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Author: Subject: Acetic anhydride preparation
ketel-one
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[*] posted on 13-9-2009 at 16:46


I don't think S2Cl2 will work, it doesn't have S to Cl atoms in right proportion.

I think SO2Cl2 (SO2 + Cl2 in activated carbon) will take you to acetic anhydride though.
3NaOAc + SO2Cl2 = Na2SO4 + NaCl + Ac2O
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DJF90
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[*] posted on 13-9-2009 at 17:30


You can't do 2+2 chemistry when it comes to organic. S2Cl2 works great - theres a method posted here using the bromide instead, and that works fine too.
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entropy51
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[*] posted on 13-9-2009 at 17:38


Since none of the reactions you have posted so far is feasible, I doubt anyone is surprised that you are out in left field once again.

See this thread for some much-needed enlightenment:

https://www.sciencemadness.org/whisper/viewthread.php?tid=90...




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entropy51
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[*] posted on 13-9-2009 at 17:41


Quote: Originally posted by ketel-one  
My mistake then, I thought S2Cl2 was an idea no-one's tested yet.

You can always use AlCl3
anhydrous AlCl3 + acetic acid = hydrous AlCl3 + acetic anhydride.


Please feel free to read a few of the posts on the forum and educate yourself on what some of the competent chemist members have done. That will help keep you from looking, shall we say, uninformed.




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ketel-one
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[*] posted on 13-9-2009 at 17:49


Ok I see, only compounds that hydrolyze in water would work, dehydration by itself won't.
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[*] posted on 13-9-2009 at 22:40


Your rule is not correct, AlCl3 also hydrolyzes in water (to a mix of chloride/hydroxide and HCl) and yet it cannot make Ac2O. If you open a container of anhydrous AlCl3 then you are welcomed by dense fumes of HCl. If you put a single drop of water on a heap of anhydrous AlCl3 then you hear a hissing noise and HCl, mixed with waper vapor, is released.






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JohnWW
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[*] posted on 14-9-2009 at 00:47


Other possible alternatives to S2Cl2 and AlCl3 for anhydride preparation in that way should be PCl3, POCl3, PCl5, AsCl3, SCl2, SOCl2, SiCl4, SnCl4, BCl3, and possibly TiCl4. The corresponding bromides may be usable insofar as they may be sufficiently stable.
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[*] posted on 23-9-2009 at 04:44


hi everyone.
I have been using the Vinyl Acetate , HCl acetic acid method proposed earlier. I have been constantly getting Ac anhydride. the yields are ok but the purity is somewhat average. its probably because i am not a chemist and my fractionating column or my procedure might be crude. anyways i wanted to thank this forum and a few people here. i have stopped making the anhydride as my purpose for doing it has been achieved. thanks again
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franklyn
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[*] posted on 6-11-2009 at 14:47
One pot synthesis of Ac2O from Trichloroethane



So claims this patent from 1932 - US 1870601
Which details hydrolysis of Methylchloroform in reflux with water catalysed by H2SO4.
On its own it hydrolyzes with water over years forming Hydrochloric and Acetic acid.
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

See " Reactivity Profile " here _
http://cameochemicals.noaa.gov/chemical/1629
See " Incompatibilities & Reactivities " here _
http://www.osha.gov/web/dep/chemicaldata/ChemicalResult.asp?...
See " Reactivity Data " here _
http://www.relton.com/pdf/rapidtap.pdf

Availability of 1,1,1-Trichloroethane is extremely limited , this is a cheap source here
Carbo-Sol was discontinued in January, 2006 , get while it lasts.
http://www.retcoalloy.com/store/product.php?productid=182773...

.

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JohnWW
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[*] posted on 6-11-2009 at 20:28


1,1,1-Trichloroethane, technical grade, is widely used as a solvent by commercial dry-cleaners. Ask a local dry-cleaning firm if they will let let you have some. (Bring along your own bottle). I was able to get about 500 ml of it from a local dry-cleaner a couple of years ago. However, it may contain other chlorocarbon impurities of similar molecular weight. It can also be used as a thinner in correction fluid, which was the main reason I wanted it.

