Author Topic: Ethyl hydrogen sulfate  (Read 18017 times)

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foxy2

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Ethyl hydrogen sulfate
« on: September 24, 2001, 12:13:00 AM »
Ethyl hydrogen sulfate can be neutralized with NaOH to get sodium ethyl sulfate which can be used in the synthesis of nitroethane on Rhodiums site.  This is the diethyl sulfate synth halfapint brought up in

Post 208329

(halfapint: "Re: OTC preperation of Dimethyl sulfate?", Tryptamine Chemistry)
.  It looks like adding some anhydrous sodium sulfate will increase the yeilds for this synthesis.

Synthesis of diethyl sulfate.     Wu, Zhiguang; Zou, Zhichen; Huang, Ruqi.    Dep. Chem.,  Shandong Teachers' Univ.,  Jinan,  Peop. Rep. China.    Huaxue Shiji  (1991),  13(3),  190, 144.  CODEN: HUSHDR  ISSN: 0258-3283.  Journal  written in Chinese.    CAN 115:158460    AN 1991:558460   

Abstract
Stirring 95% EtOH (excess) with concd. H2SO4 in the presence of Na2SO4 at 25° gave 98.8% EtOSO3H which was heated at 125-140° under reduced pressure to give 87.2% Et2SO4. 

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foxy2

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Re: Ethyl hydrogen sulfate
« Reply #1 on: September 24, 2001, 12:19:00 AM »
Based on this article I think the Na2SO4 in the above synth serves as a drying agent to increase yeilds.

Esterification of ethanol with sulfuric acid: a kinetic study.
    
Theodore, Shammi; Sai, P. S. T.     
Can. J. Chem. Eng.  (2001),  79(1),  54-64. 

Abstract
Expts. were conducted in a stirred batch reactor under isothermal conditions for obtaining kinetics of the esterification reaction between ethanol and sulfuric acid.  Reactive adsorption technique was employed to enhance the conversion.  Anhyd. sodium sulfate was used as an adsorbing agent to remove the water formed during the reaction.  The variables include the mole ratio of ethanol to sulfuric acid, reaction temp., purity of the reactants, and the amt. of adsorbing agent.  The reaction was found to be reversible and second order at low mole ratios, and irreversible and first order at high mole ratios.  The kinetic parameters of the rate law were estd.  A possible reaction mechanism was proposed and validated with the exptl. data.  The effect of the mole ratio of reactants, anhyd. sodium sulfate loading, and purity of the reactants on the yield of Et hydrogen sulfate was studied, using full-factorial search and optimized conditions were obtained by the method of steepest ascent.  More precise optimum conditions were obtained using the Box-Wilson composite method. 

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foxy2

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Dimethyl/Diethyl Sulfate
« Reply #2 on: September 24, 2001, 12:51:00 AM »
This may bee a good alternative if one of the local russian bee'z could look this reference up?

Oxidative sulfuration of alcohols in the presence of cupric chloride.    

Golodov, V. A.; Panov, Yu. I.
Kinet. Katal.  (1983),  24(5),  1276-7. 
Journal  written in Russian.   

Abstract
The title reaction of ROH (R = Me, Et) with SO2 and CuCl2 was 1st order in each reactant, and gave the corresponding (RO)2SO2 under mild conditions. 

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Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #3 on: September 24, 2001, 04:50:00 AM »
Yummmmmmmmie!!

Foxy, oh Foxy! My words fade compared to my feelings... SWIM's been waiting for this a long, long time.

I can't promise you that we can find this reference - in fact, there's only like 3 or four of us at HyperLab that have an access to the library - and they all are disgustingly slothy, and the journal is not common afaik. But i'll try to kick'em as hard as possible.

Maybee, just to try it and see if it works... There's quite a number of variations possible as to the cond's though. Well - Antoncho's gonna work on this issue - that's all he can say by now.

Antoncho

UTFSE

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Re: Dimethyl/Diethyl Sulfate
« Reply #4 on: September 24, 2001, 08:38:00 PM »
Diethyl sulfate preparation is on Rhodium page - been there over a month.

Substituting methanol for ethanol results in Me2SO4. according to Rh.

always appreciate your time and consideration

foxy2

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Re: Dimethyl/Diethyl Sulfate
« Reply #5 on: September 25, 2001, 12:19:00 AM »
Well this thread has some possible improvements.  Adding NaSO4 supposedly increases yeild.  I guess you prefer to stick with 50% yeilds, thats fine with me, others may want something better.

