12-22-03 05:00
No 478316
I know this is something that has been discussed before, but I have never seen this method used. I got the idea after reading the vandium peroxide post that LUGH pointed me to. The author uses an alcohol to extract hydrogen peroxide from the remaining water with use of a salt to separate them. The well known alcohol purification method as well.
For those who don't like having flasks permanetly ringed with acetate from distilling off gallons of water from sodium acetate then distilling with sulphuric acid this may hold some promise. At least for the initial concentration if not better. So I decided to try it out on a small scale with vinegar to see if this might work.
I took 10ml of 5% vinegar and added 2ml of anhydrous ipa and couple dashes of salt(nacl) to a culture tube. I shook untill I could get as much salt in solution as possible and extracted the top layer with a syringe and put it in a metal crucible and ignited it to verify that it was the alcohol layer. After burning a brief second I blew it out and allowed it to evap a lil more and then tested the residue with ph paper. Deep red way deeper than vinegar and then decided to smell it. Whoh damn! dumb idea! Well it is VERY PNGENT and powerful shit. I do not know pure this is. Maybe up 80% or possible in the high 90% range. I added various other salts to the alcoholic mixture to see if anymore water would separate and none did, so there is a good cance it is mostly pure AcOH???
So the next time one of you people who would rather make this stuff than buy it ry this next time it is much simpler and quicker than neutralizing with baking soda and double distilling salts. The overall idea again is to saturate the vinegal with NaCl and extract with a minimal ammount of decently dry alcohol and distill off the alcohol to leave acetic acid.
EDIT: Here is a quick follow up
I performed this as described above a total of four times and combined the alcoholic extracts with one another and into a 50ml conical flask and distilled off the alcohol leaving a small ammount of smelly residue. I scked it out and showed to be about 1.8ml on the pipet's graduations. So this is pretty efficient on the ammount obtained in such little time. Now I know that 2.0ml is pratically useless for most people, but this is scalable of course. Right now I'm extracting a 700ml portion of vinegar and will do a complete analysis to try and determine what the water content is. Though this chemical is still much more conviently purchased, but for those who got somethign laying around and can't wait to react it and need some quick HOAc then I guess thsi is about the quickest and esiest method. Making this a salt and drying then distillig over SO3 will give a rather pure glacial acetic acid.
EDIT: Oh yeah as for the anhydrous ipa... It's not actually comletely anhydrous.. Its jsut 91% thats been separated from the remaining water using NaCl, then dried ofer Anhy, MgSO4. Though plain 70-91% should work as well. You'l just need to add extra salt and shake some more once you've added that alcohol to ensure that the salt concentration is at a max to get as much of the acid as possible.
(Synaptic Self-Mutilator)
12-23-03 05:44
No 478598
Yeah it's great to use a very polar solvent like IPA or ethyl acetate to extract acetic acid from vinegar. Unfortunately you will not end up with GAA, as far as I know.
(Hive Addict)
12-23-03 08:35
No 478622
Now I know that 2.0ml is pratically useless for most people, but this is scalable of course. Right now I'm extracting a 700ml portion of vinegar and will do a complete analysis to try and determine what the water content is.
I hope you realize that to obtain a liter of GAA you need about 20 1L bottles of vinegar?
Making this a salt and drying then distillig over SO3 will give a rather pure glacial acetic acid.
I hope you mean H2SO4..
The Other War (http://www.markfiore.com/animation/drug
(Hive Addict)
12-24-03 00:50
No 478732
Yes, there was undoubtedly some water in the residual extract. After it was evaporated, there was a tiny bit of salt in the crucible. I'd say by looking at the ammount of salt, I'd guess there was probably ten percent water, maybe more maybe less I couldn't weigh it.
I'm very aware that there are only ~180ml of acetic acid in a gallon of vinegar. Though, that hasn't stopped bees from neutralizing an entire gallon, evaping a gallon of H2O off, then drying the salt, liberating the acid, etc.
It was just a reminder of a simpler method for those who might want some quick acetic acid.
I never said GAA, but a quicker route to acetic acid. I'm just saying that in the time it usually takes to obtain a salt, one could have extracted the crude acid and continue on to make it glacial. Just quicker and less of a mess.
Vitus- Why? Will SO3 react with the acid? I figured it would react with water first to make H2SO4? Am I wrong?
