Sciencemadness Discussion Board

Acetic anhydride preparation

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Sauron - 17-11-2008 at 04:20

Got an autoclave?

Because 40 C is quite a bit higher than the bp of acetaldehyde. In fact it is just about DOUBLE the bp, which is 21 C.

You'll lose it all through the condenser.

So without a pressure vessel, testing is going to be tough.

[Edited on 17-11-2008 by Sauron]

ItalianXKem - 10-12-2008 at 08:19

heat a aqueous solution of acetic acid and hydrogen sulfate (vitriol , car battery acid , sulfuric acid) H2SO4 , don't try this at home , is very dangerous , this synthesis can be make only a expert chemister

2 CH3COOH + H2SO4 ---heat---> (CH3CO)2O , evaporates H2O

Sauron - 10-12-2008 at 09:30

Sorry, that will not work. I challenge you to provide supporting chemical literature references that claim it will.

Any aqueous solution will fail, and >100% H2SO4 (oleum, fuming H2SO4, free SO3 dissolved) will chew acetic acid up to CO2 etc under the conditions you describe.

Try again.

ItalianXKem - 10-12-2008 at 09:34

doh ! :D

Formatik - 10-12-2008 at 10:01

Heating a mixture of AcOH with conc H2SO4 causes it to discolor and develop SO2 and CO2 gases in varying amounts. If one uses oleum in excess, then it heats up by itself and without evolution of gases, heating it stronger develops nearly pure CO2, which has barely 5-10% SO2. And SO3 solubilizes in AcOH without evolving any gases, and this is destroyed by water; heating this forms sulfoacetic acid. Source: Lehrbuch der organischen Chemie, Gerhardt, Wagner, p. 805. It was a nice theoretical idea, but in reality is wishful thinking. I believe the idea was discussed a few pages back.

Sauron - 10-12-2008 at 20:23

Quite right, formatik. Full marks. This scheme will not succeed no matter how expert the "chemister" may be.

The lit. on sulfoacetic acid is instructive.

Once again I recommend Roger Adams in JACS circa 1916-1919 regarding dehydration of carboxylic acids to anhydrides using oxalyl chloride. Depending on ratio of reactants one can cleanly obtain the anhydride or the acyl chloride. The mechanism is elucidated for both cases. Too bad the reagent is so costly (and nasty) or this would be a productive method. It still can be if you make your own oxalyl chloride (from anhydrous oxalic acid and TCT (cyanuric chloride) but, the nastiness is still there, and a lot of people seem unable to obtain TCT. Oh well. But there are many viable alternatives. I mention this one simply because it is one of the few examples of going straight from the acid to the anhydride without proceeding via the acyl chloride first.

hector2000 - 14-12-2008 at 14:17

Quote:
Originally posted by quarterfinal
i have been trying out the vinyl acetate method mentioneed in earlier threads and have succeeded in getting acetic anhydride . but the yield and purity are pretty bad. the yield is about 10% and the purity is about 60% or max 70%. there is a lot of acetic acid mixed with the product and its pretty hard to seperate with even careful fractional distillation.

may you explain your ratio?
before i try this method and i got nothing

[Edited on 15-12-2008 by hector2000]

triazine method

chemrox - 21-2-2009 at 12:24

There are 21 pages of this thread and so I haven't looked page by page to see if anyone posted the Na2CO3-SOCl2 method> It is simple and efficient. There is also a hydroxy 1,3,5 triazine method where the solvent ratios of DCM and 3-methyl morpholine have to be 1:1 ..odd.

Attachment: a triazine-e.g. DCMTw-a morpholine.pdf (110kB)
This file has been downloaded 1174 times

Engager - 25-3-2009 at 18:25

Acetic anhydride from thionyl chloride




Round bottom flask (500 ml) is filled with 144 ml of thionyl chloride and 120ml of glacial acetic acid is added with stirring. Reaction starts immediately, evolving steady stream of sulfur dioxide and hydrogen chloride bubbles. Process is strongly endothermic and causes strong cooling of reaction mixture, shortly after start reaction mixture separates to 2 layers. Reaction flask is left for 2 hours, allowing contents to heat slowly to room temperature (#1). Then lower layer of thionyl chloride will completely disappear, reaction flask is attached to reflux condenser and is heated on 60C water bath for 2 hours, after witch no more gas is evolved from reaction mixture. Mixture is chilled in cold water and 160g of freshly fused sodium acetate is added in portions with intense stirring (#2). After all sodium acetate is added reflux condenser is reattached and mixture is allowed to sit on hot water bath for 2 more hours. Formed slurry is gently mixed and reaction mixture is distilled on wax bath, to give 130-140 ml of acetic anhydride with 65-70% yield (#3).


Notes:

1. Reaction goes rapidly even at low temperature, and slow heating to room temperature (for 2 hours) prevents process from becoming to violent. Lower layer of reaction mixture (thionyl chloride) diminishes rapidly during course of reaction, forming SO2 and HCl bubbles on it’s border. After lower layer completely disappears gas evolution slows down, and mixture must be heated further to force reaction to complete.