Also if you are looking for nitroethane this shows approximately how NaHSO4 can be prepared in close to stoichoimetric yeild.  Then you can go on to preparing nitroethane from an easier to make precursor.

Ya know what I see a meth syth on Rhodiums page too, maybee everyone here should just quit discussing meth because hey its already at Rhodiums page so there is nothing else to talk about!!!



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Antibody2

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Re: Dimethyl/Diethyl Sulfate
« Reply #6 on: September 25, 2001, 02:06:00 AM »
deep breath foxy, btw - you on vacation? or transfered to a research library? you've become the fount of awesome posts lately 8)  

keep it up

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halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #7 on: March 08, 2002, 08:12:00 AM »
Using only the information foxy2 posted in

Post 216477

(foxy2: "Dimethyl/Diethyl Sulfate", Chemistry Discourse)
, "The title reaction of ROH (R = Me, Et) with SO2 and CuCl2 was 1st order in each reactant, and gave the corresponding (RO)2SO2 under mild conditions", I produced DMS in 66% yield from methanol, with cupric chloride bubbled by SO2. I have high praise for this method; if you can handle using dimethyl sulfate at all, this is how to get it.

Working outdoors out of respect for bad fumes, I generated SO2, by heating sulfur in sulfuric acid, from an Erlenmeyer on the hot plate. I was pleased to find that this generation is well-behaved, easily controllable by temperature, and sustainable for hours without refreshing the charge. I used the gas exhausted from the DMS vessel by bubbling it into hydrochloric acid, in hopes of coming up with some thionyl chloride in HCl. Neither that, nor the diethyl sulfate run which followed the DMS in the same apparatus arrangement, has been worked up yet. (Reduced pressure distillation at the aspirator must bee used, for neither DMS nor diethyl sulfate will stand up to atmospheric pressure distillation --- as if you'd want to!) Indications are, however, that product was formed in each case. I'm pleased as punch. << ;D >> This one's a lot cleaner than the other methods I've tried.

(I interpreted "mild conditions" as meaning warm alcohol, 30° to 40°C, supposing room temperature might have been stated as such in the abstract. The alcohol vessel was kept in a warm-water bath, which was refreshed periodically with a pot of water out of the coffee-maker.)

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Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #8 on: March 08, 2002, 10:26:00 AM »
Excellent! I admire thy work, Half-a-Pint!

Could you bee just a little bit more specific? As to, you calculate yield based on CuCl2, right? How much DMS did you get?

Your report is truly valuable (esp considering SWIM nad no luck tryin' to make the subj  by bubbling Cl2 into SO2 conc solution in MeOH.)

Now he's really glad.

Thanx,


Antoncho

foxy2

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Re: Dimethyl/Diethyl Sulfate
« Reply #9 on: March 08, 2002, 11:15:00 AM »
Sweet
I aways like to see someone make use of the ref's I dig up.
:)  
Foxy

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halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #10 on: March 09, 2002, 12:28:00 AM »
you calculate yield based on CuCl2, right?

No, Antoncho, I meant 2/3 of my methanol was converted into DMS! That's why I was so happy. Based on just the amount of methanol reacted, and not recovered in the end, yield must have been very high -- only ~3 ml of oily residue was left undistilled. Since the solid copper species left in the flask was green, I supposed it was unreduced cupric material, meaning the CuCl2 played only some kind of catalytic role, rather than serving as an oxidant consumed by reduction. I failed to check out this supposition, discarding rather than analyzing the residue. On addition, the CuCl2 was not completely anhydrous, for some green still showed. While gassing, the solid material seemed a white precipitate, beneath the dark green alcohol which had a transparent quality.

When you ask me to get more specific, you should bee sure you know what you're asking for. I have been called "wordy" by some. Since quantities just aren't critical, and since 1st order means it isn't reversible, there's little to discuss there; put more in, get more out. Also, my grasp of theory isn't deep enough to tell you what went on inside this reaction. So if you ask me for more detail, you are likely to get a vivid literary description of how I spent my morning, together with my emotional reactions to each phase of the process. Are you sure that's what you wanted to know about?

