acetic anhydride

[S. Toppholzer]

I had a dream of making some RDX...
I was waiting now for more than six month for my order to arrive and today I got it: 1,000 g of pure Paraformaldehyde! The chem supplier I bought it from also sells acetic anhydride or at least that's what he calls it. Mega's site tells of two kinds of acetic anhydride:
- acetic anhydride and
- glacial acetic acid

What I bought today was the latter and it says it's 98 percent.
Means only two percent water - the supplier told me he believes it is anhydrous because there's almost no water in it.
I asked him about the difference between glacial acetic acid and acetic anhydride - he couldn't tell.
Now one thing I think I know is that glacial acetic acid comes because it has the appearance of ice - sort of semi-opaque.
The bottle I bought containes a liquid that's absolutely clear and perfectly fluid.
So where's the difference between the two substances and could I finally make my RDX with this?

<small>[ April 18, 2002, 04:14 PM: Message edited by: S. Toppholzer ]</small>

[10fingers]

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<small>[ May 09, 2002, 12:55 AM: Message edited by: 10fingers ]</small>

[S. Toppholzer]

It says it's 98 percent - almost no water. Shouldn't glacial acetic acid be - er...- glacial?

[DBSP]

You shuld have bought the acetic anhydride, thats what is used for making RDX. Glacial acetic acid is only pure acetic acid. Check megas page.
<a href="http://roguesci.org/megalomania/synth/synthesis1.html#acetanhy" target="_blank">http://roguesci.org/megalomania/synth/synthesis1.html#acetanhy</a>

[S. Toppholzer]

:confused:
quoting from Mega's site:
"The concentration of the acetic acid obtained will be nearly anhydrous, especially if you start with thoroughly dried sodium acetate and 100% sulfuric acid."
That's what I say as well! nearly anhydrous - it's 98 percent.
Still no chanche?
You know I wouldn't want to waste any of my precious paraformaldehyde...

[DBSP]

Look at this: acetic anhydride:(CH3CO)2O........acetic acid:CH3COOH.
See the difference. It won't work. It's as simple as that.

Edit: where tha hell do you see acetic acid mentioned in the RDX manufacture??

<small>[ April 18, 2002, 04:41 PM: Message edited by: DBSP ]</small>

[S. Toppholzer]

<sigh> thanks, mate.
:mad: AAAAAAARRRGH! I'll **@#&"!** that sucker!

[VX]

They are two completely different chemicals.

Acetic acid: CH3COOH

Acetic Anhydride: (CH3CO)2 0

Anyway, Acid anhydrides react with water to form the acid.

Acid anhydrides (Or chlorides) are often used in reactions as they are much more reactive than the acids.

They are all related....but not the same.

Edit: Dame I must be a slow typer!

<small>[ April 18, 2002, 04:54 PM: Message edited by: VX ]</small>

[S. Toppholzer]

would acetic anhydride then be a powder? 'xcuse my ignorance but even though I understand that I bought the wrong stuff I'd still like to know...

[VX]

No it's a liquid. It freezes at about 17 deg C. At that point it is a solid... Thats why it is called glacial acetic acid.

Edit 16.7 deg C to be exact. :rolleyes:

<small>[ April 18, 2002, 04:57 PM: Message edited by: VX ]</small>

[10fingers]

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<small>[ May 09, 2002, 12:56 AM: Message edited by: 10fingers ]</small>

[Rhadon]

10fingers is right, but be aware when ordering acetic anhydride. Most definitely it is a controlled substance an you're likely to get 'visited' by the pigs if you order it... at least a friend of mine did.

[shooter3]

Has anyone tried the process for making AA via the methode found in KIPE #2? It seems complicated, but I think if you had the space to do it the accual synthisis would be easy.

[megalomania]

Acetic acid and acetic acid anhydride are related substances, but they are still two different chemicals. I was going to amend my website about the boron substance for the synthesis of RDX, but that thread was lost during the crash and was not restored. Does anyone happen to have that thread, or would like to restart the discussion?

[10fingers]

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<small>[ May 09, 2002, 12:57 AM: Message edited by: 10fingers ]</small>

[S. Toppholzer]

VX -now you entirely confused me...
I asked: "would acetic anhydride then be a powder?"
you answered: "No it's a liquid. It freezes at about 17 deg C. At that point it is a solid... Thats why it is called glacial acetic acid."
I understand these are two entirely different substances. Are they?

[Pu239 Stuchtiger]

Interesting fact:

Acetone and acetic anhydride are both in the same class; the reporting threshold for acetone is 50 gallons, while the reporting threshold for acetic anhydride is 250 gallons. Perhaps acetic anhydride is less watched than previously believed.

