| Pages:
1
..
30
31
32
33
34
..
44 |
chemplayer..
Awesome
Posts: 48
Registered: 12-2-2016
Member Is Offline
Mood: No Mood
|
|
We'll post this as it might be interesting; there has been some speculation in the past on this but to our knowledge no one has actually tried it. Not
that we can recommend it as a way to produce acetic anhydride though as the yield is low and the process is potentially very dangerous (toxic fumes +
explosion risk).
Nitrogen dioxide was produced in a 500ml 2-neck flask (cooled in a cold water bath) containing 68% nitric acid, by adding cupro-nickel coins (about
60g of coins in total, although some didn't react completely).
The evolved brown fumes of NO2 were dried using aan anhydrous CaCl2 drying tube and then condensed in a liebig condenser using ice cold water. The
resulting liquid NO2 was dripped onto 30g of anhydrous sodium acetate contained in a receiving flask which was cooled in an ice-salt bath. During the
generation of liquid NO2 the receiving flask was rotated to ensure even distribution of the NO2 in the sodium acetate.
The resulting blue-green mixture in the receiving flask was allowed to warm to room temperature. A fair bit of NO2 came off (unreacted). Distillation
of the mixture was carefully attempted, with more NO2 being evolved and a clear unknown liquid starting to boil with a vapour temperature of 50-55C.
At this point distillation was stopped, the mixture cooled, and then extracted using 25+15ml of dichloromethane. After filtering off the solids, the
DCM extracts were evaporated down to give 1.6g of slightly yellow liquid. Nothing else evaporated off on heating to ~100C.
Smells like acetic anhydride, catches fire like it, sinks in cold water with that characteristic 'round blob' and tiny bubble on top. Not enough to
distill and test the bp though, so purity unknown.
So amazingly it looks like this does actually work. Probably a curiosity rather than a practical method though.
The full video of the process is here on the ChemPlayer YT channel:
https://www.youtube.com/watch?v=r1tgmgG8VIY
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
| Quote: | | Smells like acetic anhydride, catches fire like it, sinks in cold water with that characteristic 'round blob' and tiny bubble on top.
|
Have you discounted the real probability that what you have may well be peracetic acid?
|
|
|
chemplayer..
Awesome
Posts: 48
Registered: 12-2-2016
Member Is Offline
Mood: No Mood
|
|
Peracetic acid? What's the water miscibility and boiling point (assuming it exists as a pure substance) of that?
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
Today some 50g of zinc acetate almost got made, intended for use in a try at acetic anhydride by vac decomposition/distillation.
250ml beaker, GAA and Zn powder + water in stoichiometric amounts.
After watching bubbles bursting and dropping fine zinc particles for a while (which is wonderful to watch) the heat and stirrer were turned on to
speed up the reaction.
Shortly after that a neighbour arrived with some sad news.
... time passes ... heated beaker forgotten about ...
On disposing of the neighbour and returning to the lab, the beaker had boiled over and there was a mess of zinc powder on the hotplate, and a New (to
me) smell in the fume hood - distinct from acetic acid, yet somehow related.
Whatever it was, it appears as if something can be obtained via the zinc acetate decomposition approach.
|
|
|
UC235
National Hazard
Posts: 565
Registered: 28-12-2014
Member Is Offline
Mood: No Mood
|
|
Quote: Originally posted by hissingnoise  | | Quote: | | Smells like acetic anhydride, catches fire like it, sinks in cold water with that characteristic 'round blob' and tiny bubble on top.
|
Have you discounted the real probability that what you have may well be peracetic acid?
|
I'm pretty sure peracetic acid is miscible with water. Also, I have no idea where the peroxy group would have come from.
A more realistic possibility is acetyl nitrate, but given that when pure, it seems to be a fuming explosive liquid that is rapidly decomposed by
water, I would tend to believe that acetic anhydride was indeed made. I suspect AcONO2 as an intermediate however.
The whole prep seems particularly unpleasant, but addition of some pre-formed Ac2O may improve yield as is the case with the bromine-sulfur route.
[Edited on 6-3-2016 by UC235]
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
| Quote: | | A more realistic possibility is acetyl nitrate. |
It occurred to me but for it to go that far would require much more NO2 than was apparently used!
It's presence is much more likely than AC2O, however . . . ?
|
|
|
chemplayer..
Awesome
Posts: 48
Registered: 12-2-2016
Member Is Offline
Mood: No Mood
|
|
Yeah definitely not recommended as a preparatory technique. The interesting thing is the colourless liquid boiling at 50-55C from the reaction
mixture. After extracting with DCM this seems to be gone, but it's definitely present shortly after the reaction completed. No idea what it is, but at
the time I remember having that intuitive "this doesn't look very friendly" feeling...
|
|
|
Waffles SS
Fighter
Posts: 998
Registered: 7-12-2009
Member Is Offline
|
|
@chemplayer,
I watched your video on Youtube and i am sure your final product is Ac2O.(I have experience on making Ac2O and working with it)
Also i watched another videos and in fact all of them are not true and logical(like Hydroxy mandelic acid)
[Edited on 7-3-2016 by Waffles SS]
|
|
|
chemplayer..