[Edited on 7-11-09 by JohnWW]
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not_important
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[*] posted on 6-11-2009 at 22:16


Um, 1,1,1-Trichloroethane is regulated by the Montreal Protocol as an ozone depleting substance and is being rapidly phased out. In many countries its sale is heavily taxed to discourage its usage. In some countries the manufacture of TCE has stopped, and it is only available from the remaining stocks until they are exhausted.

It's also fairly toxic, in California it was so listed back in the late 1980s and its use in products such as correction fluid was quickly phased out.

Tech or solvent grade TCE contains various stabilisers, as it slowly decomposes to 1,1-dichloroethylene and HCl; the stabilisers can make up over 5% of the product as sold. It's likely that you would need to determine what the additives are and devise a purification process. Note that simple distillation is not likely to work, as the majority of uses for TCE are as a cleaning solvent it was typically recovered by distillation; the stabilisers would need to not segregate from the TCE itself and so either boil near TCE's BP or form azeotropes with it.

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[*] posted on 6-11-2009 at 22:53


Quote: Originally posted by not_important  
1,1,1-Trichloroethane is also fairly toxic


It's not toxic at all. After a lifetime of inhaling the fumes I
would not be here , and in the best of health.
Just don't drink too much of it.

.
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[*] posted on 20-11-2009 at 21:09


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 ?
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hector2000
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[*] posted on 30-11-2009 at 12:20


Quote: Originally posted by franklyn  

So claims this patent from 1932 - US 1870601
Which details hydrolysis of Methylchloroform in reflux with water catalysed by H2SO4.
On its own it hydrolyzes with water over years forming Hydrochloric and Acetic acid.
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

.

This Reaction need pressure?(like patent reaction?)




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unome
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[*] posted on 2-12-2009 at 15:55


For the other devotees of Tarbutton, et al's work, here is one of the papers they actually disproved the essence of, but what is important is the fact that it is not run in a pressure vessel of ANY description, nor does it use anything more than scrupulously dry reagents in a steel pipe which is then heated to give "reportedly" PF5 (but which Tarbutton, et al, showed to be far more likely to be a mixture of POF3 and PF5) through the use of their far more elaborate apparatus - which was designed solely to ensure that they could quantify, isolate and identify the gasses evolved, not because such apparatus was needed per se...

A New Method of Preparing Phosphorus Pentafluoride

Howard J. Lucas, Fred J. Ewing
J. Am. Chem. Soc., 1927, 49 (5), p 1270
DOI: 10.1021/ja01404a501

Quote:
Excerpt from start of Note... (it is one page, if you want to read the whole thing, follow the link above to the JACS site)

It has been found that when a mixture of calcium fluoride and phosphorus pentoxide is heated, a gas is evolved, composed largely of phosphorus pentafluoride. The details of the method are as follows. A mixture of 25g. of phosphorus pentoxide with approximately 55g. of pure calcium fluoride (previously dried by heating in an iron crucible over a flame) was heated in a 2cm. iron pipe about 30cm. long, capped at one end and connect to a 1 cm. pipe at the other. Glass cannot be used. In order to reduce to a minimum the formation of hydrogen fluoride, the apparatus and materials had to be free from moisture. It was found necessary to bake out the apparatus, to use the best phosphorus pentoxide, to ignite the fluoride, to transfer it while still hot to the hot apparatus, and to measure out the materials rapidly (about 50cc. of each) instead of weighing. The ingredients were mixed by shaking. The rate of gas evolution depended upon the temperature and was quite rapid when a large flame was used. The gas fumed in moist air....


PS Before I get asked why this is here, it is in response to Sauron's claim somewhere in the last few pages (IIRC) that a pressure vessel/other expensive equipment was necessary to replicate the procedure of Tarbutton, et al. It is not. I'll throw Tarbutton, et al's paper here so people know what I mean anyhow... Seems to me that fused NaCl and P4O10 should be able to do the trick at a reasonable temperature (didn't Brauer or one of the inorganic books have a route to drying P2O5/Polyphosphoric acid (if it ain't completely dry it is not the pentoxide anymore is it?) by sublimating it in a tube?


[Edited on 3-12-2009 by unome]

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Waffles SS
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[*] posted on 8-12-2009 at 23:58


Does anyone tried Bromo Acetyl Bromide or Chloro Acetyl Chloride method for make Ethenone(ketene)?

