Acetic Anhydride via Cl2, Sulphur & AcONa

[hellman]

Ref. from Rhodium.ws

Iudexk:

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.


the only problem i see with this, is the Bromine,.
It is expensive $85.00/ 100ml
Chlorine generated is not. via Hypochlorite,.

In the above proceedure, there is no solvent upon which release the cl2 into,.
I am assuming that bromine & sulphur dissolve?
Anyway, Am I that far off the mark, in thinking that we could add a solvent and bubble cl2 gas through or maybee dump in the Pool shock, all in situ?

My thinking here is that, in the production of MeAm, Hoffman style, bromine is stated in Vogels, but we all know that pool shock in situ works just as well..
Maybee it might work here,


Then I guess we could have a more OTC AA prep,

Starting of course with GAA + NaOh-----etc,,.

??

hm

[Chromic]

The only economic way that I see to produce acetic anhydride is to setup a ketene generator. Really, it's quite easy. A flask boiling acetone, a claisen adapter, a nichrome wire (controlled by a dimmer), a condenser and a bubbler. It's a very easy setup, yeah, it sounds dangerous, but it's very easily controlled and as long as there's no oxygen in the system, there's no explosion.  

Go forth and make gallons of Ac2O.

[hellman]

I will,.
And a big hello to you,!

Ok, have we a few ketene pioneers here,?
I've read all that i can find, but am still nervously hungry,.

You know me, If I do it, I will do a complete post,
Unless there is one hiding somewhere that i didn't find.

Post 271991

(hypo: "first encouraging ketenelamp experiment", Methods Discourse)

Post 247039 (missing)

(dickdastardly: "Acetic Anhydride", Chemicals & Equipment) 

And a few others that brush it lightly,

Forth I have gone.------>

[Rhodium]

Post 462958

(Rhodium: "Na-Acetate + Na-Pyrosulfate -> Acetic Anhydride", Novel Discourse)

[politoxicomania]

These ways are possible:

1. R-COCl + R-COONa -->  NaCl + R-CO-O-CO-R

2. CH3-COH --> CH3-CO-O-CO-CH3  at 50-60°C and 0,4 MPa in Ester

3. Wacker-Way  Keten CH2=C=O + CH3-COOH in 95% yield

[hellman]

Ok,politoxicomania,
I wish i knew enough about functional groups to know exactly what you are talking about,
I draw interest to the first method,

R-COCl + R-COONa -->  NaCl + R-CO-O-CO-R

So i found some sulphur, and some sodium hypochlorite
as well as some NaAcO,

Will this work, can a solvent be used, how would I get the Cl in solution, or can the hypochlorite be added in situ?


Rhodium,
Thankyou for the Pyromethod, i will re-look at it,.
But from recent memory it seems incomplete,.

Thankyou for everyones input but....
My question is directly related to Sulphur, NaAcO and Cl2 gas generated by Sodium Hypochlorite,.Rather than using Bromine, which i have a financial, and legal aversion to.

Don;t you think that we could add a solvent, and administer cl gas into it? thus removing the need for Bromine,.

Thankyou
hm

[moo]

Check out

https://www.thevespiary.org/rhodium/Rhodium/chemistry/anhydrides.html

, there is a writeup on a variation using sulfur, chlorine gas and NaOAc.

[politoxicomania]

The easiest way to make Acetic Anhydrid in Laboratory scale is the above mentioned reaktion number one:

R-COCl + R-COONa -->  NaCl + R-CO-O-CO-R

Preparation of R-COCl :

1. 3 R-COOH + PCl3 --> 3 R-COCl + H3PO4

2. R-COOH + PCl5 --> R-COCl + POCl3 + HCl

3. 3 R-COONa + PCl5 --> R-COCl + 2 NaCl + NaPO3

4. R-COOH + SOCl2 --> R-COCl + HCl + SO2

5. R-COOH + (C6H5)3P + CCl4 --> R-COCl + (C6H5)3PO + CHCl3

CH3COCl :

1.

1 mol CH3COOH in a roundbottom flask is penetrated by 0,35 mol Phosphortrichloride. The mixture is shaked under moisture prevention. Let stand over night. Dekant the above Layer and destill fraktionated. 65% yield nD= 1,3898

2. The Thionylchlorid Method isn´t used for CH3COCl but one can try it as followed:
1 mol of CH3COOH with  1,5 mol SOCl2 is coocked under moisture prevention till no more gas builds. Destill off the SOCl2 in waterbath. The residue is destilled .
This Method is not very workable for CH3COCl cause of the small reaktivity of SOCl2.

Good Luck

[Aurelius]

Do you have a reference for this one?

[politoxicomania]

Reference is

H. Bayer, W. Walter, Lehrbuch der organischen Chemie 23. Aufl., S.267, 1998, S. Hirzel Verlag

[hellman]

I bring your attention to:

Post 468059

(hellman: "S2cl2 made in situ(anyone tried this?)", Chemistry Discourse)

You see it is essentially the same to what I am trying to accomplish, yet rather than using bromine it uses chlorine pump through,.

But, in it's simplicity, it harbours the fact that it needs AA to pre-wet the NaAcO,.
Now I would think that it is possible to probably just use GAA instead, but with a little yield loss on the first time round,.

cheers

hm

[Rhodium]

it needs AA to pre-wet the NaAcO

Not just to "wet" it, but to remove moisture from all the reactants.

[hellman]

Would would suffice, to remove the water, that is a little more OTC,

Sorry about all these god damn questions,
hm

[Aurelius]

Does anybody have the english version of the reference given above?  (please post if available)

[psyloxy]

... post the german text or send a scan to my ziplip.com account (pm me for that) ; I think my capabilities in German improved so much over the years that I finally don't even have to fear scientific texts anymore  

--psyloxy--

[politoxicomania]

Ok Aurelius
I´ll try to explain the german Text to you.
The Ref. is a standard Book of organic chemistry written in german. Chapter 2.28 is about Carbonacidhalogenides, their preparation, purification and properties.

Preparation:
By reaktion of Carbonacids or their Alkalisalts with Acidhalogenides of Phousphour and Sulfur.
.....
.....
..... ( The above mentioned reaktions are explained)
.....
.....
Under very mildly conditions one can yield Acidchlorides by reaktion of Carbonacids with Triphenylphosphin in Tetrachlormethan.
R-COOH + (Ph)3P + CCl4 --> R-COCl + (Ph)3PO + CHCl3
The Acidbromides,-iodides and some fluorides can  be prepared from the chlorides with dried Brom-,Iod- or Fluorhydrogen (or Antimonfluorides).

Comment:
The reaktion is nothing new. It can be that this reaktion is not workable for CH3COCl but one can try it as followed:

In a 250ml rbf 70ml CCl4 and 1 mol (Ph)3P are refluxed under moisture prevention, while 1 mol CH3COOH are gently dropped in through a funnel. Let reflux and stir for another 2 or 3 hours, before fraktionated destillation through vigreux 20 cm(minimum).

Properties:
The lower Acidhalogenides are colorless liquids,which smokes at the air and penetrates the mucusmembranes. The higher Acidhalogenides are kristalline substanzes. They boil higher than the Acids (f.e. Acetylchlorid at 52°C) In comparison to the Alkylhalogenides the Acidhalogenides show higher reaktivities and they are used to get the Acylrest into organics.

Further questions ?