Author Topic: Ethyl hydrogen sulfate  (Read 18021 times)

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halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #20 on: March 12, 2002, 10:55:00 AM »
Well, Antoncho, after you take your excess methanol off, you have left a heavier, more viscous fluid, mainly composed of DMS. But, pardner, it's green. The presence of copper, we may note, does some tricky things. It could easily complicate your methylation reaction. Afterward, you should easily bee able to separate your organic component -- if the methylation works...

I heard your part of eastern Siberia was really civilized. The wild East. Like everywhere else: too much development, too many left out. To get water pressure, if you have a suitable rural location/situation, I suppose you'll have to build a water tower. Then an aspirator could work at your place. When you explain all this to your significant other, I'm sure she'll approve your hydrology project.

I gassed 5 hours the first time. The exiting SO2 had very little pressure, for bubbles into the final HCl solution were rare. Except when I poured a coffeepot of hot water over the methanol vessel, to re-establish my "mild conditions", when the HCl was bubbled vigorously. Examining the second run, with 4x the copper concentration, I noted the bubbles were quickly almost consumed before reaching the surface.

a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #21 on: March 12, 2002, 06:08:00 PM »

I heard your part of eastern Siberia was really civilized. The wild East. Like everywhere else: too much development, too many left out. To get water pressure, if you have a suitable rural location/situation, I suppose you'll have to build a water tower. Then an aspirator could work at your place. When you explain all this to your significant other, I'm sure she'll approve your hydrology project.




;D  ;D  ;D  ;D  ;D LMAO! I understand you meant it as a joke, but i still feel oblidged to clarify on this - at least once on this board (yeh, a wrong forum, i know). Perhaps the mods will forgive me for offtopic.

My part of Eastern Siberia is just as civilized as any its other part, as well as any other part of the country. We do have waterpipe system :) , as well as anything else you could expect to meet in a city - the only visible difference between where i live (near Baikal lake - maybee you've heard of it) and an ordinary Northern US city w/population of ~600,000 is the fact that the closest other 'big' city is situated some 1000 kilometers to the West :) , and in the space between them there's basically nothing. A vast sea of uninhabited space covered w/forest.

The reason SWIM doesn't have a source of running water is simply his sharing apartment w/the rest of his family (that's very common here as renting or buying a place to live is very expensive) - every single member of which hates his chemistry with passion :)  - mainly beecause of odour ;D  - and won't tolerate its presence anywhere else than in SWIM's bedroom. In which there is no source of running water :)  :)  :)

So... guess you'll say SWIM's crazy to do chemistry where he sleeps, but
a) he constantly vents the room
b) he takes all possible precautions, including the fume cupboard that he built from whatever the Fate had sent him - not exactly a water tower, but still quite something! ;)  :)  ;D




Now to the chemistry. As i said, this project of yours, dear Half-a-Pint, absolutely rocks and it's been quite some time since i've been so exhilarated about something!

Say, would it bee possible, you think, to remove the residual copper salt by simply washing DMS w/water? To swim it seems OK - even though some DMS will also dissolve. After all, it can always back-extracted (although i doubt SWIM would want to do that!)

Maybee - just in case if you plan another trial  - you could check that suggestion on a coupla milliliters of your DMS? Please? Just mix it with an equal volume of water, shake until homogenous and see if the color goes to the top layer? That would mean really something for SWIM!

Another, although much less appealing, alternative would bee to dissolve DMS in benzene and wash the solution several times - that is bound to work, i think.

And - dear Half-a-Pint - Antoncho prays you! - do a detailed write up - with all the weights in grams, temps in degrees and times in hours! That way your xperience will not only bee much more reproducible, it will also certainly immediately make it to Rhodium's page.
You didn't even tell us how much DMS you actually got!

Well, i guess i'm done for now - and i'm really looking forward to hear more from you ;)

As ever,

Antoncho

uemura

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Re: Dimethyl/Diethyl Sulfate
« Reply #22 on: March 13, 2002, 01:30:00 PM »
half-a-pint!

