Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
 Pages:  1  ..  22    24    26  ..  42
Author: Subject: Acetic anhydride preparation
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 17-2-2010 at 14:32


well back a few pages ago I posted a patent in french that went down like a lead weight.

eventualy it was agreed that it would give 60+% yeild from easy to get or make reagents like acetaldehyde.
but "Mr Sauron" said that at 21 degree boiling point it was not possible to do a 40C reaction with out an
autoclave.

then I found me this :)

http://en.wikipedia.org/wiki/Schlenk_flask

check out that schlenk bomb flask truly nice.

can be had on ebay and in reasonable sizes too.

so "Mr Sauron" what say you now we could have been going the easy way ages ago but no ephoton
is not so politicaly correct.

anyway back to lurking in the depths Ill get this ring to the fires one day even if I have to chew sams ear off
on the way. :D

[Edited on 17-2-2010 by Ephoton]




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 19-2-2010 at 02:03



Quote:

"...(1) Acetic anhydride. To 50 g. acetic anhydride in a round-bottomed flask of 1500 cc. capacity, placed in cold water, 440 g. of powdered sodium acetate (dried by fusion at 320 C) and at the same time a solution of 22. g of sulfur in 320 g. bromine is added while stirring. The operation takes about 30 minutes.
"The mixture is then stirred for a further 5 minutes, after which period the initially dark brownish-red colour has changed into pale yellow, and the anhydride is distilled off from a water bath under reduced pressure. The crude anhydrie (310 g) is redistilled under normal pressure, and the fraction boiling between 134-138 C is collected. Yield, 295 g. of 98% purity = 87.5%. The so purified anhydride contains neither bromine nor sulphur compounds and leaves no residue on evaporation..."

NaOAc+S2Br2=AcO-S-S-AcO+NaBr
AcO-S-S-AcO+Heat=Ac2O+S+SO2

Quote:

Mix quickly and thoroughly 205-215 g of pulverized fine NaOAc and 10g dry sulfur powder, the mixture is quickly transferred to a wide-mouth 1 liter RBF and wetted w/25 ml acetic anhydride. Into the flask through the rubber cork extend 1) a wide tube for chlorine in-flow 2) an overhead stirrer, which is sealed with the aid of a piece of rubber tubing greased with vaseline and 3) an out-leading tube for excess Cl2 release. The flask is immersed in an ice-bath. Chlorine is initially passed in very carefully, with frequent stirring or shaking, over the passage of time the rxn gets hotter and more and more liquid, so the stirrer may bee after some time rotated with a motor. Chlorine stream should bee regulated so that almost all of it is absorbed. When the reaction mixture stops heating and Cl2 is no longer taken up, the rxn contents are distilled in vacuo at oil bath temp ~150-180�C, then redistilled at ordinary pressure, collecting the fraction boiling between 132 and 142�C. Yield ~90%.


NaOAc+S2Cl2=AcO-S-S-AcO+NaCl
AcO-S-S-AcO+Heat=Ac2O+S+SO2

In this reaction Br2 and Cl2 after produce S2X2 make AcO-S-S-AcO and finally anhydrid ,may I2 make same?

[Edited on 19-2-2010 by Waffles SS]
View user's profile View All Posts By User
User
National Hazard
****




Posts: 339
Registered: 7-11-2008
Location: Earth
Member Is Offline

Mood: Passionate

[*] posted on 19-2-2010 at 03:51


Quote:

Mix quickly and thoroughly 205-215 g of pulverized fine NaOAc and 10g dry sulfur powder, the mixture is quickly transferred to a wide-mouth 1 liter RBF and wetted w/25 ml acetic anhydride. Into the flask through the rubber cork extend 1) a wide tube for chlorine in-flow 2) an overhead stirrer, which is sealed with the aid of a piece of rubber tubing greased with vaseline and 3) an out-leading tube for excess Cl2 release. The flask is immersed in an ice-bath. Chlorine is initially passed in very carefully, with frequent stirring or shaking, over the passage of time the rxn gets hotter and more and more liquid, so the stirrer may bee after some time rotated with a motor. Chlorine stream should bee regulated so that almost all of it is absorbed. When the reaction mixture stops heating and Cl2 is no longer taken up, the rxn contents are distilled in vacuo at oil bath temp ~150-180�C, then redistilled at ordinary pressure, collecting the fraction boiling between 132 and 142�C. Yield ~90%.