BrCH2COBr +ZN(dust) ===> H2C=C=O +ZNBr2
or
ClCH2COCl +ZN(dust) ===> H2C=C=O +ZNCl2

H. Staudinger,
H. Klever, Ber. Dtsch. Chem.
Ges. 1908, 41, 594 – 600

as you know anhydrid acetic finally make from ketene




[Edited on 9-12-2009 by Waffen SS]
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[*] posted on 9-12-2009 at 10:38


Zinc Nitride? What? No wait, you mean zinc.
Um, anyway, it seems like if you have acetyl chloride you can go straight to acetic anhydride (via reaction with NaOAc) rather than messing around with ketene (which has to be bubbled through glacial acetic acid, is poisonous and so on). I suppose if I had chloro acetyl chloride but not plain old acetyl chloride, and zinc dust and glacial acetic acid on hand, and a setup for handling the ketene, it might be tempting. But in general I think it's not as good as other methods already described.
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Waffles SS
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[*] posted on 9-12-2009 at 11:17


Zn is Zinc my friend not Zinc Nitride.
If this reaction work ofcourse is easier than acetone Pyrolyze



[Edited on 9-12-2009 by Waffen SS]
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[*] posted on 9-12-2009 at 12:08


Zn is zinc, yes. ZN on the other hand is... well, I guess it's also zinc, but since there can be ambiguities when you are sloppy with capitalization, I thought I'd point it out. Hf versus HF, Co versus CO and so on.

Quote:
If this reaction work ofcourse is easier than acetone Pyrolyze


Depends on what you have I guess. Chloroacetyl chloride and acetyl chloride aren't trivial to make. If you already have them, then sure.
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Waffles SS
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[*] posted on 12-12-2009 at 08:17



Quote:

NEW METHOD FOR PREPARATION OF ANHYDRIDES AND AMIDES OF
CARBOXYLIC ACIDS USING CARBON TETRACHLORIDE

The acid anhydrides were obtained in 48-97% yield by reacting either the Na or K salt of the carboxylic acid with CCI4 in the presence of CuCl, CuCI2, FeCl2 or Cu at 18-20C and atmospheric pressure in either DMF or acetonitrile.

J. Weiss, F. Havelka,
and B. K. Nefedov

Anybody tried this method?

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entropy51
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[*] posted on 12-12-2009 at 09:38


Someone may have tried it by now. Solo posted that article three years ago in the references section. I suspect the difficulty getting CCl4 may have hindered experimentation by many of us. Thanks, it's interesting nonetheless.
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[*] posted on 12-12-2009 at 14:57


Interesting, I have some 350mL of CCl4 and access to more.
Not sure what anhydrides I will want to make though. Maybe later it will come at hand.

talking about anhydrides, a bit offtopic, but does anyone know what i could do with my 10mL of trifluoroacetic anhydride?
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[*] posted on 12-12-2009 at 17:49


TFAA mediated moffatt oxidation? I have some 900-1000mls of CCl4, but I do not find this an interest to myself as there are better ways of obtaining anhydrides.
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[*] posted on 4-1-2010 at 19:59


Quote: Originally posted by Waffles SS  
Does anyone tried Bromo Acetyl Bromide or Chloro Acetyl Chloride method for make Ethenone(ketene)?


Those reactions are only useful where you need your ketene with a high level of purity. For the most part, the byproducts of acetone pyrolysis (methane, ethene, CO, CO2) don't interfere in most cases where ketene is used (e.g. acetic esters, amides, acetic anhydride). Unless you happen to have come by the Cl-acetyl-chloride, it would be pretty pointless to do this if acetic anhydride is the goal.

Otherwise, just use a ketene "lamp", or heat the acetone vapors some other way to get your ketene.

If you're going to be working with ketene, make sure you have a good fume hood and ketene traps (dilute acetic acid works well for this, and you get more concentrated acetic acid too). Definitely study up on the possible hazards of working with ketene.
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[*] posted on 5-1-2010 at 09:41


My main problem is unknown componet that produced in absorb flask.this componet is soluble in water and has ~100-105boiling point.
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Polverone
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