2. This reaction step requires anhydrous sodium acetate to be used, it can be prepared by gentle heating of commercially available hydrated sodium acetate. This freshly fused sodium acetate is ground to fine powder and used immediately. Addition of sodium acetate cause heating, because reaction at this step is exothermic addition rate must be adjusted, not allowing temperature to rise above 45C to prevent boiling and evaporation of highly volatile acetyl chloride (boiling point 51.8C).


3. Practical yield of acetic anhydride then using distillation at normal pressure is remarkably lower then theoretical (130-140ml), due to high absorption of product in solidified sodium chloride mass. To aid evaporation of residual acetic anhydride, solid is crushed by glass rod and rest of product is distilled under vacuum. Use of vacuum distillation allows to obtain product in yield close to theoretical (185-190 ml, 92-95%).




First photo shows pure thionyl cloride, addition of glacial acetic acid start endothermic reaction, resulting in strong cooling of reaction mixture. Cooling is so remarkable that water condensate on outer surface of reaction vessel freezes into layer of ice.



After ice is remelted it's clearly seen that some thionyl chloride is separated to form new layer at the bottom of the flask. Layer deminishes slowly entering the reaction, and steady stream of SO2 and HCl bubbles are comming from upper border of this layer. After mixure is allowed to stand at room temperature, thionyl layer disappears completely and gas evolution slows down, further heating on water bath at 60C is required to force reaction to complete.



Sodium acetate, used for this synthesis must be completely anhydrous, and can be obtained by gentle heating of commercialy avialable hydrated sodium acetate. Hydrated sodium acetate is heated on metall dish, shorty after heat applied salt dissolves in it's own crystallization water and forms liqiud solution, witch loses water on furher heating and dehydrated salt is sollidified, however to ensure full removal of water heating is continued until salt finaly remelts at ~321C. Anhydrous acetate is grounded on cooling and is used imidately.



Addtion of sodium acetate causes exothermic reaction, so it must be added by portions with gentle mixing, not allowing mixture to heat above 45C. After adition is complete, reflux condenser is connected and mixture is allowed to sit on hot water bath for an hour or two to ensure complete reaction. At the end of this period mixture forms hardly stirable slurry, witch is distilled on wax bath to get reaction product - acetic anhydride.

There are also 2 video files avialale:
1. Reaction of thionyl chloride with glacial acetic acid (link).
2. Distillation of acetic anhydrige from reaction mixture (link).

[Edited on 26-3-2009 by Engager]

Sauron - 25-3-2009 at 18:52

You will be better off starting with commercial anhydrous NaOAc rather than the trihydrate. The trihydrate requires a two stage fusion and the second stage is easy to screw up.

Also there are far far better chlorinating reagents than SOCl2 for this application.

Some details you omitted

SOCl2 FW 118 d 1.63
AcOH FW 60 d 1.04

So you ran this on a 2 mol scale using stoichiometric SOCl2 rather than the usual excess, this gets around Vogel's objection to use of SOCl2 to chlorinate C2 and C3 acids. And you did not isolate and purify your AcCl. With the nodification you describe you appear to have gotten excellent yield anyway.

Lots of us still cannot buy SOCl2 and must either mmakes our own or use another reagent.

[Edited on 26-3-2009 by Sauron]

no1uno - 15-4-2009 at 18:17

Sauron, have you any ref's on using oxalyl chloride to generate AA? Rhodium has the prep'n of oxalyl chloride from PCl5 (which rather simply avoids the alpha-chlorination problem encountered using RP on GAA directly if you do).
Quote:
Preparation of Oxalyl Chloride

126g (1 mole) of anhydrous oxalic acid is ground into a fine powder and mixed slowly and thoroughly with 400g (1.92 moles) of powdered phosphorous pentachloride (PCl5) with efficient cooling in an ice bath. Chlorine gas is evolved, so it is important to perform the reaction under an efficient fume hood. The mixture was allowed to return to room temperature slowly, and was left standing for 48-72h until the mixture liquifies completely. The mixture is now distilled, collecting the fraction boiling between 60-100°C. Repeat the distillation until the phosphorus-free, pure oxalyl chloride, bp 63-64°C, is obtained. Yeild approximately 45-50% of theoery. Fractional distillation would most likely allow a quicker separation but the author made no mention of this.

Reference: Staudinger, Ber., v41, p3563 (1908) (taken from: http://designer-drugs.com/pte/12.162.180.114/dcd/chemistry/o...)


What would be the fate of the phosphorus pentachloride? Phosphoryl chloride perhaps? If so, both could be used directly from that point couldn't they?

On a more practical note, do you still have the reference (mentioned or more properly alluded to, upthread) where the method of Tarbutton, et al, was elucidated in greater detail? Tarbutton's work was nice to read, but something with more details on the chlorides would be grand.

Sauron - 15-4-2009 at 19:13

First of all forget Rhodium.

If you work out the mass balance you will quickly see that it takes a great deal of PCl5 to chlorinate a little anhydrous oxalic acid, even theoretically, and since the actual yield is 50% or less, this only gets worse not better. The reaction is a great way to make POCl3 and a crap way to make oxalyl chloride.

So forget it.

Roget Adams, that is the great Roger Adams, founding editor of Organic Syntheses, and Organic Reactions, etc. published a series of articles in JACS between 1914 and 1920 on ocalyl chloride and bromide. The reaction of oxalyl chloride with carboxylic acid to give acyl chloride or anhydride depending on molar ratio of reactants is a general one. It is most efficient with aryl carboxylix acids. With lower aliphatic acids is work better on the sodium salt. I posted the articles long ago. UTFSE or go to the ACS search engine.