Oh woops!! I see the error now. I made an error up there when I edited the post. I was thingking of the sentence where I was knocking the salt and accidentally put it in the end there. I meant to say drying over another salt then distiling over SO3....
Like anhydrous MgSO4 then distilling over the trioxide. THough for all practical purposes that isn't most peoples cup of tea. Making SO3 especially for this is quite impratical and would definately lead to a purchase.
I jsut said it cause I make my own H2So4 from pool chems and I have some laying around anyway. So of course it may just be more pratical and easier to just indeed make the salt and distill over sulfuric acid., or one could simple buy it like any sane person should ;) Though it still comes up here so much.
(Stranger)
12-27-03 19:22
No 479329
Might be a usable idea with the OTC photographic
'stop bath concentrates' non- citric of course... these concentrates are around 25% ish.
(Hive Bee)
01-02-04 05:03
No 480174
"Making SO3 especially for this is quite impratical and would definately lead to a purchase."
SO3 is easily created in the lab by decomposing ammonium persulfate at around 150C. ammonium persulfate is avaliable OTC at electronics stores as a circut board etching compound.
The shit we go through to get high...
(Chief Bee)
01-03-04 22:00
No 480283
That reaction creates SO3 together with what? Please provide more details, it sounds pretty dangerous as is.
The Hive - Clandestine Chemists Without Borders
(Hive Bee)
01-04-04 11:12
No 480352
Upon decomposition ammonium persulfate releases sulfur oxides, nitrogen oxides and carbon monoxide. sulfur trioxide is however the chief decomposition product, by a long shot. SWIC decomposed some at home, he noticed no NOx's at all.
The shit we go through to get high...
(Stranger)
01-05-04 11:33
No 480483
The sodium acetate method is extremely simple, why bother with anything else? I don't bother distilling the water; I just boil it off in a big soup pot (has the added benefit of rejuvenating my dried sinuses--lousy winter humidity). Cleans the hell out of the pot, too. Then distill with some dried drain opener, et voila, glacial acetic acid. Vitus is right, though, you do need a *lot* of vinegar. However, GAA is simply not available in my area, and with hazard shipping, the vinegar method seems to be cheaper.
Your method sounds like a whole lot of work, considering that the sodium acetate method requires occassionally checking on a pot of boiling water. I've made packaged soups that take more effort.
I've got the kind of toys you've never seen
Manmade and a bit obscene
(Hive Addict)
01-05-04 12:12
No 480488
Alot of work? Dude, all you do is take a gallon of acid add pound of salt shake, pour in some alcohol, and separate. Takes two minutes. Ramen noodles aren't even that fast!! Please explain how that is a lot of work.
You can't even neutralize the entire gallon that quick! At lest not with any carbonate bases. Which is exactly the entire point. It's a hell of alot quicker.
Ever tried to make 3l of acetic acid at home? Takes a long damn time to get rid of all that water. It is much quicker this way. I posted it to help save some bees precous time that they don't have much of..
(Hive Bee)
01-05-04 23:57
No 480596
Upon decomposition ammonium persulfate releases sulfur oxides, nitrogen oxides and carbon monoxide. sulfur trioxide is however the chief decomposition product, by a long shot. SWIC decomposed some at home, he noticed no NOx's at all.
This sounds like fun. I've always wanted a practical SO3 source. Does sodium persulfate behave similarly? And where does the carbon monoxide come from?!
19th century digital boy
(Stranger)
01-06-04 02:47
No 480642
A pound of salt per gallon, then shaking it, then separation. I don't know how well the layers separate, but I don't exactly have any 2L sep funnels sitting around. I'm skeptical that this is really that practical on a large scale, though I should probably try it before speaking further. (I'm away from my lab at the moment.) I have tried to make GAA via direct fractional distillation (bad idea) and neutralization, and in the latter case, it took perhaps 7 hours to make 500ml. Of course at the same time, I was able to do two other tasks; it requires almost no supervision. If your only time burden in your lab is making GAA, then more power to you.
One could also try killing two birds with one stone--making calcium acetate and chloroform with acetone and calcium hypochlorite, though this might contaminate the finished product with HCl. Since most of us are going to make chloroform anyway, seems like a decent use of resources. Does anyone have any experience with this method?