This is really interesting.
It is as OTC as could be.
I even thought of this method before ever seeing it.
Could the AA in the reaction be replaced for GAA ?
I can imagine that the only reason for the AA is to create a liquid medium as absorption would be very poor when doing this dry.
Also is the first distillation in vacuo for purity reasons?



[Edited on 19-2-2010 by User]




What a fine day for chemistry this is.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 19-2-2010 at 14:04


Quote: Originally posted by User  

This is really interesting.
It is as OTC as could be.
I even thought of this method before ever seeing it.
Could the AA in the reaction be replaced for GAA ?
I can imagine that the only reason for the AA is to create a liquid medium as absorption would be very poor when doing this dry.
Also is the first distillation in vacuo for purity reasons?



Quote:

To 66.5g fused AcONa (made from AcOH + NaOH) was added a soln. of 3.3g S in 48.4g Br2 over 5mins, under manual stirring. Brown colour disappears rapidly on stirring to give slightly off-white mixture. Stirring continued for another 15mins. Mixture has v. strange consistancy; becomes almost liquid while stirring but as soon as one stops stirring it becomes solid again. Thus formed sludge was scooped up and dumped in a distillation flask (spilling much in the process - do this rxn in the same flask you're gonna distil from), and distilled.
Yield of Ac2O = 29.2g as a clear pungent liquid.


No Ac2O needed.

http://www.erowid.org/archive/rhodium/chemistry/anhydrides.h...

also:
http://www.sciencemadness.org/talk/viewthread.php?tid=9096
View user's profile View All Posts By User
franklyn
International Hazard
*****




Posts: 3026
Registered: 30-5-2006
Location: Da Big Apple
Member Is Offline

Mood: No Mood

[*] posted on 23-2-2010 at 02:45


Refering back to here _
http://www.sciencemadness.org/talk/viewthread.php?tid=9&...
http://www.hsia.org/white_papers/111tri%20wp.html

.
View user's profile View All Posts By User
User
National Hazard
****




Posts: 339
Registered: 7-11-2008
Location: Earth
Member Is Offline

Mood: Passionate

[*] posted on 4-3-2010 at 11:35


Can someone tell me how AA smells?
If the compound that I made actually is what it should be it smells like acetic acid with a garlic like undertone, maybe my nose is just retarded :P

Anyone?

Lol i know that there are more scientific methods!

[Edited on 4-3-2010 by User]




What a fine day for chemistry this is.
View user's profile View All Posts By User
hissingnoise
International Hazard
*****




Posts: 3940
Registered: 26-12-2002
Member Is Offline

Mood: Pulverulescent!

[*] posted on 4-3-2010 at 15:09


I'd imagine it'd smell just like glacial acetic acid as any vapour from the anhydride would be quickly hydrolysed in air.
Putting your nose close to it, it might have added pungency!
It's guesswork, unfortunately. . .
View user's profile View All Posts By User
entropy51
Gone, but not forgotten
*****




Posts: 1612
Registered: 30-5-2009
Member Is Offline

Mood: Fissile

[*] posted on 4-3-2010 at 15:55


Ac2O smells somewhat different than AcOH, but I can't really describe it; I try to avoid breathing the stuff. Above thread these tests were cited to identify Ac2O:
Quote: Originally posted by IPN  
This is what Practical Methods of Organic Chemistry (Gattermann) says about detecting acetic anhydride:

Quote:

5 c.c. of water are treated with 0,5 c.c. of acetic anhydride. The latter sinks to the bottom and does not dissolve even on long shaking. If the mixture be warmed, solution takes place.


Quote:

2 c.c. of alcohol are added to 1 c.c. of acetic anhydride in a test-tube, and heated gently for several minutes. It is then treated with water and carefully made slightly alkaline. The acetic ester can be recognised by its characteristic pleasant odour.


Quote:

Add 1 c.c. of aniline to 1 c.c. of acetic anhydride, heat to incipient ebullition, and then, after cooling, add twice the volume of water. The crystals of acetanilide separate out easily if the walls of the vessel be rubbed with a glass rod.
As noted, it is not nearly as easily soluble in H2O as is AcOH.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 5-3-2010 at 11:45


Quote: Originally posted by Plasmapyrobattics  
Na2O (Sodium monoxide) might be a problem to procure.

What about Calcium oxide ?

2 mol 1,1,1-Trichloroethane reacted with 3 mol CaO :

3 CaO + 2 CH3C.Cl3 --> (CH3CO)2O + 3 CaCl2

168 g CaO (3 mol) with 267 g / 202 ml (2 mol) Trichloroethane.

Any thoughts ?