(edit: noticed one sentence didn't make the slightest bit of sense)

<small>[ April 19, 2002, 03:20 AM: Message edited by: Pu239 Stuchtiger ]</small>

[Rhadon]

You could be right, but I think that this strongly depends on where you live.

[VX]

Ah, good point. Sorry bout that, I cant read! :o

Acetic anhydride is a liquid aswell though.

Freezing point: -73 deg C

[cutefix]

Quote:
"I was waiting now for more than six month for my order to arrive and today I got it: 1,000 g of pure Paraformaldehyde!"

Is it A high melting or low melting point type.Did you get is product specs and noted its quality?
Paraformaldehyde are not all the same,and its quality is critical also in the synthesis of RDX by E- method.
Oneless known factor that cause the failure of this (anhydride) process in some operators making RDX is the quality of paraformaldehyde used in the reactions.It is imperative that the low molecular weight type item is to be used for best results.
Other paraformaldehyde have low solubility in reaction medium(decompose before it has time to dissolve) or tend to settle down instead of reacting with the other components; sometimes forming an insoluble sludge which is not RDX.This will also affect the yield.
The addition of the paraform must be also done very gradually to allow it to dissolve and react properly and the reaction temperature must not be lower than 65degC.
Take note that paraform has this formula (CH2O)n;where n the degree of poymerization.
It can be from 8-100 and this corresponds to difference in melting point from 120-170degC.The higher the n number the higher its melting point.Many manufacturers of
paraform do not declare if their products are low or high MP types.
Quote
"I was going to amend my website about the boron substance for the synthesis of RDX…"

I do not believe also the idea that boron trifluoride is essential in the production of this particular type of RDX.Indeed this BF3 acts like a catalyst.This item also reduce the the side reactions(formations of linear nitramines that affect the stability of the resulting RDX.) as well as reducing a bit the reaction temperature as well as faster reaction rate.This may count a lot in industrial process,but not in home synthesis and following a proper procedure is important;
BTW do not expect that the yield is very high.
It is expected that for product yield you must get an average of mole of RDX per mole of paraformaldehyde if the synthsis is done properly.

<small>[ April 20, 2002, 03:10 AM: Message edited by: cutefix ]</small>

[rikkitikkitavi]

I think that BF3 is essential in that synthesis, as well as V2O5 is essential in the oxidation of SO2 to SO3 and production of H2SO4.

True that the catalyst cant make an impossible reaction happend, but speed things up many times, perhaps even a million times.
And that is why it controlls the sidereactions, by speeding up the main reaction the side reactions have no time or reagents to take place.

BF3 is used extensivly in the chemical industry as a catalyst, due to its special electron structure. The boron-atom lacks one electron pair making it a strong electron acceptor,a k a Lewis-base, further accented by the F-atoms.

It has extensive use in the semiconductor industry to as a source of boron for doping semiconductors.

/rickard

[cutefix]

I am sorry,If I disagree with your reasoning Rick...
In inorganic chemistry such as sulfuric acid synthesis (e.g.,contact process) it really needs catalysts and there is no way you can do without it.It is different in a particular organic synthesis ,such as in the case of cyclonite where this BF3 is just an enhancer for the reaction,and the system will still run even without it.

Boron trifluoride is a highly reactive gaseous substance and reacts easily even with athmospheric moisture forming highly toxic fluorine decomposition products and would be difficult to add as ordinary chemical in normal home synthesis.Knowing these hazards you will not take risk if you can make the product in the same manner or by alternative process(whichever the experimenter is interested).
It is considered a Lewis acid(electron pair acceptor) not as Lewis Base(electron pair donor).
Its presence in the synthesis of cyclic nitramine explosives is favorable in large scale application in which its addition can be done appropriately.Its catalytic activity is well known in other areas, but in this particular application with RDX .Its mechanism can be understood by its tendency to bind with the aza nitrogen in hexamine (formed during the reaction of paraform,ammonium nitrate and acetic anhydride);resulting in an intermediate which favors temporary substitution with acetyl groups which is then displaced later by the nitro groups to obtain the cyclic nitramine-RDX.
It was added industrially for the purpose of minimizing the effect of violent and dangerous side reactions, which happens always in large scale operation using this “anhydride” method. It also favors rapid cyclization ( the formations of the triazine structure),therefore the production of unstable linear nitramines is minimized.This grave situation seldom occurs in small scale anhydride synthesis of RDX in the home(or improvised laboratory) in which addition of paraform is timed in several minutes and not in several hours ( as in commercial process).
The principle of an explosive hobbyist such as what a lot of people in this forum belongs is to obtain the explosive product easily and by simple means.Introducing another chemical which is toxic,difficult to obtain; much more to measure and add, but with insignificant effect in product yield (or even quality) is not practical. Besides purity or refinement is not given extreme consideration than in commercial process

The pioneer of these alternative RDX synthesis did it without any catalysis ,but just using sound chemical knowledge and observance of good laboratory practice coupled with common sense.