I've got the kind of toys you've never seen
Manmade and a bit obscene
(Hive Addict)
01-08-04 11:10
No 481129
The layers don't separate! You have to use a solvent to extract the HOAc. I did this in a 500ml sep funnel. All you have to do is add a few hundread milliters at a time! The top alcoholic layer can stay in for at least 2-3 separations with fresh salt/vinegar solution. Then once you suspect that the alcohol is saturated you use fresh alcohol.
If anybody is actually to try it, I'd try something like ethyl acetate instead of alcohol. I would have done it with ethyl acetate, but didn't have any handy. I just wanted to know if it would work. Ethyl acetate should provide much better results.
I made 100ml of acid in about twenty minutes using a 500ml sep funnel. Not including the ten minutes it took to rotovap off the alcohol. Of course if one were to use a 1L+ sep funnel, you could easily process 2-3 gallons per hour or more.
I didn't say this was the only fucking way to do it and it by far the best. I'm just sharing it becasue it is a lot quicker for making lots of homemade acetic acid. If you want to mak it quicker don't wait for 2min for separation. It forms layers in a few seconds. But 3000ml x300ml portions= 10 washings x2min= 20minutes= 300ml an hour or 600ml if you don't wait 2min for each wash or 1200ml if you just wait thirty seconds which is still quite a bit of time.
Either it will be useful or it won't!
Chewy-- Could you elaborate a lil more on that prep? It looks very enticing and a hell of a lot simpler than decomposing bisulfate salts. Seems that it would be alot quicker also with the low heat compared to teh bisulate. Just raise a 150c oil bath to a flask with salt and stirring? that simple huh? Nothing to be careful of or special steps requirements?
(Stranger)
02-13-04 08:48
No 488303
or you could just extract w/ an ether. dont evap, just move on to the next gallon of vinegar. beware peroxides as usual, maybe AcOH inhibits? or promotes? peroxide formation. that said, neutering w/ Ca(OH)2 isnt much of a pain. just boil away in a big stock pot. As for acetate via haloform, beware unreacted OCl. that goes for you'se making formate via EtOH instead of acetone. better to make formate/chloroform via chloral but thats off-subject.
love (the drug not the emotion)
(Hive Bee)
02-14-04 01:24
No 488470
Could one avoid all that H2O by oxidising ethanol with acidified KMnO4 or similar, and then distilling off the acetic acid?
e( i*pi)+1=0
(Moderator)
02-14-04 01:42
No 488475
Could one avoid all that H2O by oxidising ethanol with acidified KMnO4 or similar, and then distilling off the acetic acid?
You could start with Post 435660 (lugh: "Acetaldehyde", Novel Discourse); then read the rest of the posts in that thread You may find many more old threads with useful information, by clicking this link:
https://www.the-hive.ws/forum/search.pl?
Chemistry is our Covalent Bond
(Hive Bee)
02-14-04 07:45
No 488563
Based on my experience, the answer is no. First of all, the reaction between ethanol and KMnO4 is very violent, so unless you want ethanol boiling up in your face, you should buffer the solution with a whole lot of water.. Second, there is a brown precipitate which forms. It's not MnO2--it's a much lighter brown, and turns dark at the surface upon standing. I presume it's the relatively insoluable Mn(OAc)3, but have no way to test that. In any case, you would need a whole lot of KMnO4 to get any appreciable quantity of AcOH.
Edit: I should mention that I was using the ethanol as gunk to be oxidized so that I could obtain Mn2+ ions, not with the intent of making acetic acid.
This is in no way an endorsement of Birch reduction.
(Hive Addict)
02-14-04 19:38
No 488633
Making your own acetic acid from ethanol is quite expensive. By the time you buy the alcohol you could have just bought the acid. Permanganate isn't very expensive and especially if you raise "koi fish". But that is a bit extreme for homemade acid.
I don't see how this thread survived this long. Just buy the stuff!!
BTW I'm not sure how well that ethyl acetate will work. I think it forms an azeotrope with the acetic acid. Though, it shouldn't be much loss.
(Newbee)
02-16-04 10:43
No 489009
yeah, forgodsakes, 80% acetic acid is available at any photographic supply as stop bath (get the ones without indicators) and from that form of acetic acid i'm sure it's not hard to get to the final result (glacial) i am thinking drying and distilling, i might be wrong... actually, i don't see why that would work even with 5% acetic (ie white vinegar), all the salts added to draw out the water won't absorb the acetic acid.
