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Author: Subject: Acetic anhydride preparation
Sauron
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[*] posted on 8-3-2007 at 03:27


I see. It is speculative at this point.

Well, I guess you guys can always build yourselves ketene lamps and run the ketene into acetic acid. If I remember correctly this gets you about half a mol an hour.

The hassle is carbonization on the nichrome filament. The OTHER hassle is that ketene will kill you if you let it. But it's a reliable process and as long as you can get acetone or make it from 2-propanol, you are good to go.

If you make 2-3 filament assys you can change them out when one gets dirty and clean that one while the other is working.

The lit. describes scraping the carbon off the nichrome. There must be a better way. Burn it off? Ultrasound? Anyone have any ideas? How about using chlorine or bromine to react with the carbon? Ought to work, especially if the nichrome is electrified to an appropriate temperature. The nichrome ought to be immune, or at least react slowly relative to the carbon. Worth a try?

I'm not going to mess with ketene myself, I have no problem buying TCT, oxalyl chloride, and benzoyl chloride, already have beaucoup TCT on hand. Lucky me.

[Edited on 8-3-2007 by Sauron]
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[*] posted on 11-3-2007 at 05:29


Quote:
you ca make acetyl chloride from benzoyl chloride and then react the acetyl chloride with sodium acetate.


Great, I´ve benzoyl chloride but don´t know how to prepare acetyl chloride with it.
Can you give me a instruction for this preparation please?

Or ís it possible to prepare acetyl chloride by reakting acetic acid and Cl2?
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[*] posted on 11-3-2007 at 05:41


The use of benzoyl chloride to prepare volatile acid chloride (and acetyl chloride is one of the most volatile) is detailed in the H.C. Brown article from JACS in the 1930s attached earlier in this thread. Volatile here means more volatile than benzoyl chloride. You mix the benzoyl chloride in excess with the acid (acetic acid in this instance) and react them under reflux, the acid chloride will distill over. The yield is about 90%, the article gives details. About 12 examples are given including acetyl chloride.

H.C. "Boron" Brown was a very famous chemist. It's a good procedure. Let me know if you can't find it in this thread and I will post it again or else email it to you (PM me with your email address if it is not listed in member directory)

You can also make acetyl chloride from acetic acid (or sodium acetate) and TCT (cyanuric chloride) or oxalyl chloride.

You can make oxalyl chloride from oxalic acid or sodium oxalate and TCT.

But if you already have benzoyl chloride then you are all set.

It is not possible as far as I know to prepare acetyl chloride directly from Cl2. It is possible to prepare acetic anydride from Cl2 or Br2 and sulfur (making the sulfur halide in situ) and anhydrous sodium acetate but it is not very convenient in the case of chlorine unless you preform the SCl2 by running dry Cl2 into molten sulfur, or by chlorinating CS2 over granular activated carbon then distilling the SCl2 from its mixture with CCl3SCl. Nasty stuff! (well, both of them). Then you could convert the Ac2O to acetyl chloride but most of us would go in the other direction.

Anyway all that is the long way round the block compared to the simple elegant benzoyl chloride method.

Link to H.C. Brown article:

http://www.sciencemadness.org/talk/viewthread.php?action=att...

[Edited on 11-3-2007 by Sauron]
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[*] posted on 12-3-2007 at 11:09


Thanks Sauron,
theres one more thin:
benzoyl chloride is C7H5OCl, right?
I´ve just C6H5Cl, :(I confused them I think.

By this I would say that the Na2S2O7 method is the best for me, theres just the problem with the price of Na2S2O8.

Because we´re talking about chlorination(hope this word exists) I would ask if it´s possible to chlorinate oxalic acid with S2Cl2, ones say that it´s possible and the others say that it wouldn´t work.
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[*] posted on 12-3-2007 at 12:42


More like;y SCl2 if at all. And starting with sodium oxalate (anhydrous). I have not seen any examples of this reaction in the literature with formation of oxalyl chloride but at least there's analogy to other chlorides.

Oxalyl chloride is best prepared from anhydrous oxalic acid by PCl5 if you have it; and by TCT or TCT/DMF if you don't.

Too bad you have chlorobenzene not benzoyl chloride.
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[*] posted on 13-3-2007 at 09:34


I haven´t red phosphorous jet so I don´t have any PCl5 too.
Also would a sulfuric chloride be much cheaper than a phosphorous chloride.

After all S2Cl2 doesn´t work and I imagined that I found a good synthesis for cheap preparation of oxalyl chloride.

