Sciencemadness Discussion Board

Ethylene oxide synthesis

Ramiel - 26-10-2004 at 18:53

I would prefer not to create a new post, but:

I'm looking for a route to ethylene oxide.
This will probably be from the old (2-chloroethanol + base) reaction

Is it possible to halogenate say ethylene glycol?
HO-CH<sub>2</sub>-CH<sub>2</sub>-OH + HCl (37%) <==> HO-CH<sub>2</sub>-CH<sub>2</sub>-OH<sub>2</sub><sup>(+)</sup>Cl<sup>(-)</sup> <==> HO-CH<sub>2</sub>-CH<sub>2</sub><sup>(+)</sup>Cl<sup>(-)</sup> + H<sub>2</sub>O --> HO-CH<sub>2</sub>-CH<sub>2</sub>-Cl + H<sub>2</sub>O

if the glycol is in excess, the 2-chloroethanol would be favored over di-tri-chloro's and less so over 1,2-dichloro's, correct?

probably about 20% would be 1,2-dichloro in retrospect, anybody agree?

I love organic chem :D

- D

ps. dont lecture me about toxicity thank you, anyone. I used to be a walking 14 year old MSDS database too. :P

pps. changed topic title to <i>correct</i> title! oops

Mendeleev - 26-10-2004 at 19:46

I don't think the hcl route would work. It works with some things like benzyl alcohol, but I don't believe hcl will chlorinate ethanol, and thus most likely not ethylene glycol either.


Edit: Wait, isn't ethylene oxide ketene? In that case passing acetone through a catalyst tube at 400-500 C would get you ethylene oxide/ketene. Before people go off saying how bad catalyst tubes are at such micro-lab levels, let me say this, yes they are difficult to construct and properly operate, but they do work even at the lab level, I have seen several articles in Organic Synthses that employ them, it's just difficult to construct. Often times the main problem is is surface area of the the catalyst and proper temperature control.

Nichrome can be used as a catalyst, but having a couple of strands won't to it, you would need almost a nichrome sponge, so to speak, to achieve good efficiency. Or you could have bad efficiency and simply condense the acetone that is not converted to ketene in the tube back into some sort of reservoir. Your apparatus would look something like a distillation setup. except your condenser would actually be a catalyst tube, and your receiving flask should have a condenser above it to recycle the acetone, meanwhile ketene will leave throught the top of the condenser because as a gas it does not condense.

[Edited on 27-10-2004 by Mendeleev]

chemoleo - 26-10-2004 at 19:52

I don't think so either, at least the various books I checked don't state such a route.
Instead, 2-chloro-ethanol can be produced by reacting ethylene gas with hypochloric acid, or an acidified solution of NaOCl (sodium hypochlorite). This may be an interesting route if ethylene gas is available (I have various routes to this, if interested).
Then, the Chlorohydrine (2-chloroethanol) is converted to ethylene oxide by distilling 2-chloroethanol with dissolved KOH (or Ca(OH)2), according to
H2ClC-CH2OH + KOH --> (CH2)2O + KCl + H2O.
The ethylene oxide is a gas, so I guess it'd have to be used right away.

Why do you want to make it? - or, I should ask - there are a zillion and one uses for it, which is the one you intend it for?

[Edited on 27-10-2004 by chemoleo]

S.C. Wack - 26-10-2004 at 20:45

It can be done. The best way would probably be to warm up the glycol and suck HCl gas through it, distilling off the ethylene chlorohydrin as it is formed. Yield and time, well the devil is in the details.

EDIT: And ethylene glycol/HCl was the original preparation of the chlorohydrin, by Wurtz. Here is a later one, showing a 60% yield in 16 hours at 148°:

Glycol wird in einem Destillationapparat auf 148° erhitzt und gleichzeitig ein langsamer Strom trockner Salzsäure hindurchgeleitet. Das gebildete Wasser und Glycolchlorhydrin destilliren ab und werden in tubulirten Vorlagen aufgefangen. Nach und nach wird die Temperatur des Bades bis etwa 160° gesteigert, wo dann bis auf einen unbedeutenden Rückstand die angewandte Glycolmenge vollständig zerlegt wird. Bei der Verarbeitung von 100 g. Glycol sind etwa 16 Stunden nöthig.

Das Destillationsproduckt wird mit dem 2-3 fachen Volum Aether versetzt und durch Kaliumcarbonat zunächst von vorhandener Salzsäure befreit. Dann wird die ätherische Lösung abgesaugt und über frisch geschmolzenem Kaliumcarbonat vollständig getrocknet. Zwei Destillationen liefern ein reines zwischen 128° und 131° siedendes Produkt und zwar etwa 60% der theoretischen Ausbeute.

