

That should work just fine, however 20 minutes at reflux temp of toluene is a bit too long.  If you insist running at reflux temp, do it in a HUGE flask because when you add the glycol or formyl glycol there will be a massive effervescence and it really sucks to see your hard work sprayed onto the ceiling.  I recommend you try a temperature in the 100'C range instead of full reflux temp.  When you try this rxn for the first time you will quickly understand why I suggest this!

Chromic

  • Guest
Ok, thanx Ritter. I'm preparing the tosic acid ...
« Reply #39 on: August 05, 2002, 11:22:00 AM »
Ok, thanx Ritter. I'm preparing the tosic acid now. I used 0.5ml sulfuric and 0.5ml water with 100ml toluene (I know that a bit of an excess, but I felt weird using any less) and am refluxing with tons of stirring and a dean stark... it seems to have the characteristic smell of tosic acid (of other runs I've done), but, there's this black sludge coating the flask. I hope it's just the dirty tosic acid dissolved in water... I hope after refluxing for a few more hours that that water in the sludge collects in the trap and the contents of the flask form some sort of homogeneous solution.

I feel so close to completing this...