Should somebody do this with me, I won't bee jealous.




You give Uemura a hard time, half-a-pint. First, your sodium-phosphite/CuCl2 (*) method for the trimmethylphosphate looked so much better than the Uemura P2O5 approach. Having finally all bits and pieces for this rxn together, you now invite Uemura to use his CuCl2 (**) to make DMS  :) .

Not having as much concern as Antocho has with respect to the DMS toxidicy (Uemura has reasonable semi-prof lab equipment and has long time ago blown out 500ml RB with metyhlation in progress -wasn't that much nice-) he still isn't sure if DMS is much superior to trimethylphosphate. He thinks DMS is just always used because it is cheaper and it is easy available to professional chemists.

When joining and chross-checking your rxn, Uemura would prefer to generate the SO2 from NaSO3 and H2SO4, followed by drying over CaCl2 (***). Questions: what was the molar amounts of MeOH, CuCl2 and SO2 used in your rxn? Anything warmed up / refluxed?

Uemura will consider to verify your method!
(*) This CuCl2 catalised rxn looks anyway very similar to the method discussed here.
(**) uemura fully confirms the method for the CuSO4/CaCl2 -> CuCl2/CaSO4 followed by just boiling away the water to get the brown anhydroneous CuCl2 salt.
(***) Would it be better to bubble thru H2SO4?


Carpe Diem

otto

  • Guest
Re: Dimethyl/Diethyl Sulfate
« Reply #23 on: March 13, 2002, 08:22:00 PM »
indeed halfapint,

otto prepared some copper-(I)-chloride a while ago. this is a white solid, insoluble in water or methanol. upon exposure to air it turned green very quickly, especially when humid.

otto has strong believe that your green residue is some copper(II)-oxychloride or -hydroxychloride (which isnt soluble in water, check with your precipitate!). you should be able to dissolve it in HCl, bubble air into the solution (or H2O2) to reoxidize any remaining copper(I)species and you end up W/ a solution of copper(II)-chloride in HCl.

a suggestion, otto isnt sure of: mix your green copper-residue (after giving it some time to fully get oxidized by exposure to air, preferably with some water as oxidation will be faster then) with an excess (say: 5 times) of NH4Cl and heat it until no more NH4Cl-fumes will come out. you should end up w/ dry CuCl2.

otto

uemura

  • Guest
Re: Dimethyl/Diethyl Sulfate
« Reply #24 on: March 17, 2002, 09:55:00 AM »
Good Morning Half-a-pint,

Uemura again comes up with questions where he wants to join the requests of Antocho. It would bee helpful to provide us with some quantitative figures for the rxn, espec. the amount of CuCl2 used in the method.

One of reasons why Uemura may want to repeat your experiment is that methylation of gallic acid with trimethylphosphate was found to be only 50% as effective as with DMS (which he did succesfully long time ago).

All bees would appreciate your inputs!

Carpe Diem

Antoncho

  • Guest
The original article
« Reply #25 on: March 22, 2002, 05:01:00 PM »
A Hyperlab friend of ours, Diafrag, retrieved the original article on CuCl2 oxidation by Golodov and Panov. There isn't a single word on any disproportionation or anything like that in it - they plainly state that CuCl2 is an oxidant.
They state the rxn equation as:

2ROH + 2CuCl2 + SO2 ---> (RO)2SO2 + 2CuCl + 2HCl

R=Me, Et. It goes equally well w/both.

The article deals mainly w/kynetics , so the yields or some such aren't given.
The xperimental details are: 30 C, SO2 and MeOH aren't crucial , however, they measure the rxn kynetics at SO2=100% vol. of MeOH. That is, not much at all??? CuCl2 concentration 0.05-0.2 mole/liter. Time not specified.

????

Maybee, smth different happens when you use a very large xcess of SO2???

Also - Half-a-Pint, a thought occurred to me that some of your DMS that was left in the flask after didtilling off MeOH might actually have been HMeSO4 - which was converted to DMS anyway after distillation. If you ever do it again, PLEASE, check the initial (pre-distillation) product's water solubility!