I couldn´t find anything about TCT in german, can you give me please a structure or the full name?
But i´ve an suspicion, is it C3N3O3Cl3?
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[*] posted on 13-3-2007 at 09:55


TCT is cyanuric chloride (CC) an inexpensive feedstock for agro chemicals, it is the trimer of cyanogen chloride. But I am told that in Germany you will have a hard time buying it because they classify it as toxic.

If you do a search on this forum tou will find quite a few threads about CC aka TCT (trichloro-s-triazine) relating to its application to making alkyl chloriced and acid chlorides.

SCl2 not S2Cl2 can chlorinate acetic acid or sodium acetate (anhydrous, fused) and that procedure (using SBr2) can be found on this forum as well as in Rhodium archive.

If you can't find the CC/TCT refs let me know and I will dig them up for you. But they won't do you much good if you can't buy CC, and you can't really make it yourself unless you like working with neat HCN and anhydrous HCl. CC is a pungent solid easily manipulable and I do not know what the fuss is about, I have many Kg of it in my house.

By the way do not confuse it with TCCA which is related but not same. That is trichloroisocyanuric acid.
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[*] posted on 13-3-2007 at 10:10


TCT is a chemical which has until now not been mentioned on the german forums. It is not available OTC, and it is classified as T+. You would have to order this from a chemical supplier via e.g. a pharmacy which is willing to cooperate.



www.versuchschemie.de
Das aktivste deutsche Chemieforum!
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[*] posted on 13-3-2007 at 18:29


If in Germany you can buy SOCl2 more easily than CC/TCT then why not do so and use that to make your benzoyl chloride? Or use whatever method to make benzoyl chloride that is available to you, then employ the benzoyl chloride to make oxalyl chloride and you are home free.

If you want to prepare SCl2 by chlorination of molten sulfur the hassle is that a lot of sulfur will remain dissolved in the resulting mixture of SCl2 and S2Cl2. The product needs to be distilled at reduced pressure and still tends of throw a thin layer of S on all glass surfaces. The best technique for obtaining a pure and unequivocal SCl2 is to slowly run it through a column of granular AC at 40-60 C and all S2Cl2 is converted to SCl2. I have references in English and German on this if you want them. The technique is used to remove S2Cl2 from the mix produced by chlorination of CS2 which simplifies distillation of the mix, prior to reducing one of the two components (CCl3SCl) to CCl4 with iron filings. That is the best way to make SCl2 by the way and gets you CCl4 besides. the hassles are that CS2 is so flammable, and that the intermediates stink and are corrosive and toxic.
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[*] posted on 15-3-2007 at 02:28


As promised, Gmelin. Its enthusiasm is indeed from that JACS article.

Band 61 B5, Seiten 125-6.

2.2.7.2 Thermische Zersetzung

Die Zersetzung von AgCH3COO, die bereits von Chevenix [1] beim Erhitzen über einer Kerzenflamme (starker Geruch nach Essigsäure) beobachtet wurde, setzt bei 210°C ein (Dunkelfärbung), erfolgt hauptsächlich zwischen 220 und 240°C und ist vollständig bei etwa 300°C [2]. Beim Erhitzen im offenen Rohr oder im bedeckten Porzellantiegel werden als Zersetzungsprodukte im wesentlichen Essigsäure und Ag neben wenig C02 und C beobachtet entsprechend 4AgCH3COO ->4Ag + 3CH3COOH + CO2 + C [3 bis 5]. Von Kachler [2] werden als Reaktionsprodukte gefunden (in Gew.-%, nach vorstehender Gleichung berechnete Werte in Klammern): 64.61 Ag (64.67), etwa 26 bis 27 Essigsäure (26.95), 4.09 bzw. 8.42 CO2 (6.59) und 1.21 C (1.79). Auch bei thermogravimetrischer Untersuchung wird als Zersetzungsprodukt (bei 280°C) metallisches Ag und kein Ag2O erhalten [6]. Erfolgt die Zersetzung jedoch unter streng wasserfreien Bedingungen, so werden als Zersetzungsprodukte nur Ag2O und Essigsäureanhydrid erhalten nach 2AgCH3COO -> (CH3CO)2O + Ag2O. Bei der Zersetzung von 2.1077 g trocknem AgCH3COO bei 300 bis 400°C in einem Quarzgefäß unter Argon (1 atm) werden nahezu quantitativ Ag2O (96% der Theorie) und Essigsäureanhydrid (93%) gebildet neben wenig Ag (0.012 g) und CO2 (0.016 g) [7]. Die primäre Essigsäureanhydridbildung ist bereits von Kanewskaja, Schemiakin [8] bei Untersuchung der thermischen Zersetzung von AgCH3COO (im Gemisch mittrocknem Sand) unter einem CO2-Strom von 20 bis 25 Torr angenommen worden. Zwar fanden diese Autoren nur wenig Essigsäureanhydrid neben viel Essigsäure (entsprechend den früheren Angaben von Kachler [2] und Iwig, Hecht [4]), doch ist dies auf die leichte Hydratisierung des Essigsäureanhydrids zurückzuführen, die sowohl durch H2O-Spuren in dem schwer zu trocknenden Silberacetat als auch durch H2O erfolgen kann, das beim teilweisen Zerfall der Essigsäure gebildet wird.
Für die vollständige thermische Zersetzung von AgCH3COO in Gegenwart von H20 muß auf etwa 230 bis 340°C erhitzt werden. Abweichend von der trocknen Destillation wird neben den Hauptprodukten der Zersetzung Ag, Essigsäure und CO2, kein Kohlenstoff gefunden [2].
Über die Darstellung von Ag-Schwamm durch Erhitzen einer getrockneten Paste von AgCH3COO im Tiegel auf 400 bis 500°C s. [10].