OK -- in the workup, I distilled methanol at atmospheric pressure, venting vile vapor through a tube from a vacuum adapter leading out the window, until the vapor temperature rose to 76°. Without stirring, I could see the surface, which showed an anomoly: all the time methanol was coming over at 2-3 drops per second, temperature 60°-70°, there was no ebulliation in the flask, it wasn't bubbling. At the time the temperature began to rise, when I shut down the distillation, patches of a skim began to appear on the surface of the green liquor. This must have been copper salt coming out of solution as its methanol phase was exhausted. Briefly I entertained a fantasy, that it might have been made from some particles of filterable sulfur, but to have got through the glass filter I used, they would have to be ultra teeny weeny.

I let the solution cool nearly to room temperature, then added 5 silica gel beads as boiling stones, to prevent bumping. Then I proceeded with the low-pressure phase of the distillation, with the water aspirator. The bulk of the material was still in the flask; as I said, almost all of that was DMS. This was verified by methylation of hydroquinone, to para-dimethoxybenzaldehyde.

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Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #11 on: March 09, 2002, 07:56:00 AM »
:o  :-[  :o

Half-A-Pint, but that's plainly impossible!

Sulfur in SO2 has a +4 state of oxidation, whereas in DMS it has a+6 charge. So there absolutely must bee smth. to oxidate it!! If you say that Cu color stayed green all the time - then, obviously, it wasn't reduced, huh?

I wonder if there possibly is a typo in the abstract and it is dimethylsulfite that one gets in this rxn?

Foxy2, can you certainly say that the article said "sulfate"?

Half-a-Pint, can you describe in all possible precision the physical prop's of the product you've got? Dimethylsulfite boils at 127 at atmospheric pressure and it has a specific gravity of 1,29 g/cm3.

DMS is somewhat heavier (1.33 g/cm3) as well as higher-boiling (189 C - but of course, w/decomp'n - i wonder if the former also decomposes at its bp?)

Also, what do you mean by p-dimethoxybenzaldehyde? :-[

Yes, dimethylsulfite is also a good methylation agent. The leftover aqueous phase from methylation - do you, by chance, have a sample of it left? If you do, or methylate smth. else w/the product you've got, please, try to acidify the remaining liquor and smell it for presence of SO2.

How much product, in mls , you got from how much MeOH?

Antoncho

uemura

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Re: Dimethyl/Diethyl Sulfate
« Reply #12 on: March 09, 2002, 10:11:00 AM »
Half-a-pint and Antocho!
First, Uemura is impressed of this method to get a methylation agent. Now

Half-A-Pint, but that's plainly impossible!



To add some simple calculation:
1) Suppose the CuCl2 is not changed in the rxn and
2) everthing is anhydroneous and
3) 100% conversion of MeOH takes place

Then only two possibilities can happen:
1) ROH + ROH + SO2 -> R2SO4 + H2 or
2) ROH + ROH + SO2 -> R2SO3 + H2O.

1) seems a bit unlikely, 2) makes more sense. But this would mean Antocho is right, it is the Dimethylsulfite which seems to be produced.

foxy, could you check if your reference say 'sulfite' or 'sulphate'?


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halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #13 on: March 09, 2002, 10:17:00 AM »
The solid copper precipitate went white in the course of the reaction; it could have been re-oxidized at the end of the final distillation, to turn it back to green. Thanks for pointing out the change in oxidation states, which helps me to understand this reaction better.

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Rhodium

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Re: Dimethyl/Diethyl Sulfate
« Reply #14 on: March 09, 2002, 06:37:00 PM »
Antoncho: p-dimethoxybenzaldehyde = para-dimethoxybenzaldehyde = 2,5-dimethoxybenzaldehyde

foxy2

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Re: Dimethyl/Diethyl Sulfate
« Reply #15 on: March 10, 2002, 01:01:00 AM »
It was cut and pasted so I am positive thats what it said.

Noone has thought about pH implications?
Maybee they buffer it to run under mildly basic conditions whereby the excess hydrogens ca bee gobbled by the buffer.  There are more than the two possibilities umeura suggested.

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Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #16 on: March 10, 2002, 06:03:00 AM »
2 Rhodium:  :)  :)  yes, i was just wondering how Half-a-Pint managed to make that by methylation of hydroquinone :-[

2 Half-a-Pint: soooo.... i still think it's DMS'ite - the copper salt turning white could just mean it serves as a catalyst - the extra chlorines being constantly 'in use' throughout the rxn.

What do you say about the bp of the product? Could you,by chance, try to boil it outdoors and see if it heats beyond 130 C?