Awesome
Posts: 48
Registered: 12-2-2016
Member Is Offline
Mood: No Mood
|
|
Yes the hydroxymandelic acid looks to be a failure. We tried again and got the same result. The prep was actually from a very old textbook (which are
usually more reliable than say Tetrahedron letters, but not this time it would seem!).
As we point out in the video we couldn't find much info on the product and so we couldn't confirm what we got in the end.
|
|
|
clearly_not_atara
International Hazard
Posts: 2787
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
If I had to guess I'd assume the reaction of NO2 with NaOAc is just like other reactions with dinitrogen tetroxide, which usually reacts as though it
were nitrosyl nitrate, (NO)NO3. So initially:
NONO3 + AcONa >> AcONO + NaNO3
The acetyl nitrite is oxidized by NO2 -- the monomer this time -- to acetyl nitrate, giving off nitric oxide:
ACONO + NO2 (l) >> AcONO2 + NO (g)
Acetyl nitrate will acetylate sodium acetate:
AcONO2 + AcONa >> Ac2O + NaNO3
In the background, the equilibrium 2NO2 >><< NONO3 allows both reactions to occur. The driving force is thus not dehydration, but redox,
which explains why the reaction is favorable.
|
|
|
Rynoaus
Harmless
Posts: 27
Registered: 13-3-2016
Member Is Offline
Mood: No Mood
|
|
After reading pages and pages I still can't find a definitive yes or no for AA via sodium acetate and disulphur dichloride. Has anyone experienced
performed this I've seen a couple of one time posters saying that it had worked but looking for a bit more confirmation and insights Into the
reaction if any cheers.
|
|
|
clearly_not_atara
International Hazard
Posts: 2787
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
I honestly think the bigger question is how are you going to produce S2Cl2?
There's a reason methods like this tend to show up and hang around the discussion for years and years without solid confirmation: they're hard to do.
The method has been reported on Rhodium's Archive with 90% yield, but the production of S2Cl2 requires Cl2 gas, which most people don't have the
equipment to handle, and those that can usually are also able to make acetic anhydride some other way. Plus there's the possibility of generating SCl2
and SOCl2 byproducts which are quite toxic.
https://www.erowid.org/archive/rhodium/chemistry/anhydrides....
You might be able to do 2 CuCl2 + 2S >> 2 CuCl + S2Cl2 by reacting sulfur with anhydrous (brown) cupric chloride, by analogy to the well-known
reaction:
2Cu2+ (aq) + SO2 (aq) + 2OH- + 2 Cl- >> 2CuCl (s) + H2SO4 (aq)
https://en.wikipedia.org/wiki/Copper%28II%29_chloride#Redox
[Edited on 18-3-2016 by clearly_not_atara]
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
S2Cl2 is simply a matter of passing chlorine over sulphur.
Molten sulphur is more efficient, yet normal powdered sulphur works fine.
Well, it did for me on two occasions.
Plenty of threads on SM regarding the production of this.
Here was my second successful attempt.
http://www.sciencemadness.org/talk/viewthread.php?tid=62254
It is nasty stuff to store.
Jammed up the glass stopper making it necessary to use a hammer on glass to get it out).
[Edited on 18-3-2016 by aga]
|
|
|
clearly_not_atara
International Hazard
Posts: 2787
Registered: 3-11-2013
Member Is Offline
Mood: Big
|
|
| Quote: | | the production of S2Cl2 requires Cl2 gas, which most people don't have the equipment to handle, and those that can usually are also able to make
acetic anhydride some other way. |
aga: does my dilemma apply to you? ^,~
|
|
|
aga
Forum Drunkard
Posts: 7030
Registered: 25-3-2014
Member Is Offline
|
|
No, sorry.
I just thought that the closed-system approach might be useful.
|
|
|
Rynoaus
Harmless
Posts: 27
Registered: 13-3-2016
Member Is Offline
Mood: No Mood
|
|
In regards to the SCI2 or and SOCI2 could one just leave it air for a period until one notices the sulphur start to come out of solution the
biproducts if any should have been reconverted back. And I can't see that a little sulphur is going to cause problems with AA synth as this method is
pretty much the same as using the sulphur sodium acetate and chlorine in situ to produce AA so a tiny amount of sulphur shouldn't worry anything
should it?
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
Thionyl chloride is most convenient as the byproducts are SO2 and HCl!
|
|
|
Rynoaus
Harmless
Posts: 27
Registered: 13-3-2016
Member Is Offline
Mood: No Mood
|
|
Indeed aga has shown u could do this at room temp and if one had a way to add an amount of chlorine gas to closed vessel with sulphur and allow to
react then replenish gas and go again until full reaction occurs then distill as recommended I know it would take time but the reaction would surely
proceed wouldn't it?its just very OTC and as such appealing though out of my reach until I get a decent distillation set. Thionyl chloride I'll have
to research that.
