ArOR, Alternatives to dimethyl sulfate

[PolytheneSam]

Antoncho, have a look at that British patent, especially page 3. 

Post 226605

(PolytheneSam: "Re: ArOR, Alternatives to dimethyl sulfate", Novel Discourse)
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[UTFSE]

yep there's that SO3 arearing its stinky little head again.

oxidize SO2 over catalyst (CU?) and pass directly into H2SO4 and don't drink any. well???
always appreciate your time and consideration

[PolytheneSam]

This comes from Experimental Organic Chemistry by J. F. Norris 1933, pages 84-85.  I wonder how it would work with methanol.

Preparation of Potassium Ethyl Sulphate  (a) Pour into a small flask 20 cc. of ethyl alcohol, and add slowly with constant shaking 10 cc. of concentrated sulphuric acid.  Connect the flask with a reflux condenser and heat on a boiling water-bath for one hour.  Cool the liquid and pour it slowly into 200 cc. of cold water.  The solution contains ethyl sulphuric acid, alcohol, and sulphuric acid.  The acids are separated by making use of the fact that barium ethyl sulphate is soluble in water and barium sulphate is insoluble.  Add to the solution, with constant stirring, small quantities of barium carbonate¹ as long as carbon dioxide is evolved. Filter in a porcelain funnel, and wash the precipitate twice with about 20 cc. of hot water.  The filtered solution contains barium ethyl sulphate.  Write equations for all the reactions.  Test 5 cc. of the solution for barium in the usual way.  (Eq.) Test the solutiion for a sulphate.  Result?  Heat about 5 cc. of the solution with about 1 cc. of dilute hydrochloric acid.  (Eq.)

(b)Conversion of barium ethyl sulphate into potassium ethyl sulphate. -- Heat the rest of the solution of barium ethyl sulphate to boiling and add a solution of potassium carbonate until the solution is slightly alkaline.  (Eq.)  Filter hot, wash the precipitate twice with a small amount of hot water, and evaporate the filtrate to crystallization on a steam bath.  When cold, filter off the crystals and wash them with a little cold alcohol; dry on a porous tile.  The salt can be recrystallized from boiling alcohol.

¹ If barium carbonate is not available, calcium carbonate may be used.

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[PolytheneSam]

It says in the Merck Index 9th edition under methyl sulfate.

5995. Methyl Sulfate.   sulfuric acid monomethyl ester;  methylsulfuric acid;  methyl hydrogen sulfate; monomethyl sulfate; acid methyl sulfate;.....

from methanol and sulfuric acid:  Dumas, Peligot, Ann. 15, 40 (1835).....

Oily liquid: does not solidity at -30º C.  d¹⁵ 1.45-1.47.  Freely soluble in water, less soluble in alcohol.  Miscible with ether.
See also Dimethyl sulfate.
Barium salt, C2H6BaO8S2, barium methyl sulfate.Dihydrate, efflorescent crystals.  Poisonous! Sol. in water, alc.
Calcium salt, C2H6CaO8S2, calcium methyl sulfate, calcium sulfomethylate. Crystals.  Soluble in water.

Note that both the barium and calcium salts of methyl hydrogen sulfate are soluble in water.  Barium sulfate is practically insoluble in water (1 gram dissolves in 400,000 parts), dilute acids and alcohol.  Calcium sulfate is soluble in water (0.2 parts/100 parts at 18º C anhydrous CaSO4). (source:  Merck Index 9th edition).  In the Handbook of Chemistry and Physics CaSO4 (anhydrous), the hemihydrate (Plaster Paris) and dihydrate are listed.  Solubilities in cold water (20-30º C) for each are about 0.2-0.3 g/100 ml water.

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[foxy2]

I wonder if Barium hydroxide can bee used instead of the carbonate?  Would it decompose the product?
Do Your Part To Win The War

[Antoncho]

Sam, i'm sorry to say that but this is essentially the same procedure that is sitting at Rh's like for ages      - the problem with it is the filtrations. They are not only - to put it mildly - a major pain in the ass - but also yield-killers.
This US patent that you gave me, Sam, - 2,176,005 describes an easy way to avoid this problem.
You could use alkali earth hydroxides as well, at least w/Ca(OH)2 it is a standard way they make it in Russian literature.