(Wonderful Personality)
02-16-04 16:35
No 489061
Where I live, 8% vinegar is the best you will get by now (I hope this to change to 25% soon) and at photographers supply houses you get citric acid and no acetic at all.
Dont ask me why. I can buy 98% H2SO4 as draincleaner, 30% H2O2, 33%HCl, toluene by the barrel and much much more, everything OTC but no fucking acetic acid.
(Hive Addict)
02-16-04 22:34
No 489128
I remember seeing 10-20% distilled vinegar by the gallon, but the store quit carrying it for some reason.
I could live without an OTC source of acetic acid if I could get OTC source of 30% H2O2. And no, I don't consider wood bleaching kits as an OTC source. Maybe moving to Arizona where all of those rocket guru's live I could find it. I saw a company that sells stills for making 90% H2O2 from 50%.
I need to dig up that old reference for using fuel cells to produce H2O2.
(Hive Bee)
02-17-04 02:13
No 489182
Regarding the method of production of Acetic Acid by salt separating vinegar into Acetic Acid/Isopropanol and Water/Salt layers:
When a large excess (like 300G) of "Rock Salt" (crushed in mortar/pestle) was left in 200ml of 5% clear vinegar and 50ml of Isopropanol overnight in a seperatory funnel, a top layer of roughly 60ml formed, upon collecting this layer (the excess salt stayed in the sep funnel), it was found NOT to react with baking soda. Upon addition of 1ml of water, it reacted violently with baking soda.
This leads me to believe that this layer contains 0% water, 83.3% isopropanol, 16.6% acetic acid.
If you require pure acetic acid, the difference in boiling points is large enough that simple distillation can remove the isopropanol.
sYnThOmAtIc: 35% H2O2 can be found in some hippy food stores... Also in beauty supply stores...
I vote this the easiest method of production of acetic acid.
Thank you sYnThOmAtIc!
(Hive Addict)
02-17-04 02:52
No 489192
I appreciate the comment.
Just for clarity
But 3000ml x300ml portions= 10 washings x2min= 20minutes= 300ml an hour or 600ml if you don't wait 2min for each wash or 1200ml if you just wait thirty seconds which is still quite a bit of time.
Just for clarity, the ammount I'm refering to is the ammount of acid obtained not liquid processed.
All hardware stores and large shopping centers with W-k arts stopped selling the 95% clear H2SO4 in the 2l cream white bottles. I found the conc black crap the other day. I'm unsure of what they use as the dye to indicate spills, but I don't think I would try to use or clean it. This methamphetamine lab shit has made it hard to get common chems OTC.
I though about looking or inquiring about an order of conc H2O2 at a health food store after reading that people add a few drops of it to elixers and other drinks to add oxygen to their body. So I guess I'll start the hunt again.
(Hive Bee)
02-17-04 03:44
No 489197
"forgodsakes, 80% acetic acid is available at any photographic supply as stop bath (get the ones without indicators)"
This is false. Not all photo stores are equal, especially in medium-small towns vs. big cities. Why do you think people would fuck with vinegar if we could go to the photo store? The closest I could find was 30% with shitloads of other stuff in it.
This is in no way an endorsement of Birch reduction.
(Hive Addict)
02-17-04 05:43
No 489223
Same here. I can only get premixed stop bath solutions. It come in two containers and each is contaminated. I would hope anybody that has means would buy it. I can only get it by mail order. When I look at the suppliers list and 40% H2SO4 requires DEA form I don't buy anything. I'd rather screw around with vinegar. Single people need things to keep them busy anyhow
.Besides even if you can get it and you don't buy any other photo chems but maybe one or two others quite frequenty, you have to worry about how that might look! So it is nice to rotate and enjoy the lower forms of chemical acquisition
(Newbee)
02-17-04 19:52
No 489354
You could destill acetic acid, but you would need a stronger vinegar than 5%, because there is an azeotrope betwen water and 3% acetic acid. I use 30% vinegar essence and destill trough an vigereux column at a veeeery slow rate.. the destillate came over at 100 C and smells acetic, but fairly as strong as the essence.. After a while the temp will raise and acetic acid will come over, this could then be dried with a proper drying agent..