Antoncho

halfapint

  • Guest
I quit theorizing, so gimme a break.
« Reply #26 on: May 08, 2002, 07:36:00 AM »
When I got back to Hive this time, took me a while to find this thread. And my notes are scrambled, so from memory: yield on my 3rd run amounted to 78% calculated on the basis of CuCl2. No metaphysical reoxidizing happened, the copper was reduced. Yes, about 2/3 of my methanol became DMS, like I said, but that was an artifact of the amount used. The cuprous precipitate does whiten in its reduction. I also did have a small amount of sulfur sublimation, since no trap was used in the SO2 line. This has AFAIK no effect on the reaction, still maintain no trap is needed, for any vapor from sulfuric acid is dry. I reiterate, this is the cleanest generation for dimethyl sulfate I know: cheap, easy, efficient, low hazard, low fumes. Diethyl sulfate was also obtained in this way, but that run has not been repeated for quantitative reporting.

a half a pints a half a pound a half a world a half a round
Sidearm n. Flask neck tube.

Antibody2

  • Guest
hi halfapint i like you rxn, i have a question ...
« Reply #27 on: July 20, 2002, 12:47:00 AM »
hi halfapint

i like you rxn, i have a question though, something i haven't been able to puzzle out on my own, perhaps you can enlighten me.

you got 78% yeild based on CuCl2, yet CuCl2 and MeOH are consumed in equimolar proportions, so by my calculations if 66% of the MeOH (2M let say) was converted (42g) that would require 176g CuCl2, if your yeild based on CuCl2 was 78% that means you used 225g of CuCl2.

I don't understand how you dissolved you dissolved 225g CuCl2 in that minute amount of MeOH (64g). Was it added in portions with the reduced CuiCl being filtered?

2M MeOH = 64g
2M CuCl2 = 268g

Antibody2

  • Guest
otto has strong believe that your green residue ...
« Reply #28 on: July 21, 2002, 12:52:00 AM »
otto has strong believe that your green residue is some copper(II)-oxychloride or -hydroxychloride (which isnt soluble in water, check with your precipitate!). you should be able to dissolve it in HCl,

the residue after distillation is indeed insoluble in MeOH as well as H2O, but is easily digested by 31%HCl, for whatever that is worth. Further, after the SO2 generation is finished, if the flask is allowed to sit overnight the precipiattion of the copper byproduct increases considerably, i don't know if just takes a long time to crustallize or if the rxn continues for some time after the SO2 generation stops.

Mountain_Girl

  • Guest
Patent: DMS/DES from MeOH/EtOH & H2SO4
« Reply #29 on: April 02, 2003, 09:01:00 AM »

Patent GB581115

:

Alkyl sulphates wherein the alkyl radical contains not more than four carbon atoms are prepared by heating sulphuric acid with an aliphatic alcohol containing not more than four carbon atoms, preferably at a temperature of about 80  to 120 °C, passing a stream of an inert gas into and through the reaction mixture to entrain in the vapour phase water and alkyl sulphate formed by the reaction, removing the issuing gas stream laden with water and alkyl sulphate vapours and recovering the alkyl sulphate from the gas. The process may be carried out in a continuous manner in a system involving a reaction vessel interconnected with a condenser, a receiver and a gas pump, by continuously or intermittently introducing into the reaction vessel sulphuric acid and the aliphatic alcohol, heating the mixture therein to a temperature between 80 and 120 °C, continuously injecting a stream of an inert gas into and through the reaction mass and continuously moving the issuing gas stream laden with water and alkyl sulphate vapours into the condenser where the water and alkyl sulphate condense, whereupon the gas stream is reinjected into the reaction mass, the pump recirculating the stream of gas through the system to thereby continuously remove the water and alkyl sulphate formed. The condensate in the receiver forms two layers, whereby the alkyl sulphate may be separated and recovered; the water layer containing some ethyl hydrogen sulphate may be concentrated and returned to the reaction vessel. Preferably, the reaction is commenced and maintained with the sulphuric acid in excess of molecular proportions, for example an initial ratio of between 2 : 1 and 1 : 1 is suitable, followed by addition of alcohol and acid in a 2 : 1 ratio to balance the consumption in the reaction. Methyl and ethyl alcohol are preferably reacted at a temperature of 100 to 105 °C and the propyl and butyl alcohols at 90 to 95 °C. Inert gases specified are air, carbon dioxide, hydrogen and nitrogen. Examples illustrate the preparation of ethyl sulphate and methyl sulphate by the continuous method described above.