I did this reaction
That was unsuccessful.no anhydrid acetic made
I mixed 168 g CaO and 202 ml TCE.and reflux for 1 hour in normal pressure and then distil.no anhydrid come.
View user's profile View All Posts By User
entropy51
Gone, but not forgotten
*****




Posts: 1612
Registered: 30-5-2009
Member Is Offline

Mood: Fissile

[*] posted on 5-3-2010 at 12:21


Quote: Originally posted by Waffles SS  
I did this reaction
That was unsuccessful.no anhydrid acetic made
I mixed 168 g CaO and 202 ml TCE.and reflux for 1 hour in normal pressure and then distil.no anhydrid come.

Proving one more time that just because you can balance an equation doesn't mean it will work.
Quote: Originally posted by franklyn  

Accordingly it seems much more sensible to just heat together stoichiometric
amounts of 1,1,1-Trichloroethane and caustic soda , Na2O.
1,1,1-Trichloroethane is known to be incompatible with caustic soda.

2 CH3CCl3 + 3 Na2O -> (CH3CO)2O + 6 NaCl
The conditions cited in the patent are very different than those you tried (150 C vs reflux at 75 C) for starters.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 8-3-2010 at 10:57


Quote: Originally posted by entropy51  

The conditions cited in the patent are very different than those you tried (150 C vs reflux at 75 C) for starters.

In patent water react with TCE and make anhydrid acetic and HCl in autoclave.
Sure autoclave must made from special stainless steel because HCl in 150c will dissolve it.
View user's profile View All Posts By User
halogenstruck
Hazard to Self
**




Posts: 61
Registered: 24-9-2009
Member Is Offline

Mood: No Mood

[*] posted on 3-4-2010 at 13:56


the easiest method is to use NaHSO4 and heating[maybe in microwave] and preparing Na2S2O7 and then heating with Dry Sodium Acetate[dried in microwave beforehand] in acetic acid or anhydride solvent.us patent no. 1430304
View user's profile View All Posts By User
Formatik
International Hazard
*****




Posts: 927
Registered: 25-3-2008
Member Is Offline

Mood: equilibrium

[*] posted on 4-4-2010 at 00:23


That patent was mentioned in the very beginning of this thread. It's also attached below.

Attachment: US1430304.pdf (194kB)
This file has been downloaded 1320 times

View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 4-4-2010 at 01:12


I tried it several time but was unsuccessful(1430304 )
I used Merck Sodium Pyrosulfate but no anhydrid come just H2S and AcOH.
View user's profile View All Posts By User
JohnWW
International Hazard
*****




Posts: 2849
Registered: 27-7-2004
Location: New Zealand
Member Is Offline

Mood: No Mood

[*] posted on 4-4-2010 at 02:06


For some reason. it seems that it has recently become IMPOSSIBLE to download ANY attached PDF files here beyond 64 Kb! At that point, the downloads all cut out.
View user's profile View All Posts By User
Satan
Hazard to Others
***




Posts: 126
Registered: 1-5-2009
Member Is Offline

Mood: No Mood

[*] posted on 4-4-2010 at 02:18


Quote: Originally posted by Waffles SS  
I tried it several time but was unsuccessful(1430304 )
I used Merck Sodium Pyrosulfate but no anhydrid come just H2S and AcOH.

Patent also sugest using diluent, but I think you didnt use any, am I correct? Good method might be to grind both reagents with acetic anhydride and then distil.

@JohnWW downloads works for me. It might be your computer.
View user's profile View All Posts By User
Waffles SS
Fighter
*****




Posts: 990
Registered: 7-12-2009
Member Is Offline


[*] posted on 4-4-2010 at 02:26


Also I used diluent(AcOH and Ac2O) but no anhydrid produced(i did this method several time and in diffrent condition)



[Edited on 4-4-2010 by Waffles SS]
View user's profile View All Posts By User
Ephoton
National Hazard
****




Posts: 463
Registered: 21-7-2005
Member Is Offline

Mood: trying to figure out why I need a dark room retreat when I live in a forest of wattle.

[*] posted on 16-4-2010 at 22:08


the best discription I can give for the smell of AA is burnt polystyrene.

very acrid and cutting but a lot thinner and etherial than GAA smells.