[Edited on 27-10-2004 by S.C. Wack]

Esplosivo - 26-10-2004 at 22:44

It will take a very long time of continuous reflux but the reaction of ethanol with HCl can be done in the presence of Zinc Chloride. All the reactants must be in the anhydrous state, and the time required for a such a reaction to occur will most probably not allow you to calculate when to stop the halogenation, such that yields of the 2-chloroethanol would be most probably low while yields of 1,2-chloroethane would be 'high' - if you know what I mean.

IMHO I would suggest the methods mentioned previously by chemoleo and Mendeleev. Chemoleo's method seems quite simple indeed, and could yield a good result, while the one mentioned by Mendeleev's is the way it is produced industrially as far as I know - the only disadvantage being the nichrome 'sponge' mentioned.

[Edited on 27-10-2004 by Esplosivo]

DDTea - 27-10-2004 at 16:03

NBK once made mustard using Ethylene Chlorohydrin, prepared via HCl fumes and Ethylene Glycol. Indeed, it does work; but I'm sure there are better ways.

What if Dichlorosulfuric Acid were used in place of HCl? It would serve as a chlorinator and a dehydrating agent:

2 HO-CH2-CH2-OH + Cl2SO2 --> 2 HO-CH2-CH2-Cl + H2SO4

And no doubt, some 1,2-dichloroethane in the product. But if the Ethylene Glycol were in excess, the possible yield of 1,2-dichloroethane should be minimized.

Ramiel - 27-10-2004 at 16:31

Thank you all for excellent answers.
The problem I see with a catalyst tube type setup isn't the efficiency (I love catalyst tubes no matter what people say, and I suspect chemoleo does too :) ). The main problem is Ethylene oxide's tendancy to <i>burn in it's own atmosphere</i>. This makes me edgy. Autoignition is somewhere like 430*C, you'd want good temperature control (now who's the walking MSDS).

ethene isn't really available, I don't like the silver catalysed oxidation route, but it should be noted for posterity that this would probably be the ideal route.

Just out of curiosity, do you mean cracking to get ethene, Chemoleo?

ethylene oxide is miscible with... uh, everything. :D
Why do you always ask what I want it for... like asking a mouse what it wants cheese for I would have thought.

Polverone related recalling someone telling him that, "ethylene glycol could be effectively chlorinated with HCl gas if it were first dissolved in acetic acid." I think this deems furthur investigation.

- D

BromicAcid - 27-10-2004 at 19:48

I went to a book reference and copied it out instead of going from memory:

From 'Thorpe's Dictionary of Applied Chemistry'
Quote:
Ethylene oxide:

Prepared from C2H4(OH)Cl and KOH, from C2H4I2 and Ag2O at 150 C, and C2H4Br2 and Ag2O at 250C; from C2H4Br2 and Na2O at 180C; from chloroethyl acetate and KOH; by slow addition of aqueous chlorohydrin to CaO under reflux: yield 90%. It is manufactured from C2H4(OH)Cl in various ways: the vapor and steam are passed into a packed tower meeting a counter-current of concentrated NaOH and NaOH solution at 10 - 20C, and introduced into a packed collum at 35 - 50C under 95 - 105mm. pressure, when the oxide separates and is distilled; from B-chloroethyl acetate and aqueous alkali at 40-150C and from C2H4, air, and an inert gas (CO2) by passage over Ag, Au*Ag, or Ag*Cu catalyst at 300 - 400C under pressure.


References for each avalible upon request.

[Edited on 10/28/2004 by BromicAcid]

ziqquratu - 29-10-2004 at 22:01

Um, just one thing that's kind of important... ethylene oxide and ketene are NOT the same molecule...
Ethylene oxide is the epoxide of ethene. Ketene is essentially the ketone of ethene (C=C=O). Ethylene oxide cant be made by dehydration of acetone (as far as I know!).

As to oxidation of ethene gas, cant you make ethene in a similar way to making ether, by dehydrating ethanol with sulfuric acid? I cant remember, but you either use more acid or higher temperatures or something... I can try and find it if need be, but I'm sure it's on the web (maybe Rhodium's page?).

DDTea - 30-10-2004 at 14:55

Quote:

As to oxidation of ethene gas, cant you make ethene in a similar way to making ether, by dehydrating ethanol with sulfuric acid? I cant remember, but you either use more acid or higher temperatures or something... I can try and find it if need be, but I'm sure it's on the web (maybe Rhodium's page?).


It's a bit different from making ether; the difference is that Aluminum is also added to the Ethanol/Sulfuric Acid mix, and the mixture heated slightly.

Esplosivo - 30-10-2004 at 23:05

As far as I know the process for ethene synthesis requires only ethanol and conc. sulfuric acid, with the acid being in excess and heating to a temperature of approx. 180 deg Celcius. Results in some charring though. I've never heard about adding aluminium to the mix.