Antoncho

  • Guest
Triple wow.
« Reply #30 on: April 02, 2003, 03:08:00 PM »
All i can say to this is:

WOW!!!

WOW!!!

WOW!!!




M_G, you have just provided us with a completely OTC synthesis of all imaginable alkylating agents! I mean,.... Oh well...


Now, this synthesis is DANGEROUS. Dialkyl sulfates are deadly carcinogenic compounds and a great care must bee exercized.

The only real obstacle in performing this synth i see is the need for thorough mixing of the reagents. Some real vigorous stirring or shaking, probably... Can you fit a mechanical stirrer into the rxn flask so tightly as to prevent ALL leaks thru which DMS-saturated vapours will escape into your atmosphere?


Any other suggestions?


Very good, M_G, i didn't hope to ever see such a synthesis! (and it's good that i didn't know about it a year ago, i would've already poisoned myself ;D  ;D  ::) )




Antoncho



P.S. Oh, yeah. DMS's azeotrope w/water: bp 98 C, 27% DMS.

moo

  • Guest
I'm impressed... It is beautiful!
« Reply #31 on: April 02, 2003, 06:21:00 PM »
I'm impressed... It is beautiful! ;D

You could make a paraffin-sealed stirrer as there seems to be no risk of pressure changes. It could happen if someone managed to close the system somehow, but that would be a catastrophe anyway. Some people might just settle for sealing a grass stirrer shaft with telfon tape, with careful testing of course.

Antoncho

  • Guest
Further thoughts...
« Reply #32 on: April 02, 2003, 06:49:00 PM »
Hey, beez. 1st of all, here's a quote from the patent text: "...or the reaction vessel can bee filled w/Raschig's rings, in which case stirring is unnecessary".

So, you see that there's at least 1 solid way to make things easier (can anyone think of an OTC substitute for Raschig's rings? ;) )


Then, if you remember what the patent says, the rxn represents a classic case of an equilibrium rxn. It is precisely the removal of BOTH water and dialkylsulfate from the rxn mass which makes it work.

So i suggest the following:

Combine equal volumes of toluene and HAlkSO4 of your choice. Add an xcess molar amt of some drying agent that is capable of holding water at 100 C. Place the flask into boiling water w/frequent stirring or shaking. When (that is, IF) the phases disappear, cool and decant the upper layer (hopefully, the salts will settle).

Alternatively, chill the stuff in freezer and wash out the salts w/ice-water (dialkyl sulfates, esp. DMS, are readily hydrolyzed w/aqua, but at this temp the losses should bee negligible). Dry the mixtr while still cold (here, again, we need a drying agent that will suck water at LOW temp) and strip off tolly (actually, this toluene solution can bee used for methylation as is, but stripping it off from the resulting product will bee more ruinous to the enterprize).


Sounds complicated? Well, but you don't have to

a) buy an air pump
b) risk breathing DMS

To summarize said above, SWIM has quite a bit of xperience in ghetto chemistry (i assume, if one can't get DMS, you probably works in ghetto conditions, right? :) ) and he knows that he wouldn't want to build a potentially non-hermetic vapor-phase system for production of such substances...



I have a big question for everyone: does anyone know what drying agents hold water at >100 C? And how many molecules of water they bind? Namely, what do you think of MgSO4 and CuSO4?