[Edited on 17-4-2010 by Ephoton]




e3500 console login: root
bash-2.05#

View user's profile View All Posts By User
crossf!re
Harmless
*




Posts: 1
Registered: 23-2-2010
Member Is Offline

Mood: No Mood

[*] posted on 17-5-2010 at 10:50


...ive tried the reaction with S2Cl2 and NaOAc. On the temperature between 60C°-70C° the reaction was vigorous - than i take out the AA with Vacuum ( first without heating, at the end of the reaction i take an it in a oilbath). First ive mixed The Sodiumacetate with S2Cl2 in a beaker because it was a siroupy mass, which was not easy to stir and to get it into a round flask.

but the Result was a liquid that boils between 139C° and 140C°.


the yield was round about 80%

and it has the typical smell of AA...but with a little smell of acetic acid..
View user's profile View All Posts By User
Fleaker
International Hazard
*****




Posts: 1243
Registered: 19-6-2005
Member Is Offline

Mood: nucleophilic

[*] posted on 21-5-2010 at 18:21


I would far rather make a tube furnace and do acetone pyrolysis and deal with ketene than bother with the sulfur halides.

This has been a very impressive thread so far.

I'm surprised more people haven't attempted the pyrolysis method?




Neither flask nor beaker.


"Kid, you don't even know just what you don't know. "
--The Dark Lord Sauron
View user's profile View All Posts By User
Sedit
International Hazard
*****




Posts: 1939
Registered: 23-11-2008
Member Is Offline

Mood: Manic Expressive

[*] posted on 21-5-2010 at 18:41


I want to big time and am 99% sure I can do it but my mind thinks back to people who thought they could do something but the corner said it didn't go to well.




Knowledge is useless to useless people...

"I see a lot of patterns in our behavior as a nation that parallel a lot of other historical processes. The fall of Rome, the fall of Germany — the fall of the ruling country, the people who think they can do whatever they want without anybody else's consent. I've seen this story before."~Maynard James Keenan
View user's profile View All Posts By User
hypnos
Harmless
*




Posts: 4
Registered: 22-9-2009
Location: land of oz
Member Is Offline

Mood: curious

[*] posted on 23-5-2010 at 18:08


I read that one can make AA by bubbing CO through sodium acetate...has anyone seen this synth anywhere? Does it 'make sense'...looks very easy...
CH3CO2CH3 + CO → (CH3CO)2O

[Edited on 24-5-2010 by hypnos]
View user's profile View All Posts By User
bbartlog
International Hazard
*****




Posts: 1139
Registered: 27-8-2009
Location: Unmoored in time
Member Is Offline

Mood: No Mood

[*] posted on 23-5-2010 at 18:57


Your equation shows methyl acetate, not sodium acetate. Looks totally implausible to me but if you can actually remember where you read it I'd love to take a look.
View user's profile View All Posts By User
hypnos
Harmless
*




Posts: 4
Registered: 22-9-2009
Location: land of oz
Member Is Offline

Mood: curious

[*] posted on 27-5-2010 at 16:03


ahem yeah oops methyl acetate it is.....i saw it mentioned in Wiki in the 'Acetic Anhydride' entry
Acetic anhydride is produced by carbonylation of methyl acetate:[1]

CH3CO2CH3 + CO → (CH3CO)2O
This process involves the conversion of methyl acetate to methyl iodide and an acetate salt. Carbonylation of the methyl iodide in turn affords acetyl iodide, which reacts with acetate salts or acetic acid to give the product. Rhodium and lithium iodides are employed as catalysts. Because acetic anhydride is not stable in water, the conversion is conducted under anhydrous conditions. In contrast, the Monsanto acetic acid process, which also involves a rhodium catalyzed carbonylation of methyl iodide, is at least partially aqueous.

does sound too good to be easy
View user's profile View All Posts By User
not_important
International Hazard
*****




Posts: 3873
Registered: 21-7-2006
Member Is Offline

Mood: No Mood

[*] posted on 27-5-2010 at 17:51


It isn't too good to be true, just a little challenging for amateurs - 140 C and 5 bar CO for a complexed Pd catalyst http://www.rsc.org/delivery/_ArticleLinking/DisplayArticleFo... 25 to 100 bar and a bit hotter for Rh/LiI, up to 200 bar or more and often hotter for Ni based systems.

Getting even 5 bar pressure of carbon monoxide will be a little tricky, you'll need to watch out for nickle-containing alloys as the can produce nickle carbonyl which is just a little tiny bit toxic. MeI is kinda fun too, especially if you've more than a few years of life expectancy before you start messing with it as a hot gas under pressure.

And you need some good fractionation gear, too.

View user's profile View All Posts By User
 Pages:  1  ..  22    24    26  ..  42

  Go To Top