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ketel-one
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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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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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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=9096
Thinking creates entropy...Leo Szilard
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entropy51
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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.
Thinking creates entropy...Leo Szilard
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ketel-one
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Ok I see, only compounds that hydrolyze in water would work, dehydration by itself won't.
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woelen
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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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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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quarterfinal
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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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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?RecNo=4...
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&cat=0&page=2
.
Attachment: Ac2O by CH3CCl3 pat1870601.pdf (171kB)
This file has been downloaded 9 times
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JohnWW
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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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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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franklyn
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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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