Tarbutton also in JACS in 1940 and no you will not find more details elsewhere. The reaction between P2O5 and NaCl or CaCl2 works, and is probably the best way to make POCl3 and possibly PCl3 that does not involve elemental P or preformed PCl5.

benzylchloride1 - 26-4-2009 at 15:23

Success with acetic anhydride synthesis:

I tried one of the rodium procedures today and I got some acetic anhydride. 3.5 g of sulfur powder was dissolved in 20 mL of bromine prepared from sodium bromide sulfuric acid and 35% hydrogen peroxide and dried with sulfuric acid. 66.5 g of commercial anhydrous sodium acetate was added to a 500 mL round bottomed flask. A pressure equalizing addition funnel was attached to the flask. The sulfur bromide was poured into the funnel. The sulfur bromide was added to the mixture in small portions. A reaction ensued and orange colored liquid refluxed. After the addition, the mixture was stirred with a glass stirring rod until the mixture has turned to a white solid in a clear liquid. A distillation apparatus was assembled and the mixture was distilled, collecting the fraction between 120 C -125 C @ 580 mm Hg. A clear irritating smelling liquid was obtained. Around 16 g was obtained. Much acetic anhydride remained in the flask, the distillation was stopped because of charring in the bottom of the flask. O-toluidine was dissolved in dilute HCl. 0.5ml of the acetic anhydride was added along with 1 g of sodium acetate, the mixture was stirred and a oil formed. The mixture was poured into cold water and lumps of o-acetyltoluidine formed. The o-acetyltoluidine was dissolved in boiling water, filtered and cooled. Needles of the product formed. A melting point will be taken once the derivative is isolated. This procedure indeed works; I will try it again on a larger scale. The acetic anhydride produced smelled like the acetic anhydride I used at the university. I will take my product to the university and get an IR spectrum. I wish I had my IR spectrophotometer running. I plan on trying the S2Cl2 method in a few weeks.:cool:

JACS paper on acid anhydrides

chemrox - 3-5-2009 at 11:51

Wallace and Copenhaver, March 1941, JACS, Anhydrides of the Normal Aliphatic Saturated Monobasic Acids.

In the paper the following is stated:
In general the method of Holde and Tacke was used.
The acids were refluxed for six to eight hours in a flask, with
ground-in condenser, with three equivalents of acetic
anhydride. The acetic acid and excess acetic anhydride
were distilled off under vacuum and the resulting anhydrides
purified by vacuum distillation or by recrystallization
from a suitable solvent. The anhydrides from heptylic
through pelargonic were distilled under vacuum and
capric through stearic were recrystallized three or four
times from either diethyl or petroleum ether by cooling in
an ice-salt-bath or with dry-ice. The yields ranged
from 50 to 80%.

The question is, what is unique about acetic anhydride in facilitating the dehydration of other monobasic acids? What is the mechanism? Is there another anhydride, say with a much higher boiling/melting point that would accomplish the same thing?

Attachment: JACS Wallace & Copenhaver 1941 anhydrides.pdf (218kB)
This file has been downloaded 1160 times

Sauron - 3-5-2009 at 20:21

Ac2O was and for some still is cheap and ubiquitous,

Vogel also describes this reaction.

I doubt that you need reminding that anhydrides are available from their acyl chlorides snd the acids, or sodium salts of the carboxylic acids. or the acids or salts with oxalyl chloride.

See the Fresh Look thread I started some time back, as benzylchloride had the good sense to bypass the irksome double fusion of sodium acetate trihydrate which several members got all vexed about. He did what I recommended way back and simply purchased anhydrous NaOAc and he SUCCEEDED in making Ac2O from either preformed S2Cl2, or from S and Br2. In fact he did not even gibe his NaOAc a simple single fusion, he used it out of the bottle. (Not recommended.) And he needed a little nudge about vacuum to get his yields up but that has been accomplished.

So follow his lead and you can have all the Ac2O you need and therefore all the other anhydrides through it.

SYDN - 11-5-2009 at 22:44

Engager, could you to downloud video again please

hector2000 - 22-5-2009 at 01:37

Another way for making Ac2o is carbonylation of methyl acetate
Accoding to patent number 4556519 we should use Nickel powder, Methyl iodide, Stannous acetate and Lithium acetate as catalyst and we should use 80 bar pressure
80 bar pressure is not huge pressure for example oxygen capsule has 150-180bar(~atm) pressure.
Usng these catalyst is necessary?
This is possible to use just Acetic acid,Methyl acetate+CO with 80-100 bar pressure?

JohnWW - 22-5-2009 at 14:33

Quote: Originally posted by hector2000  
Another way for making Ac2o is carbonylation of methyl acetate
Accoding to patent number 4556519 we should use Nickel powder, Methyl iodide, Stannous acetate and Lithium acetate as catalyst and we should use 80 bar pressure
80 bar pressure is not huge pressure for example oxygen capsule has 150-180bar(~atm) pressure.
Usng these catalyst is necessary?
This is possible to use just Acetic acid,Methyl acetate+CO with 80-100 bar pressure?

http://www.freepatentsonline.com/4556519.pdf
(Need to log in first)

not_important - 22-5-2009 at 23:48

Quote: Originally posted by JohnWW  

http://www.freepatentsonline.com/4556519.pdf
(Need to log in first)


http://www.pat2pdf.org/

No login needed.