...

[1] R. Chevenix (Ann. Chim. [Paris] 69 [1809] 5/58, 19, 22; Ann. Physik 32 [1809] 156/201, 167, 179). — [2] J. Kachler (Monatsh. Chem. 12 [1891] 338/49, 340). — [3] K. Birnbaum (Ann. Chem. 152 [1869] 111/21, 119). — [4] F. Iwig, 0. Hecht (Ber. Deut. Chem. Ges. 19 [1886] 238/42). — [5] J. Redtenbacher, J. Liebig (Liebigs Ann. Chem. 38 [1841] 113/40, 131).
[6] D. A. Edwards, R. N. Hayward (Can. J. Chem. 46 [1968] 3443/6). — [7] A. D. Kirschenbaum, A. G. Streng, M. Hauptschein (J. Am. Chem. Soc. 75 [1953] 3141/5, 3143).— [8] S. J. Kanewskaja, M. M. Schemiakin (Ber. Deut Chem. Ges. 69 [1936] 2152/7, 2154). — [9] V. I. Yakerson (Izv. Akad. Nauk SSSR Otd. Khim. Nauk 1963 1003/11, 1007; Bull. Acad. Sei. USSR Div. Chem. Sci. 1963 914/21, 916). — [10] T. Yamanaka, H. Nidorikawa (Japan.P. 6720 [1956] nach C.A. 1958 10462).

And now, quite possibly pages of off-topic prattle on subjects that have already been discussed elsewhere:
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Sauron
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[*] posted on 15-3-2007 at 03:00


Some members, despite these issues having been covered in other threads, obviously still are perplexed about how to achieve very simple and basic transformations such as Ac2O, acetyl chloride, propionyl chloride, benzoyl chloride, oxalyl chloride etc. @Per seems neither lazy not stupid and I'd rather be helpful than just brush him off with a "Use the search engine" or some such dismissal.

If for helping a fellow member I earn only scorn from you, well, then I don't want your approval.
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[*] posted on 17-3-2007 at 10:50


Yes, I should search before I´d ask some questions.

I would prepare my SCl2 by chlorination of sulphuric under boiling CHCl3.
The problem with SCl2 is that I can´t distill it without vacuum because it´s decomposing at 59°C.
Maybe I could try to produce it with S2Cl2 and Cl2 ( should work with liquid Cl but I don´t know if it´s work with the gas).

I don’t know if it’s easy and cheap to buy SOCl2 in Germany (would inform me about that).

And thanks for helping me and the Gmelin instruction.
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[*] posted on 17-3-2007 at 13:25


You can't make SCl2 from S2Cl2 and Cl2

That's because you make S2Cl2 from SCl2 and Cl2!

When chlorinating molten sulfur SCl2 forms first and continued chlorination gives S2Cl2. In practice this is complicated by the great solubility of sulfur in SCl2 (60%) and you will always have a mixture of SCl2 and S2Cl2 plus dissolved sulfur in the pot. You need to continue chlorinating till all the sulfur is reacted and that means you predominantly have S2Cl2.

You can follow the progress of the reaction by weight.

As it is SCl2 you want, and not S2Cl2, you convert the mixture to pure S2Cl2 by passing it through a granulated AC column at c.60 degrees as detailed by Rupp and Meyer.