Antoncho

Vitus_Verdegast

  • Guest
raschig rings
« Reply #33 on: April 02, 2003, 08:14:00 PM »

So, you see that there's at least 1 solid way to make things easier (can anyone think of an OTC substitute for Raschig's rings?)




What about glass tubing cut in 1/4 pieces with a glass file?






Aurelius

  • Guest
works
« Reply #34 on: April 02, 2003, 09:16:00 PM »
That works fine, just don't go trying to use diazomethane with it :P

lugh

  • Guest
Tedium
« Reply #35 on: April 03, 2003, 03:03:00 AM »
Flame annealing of each edge will solve that problem  :)


Aurelius

  • Guest
Tedium
« Reply #36 on: April 03, 2003, 07:34:00 AM »
And I thought typing patents sucked! :P

Vitus_Verdegast

  • Guest
raschig rings are kinda OTC
« Reply #37 on: April 03, 2003, 06:19:00 PM »
They're not hard to get, if distilling your own booze is legal in your country  :P . Look for online brewery and distillery supply stores.


Mountain_Girl

  • Guest
Antoncho, the wild enthusiasm of your posts is
« Reply #38 on: April 04, 2003, 09:43:00 AM »
Antoncho, the wild enthusiasm of your posts is always entertaining and contagious to me  ;D

Thoughts:

* What I find strange about this method is that the more volatile alcohol is not preferentially entrained in the gas. The initial conversion to the HAlkSO4 is itself an eqbm reaction, which means there will be unreacted alcohol present to be volatilised. I guess this step lies enough to the right so that the method remains effective overall. However it would still make sense to me to slowly drip the alcohol into a large excess of acid so that most of it is converted before it can be carried away.

* When the patent refers to Raschig rings I believe what they really mean is a packed bed through which liquid and vapor are passed counter currently, a common industrial practice. Rachig rings and other forms of packing are used to increase the liquid/vapor interfacial area but I don't think they would be effective in a static medium, i.e. simply sitting in a reaction flask.
Personally I expect that the agitation supplied by the bubbling of gas will be sufficient.

* To further improve yields I would suggest charging the reactor with dried alcohol, and passing the carrier gas thru conc. H2SO4 1st.

* Combine equal volumes of toluene and HAlkSO4 of your choice. Add an xcess molar amt of some drying agent that is capable of holding water at 100 C.

Instead, perhaps you could remove the water by distilling off the toluene/water azeotrope, and replenishing with dry toluene as it is removed ?
Also, a product of the decomposition of HAlkSO4 to (Alk)2SO4 is H2SO4 which...wait - if u have the HAlkSO4 then surely dewatering is not the issue ..the reactions are:

1) AlkOH + H2SO4 <---> AlkHSO4 + H2O 
2) AlkHSO4 <---> (Alk)2SO4 + H2SO4

Dewatering drives the 1st reaction not the second ??
Me confused or u confused ?


moo

  • Guest
Instead, perhaps you could remove the water by
« Reply #39 on: April 04, 2003, 04:17:00 PM »
Instead, perhaps you could remove the water by distilling off the toluene/water azeotrope, and replenishing with dry toluene as it is removed ?

Using a Dean-Stark trap or even plain distillation setup sounds like a good idea, but having H2SO4 around with toluene might lead to formation of toluenesulfonic acid, which as water is removed might react to the alkyl toluenesulfonate. But removing water from the receiving flask with this kind of setup could be fruitful, although there are other separators in the existence as well. :)

Also, a product of the decomposition of HAlkSO4 to (Alk)2SO4 is H2SO4 which...wait - if u have the HAlkSO4 then surely dewatering is not the issue ..the reactions are:

1) AlkOH + H2SO4 <---> AlkHSO4 + H2O
2) AlkHSO4 <---> (Alk)2SO4 + H2SO4

Dewatering drives the 1st reaction not the second ??
Me confused or u confused ?


Formerly I thought that the monoalkyl sulfate reacted with another mole of alcohol, but given the fact that dimethyl sulfate can be vacuum distilled from monomethyl sulfate, I guess the patent is right on this point. Removing the water drives the first reaction.