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
Thionyl chloride is SOCl2 . . .
|
|
|
Rynoaus
Harmless
Posts: 27
Registered: 13-3-2016
Member Is Offline
Mood: No Mood
|
|
Ah I've been reading wiki too much and looking at the formula not names and because that didn't interest me that much I hadn't looked at it just that
it will regress but thanks also I hav'nt seen the route for using that though I was reading through trying to see if the method on rhodium erowid had
been tried and was possible so I'll go back to the start and reread
|
|
|
100PercentChemistry
Hazard to Others
Posts: 117
Registered: 21-8-2015
Location: On the island of stability
Member Is Offline
Mood: No Mood
|
|
NIle Red made a video on the ketone process. I may try it.
|
|
|
hissingnoise
International Hazard
Posts: 3940
Registered: 26-12-2002
Member Is Offline
Mood: Pulverulescent!
|
|
Did you mean the ketene process?
|
|
|
Loptr
International Hazard
Posts: 1348
Registered: 20-5-2014
Location: USA
Member Is Offline
Mood: Grateful
|
|
Be careful with ketene. By the time you have smelled it you are already over the exposure threshold, and not to mention, it's pretty poisonous for
humans.
It's formal name is ethenone, so many that's where you got the -one from? 
|
|
|
dawt
Hazard to Self
Posts: 74
Registered: 9-5-2016
Location: EU
Member Is Offline
Mood: fluorescent
|
|
Seems nobody has mentioned this paper before. They claim to have prepared AA from acetic acid in a 90 % yield after 2 h at 40 °C using a PTC and
zirconia catalyst. Sounds too god to be true, eh? The fact that it was published in some Ethiopian journal doesn't raise my confidence, but it looks
cheap enough for me to give it a shot some time next month when I have money 
| Quote: |
Preparation of sulfated zirconia
The sulfated zirconia catalyst was prepared by equilibrium adsorption of sulfate species on the surface of hydrous zirconium oxide samples. The
hydrous zirconia catalysts were prepared by precipitation method using ZrOCl2.8 H2O and liquid ammonia solutions. Required
amount of zirconyl chloride solution was added dropwise to deionised water. The pH was maintained at 10.0 by controlled addition of ammonia solution
to the reaction mixture. The precipitated solution was stirred for 16 h at 35 °C followed by filtration and washing with double distilled water until
free from chlorine ions. The hydroxide precipitate were subsequently dried overnight at 100 °C and calcined at 250 °C for 24 h. To prepare sulfated
ZrO2 catalyst, a portion of the obtained hydrous zirconia sample was ground to fine powder and immersed in 1 M H2SO4
solution. Excess water was evaporated on a water-bath and the resulting sample was oven-dried at 120 °C for 12 h and calcined at 500 °C for 4 h in
air atmosphere and stored in vacuum desiccator.
General procedure for the preparation of symmetrical carboxylic anhydrides
To a stirred solution of carboxylic acid (10 mmol) and PEG-1000 (5 mmol) was added SO42-/ZrO2 (3 mmol) at room
temperature and stirring was continued at 40 °C for the appropriate time. After completion of the reaction, as indicated by HPLC, the product was
extracted with methylene chloride (3 × 5 mL). The combined organic layer was dried over anhydrous Na2SO4 and then filtered over
a pad of flash silica gel. Removal of the solvents in vacuo furnished the corresponding pure symmetrical carboxylic anhydrides. Fresh substrates were
then recharged to the recovered catalyst system and then recycled under identical reaction conditions.
|
Ref:
Lin Hu, Y., E Zhao, X. & Lu, M., 2011. Efficient and convenient synthesis of symmetrical carboxylic anhydrides from carboxylic acids with sulfated
zirconia by phase transfer catalysis. Bull. Chem. Soc. Eth., 25(2). Available at: http://dx.doi.org/10.4314/bcse.v25i2.65900.
[Edited on 9-5-2016 by dawt]
[Edited on 9-5-2016 by dawt]
[Edited on 9-5-2016 by dawt]
|
|
|
byko3y
National Hazard
Posts: 721
Registered: 16-3-2015
Member Is Offline
Mood: dooM
|
|
Rynoaus, sodium aetate + sulfur halide definitely works, but is tricky to perform and leads to different yields dependingon
conditions, which is even more complicated because the reaction mechanism is poorly known, despite the fact dibenzoyl-disulfide and
bis(trifluoroaceto) disulfide have been prepared and shown to lead to the anhydride production via thermal decomposition.
clearly_not_atara, i see no problem with preparation of Cl2 or Br2. Toxic concentrations of halogens are almost unbearable. You can
use any of SCl2, S2Cl2, S2Br2, or their mixture with each other and any other crap.
dawt, this article looks like a gorrible bullshit. I see no dehydration agents there at all.
PS: once again want to ask you that I'm looking for some book about sulfur inorganic/simple organic coumpounds, especially about sulfur chlorides,
every author seems to be afraid of writing about sulfur chlorides.
[Edited on 10-5-2016 by byko3y]
|
|
|
| Pages:
1
..
30
31
32
33
34
..
44 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