In answer to hector's question, there are a number of articles in the journals on this general reaction and a search will quickly direct you to some of them. The short summary is "yes, the catalysts are needed, for a variety of reasons."

unome2 - 24-5-2009 at 01:31

Sauron, I don't recall the article by Tarbutton, et al, requiring a pressure vessel... The reaction between P2O5 and NaCl does, according to that paper, commence @ around 250C:
Quote:
The Reaction of Phosphorus Pentoxide with Metal Chlorides.*-The reaction of phosphorus pentoxide with calcium chloride and with sodium chloride in an iron or stainless steel vessel produced a mixture of phosphoryl trichloride, phosphorus trichloride and hydrogen chloride. The weight of the first compound was from three to ten times that of the second and the weight of hydrogen chloride formed was proportional to the water in the charge. The phosphorus trichloride could have resulted from the reduction of phosphoryl trichloride by the metal reaction vessel. A trace of elemental chlorine was detected among the volatile products, but no phosphorus pentachloride was obtained. The reaction between phosphorus pentoxide and sodium chloride began at about 250C and the analogous reaction between phosphorus pentoxide and calcium chloride at about 400 C.

* Taken from Tarbutton, et al, 'Phosphorus Halogen Compounds from Phosphorus Pentoxide and Halides: Properties of Phosphorus Trifluoride and Phosphorus Oxyfluoride' (1941) 63(7) JACS 1782, 1785}


There would appear to be NO need for a pressure vessel, merely condense the product of the destructive distillation (although a steel vessel probably would be sane). Nonetheless, by using a basic design - solvent can and steel condenser - it should be thereotically possible to produce enough POCl3 to make a serious quantity of Acetic anhydride at home.

In fact, this could be remarkably OTC IF we can work out a decent route to P2O5 @ home... I wasn't answered before, but would a lime-kiln (propane flame) design with a fine spray of phosphoric acid coming in from the top work? (ie. spray drying the acid - H3PO4 - to the anhydride - P2O5)

As to the production of SO2Cl2 you cited before using Camphor/Activated charcoal, here's a present:D

Attachment: SO2Cl2.InorganicPreparations.Henderson.Fernelius.140.3.pdf (92kB)
This file has been downloaded 939 times

pHzero - 8-6-2009 at 06:19

How about heating zinc acetate in a vacuum? Wiki says that makes acetic anhydride. http://en.wikipedia.org/wiki/Zinc_acetate

hissingnoise - 8-6-2009 at 08:23

It's certainly tantalising at first glance---but vacuum may mean vacuum in this case rather than reduced pressure. . .
Some investigation would seem to be in order, anyway.
If it worked at all that salt will be popular!
On second thoughts, it's way too good to be true. . .



[Edited on 8-6-2009 by hissingnoise]

497 - 8-6-2009 at 11:07

I think it's true. According to the attached paper 250*C at 0.2mm for 6 hours does the trick. The yields of the "basic acetate" are around 50%, so I would imagine the yields of acetic anhydride would be similar, although they did not say.

They give the equation:

4(RCO2)2Zn --> (RCO2)6Zn4 + (RCO)2O

I wonder if a 0.2mm vacuum is necessary for yielding acetic anhydride. It may be that the acetic anhydride and basic zinc acetate are formed at lower vacuums, but the acetate decomposes making it useless to prepare the acetate (which is all the researchers are intersted in)

Unfortunately, it would probably take over 1000g of zinc acetate to yield 100g acetic anhydride..

Attachment: BasicZincAcetate.pdf (250kB)
This file has been downloaded 2423 times

[Edited on 8-6-2009 by 497]

hissingnoise - 8-6-2009 at 14:09

Thanks for that 497, it's interesting but for me pyrolysis of acetone still seems to be the least unattractive method so far. . .


pHzero - 16-6-2009 at 04:40

I just heated some dry ASA (acetylsalicylic acid, aka aspirin) with a tiny bit of water and it smelt strongly of vinegar. I'm guessing that smell came from acetic anhydride since i only added a tiny bit of water.

This formula seemss to suggest so (note only 1 mole of water for every 2 moles of aspirin):
2C6H4COOHOAc (aspirin) + H2O --> 2C6H5COOH (salicylic acid) + Ac2O

Whereas with an excess of water, presumably you'd make acetic acid:
C6H4COOHOAc (aspirin) + H2O --> C6H5COOH (salicylic acid) + AcOH

I used up all my aspirin trying that though, but I'm going to head off to the supermarket to get something to eat, so i'll get another 32 tablets (9.6g of ASA) while i'm there, then I might try it again with a proper still setup to condense the vinegary vapours

[Edited on 16-6-2009 by pHzero]

entropy51 - 16-6-2009 at 05:48

When I smell vinegar, I think "acetic acid". Ac2O has a different smell, to me at least. This was discussed, possibly upthread.

All of my organic texts and some of the literature I looked at say that hydrolysis of an ester yields the carboxylic acid. Normally you don't make an anhydride in an aqueous environment, since anhydrides react with water to yield the acid.