The whole point in all this is the fact that one doesn't need pure methylsulfate neither for methylation (as the russian patent suggests) nor for nitroalkane synth - my collegue Vitsh's uncle's third cousin's dog reports a 28% yield (based on ethylsulfate) from 50/50 mixtr w/sulfate.

SWIM tried to pull that Ca procedure (he didn't read that patent at the time though) and he shivers at the very thought of possibly having to repeat it one day.

Antoncho

[PolytheneSam]

I remember seeing something posted about it, but when I UedTFSE on Rhodium's site using the keywords sodium, ethyl and sulfate I didn't find it.  I think I tried ethyl and sulfate alone, but still didn't find it.
Are you talking about this? 

https://www.thevespiary.org/rhodium/Rhodium/chemistry/diethylsulfate.txt

That's on diethyl sulfate not salts of monoethyl sulfates.
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[Rhodium]

It's in here:

https://www.thevespiary.org/rhodium/Rhodium/chemistry/nitroalkane.html

[PolytheneSam]

Oh, yeah.  Nitroethane from sodium ethyl sulfate.  Thanks, Rhodium.  Now can anyone find information about the equilibrium constants of methyl hydrogen sulfate and ethyl hydrogen sulfate in water?

MeOH + H2SO4 = MeHSO4 + H2O
EtOH + H2SO4 = EtHSO4 + H2O
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[halfapint]

Sam, I don't have the detailed info you need, but a darn good approximation is: don't put 'em in water. They hydrolyze instantly. That's why drying agents are used in their production, right?

Your correct link above is

https://www.thevespiary.org/rhodium/Rhodium/chemistry/diethylsulfate.html

Gotta get up pretty early in the morning to keep up with Rhodium. He's always upgrading his site.
turning science fact into <<science fiction>>

[PolytheneSam]

That link worked when I posted it.  Also, I read that alkyl hydrogen sulfates and dialkyl sulfates hydrolyze slowly in water.
http://www.geocities.com/dritte123/PSPF.html

[Rhodium]

They hydrolyze slowly enough to make water a usable reaction solvent for alkylations of phenols.

[Antoncho]

Well guys what would you think – NaMeSO4  methylation (according to SWIM’s astral projection’s memoirs) clearly works on hydroquinone. p-diMeO benzene is distilled out fast - as soon as it forms, as it seems. SWIM ain’t sure of yield though because he had an accident as a result of which… oh well- you all probably know what kind of a chemist he is  The condenser tends to get plugged w/the product crystals, so watch it (and make an “emergency outlet” in the stopper).

SWIM will try to re-do it properly and do a write-up, but he has an important question – please, help him.

What if instead of steam-distilling the p-diMeOB, one just poured some toluene on top of the rxn and refluxed it for some time? Actually, the Q is – would the product evaporate appreciably when later distilling off toluene (at atm. pressure)?

SWIM, let alone Antoncho, is totally uneducated in this field

Thanks ahead,

Antoncho

[Rhodium]

1,4-dimethoxybenzene is a solid at room temp (melts at 40-50°C?) and it will not evaporate readily. However, it has a tendency to sublime even at room temp, but as I understand it, solids cannot sublime as long as they are covered with solvents (the toluene). The general idea I'm trying to convey here is to not heat the product too much after the toluene has evaporated. If it is at all possible, extract the product with a more low-boiling solvent.

[PolytheneSam]

Here's some information from the 60th edition of the Handbook of Chemistry and Physics.  Hydroquinone dimethyl ether is under benzene, 1,4-dimethoxy- in the 60th edition.  Mol. Wt. = 138.17, lf(w) ...., m.p. = 58-60, b.p. = 212.6, 109²⁰, density = 1.0526 at 55º C, slightly soluble in water, soluble in alcohol, very soluble in ether and benzene.

lf(w) means leaflets from water so it looks like you can recrystalize it from water.  109²⁰ means the boiling point is 109º C at 20 mm pressure (212.6 at atmospheric pressure).  Since the melting point is 58-60º C maybe you could try an air cooled condenser or use hot water in your condenser.  To get all the steam to condense, cool the receiver in an ice bath and use a stopper and/or adaptor between the condenser and receiver.  The crystals should form in the receiver.  I would just stay with the steam distillation. 
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[Antoncho]

Thanks for the replies, and i will certainly take advantage of Sam's advice if i decide to go via 'classic' route.

