Author Topic: H2SO4 + toluene --> p-tosic acid  (Read 5831 times)

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psyloxy

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H2SO4 + toluene --> p-tosic acid
« on: May 07, 2004, 07:23:00 PM »
p-toluene sulfonic acid

110 parts toluene are sulfonated with 600 parts concentrated sulfuric acid at ordinary temperature. After all toluene is dissolved 250 parts ice or water are added with external cooling and stirring until the whole mass to solidified to a thick mash. Next the rxn mixture is vacuum filtrated. Crystalline p-tosic acid remains.

Patent DE57391



--psyloxy--

Aurelius

  • Guest
ordinary temperature?
« Reply #1 on: May 07, 2004, 10:33:00 PM »
Do you mean 'room temperature'?  As in, needing no external source of heat?

(I presume this is what you meant as the details were scant.  Taking from your others posts, this means the procedure is damn easy.)


psyloxy

  • Guest
gewöhnlich
« Reply #2 on: May 07, 2004, 10:39:00 PM »
Ordinary is what the patent said, which is old fashioned for room temp. No other details were available from the text (the translation is 1:1), I presume that's because the authors took for granted everybody knew what the standard conditions of toluene sulphonation are, the invention doesn't directly relate to the production of tosic acid, but to the separation of the isomeres, the given example beeing a combination of both.

--psyloxy--

psyloxy

  • Guest
toluene + H2SO4 --> o-tosic acid (50% yield)
« Reply #3 on: May 13, 2004, 11:08:00 PM »

Patent DE35211

preparation of ortho-toluenesulphonic acid

Toluene is sulfonylated by ordinary concentrated sulfuric acid with constant stirring at a temperature that must not exceed 100°C and regarded as finished as soon the top layer of toluene is gone. The mixture is decanted into cold water, neutralized with CaCO3, filtered off the CaSO4 and decomposed with Na2CO3. The water is removed by heating the mix. Content of the ortho-isomere : 40-50%.

See

Patent DE57391

and

Patent DE137935

for resolution of the isomeres. Basically the ortho is hardly dissolved by 45-55% H2SO4, the para by 66-71%, both are precipitated by cooling to become ~90% pure. Fractionated crystallization is the magic word.

note in the procedure in the post above the filtrate contains ortho-TsOH in amounts approximately equaling those obtained by the procedure here, both are essentially the same anyway.

--psyloxy--

sYnThOmAtIc

  • Guest
Orhto?
« Reply #4 on: May 14, 2004, 06:15:00 AM »
What would happen to a glycol that is treated with ortho? Nothing? I was wondering if the p-tosic is contaminated, would it screw things up or should one just correct for the loss of the active p-isomer. So I guess my point woudl be, will the ortho do the same job, be inert in that type reaction, or screw sometign up(side reactions that aren't wanted causing loss in yield)?

Just wanted to be clear on what "essentally the same" means since I don't know what intended usage it is essentially teh same for.  Also will other sulphonated aromatics do teh same thing? Might try sulphonating xylene and doing a rearrangment if I find a procedure for its prep seeing as toluol is hard to get these days.

Edit:After a quick search it seems that xylens sulphonate is motre acidic than toluene sulphonate. Is that good or bad? Basically just want to know if it is practical or if it has ever been kown to work.


Type:10 cps Para-toluene sulphonic acid
Appearance:  Clear amber
Specific Gravity @ 25°C: 1.25 gm/cc
Total Acidity % 68-72%
Viscosity: 10 cps
Free Sulphuric Acid: 1.2% max.
Shelf Life @ 20°C: 24 months.


Type: Xylene Sulphonic
Appearance:  Brown
Specific Gravity @ 25°C: 1.27 gm/cc
pH 2
Free Sulphuric Acid: 3% max.
Total Acidity: > 90%
Shelf Life @ 20°C: 24 months.

psyloxy

  • Guest
clarification
« Reply #5 on: May 14, 2004, 06:49:00 AM »
What's the stuff useful for ? __>

Post 506492

(psyloxy: "o-cresol from potassium o-toluenesulphonate", Methods Discourse)


'Essentially the same' meaning: both procedures are sulphonylations of toluene with conc. sulfuric acid at relatively low temperatures, both producing a ~45%/55% mixture of ortho and para-isomeres, in the first one the para is isolated, while the ortho stays in solution, in the second one it's the other way around.

--psyloxy--

acx01b

  • Guest
somebody has some informations about the use...
« Reply #6 on: May 18, 2004, 02:07:00 AM »
somebody has some informations about the use of ptsa in imines synthesis ?
(toluene amine ketone and a few ptsa is refluxed in Dean-stark)

imine can also be prepared without refluxing:
amine+ketone+drying agents
drying agents can be molecular sieves, MgSO4, CaCl2, KOH...

what about the use of small amount of conc. H2SO4 and toluene, or directly ptsa?
amine + ketone + drying agents + 1ml Conc. H2SO4 + 5ml toluene

maybe it reacts faster ?

phenethyl_man

  • Guest
substituted toluhydroquinones from o-cresol
« Reply #7 on: October 10, 2004, 09:56:00 PM »
The sodium salt of o-toluenesulfonic acid should also be able to be used in the fusion w/alkali to produce o-cresol.

toluhydroquinone from o-cresol in 95%+ yields through acetylation to 3-methyl-4-hydroxyacetophenone and subsequent oxidation w/hydrogen peroxide.

Patent IE904369



substituted hydroquinone acetals (i.e. toluhydroquinone monoacetate) through acetylation followed by oxidation w/ a percarboxylic acid.

Patent FR2655335



Any use for toluhydroquinone monoacetates? Perhaps in the preparation of "tweetios" of DOM..?  (which were so elegantly named "Florence" and "Iris" by Shulgin)

It's too bad there is no route to MMA from o-cresol (or at least I can't think of one.)  It would be impossible to introduce an aldehyde group para to the methyl due to the para-activating effect of the hydroxyl.  However, perhaps iso-MMA would be interesting.  Anyone have any literature on 3-methyl-PMA (3-methyl-4-methoxyamphetamine)?

If you formylated first, you could get p-tolualdehyde in high yield from the Gattermann formylation on toluene at high temperature.  I'm not sure if p-tolualdehyde could be sulfonated but even if it could, the fusion w/alkali would undoubtedly yield 3-hydroxytoluic acid.  Which I guess could be reduced to the alcohol with LAH and oxidized to the aldehyde but why bother?