Hydrolysis of esters has been extensively studied and something as odd as you speculate had happened it might have been reported. I can't find it.

not_important - 16-6-2009 at 06:56

Quote: Originally posted by pHzero  
I just heated some dry ASA (acetylsalicylic acid, aka aspirin) with a tiny bit of water and it smelt strongly of vinegar. I'm guessing that smell came from acetic anhydride since i only added a tiny bit of water.

This formula seemss to suggest so (note only 1 mole of water for every 2 moles of aspirin):
2C6H4COOHOAc (aspirin) + H2O --> 2C6H5COOH (salicylic acid) + Ac2O
...


Nope. ASA is the acetic acid ester of 2-hydroxy-benzoic acid (salicylic acid). You can not easily remove the HO- from the benzine ring, as you show in your proposed reaction - getting C6H5COOH instead of the actual C6H4(OH)COOH; hydrolysis of the ester linkage is what you will obseve.

C6H4COOHOAc + H2O --> C6H4(OH)COOH + AcOH



pHzero - 16-6-2009 at 07:00

Quote: Originally posted by not_important  
Quote: Originally posted by pHzero  
I just heated some dry ASA (acetylsalicylic acid, aka aspirin) with a tiny bit of water and it smelt strongly of vinegar. I'm guessing that smell came from acetic anhydride since i only added a tiny bit of water.

This formula seemss to suggest so (note only 1 mole of water for every 2 moles of aspirin):
2C6H4COOHOAc (aspirin) + H2O --> 2C6H5COOH (salicylic acid) + Ac2O
...


Nope. ASA is the acetic acid ester of 2-hydroxy-benzoic acid (salicylic acid). You can not easily remove the HO- from the benzine ring, as you show in your proposed reaction - getting C6H5COOH instead of the actual C6H4(OH)COOH; hydrolysis of the ester linkage is what you will obseve.

C6H4COOHOAc + H2O --> C6H4(OH)COOH + AcOH





Hmm, do you think that'd even happen if you used an excess of ASA?

not_important - 16-6-2009 at 07:20

Yes, it happens all the time within a bottle of ASA; the acetic acid smell in an old bottle is a result of hydrolysis by moisture in the air - certainly a case of excess ASA.

A phenolic OH group is difficult to remove, particularly for rings with only a few bland substitutes. The old school way to do so was distillation with zinc dust, giving low yields of the vase aromatic hydrocarbon. A little warm water isn't going to touch the OH on the ring.

Lambda-Eyde - 16-6-2009 at 07:23

pHzero: How would a hydrolysis reaction proceed without water? If you're using an excess of ASA, then the water will be the limiting reactant. The reaction will just stop when the water is consumed, and you will have some acetic acid along with the excess ASA.

[Edited on 16-6-2009 by Lambda-Eyde]

4-Aminophenol - 17-6-2009 at 03:40

Hi,


a very easy way to synthesise Acetic anhydrid ist out of acetyl chloride. The problem that its hard to buy acetyl chloride. But there is an easy way to make acetyl chloride out of benzoyl chloride. First you have to chlorinate benzaldehyd (oil of bitter almonds). The benzaldehyde reacts with the Chlorine to benzoylchloride. For the next step you need anhydrous acetic acid and zinc chloride as catalyst. Heat up the benzoylchlorid with the zinc chloride. Now you add the acetic acid slowly with a dropping funnel. When all the acetic acid is added you have to distill it with a column. In the receiver you get nearly pure acetyl chloride.

greeting

[Edited on 17-6-2009 by 4-Aminophenol]

[Edited on 17-6-2009 by 4-Aminophenol]

Magpie - 17-6-2009 at 07:30

Greetings 4-Aminophenol!

Thank you for a most interesting route to acetyl chloride. Can you provide references to any of the procedures? I'm especially interested in the conversion of benzaldehyde to benzoyl chloride.

Is any of this described already on versuchschemie.de, or elsewhere?

(My apologies to Sauron if he has already suggested such a route.)

entropy51 - 17-6-2009 at 09:03

Magpie, the chlorination of benzaldehyde to yield benzoyl chloride is in one of the BzCl threads. The thread is

http://www.sciencemadness.org/talk/viewthread.php?tid=9121#p...

The reference is British Patent 310909, posted by garage chemist:

http://v3.espacenet.com/publicationDetails/originalDocument?...

Catalysis by UV, peroxides, or sulfur with preps is give in US 3,894,923

http://www.google.com/patents/about?id=Z4EyAAAAEBAJ&dq=3...

There may also be a prep in Systematic Organic Chemistry in the forum library.

The use of BzCl to prepare AcCl from AcOH is given in this article by H.C. Brown, posted by Solo in the propionyl chloride thread, but it doesn't use zinc chloride:

http://www.sciencemadness.org/talk/files.php?pid=87977&a...

[Edited on 17-6-2009 by entropy51]

[Edited on 17-6-2009 by entropy51]

[Edited on 17-6-2009 by entropy51]

Magpie - 17-6-2009 at 13:28

Thank you entropy51.

My apologies also to garage chemist.