[Edited on 31-10-2004 by Esplosivo]

unionised - 31-10-2004 at 03:19

Might we be muddling two things up?
Ethanol can be dehydrated to ethylene with sulphuric acid, it can also be dehydrated over hot alumina.
http://www.kcpc.usyd.edu.au/discovery/9.2.3-short/9.2.3_Dehy...

Oxidation of the ethylene with oxygen over hot silver will produce ethylene oxide.
It's very volatile, explosive and a confirmed carcinogen.
How badly do you want to make it?

DDTea - 31-10-2004 at 10:04

Quote:
It's very volatile, explosive and a confirmed carcinogen.


It's also quite poisonous. A few years ago, Russia tried to set off a Fuel Air Explosive in Grozny, but it didn't detonate properly. The cloud of Ethylene Oxide that was left behind gassed about 30 Chechens to death.

Something to keep in mind. But again, a bit of danger keeps things exciting.

Ethene oxide

hinz - 29-4-2005 at 10:12

Is it possible to oxidize ethene with a copper catalyst? I know that it works with a silver catalyst, but I have no silver. I dehydrated vapourised ethanol with a cathalyst tube, containing Al2O3 (powdered ceramic). The tube is a steel pipe (heated in a fire on appr. 450 C) on which I've welded two long,thin steel pipes. This gives me very cheap ethene, I only need ethanol.

Now I tried to oxidize the ethene.
I used a copper catalyst, (also in a steel pipe) in wich I blew a little bit air. But I think this catalyst pipe didn't work, because on it 's outlet I can still smell the caracteristic odor of the ethene.

...................Cat. 450C
C2H5O-H --------------->C2H4 + H2O
....................Al2O3

.......................................................O
.......................Cat. 300C............../....\
2 C2H4 +O2 ------------------->2 CH2-CH2
........................Copper wires





[Edited on 29-4-2005 by hinz]

Mr. Wizard - 29-4-2005 at 15:15

"I can still smell the characteristic odor of the ethene."

You should check the toxicity levels of ethene or ethylene oxide before you start checking the smell of the stuff.
http://ptcl.chem.ox.ac.uk/MSDS/ET/ethylene_oxide.html

This stuff is SO toxic it is used to sterilize medical instruments and waste! Not only is it toxic, but it is a mutagen and carcinogen. Find another way to test for it, besides sniffing for ethene, which doesn't prove anything.

Inny_G - 11-1-2013 at 06:59

I'm wanting to do the same thing and rather than starting a new thread for my maiden post and told to UTFSE I thought i'd revive this thread.

My idea is to make ethene gas by dehydration of ethanol and bubble it through a solution of potassium peroxymonosulfate. Wiki says "Ethylene can be directly oxidized into ethylene oxide using peroxy acids" so I think it should work.

ChemistryGhost - 1-5-2013 at 09:25

Wikipedia says:
"With a high yield (90%) ethylene oxide can be produced by reacting calcium oxide with ethyl hypochlorite; substituting calcium by other alkaline earth metals reduces the reaction yield:[54]

2 CH3CH2–OCl + CaO → 2 (CH2CH2)O + CaCl2 + H2O
In turn, ethylhypochlorite is synthesized as follows:

Cl2 + NaOH + CH3CH2OH → CH3CH2OCl + NaCl + H2O"
What procedure would be done to obtain ethylene oxide using the ethanol method? :)

[Edited on 1-5-2013 by ChemistryGhost]

fractional - 2-5-2013 at 23:35

Quote: Originally posted by ChemistryGhost  
Wikipedia says:
"With a high yield (90%) ethylene oxide can be produced by reacting calcium oxide with ethyl hypochlorite; substituting calcium by other alkaline earth metals reduces the reaction yield:[54]

2 CH3CH2–OCl + CaO → 2 (CH2CH2)O + CaCl2 + H2O
In turn, ethylhypochlorite is synthesized as follows:

Cl2 + NaOH + CH3CH2OH → CH3CH2OCl + NaCl + H2O"
What procedure would be done to obtain ethylene oxide using the ethanol method? :)

[Edited on 1-5-2013 by ChemistryGhost]


Ethylhypochlorite is dangerously unstable and explosive. I have once inadvertently produced few ml of it and I would not like to repeat the experience: it exploded violently and without any warning, sending glass shrapnel all over the lab. I have posted pictures of the effects on the interior design on a German forum:

http://www.versuchschemie.de/htopic,12979,.html

So IMHO one should never isolate ethylhypochlorite and I would not attempt this reaction, unless the hypochlorite were strongly diluted in a suitable solvent at all times.

paw_20 - 3-5-2013 at 04:59

Whoa, that's some frag damage. Hope you weren't in range.

fractional - 5-5-2013 at 11:59

Quote: Originally posted by paw_20  
Hope you weren't in range.

No collateral damage, thankfully. I found a few tiny glas splinters embedded in my protective glasses, though...food for thought...