[rikkitikkitavi]

shure, there is only one way to find out. Chemistry IS a empirical science, based on experiments.

I know that BF3 is very nasty, so for RDX synthesis I would probably do another route.

It is time to go to bed for some nice dreams , right :)

/rickard

<small>[ April 21, 2002, 02:50 AM: Message edited by: rikkitikkitavi ]</small>

[10fingers]

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<small>[ May 09, 2002, 12:58 AM: Message edited by: 10fingers ]</small>

[Phoenix]

i made rdx with this method but the yield is so bad it is really a waste of chemicals and you have to use really huge beakers the first tiem i used a 1000 ml beaker with 260 ml aceticanhydrit and she hole stuff bubbled over my table

[VX]

Thats why we add things slowly <img border="0" title="" alt="[Wink]" src="wink.gif" />

[Hex]

I've successfully made RDX by this method. However, I (lucky me) have access to Analar chemicals. Your paraformaldehyde is unlikely to contain water, pf hydrolyses fairly quickly so any water that's in there will soon end up leaving as gaseous formaldehyde. Your acetic anhydride is another story...contrary to what I used to think, it doesn't react very quickly with water (if you mix water and AA it will literally take days before the 2 phases disappear)
Why exactly are acetone and AA watched? TATP has been used in bombing incidents, but only in quantites that would require a lot less than 50gal (although Palestinian suicide bombers are apparently using TATP as the main charge on their belts!!). As far as I'm aware, home-made RDX has never been used by domestic terrorists in the UK or US. I'm not aware of any illicit drug synthesis that requires either chemical - so why are they monitored? I would also reckon that acetone is used in such bulk quantities by industry that there's not much point in watching it anyway!

[Rhadon]

Although it may be possible to "bypass" the use of acetic anhydride when producting drugs, it is widely used for this purpose.
Just one example: <a href="http://www.erowid.org/library/books_online/tihkal/tihkal11.shtml" target="_blank">http://www.erowid.org/library/books_online/tihkal/tihkal11.shtml</a>

[vulture]

I suppose oxidizing acetic acid with potassiumpermanganate or(and??) sulfuric acid won't work?

[10fingers]

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<small>[ May 09, 2002, 12:59 AM: Message edited by: 10fingers ]</small>

[Rhadon]

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica">I suppose oxidizing acetic acid with potassiumpermanganate or(and??) sulfuric acid won't work?</font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">I expect H2SO4 is possible, but the number of byproducts should would be high. If I had acetic anhydride I wouldn't use it to make explosives :) , and for later ingestion it had to be clean...

[FragmentedSanity]

Acetic Anhyride is watched because its a simple one step reaction from morphine (or traditionally opium) to heorine. Not to mention its use in various other narcotics. pyridine hcl will give you morphine from codeine - so if AA and pyridine werent watched we would have OTC Heroine.
what country can you buy 250 gallons of AA before getting "watched" do you have any idea how many Kilos that would make? Sounds odd to me.

[nbk2000]

I've got an idea in mind for a one piece ketene generator for converting AcOH to AcO.

A single long glass tube (3 feet or so long, 2" dia) is sealed on one end. The acetone is poured into the bottom and the tube purged with CO2 gas to remove oxygen (air).

The bottom is heated to boil the acetone.

The acetone vapor passes over a red-hot grid of nichrome wire suspended from a 2 hole rubber stopper in the open end of the glass tube.

The uppper part of the glass tube is surrounded by a water jacket to act as a condenser to recycle the unreacted acetone back down to the bottom to be reboiled.

In one hole of the stopper is a very long piece of glass tubing that reaches down into the acetone. Through this is a continuous slow flow of CO2 gas to keep the ketene flowing out of the reactor.

The other hole leads to the AcOH vessel where the ketene reacts to form the AcO.

This design obviates any need for suspicious, or expensive, glassware purchases. All you need is one piece of large glass tubing that'll cost about $30.

I'd draw you a picture, but I'm not at my computer at the moment.

[vulture]

BF3 can be prepared by neutralizing boric oxide, borates or boric acid with hydrofluoric acid and sulfuric acid.
Boric acid is available from pottery stores while hydrofluoric acid can be found in well equipped paint stores.

This is a very nasty synthesis with a very nasty product, BF3 is an extremely toxic gas. I would not attempt this without a hazmat suit and breathing apparatus.