Looks like I have some interesting lab work ahead of me. :)

benzylchloride1 - 17-6-2009 at 13:44

Magpie, Organic Syntheses Collective volume 1 gives a procedure for the preparation of o-chlorobenzoyl chloride from o-chlorobenzaldehyde. This procedure can be adapted to benzaldehyde. The chlorination takes a very long time for 1 mole of the benzaldehyde, 15 hours.

entropy51 - 17-6-2009 at 14:17

But US patent 3,894,923 that I posted above converted 1 mole of benzaldehyde in 1.5 hours with a sulfur catalyst.

Nicodem - 20-6-2009 at 01:27

pHzero, the hydrolysis of aspirin can not give acetic anhydride, but its pyrolysis might give acetic anhydride and acetic acid as the main volatile products. The only mention I could find of aspirin pyrolysis in Aspirin and related drugs by K. D. Rainsford is a single paragraph on page 53 which discusses only solid products of the pyrolysis and does not mention any volatiles, but gives this reference:

J. C. Reepmeyer. Thermal decomposition of aspirin: formation of linear oligomeric salicylate esters. Journal of Pharmaceutical Sciences, 72 (1983) 322-323.

I suggest you to check this paper as it might have some information about acetic anhydride formation. Making acetic anhydride from aspirin would surely be an incredibly retarded method, but as an experiment it is actually interesting.


Benzaldehyde oxidation to benzoyl chloride can be done with trichloroisocyanuric acid as well (FR2633616). No need to use Cl2. This route to acetic anhydride was actually already discussed on the page 20 of this thread.

hissingnoise - 26-6-2009 at 09:42

Since may 'O2 every possible route to Ac2O has been discussed in this thread and all are equally difficult. . .
When all social drugs are legalised the nightmare will end!
Until then, fuck politics *and* politicians!

Acetic Anhydride preparation

birdman - 21-7-2009 at 17:45

Hello,
I haven't read all the dialogue in this thread, so perhaps somebody has already offerred this, but the acyl chloride of acetic acid and sodium salt of the same acid should give acetic anhydride in very good yield. were the salt and chloride of different carboxylic acids used, one would get three products, those being the mixed acid anhydride, and the two respective symmetrical anhydrides.

manimal - 23-7-2009 at 10:29

No shit. That is the classical synthesis of AA.

hissingnoise - 23-7-2009 at 11:16

Yeah, if we could get acetyl chloride OTC or if its synth was easy this thread wouldn't exist (frustrations section!). . .
Anyway, welcome to SciMad (yep, I'm heavily sedated?) birdman.
Just give us your source of that damn acid chloride, or we'll send the boys round.

birdman - 23-7-2009 at 14:13

Sorry guys,
I'm just a dumb-dumb who's read too many books. I spent five years reading all the chem texts I could get when I had nothing else to do and no opportunity to try any of it. Now that I am able to get some practical lab experience, I am playing around. But I only just got done examining the boiling point elevation of sucrose and NaCl soloutions and ended up getting molar mass determinationsPISSED and insecure all at the same time. I should probably keep my mouth shut to lessen the risk of getting my foot stuck in it.

birdman - 23-7-2009 at 14:30

Hey again,
For some reason my recent reply posted with text missing. I was writing that I just attempted molar mass calculations based on boiling point elevation of some lousy sucrose and NaCl solutions and they didn't even come out CLOSE to right. Very confidence inspiring for a wishfully aspiring chemist. That, however, is the the extent of my intimidating expertese.
Regarding Acyl chlorides however,... are they really THAT hard to get? Even Ac2O itself,... I mean, I understand it is a List II chem, but can't somebody purchase it in amounts below the threshhold quantities w/o serious scrutiny? I recently ordered some HgCl2, which I am given to understand is a watched chem in California but it's sold by hobbiest chem outlets and I have perfectly legal experiments planned for it. Should I expect a visit from Men In Black or parole agents in HAZMAT suits?

[Edited on 23-7-2009 by birdman]

Magpie - 23-7-2009 at 21:50
Quote:

I just attempted molar mass calculations based on boiling point elevation of some lousy sucrose and NaCl solutions and they didn't even come out CLOSE to right.


Give us all the details of these failed experiments and we will be glad to help you troubleshoot. Preferably do this in another thread under Beginnings.

There is often a world of separation between literature syntheses and home lab capability. A requirement for extreme temperature and/or pressure conditions is one reason. Availability of reagents to the private citizen is another.

Will you be questioned if you order Ac2O? I don't know. Will you be questioned if you order KCN? Probably. There's no hard and fast rules out there. You have to use your own judgement. It's your neck and you are on your own. If you stay with this forum long enough and read enough of the existing threads you will develop your own sense about this.

birdman - 24-7-2009 at 11:40

Thanks Magpie,
I prepared my solns all over again last night, paying closer attention to masses and volume measurements. this morning I noticed that the thermometer I had used has the word 'total' on it. I'm assuming that means it's a total immersion thermometer. My ground glass adapter, stillhead thermometer is 75 mm immersion, but I don't have 75 mm of fluid in my samples. I have a cheap, alcohol candy thermometer. I'm going to measure ambient temperature with them all, then the boiling point of distilled water and see how they compare. I'll probably go with the candy therm of it shows reasonable linearity in that range.
I love setting up my ground glass and watching condensate spin down the coils of my graham condenser and yelling in my garage about having perfected the flux capaciter, so I'm having fun, no matter what. I'm going to go check out the Beginings forum.