I can give you the references.

It is actually easier though no less unpleasant to chlorinate CS2 which afford you about half CCl3SCl and halg SCl2/S2Cl2 and you pass this mixture through such a column and eliminate the S2Cl2. Then it is easy to seperate the remaining two components by fractionating under reduced pressure. The CCl3SCl you can use to prepare CCl4 by treating it with Fe filings.

My guess is that you will have a hard time buying SO2Cl2 in Germany but it is easy to make - although once again, irritating and smelly. SO2Cl2 is prepared from SO2 and Cl2 by passing them through yet another GAC column bed (this time with cooling). Camphor is also a good catalyst for this.

[Edited on 18-3-2007 by Sauron]
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[*] posted on 18-3-2007 at 00:37


Then maybe it´s the best way for me to only produce S2Cl2 which seems to be very easy.

The difficult with CS2 is that it´s very expensive. Sulphur cost´s me much less than CS2, 1kg just a few €.

I don´t know how strong the separate chlorination reagences are, so I don´t know if it´s worth to produce some else than S2Cl2, is there a big difficult between S2Cl2 and SCl2, SO2Cl2?

How is the rating of them, maybe:
S2Cl2 < SCl2 < SO2Cl2 ?
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[*] posted on 18-3-2007 at 00:51


For the preparation of Ac2O you want SCl2 not S2Cl2. I do not know of any way to easily end up with only S2Cl2 anyway because it disproportionates to SCl2 on standing anyway and in the chlorination of S there will always be both products plus dissolved sulfur.

The Rupp-Meyer method is good for purifying SCl2 not S2Cl2.

Their method applies both to the mixture from chlorination of CS2 and to the mixture from chlorination of molten sulfur.

I will prepare a zip file of the articles and patents and attach for you. The information you need is in there, you will need to read a bit to find it.



[Edited on 18-3-2007 by Sauron]

Attachment: AF.zip (1.1MB)
This file has been downloaded 771 times

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[*] posted on 18-3-2007 at 01:46


Thanks for the zip file,
I would try the synthesis with sulfur and CHCl3 and talk about the results later.
If I distil the reactions product after I distilled the CHCl3 away I should obtain pure S2Cl2 I think, firstly S2Cl2 should be enougt.
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[*] posted on 18-3-2007 at 11:12


Pardon me, what reaction of S and CHCl3 to give S2Cl2? I have never heard of such a reaction. References please.

Once again why do you want S2Cl2? Because I thought you wanted to make Ac2) and S2Cl2 is useless for that.

Also SO2Cl2 is useless for that.

With some effort you can make SCl2 from S2Cl2 or from SO2Cl2 but that is going long wway round.

If you want these for other purposes just say so.
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[*] posted on 19-3-2007 at 06:48


The CHCl3 doesn´t react in my synthesis, it´s just a solvent for the sulfur because when the sulfur is molten it´s very nasty to clean the reaction bottle. While the reaction you have to condense the CHCl3 in a reflux cooler but you´ve to heat just to 61°C, these are big advantages against the method with molten sulfur.

With the S2Cl2 I want to try to make Oxalic chloride and I want to prepare it because I haven´t it until jet.
I would try to make the Ac2O otherwise, maybe it´s a good method to make it with Na2S2O7 which I´ve to get from Na2S2O8 which I got from Conrad electronics.
That woudn´t be a cheape but easily.
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[*] posted on 19-3-2007 at 09:02


Well, I wish you luck trying to make oxalyl chloride with S2Cl2. That would be quite novel.

I only know two methods to make this:

oxalic acid and PCl5

Oxalic acid and TCT (or sodium oxalate and TCT)
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[*] posted on 21-3-2007 at 08:52


Now other persons told me that it wouldn´t work with S2Cl2, but it should work with SOCl2, but the gases (SO2, HCl) would make the yield low.

If I´ll find an cheap supplier I´ll try this method.
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[*] posted on 22-3-2007 at 04:31


According to Ullmann's (2003) CD edition, vinyl acetate (cheap solvent) can be reacted over Pd(II) catalyst (most likely PdCl2/CuCl2 system) to give a mixture of acetaldehyde and acetic anhydride, and that formerly this was an industrial process for acetic anhydride production. They also mention ethylidene diacetate but that is a LOT more expensive so don't bother with it. Vinyl acetate 2.5 L from Acros $33.3 US, ethylidene diacetate 100 g same supplier $122 US.