[Einstein]

In Finland you need somekind of license or authorisation from the police to obtain acetic anhydride. Ain't good. Shit...

But it is easier to make ANNM (at OB) than RDX to get goo´ol´ HE :D

[Sam]

I don't know whether or not anyone already knows this, but anhydrides are made by dehydrating acids and bases, so I suppose if one could dehydrate acetic acid, they could get acetic anhydride. I have no idea how one could do this as of yet. I'll have a look though if anyone is interested. Or if someone already knows, plese feel free to explain.

[bonnsgeo]

hey Hex you said *I've successfully made RDX by this method* it's cool...but me i have anhydride acetic acid (in France its ok for under 20 L per year per person) and paraformaldehyde but i never obtain any RDX (i tried a lot of times).... (did you use BF3 ?? (me i dont want use this shit) )

ci@o

[kingspaz]

sam, i believe it can be obtained by refluxing acetic acid with concentrated (98%) H2SO4. then it must be distilled from the reaction vessel which is the hard part since its vapour is very toxic and it is also flammable.

[Sam]

Yes, thankyou kingspaz, the toxic vapours are a worry, but shouldn't be a problem if you own or have access to a fume hood. I might try making some in my dreams soon if I can get the time.

[PrimoPyro]

Hello everyone. :)

This topic may be bee old by now, but it is a chance for me to pipe in and say something.

The reason for acetic anhydride and acetone being in the same class of Listed compounds is due to import/export restrictions. If you check out the US Dept. of Justice online, you will find that the List two classifications require a threshold to be crossed before reporting. Each chemical has its own threshold of course. Acetic anhydride is used in many clandestine syntheses, most often in the olden days when methamphetamine was manufactured via the P2P process.

Acetone however, will get you into no domestic trouble. The threshold for acetone is much lower because of import/export (specifically EXPORT) restrictions. The DEA does not want US companies exporting 200L of acetone or MEK or MIBK to Columbia for example, because it is a prime extraction solvent for cocaine. Domestic purchases of these lab solvents should not warrant any unwanted guests.

The notion that acetic anhydride is less "watched" than acetone, is unfortunately incorrect. If I were to purhase a quantity of Ac2O greater than say 500mL I would never use my real contact information or identity, but that's just me. I'd have no iddues about buying 3 gallons of acetone, though.

For acetic anhydride syntheses, see:

<a href="http://www.rhodium.ws/chemistry/anhydrides.html" target="_blank">http://www.rhodium.ws/chemistry/anhydrides.html</a>

And also via the Ketene Process:

<a href="http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0330" target="_blank">http://www.orgsyn.org/orgsyn/prep.asp?prep=cv1p0330</a>

Ketene reacts (vigorously) with water to form acetic acid, CH3COOH, and with acetic acid to form acetic anhydride. Please note that ketene is very corrosive and precautions should be taken when synthesizing it and working with it. It should preferably be made in lab glass and in a facility with good ventillation.

PrimoPyro

[Sam]

Hmmm, this is off topic, but when u mentioned M.E.K. (I assume you mean methyl ethyl ketone), i just started wondering if it has any uses apart from paint removal. As I have 2 litres of 100% pure MEK in my garage. I do know that its a carcinogen, and is toxic, but thats about it.

[PrimoPyro]

Sure it does. Use your imagination. :D

It can also form peroxides, its a great acetone substitute as a solvent, and it can be chemically transformed into many useful compounds that are otherwise out of our reach due to illegalization or "watchedness" by the government.

Two such compounds would be propionic acid and ethylamine. Byproduct of changing MEK into propionic acid is chloroform by the way.

MEK + hypochlorite --&gt; propionic salt (same salt as hypochlorite was) + chloroform + (hypochlorite cation)'s hydroxide.

Here's a simple translation of that chemi-speak:

C2H5COCH3 (MEK) + 3NaOCl (sodium hypochlorite) --&gt; NaOOCC2H5 (sodium propionate) + 2NaOH (sodium hydroxide) + CHCl3 (chloroform)

This is called the haloform reaction and works with ALL methyl ketones and all alkalai metal hypochlorite AFAIK. The haloform reaction prefers an acidic environment, but dont go crazy with the acid, or you'll end up with Cl2! <img border="0" title="" alt="[Eek!]" src="eek.gif" />

As for the ethylamine, look up the Hoffman Hypohalite Degradation of Primary Amides. Classic textbook reaction, and one of my personal favorites. Use your propionic acid with urea to make propionamide, then use more hypochlorite to transform that into ethylamine.

Don't ask what these two compounds are used for, or you'll get more imaginative responses from me. Use your imagination! lol chemistry is fun if you make it devious.

PrimoPyro