2 Foxy: whaddayamean? Hydrogens eaten up by a buffer? Well, then it should bee H+, not H2, right? I mean, where do the extra electrons go? If only we could have that article...[sigh]

Antoncho

halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #17 on: March 11, 2002, 07:34:00 AM »
The "benzaldehyde" was a mis-statement. Meant dimethoxy-benzene, which has a trivial name I don't remember either. Count that as a spelling error.

A repeat run was sabotaged by suckback and much of the apparatus is in other use at the moment, but the presumptive diethyl sulfate is yet undistilled. Excuse the furor raised by my (1) grammatical error, saying benzaldehyde when I didn't mean it, and by (2) my incorrect guess, that the cupric chloride does not serve as oxidant here. The reaction works as stated, I'm sure the dialkyl sulfate was formed. It's a substance I have distilled before, and it showed its familiar behavior in the distillation, after the "quasi-sublimation" of the methanol. In breaking down a still, you often get a whiff of odor. DMS smell you don't forget. I just didn't state the specifics of the reaction right.

Since this reaction must bee an oxidation mediated by cupric chloride, there ought to be a way to regenerate this species to attain a higher turnover of copper. SO2 can serve as an oxidant, as when it bleaches straw hats in Panama. Could some of the white solid material in the gassing have been finely divided sulfur?

Are there no reduced copper species, or methanolates or dimethylsulfate complexes showing a green coloration, to explain the re-greening of the solid residue near dryness? If the final residue did include sulfur, that would explain how a copper (II) oxidation state could have been maintained throughout, by reduction of SO2 to sulfur, regenerating the CuCl2. Like you said, Antoncho, the chlorines don't get away.

And, uh, who says the dimethyl sulfite is also a good methylating agent? Would that mean, possibly, that trimethyl phosphite would also serve as a good methylating agent? Come on, I collect these things.

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halfapint

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Re: Dimethyl/Diethyl Sulfate
« Reply #18 on: March 12, 2002, 07:19:00 AM »
Did Half-a-Pint stumble into a correct answer for once? So if a run of this formulation has filter isolation of sulfur, I guessed it right, and the SO2 is refreshing the copper in its high oxidation state. If I read enough of my old books, I could calculate the relative oxidation potentials, to see if cuprous chloride in methanol could reduce sulfur dioxide to sulfur. Or perform the experiment, which is just to repeat the run, and record every measurement. Which was my job all along.

Should somebody do this with me, I won't bee jealous. I got my cupric chloride by mixing cupric sulfate (CuSO4*6H2O, tree root killer for sewer lines) completely dissolved in hot water, with a hot water solution of calcium chloride (CaCl2, driveway de-icer), sedimenting, decanting, filtering, boiling to dryness. Amounts were equimolar. Color change was blue to green. (Residue heated only sufficiently for drying, the yellow "dried" material darkens with generation of bad gas on overheating.) My sulfur was soil sulfur; my sulfuric acid was drain cleaner. My methanol was distilled from windshield washer concentrate, from the oil company with the seafood symbol. Won't take you too long, to check on what I'm saying. I say you can make dimethylsulfate that way, easier than any other way, and far more satisfactory in terms of scale.

Edit: Filtration of the failed flooded run shows a small amount of water-insoluble white powder. There it is, beez. Anybody finished the redox calculation yet, to see if it's possible?  :)  (Must allow the alternate possibility, though, of sulfur sublimation from the SO2 generator.)

Antoncho

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Re: Dimethyl/Diethyl Sulfate
« Reply #19 on: March 12, 2002, 09:50:00 AM »
! ! !

Wow. Is it true?

SWIA could perform this experiment too, having all available ingredients at hand - the only 2 things that hold him back are - 1) he lacks a vacuum distillation facility and 2) he's really afraid of working w/DMS, even having a small fume hood :)  :)

But this is too tempting so he might eventually give it a try (partially, to see w/his own eyes how it works and possibly finding out the reason why).

The weird thing is that sulfur in your proposed equation is both being reduced and oxidized at the same time! Of course, looking closer at it, there turns out to bee nothing wrong: Cu2+ oxidizes SO2 to SO3, while Cu+ reduces it to S... Would bee really interested about that electropotentials data...

Say, Half-a-Pint,could you recommend some way of purifying, or at least sepaprating the DMS from the rxn mixture w/out vacuum distillation? SWIM doesn't even have a source of running water, so that's out of question for him ::)

And one more question: for how long did you gas your methanol and was there much SO2 escaping?

Sincerely,

Antoncho