Ref: Ullmann's 3 ed 6, 804. I do not have access to this print edition, this was cited in the CD-ROM damn it. Can anyone obtain the details?

Also the 2003 edition CD describes reaction of three chlorinating reagents with sodium acetate in a two stage reaction. First stage one eq acetate reacts to form acetyl chloride, second stage the acetyl chloride formed in situ reacts with second eq sodium acetate to give acetic anhydride.

The three usable chlorinatign reagents are:

SOCl2
SO2Cl2
POCl3

My comments are: the sodium acetate needs to be anhydrous (freshly fused). Otherwise water will use up reagent and depress yield.

Also, I would add the following reagents to the list:

TCT (CC)
Oxalyl chloride (not reacted w/sodium acetate but with acetic acid in appropriate ratio produces either acetyl chloride or acetic anhydride per Roger Adams in JACS articles 1916-1920. Furthermore you can make oxalyl chloride from TCT w/oxalic acid (anhydr.) or sodium oxalate (anhydr.)

So your choice of the above depends on what you can get. Need we poit out that thionyl, sulfuryl, oxalyl and phosphoryl chlorides are operating here not as chlorinating agents per se but as dehydrating agents?

--------------------------

Kirk-Othmer has a little bombshell hidden well away. In a small section of their Acetic Anhydride monograph devoted to prosspective future processes they mention a 1930s Russian discovery that they deem to still be of some potential. The dry reaction of anhydr. sodium acetate with dinitrogen tetroxide (N2O4) produces acetic anhydride and sodium nitrite in 85% yield. See Ref.48 which is a trio of abstract citations, two in C.A. and the third in Chem.Zentr. They point out the favorable economics of this reaction as the N2O4 is regenerable.

V.M. Rodionov, A.I.Smarin, T.A.Obletzeva, C.A. 30, 1740, 4149 (1936)

V.M.Ridionov, T.A.Obletzeva, Chem.Zentr. 1938(II) 4054

V.M.Rodionov, T.A.Obletzeva, C.A. 34, 6572 (1940)

2 NaOOCCH3 + 2 N2O4 -> (CH3CO)2O + 2 NaNO2 + N2O3

The reaction proceeds according to:

This is extremely tantalizing as both Ac2O and NaNO2 are highly desirable.

Incidentally Kirk-Othmer states that the Russians reported sodium propionate was converted in similar high yield to propionic anhydride and sodium butyrate to butyric anhydride. This ought to pique the interest of those who are into such reagents.

[Edited on 23-3-2007 by Sauron]
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[*] posted on 23-3-2007 at 02:41


Pd may not be necessary with vinyl acetate. See US1856251, which may work as detailed there or not.
The oxychlorides of Si can also be used with acetate salts, not that they are any more OTC than the SiCl4 already mentioned.
US1870601 claims AA from hydrolysis above the BP of the banned TCE solvent methyl chloroform, without providing an experimental.
The N2O4 citation has already been mentioned in this thread.
Yeah, I'm so way off base; and unable to see how people are, and make predictions based on this.
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[*] posted on 23-3-2007 at 03:02


Kirk-Ohmer mentioned two other "prospective" routes but these seemed so far fetched that I have paid little attention to them, I will review them here for sake of completeness.

Ethylene + carbon oxides -> ketene according to a French patent

Sodium acetate (aq) + carbon dioxide -> sodium bicarbonate + Ac2O

The problem with second being how to get the anhydride out of the water before it is destroyed, the devil is always in the details. Another French patent.

Kirk-Othmer also mentioned the dry distillation of metal acetates including silver and copper and nickel but not lead. They recited various obstacles to the industrialization of this simple method, mainly limitations on solid handline and a lack on knowledge of process details. The latter seems a bit weak. More excuse than reason.
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[*] posted on 23-3-2007 at 05:33


@S.C., those two US patent number you cited appear to be wrong, two different patent sites rejected them (www.freepatentsonline.com and patentstorm) and Google drew a blank.

Can you let me have inventor name and/or date?
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[*] posted on 23-3-2007 at 08:00


Quote:

Kirk-Othmer also mentioned the dry distillation of metal acetates including silver and copper and nickel but not lead. They recited various obstacles to the industrialization of this simple method, mainly limitations on solid handline and a lack on knowledge of process details. The latter seems a bit weak. More excuse than reason.


Simply dry distilling something like copper acetate sounds really simple. Too simple, in fact. However, it would not be the first time I see a thread several pages long discussing complicated routes to a product that has one rather simple sinth.




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