S.C. Wack - 25-7-2009 at 10:02

It seemed odd that the oldest literature on the S2Cl2/carboxylic acid reaction in this language, 100 year old JCS articles by Denham, haven't been posted anywhere; so I thought that I'd post some excerpts, even though this is not something that you may be interested in, has been touched on before, and in fact barely mentions acetic anhydride. It seems better to dump all this related crap here than to put it in any one of 50 threads by Sauron about the same thing over and over again. So:

The author has found that the sodium, or better, the silver, salts of many monobasic organic acids react smoothly with sulphur monochloride in presence of such solvents as light petroleum, ether, or benzene to give the chloride of the metal and unstable derivatives of the acids, in which, apparently, sulphur replaces the hydrogen of ths hydroxyl group. These compounds decompose even when kept in sealed tubes, and the products of decomposition are found to be the anhydride of the acid, sulphur dioxide, and free sulphur. The following equations may perhaps be taken as representing respectively the formation and decomposition of the benzoic acid derivative:

2C6H5COONa + Cl2S2 -> (C6H5COOS)2 + 2NaCl
2(C6H5COOS)2 -> 2(C6H5CO)2O + SO2 + 3S

Action of Sulphur Monochloride on Sodium Benzoate. - This reaction has been carried out repeatedly in slightly varying ways, using different solvents; the following may be taken as typical. 2.9 g. of dry, powdered sodium benzoate were mixed with about 20 ml. of light petroleum, and the calculated quantity (1.4 g.) of sulphur chloride dissolved in a few ml. of the same solvent was added all at once. The mixture was then boiled on the water-bath for an hour and a-half under a reflux condenser provided with a calcium chloride tube; a slight odour of sulphur dioxide was noticed during this operation. About one gram of freshly reduced copper powder* was then added, and the boiling was continued for half-an-hour longer. The copper became black, and the solution green, but, on filtering, a clear, colourless liquid was obtained, from which crystals separated on cooling. In this way a good yield is obtained of the substance, (PhCOOS)2, in well-defined, colourless crystals, which, however, soon turn yellow and evolve sulphur dioxide, leaving sulphur and benzoic anhydride. This decomposition takes place even in an atmosphere of carbon dioxide, and in warm weather may occur instantaneously with the formation of a liquid mass consisting of a mixture of sulphur and benzoic anhydride. The compound is easily soluble in alcohol, ether, benzene, carbon disulphide, or glacial acetic acid, more sparingly so in light petroleum. The solution in benzene may be kept for a day or two without evidence of decomposition, whilst that in glacial acetic acid soon decomposes.

* The copper is not essential. It was added in one experiment to see if it would remove the sulphur and leave benzoyl peroxide, but this did not happen. The use of it was continued in after experiments, since it appeared to destroy final traces of sulphur chloride and to be better for this purpose than excess of sodium benzoate.

This compound, (PhCOOS)2, may be prepared more readily by shaking together dry silver benzoate and a solution of sulphur chloride in ether in the manner described below for other silver salts.

Action of Sulphur Monochloride on Silver Acetate. - Since sulphur chloride does not react readily with sodium acetate, the silver salt was employed, and after a number of preliminary experiments, the following simple method was found to give satisfactory results.

To 2.5 g. of dry silver acetate, about 20 ml. of dry ether were added, and then 0.4 ml. (rather less than the calculated quantity) of sulphur chloride, dissolved in a few ml. of dry ether. The containing vessel was closed and shaken for a minute, when the mixture became warm and the yellow colour of the sulphur chloride disappeared.

After filtering, the ether was distilled off, the last traces being removed by means of a current of dry hydrogen. The compound, (CH3COOS)2, was thus obtained as a clear, faintly yellow, viscous liquid with a faintly pungent odour. Some of it, after being kept for three days in a closed flask in the ice-chest, was found to be completely decomposed into sulphur dioxide, sulphur, and acetic anhydride.

Preparation of Propionic Anhydride from Silver Propionate. - To 18.1 g. of dry silver propionate in about 50 ml. of dry ether, 4 ml. of sulphur chloride in 20 ml. of dry ether were added; this addition must be made gradually, as otherwise the reaction may become too vigorous. The mixture was then shaken for a minute, and after filtering off the silver chloride and removing the ether by distillation, the syrup obtained was heated on the water-bath for an hour or two until decomposition was complete. The clear liquid was then decanted and distilled, the distillation being stopped as soon as the distillate appeared yellow; 5.5 g. of the crude anhydride distilled between 160° and 170°, the greater portion above 165°. The boiling point of propionic anhydride is 168°, and the calculated yield from 18.1 g. of silver propionate is 6.5 grams.

Preparation of Propionic Anhydride from Sodium Propionate. - 9.6 g. of dry sodium propionate were boiled for an hour under reflux with 4 ml. of sulphur chloride in presence of 40 ml. of light petroleum, a little copper powder being added towards the end. The solution was then filtered from sodium chloride and treated as just described in the preparation from the silver salt; 4.5 g. of the crude anhydride distilled over at a little below 170°. The theoretical yield is 6.5 grams.