But still there are more questions.

1st of all - diMeOB is a liquid at 110 C, more so, its bp is only a 100 C higher than that. What i meant is - won't it form an azeotrope or some such or just co-evaporate (the way MeOH does w/water) - in this case it may bee ruining.
And the whole point of doing this w/toluene (SWiM does have some low-boiling solvts ) is that rather than steam-distilling it and then doing all that work-up, one would get all his DMB immediately absorbed into the toluene layer, which i believe would remove it faster from the alkaline envir't (thus increasing the yield) as well as simplify whole thing technically - IF and only if toluene could bee boiled off.

Would a glass-filled 50 cm fract. column bee of help in this?

What if it was just left to evap. at RT under a fume hood - or will that make for a yet higher DMB sublimation rate?

Or - will p-diMeOB, possibly, fall out of it if chilled to well below zero?


     - i know asking questions is easy.

Antoncho

[Rhodium]

I don't know about the sublimation rate, I have seen two containers of dimethoxybenzene, and one had some crystals hanging from the lid, and the other had not. I took that as an indication of that the compound was able to sublime. I have no other proof.

If the boiling points are 100°C apart, you don't need a column. IF you chill the toluene solution, it is possible that some dimethoxybenzene will precipitate, but definitely not all of it.

My suggestion is that you try a small-scale run with the reaction, and then distill off the toluene using the procedure you suggested, and as soon as toluene stops coming over, chill the distillation flask, and you will get your crystalline product. Purification suggestions are either vacuum distillation or recrystallization from something (dunno what).

If sublimation or azeotrope formation (the latter I find unlikely) is a problem, you will notice this by a lower yield, and dimethoxybenzene-smelling toluene in the distilling flask, or dimethoxybenzene crystals forming in the distuillation head/condenser after cooling. But this is no serious problem, as all your product is still left in the distillation apparatus and/or toluene. Try it - any success story goes right on my page.

[PolytheneSam]

I remember CHEMMAN saying something about some phenylacetone distilling over with toluene. I think this is the post 

Post 52419 (missing)

(CHEMMAN: "Ketone purity", Methods Discourse) . Also I heard of someone distilling off toluene from amphetamine base after extracting it with toluene.  After a while the amphetamine base distills over with the toluene.  He figured this out by adding H2SO4 (sulfate precipitates) to the toluene which distilled over.  He filtered out the ppt. and left the toluene filtrate in a pan to evaporate to get more of the infamous sulfate.
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[Rhodium]

Okay, but there is no such agent that can be added to trap dimethoxybenzene, unfortunately.

[Antoncho]

Well fuck my life I must confess it ain’t as good at all. The yield sucks. Specifically it was 17,7% in SWIM’s case.

SWIM made a rxn w/150 ml water, 70 g of 50% NaMeSO4, 10 g NaOH  - to that 9 g HQ in 100 ml water was added in 4 portions over 3 h at reflux (bath temp 140 C, yes that’s how it should bee) – everything under inert atm. 30 min after that time no more oily drops/crystals appeared in the condenser, ~150 ml distillate collected, pure white product filtered out, pressed dry & air-dried, water phase extr’d w/50 ml DCM, dried/evap’d – yielded really negligible amt, ~100 mg of reddish stuff. The weight of the product was 2 g.
SWIM didn’t extract the rxn mixture itself, as he doubts there’s much in it – and it is doomed to bee dirty (the mxtr gets pretty brown at the end)
Well I think it’s not ultimate yet – 1st of all methylsulfate was quite dirty (which SWIM found out only when he got to the rxn – obviously, the Na2CO3 SWIM used to neutralize HMeSO4 contained some washing powder (!!!    I know what you’re thinking of SWIM now – and he deserves it ) And, in addition to that – that methylsulfate contained an unknown quantity of Na2CO3, and, what’s worse, possibly, NaHCO3 (neutralizes NaOH) – so, to summarize all said above, it was again not a scientific experiment  

SWIM thinks he’s going to do that one more time – this time precisely like in the patent (BTW, I noticed they actually used toluene for all extractions! – didn’t specify how they removed it, though)

So there still might bee something similar to a success story yet, although I’m not nearly as optimistic now as I used to bee.

Antoncho