---

Similarly, although less readily and less smoothly, sodium benzoate when heated with sulphur chloride in equimolecular proportions gives essentially benzoyl chloride, sodium chloride, sulphur dioxide, and free sulphur (Carius, Annalen, 1858, 106, 291). Benzoyl chloride is formed also when benzoic anhydride is heated with sulphur chloride...The two stages represented by the equations:

2C6H5COONa + 2S2Cl2 -> (C6H5CO)2S + 2SOCl2 + Na2S -> 2C6H5COCl + 2NaCl + SO2 + 3S

Sulphur Chloride and Silver Benzoate. - 12.5 g. (instead of 11.5 g.) of silver benzoate suspended in 50 ml. of dry ether were treated with 3.4 g. of sulphur chloride, and the mixture was shaken vigorously. After filtration from the silver chloride and removal of the ether, 7.5 g. of benzoyl thiosulphite were obtained as a colourless syrup, which soon crystallised with marked evolution of heat, and afterwards decomposed. From the products of decomposition 5.6 g. of the crude anhydride were extracted by means of ether, and 0.96 g. of sulphur was left. The calculated quantities (reckoning on the amount of sulphur chloride used) are 7.6 g. of benzoyl thiosulphite, 5.65 g. of benzoic anhydride, and 0.95 g. of sulphur, if the reactions which occur are represented by the equations:

2C6H5COOAg + Cl2S2 -> (C6H5COO)2S2 + 2AgCl
(C6H5COO)2S2 -> 2(C6H5CO)2O SO2 + 3S

The crude anhydride was now mixed with 3.4 g. of sulphur chloride and heated under reflux for four hours. On extraction of the product with ether, 1 g. of sulphur was left, and the ethereal extract contained 6 g. of dissolved matter, which consisted chiefly of benzoyl chloride. The calculated amounts are 1.2 g. of sulphur and 7.1 g. of benzoyl chloride on the assumption that the reaction is represented by the equation:

2(C6H5CO)2O + 2S2Cl2 -> 4C6H5COCl + SO2 + 3S

S.C. Wack - 10-8-2009 at 18:44

Well I was thinking that there must be a variant in the literature of this preparation of acetyl chloride, changed in the obvious way for the production of acetic anhydride. And I seem to remember some stuff at the Hive or here close to that, perhaps using solvent, but really I was looking for GB190825433, and it was found. Thought I'd mention it since I'm going on about sulfur.

ammonium isocyanate - 10-8-2009 at 19:17

I know that the rhodium archives has a chemically similar prep that is archived on erowid using bromine as a solvent and reactant as well as a small amount of sulfur to produce Ac2O from AcONa in pretty good yields through the same intermediate. NaBr is of course generated as a byproduct and thus using chlorine gas one could regenerate the bromine, which being a liquid is more convenient for a one-pot synthesis than chlorine, though with an additional solvent I imagine a chlorine based synthesis might be workable.

Saber - 31-8-2009 at 05:45

Has anybody tried the Sodium acetate + S2Cl2 route to acetic anhydride?
This seems the most simple as the S2Cl2 is REALY easy to make and anhydrous Sodium acetate is cheap! I agree with Sauron, but the anhydrous salt instead of trying to dry the trihydrate, its more trouble than its worth and its hard to get a fully dry solid without burning the solid.

entropy51 - 31-8-2009 at 14:13

NaOAc trihydrate is easily dried. It will lose about 2 moles of H2O in a vacuum dessicator. Then heating while stirring constantly until it melts and then solidifies again works every time for me. It's just a pain to keep stirring, but otherwise no problem.

ketel-one - 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

DJF90 - 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.

entropy51 - 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...

entropy51 - 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.

ketel-one - 13-9-2009 at 17:49

Ok I see, only compounds that hydrolyze in water would work, dehydration by itself won't.

woelen - 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.


JohnWW - 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.

quarterfinal - 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

One pot synthesis of Ac2O from Trichloroethane

franklyn - 6-11-2009 at 14:47


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...

.

Attachment: Ac2O by CH3CCl3 pat1870601.pdf (171kB)
This file has been downloaded 969 times

JohnWW - 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]

not_important - 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.

franklyn - 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.

.

Plasmapyrobattics - 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 ?

hector2000 - 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?)

unome - 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]

Attachment: Tarbutton.POCl3.from.P2O5.NaCl.pdf (802kB)
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Waffles SS - 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]

bbartlog - 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.

Waffles SS - 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]

bbartlog - 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.

Waffles SS - 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?

Attachment: ccl4.pdf (335kB)
This file has been downloaded 2093 times

entropy51 - 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.

Jor - 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?

DJF90 - 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.

Foss_Jeane - 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.

Waffles SS - 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.

Ephoton - 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]

Waffles SS - 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]

User - 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]

Waffles SS - 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

franklyn - 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

.

User - 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]

hissingnoise - 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. . .

entropy51 - 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.

Waffles SS - 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.

entropy51 - 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.

Waffles SS - 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.

halogenstruck - 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

Formatik - 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 1445 times

Waffles SS - 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.

JohnWW - 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.

Satan - 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.

Waffles SS - 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]

Ephoton - 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]

crossf!re - 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..

Fleaker - 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?

Sedit - 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.

hypnos - 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]

bbartlog - 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.

hypnos - 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

not_important - 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.

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