(Wonderful Personality)
02-17-04 21:37
No 489377
Admitted, this is not so fast and and easy as the IPA - salting out method or the sodium acetate, but it has some other advantages....
A coppertube of about 70cm length and about 3mm inner diameter is connected to a vessel/flask where acetone is brought into a gaseous state of matter (aka boiling). A batwing propane-burner is installed under the part of the tube at the outlet side which heats the tube to a dull red glow. (The burner is positioned at about 50cm from the tubes inlet). The outlet of the tube leads straight into a big vessel with vinegar. This vessel should be halfway filled with broken glass and be hold at a temperature of about 70°C. The vessel has to be closed except for an outlet connected to an smoothly running aspirator.
Operation:
The acetone is brought to an straight boil and the tube is purged by the acetone. The burner is started and soon after the tube reached a dull red heat direct over the burners flame ketene will be formed by thermal decomposition of the acetone. The ketene reacts with the acetic acid in the vinegar to form acetic anhydride which reacts with the water to form acetic acid. It is possible to use straight water from start instead of vinegar but this is unfavorable as the reaction of water and ketene is rather slow and ketene would escape. Ketene is poisonous so the aspirator which must run down the drain - no aspirator-station like design here.
After some time you will have a mixture of GAA and acetic anhydride which can be separated by simple distillation. The GAA will be absolute anhydrous. The ridiculous acetic anhydride may be converted to GAA by the addition of water. This should be done ASAP as acetic anhydride is a scheduled compound and might cause legal trouble.
This is a little bit a piggy-setup as the unreacted acetone is washed down the drain and not recovered. But it spares all these washbottles and scrubbers and condensors and stuff, and acetone is asscheap and not regarded enviromental dangerous. (at least the bottles I buy carry no such warning)
Yields: At least 50% from theory, up to 80% with some finetuning.
Ok, it is some work included. But once the work is done you have a neverending source of GAA....
(Hive Addict)
02-19-04 00:58
No 489631
Tube furnace is the shit! I used to know of about three or four wonderful thing that could be made with one, but have forgotten them all.. I built a nice tube furnace a while ago and I have three different tubes, copper, glass, and porcelain. The porcelain one has some palladium catalyst packing for some reason
Only got around to wrapping one with a homemade heating mantle. Shit got expensive once it came time to wrap in wire and glass fiber sheeting. Thanks for pointing this one out. I didn't know about acetic acid from a tube furnace. Actually, I like it alot.
Oh yea, I think I was going to make benzene or something. And nitrobenzene from that for some oxidation of eugenol. I have decided that is a bit of work for vanillin. There were a whole slew of things I found out about here that I can't remember.
(tourbee)
02-20-04 16:45
No 489987
Hey now,
HOws it going all?I have a quick question about the shelf life of GAA.Ive had a bottle for probably 4 years is it still good?
The bus came by,and I got on.Thats when it all began. -GD
(Hive Bee)
02-21-04 06:23
No 490108
That's a wonderful procedure Org - thanks.
I intend to build such a reactor and document it when situations allow.
But as you said it's a "piggy setup"
I plan to make it a bit more elegant.
having an empty flask in an ice-salt bath or similar preceding the acetic acid would do well as an acetone trap, yes?
What I have a question about is this; My uncle buck doesn't have sufficient running water at his lab to run a water aspirator continuously like that.
I've read hypo's posts about burning the ketene, and frankly I'd rather not purposely introduce fire into the equation.
Ketene is decomposed by alcohol and ammonia yes? What if one placed a vessel of either between the acetic acid and the vacuum source? Would that be sufficient to be able to use say a rotary vane pump, vented outside of course, or a recirculating aspirator safely?
Another thought that just crossed my mind was placing the whole aspirator station outside and just running a line to the apparatus.
We'll see how it works out I suppose.
Thanks
T
(Hive Addict)
02-21-04 21:40
No 490193
I don't know exactly what it decomposes to, but according to msds "expect co/co2 evolution". I'm assuming that it may decompose slowly into methanol. CH3COOH minus co gives methanol, CH3OH, CH4O? I'dd say that as long as the bottle hasn't exploded yet it should be good for most purposes? If it plays a critical role as a reagent or something you might want to oven dry some glass and distill it, but that may be completely unnessecary..
(Hive Bee)
02-22-04 03:19
No 490275
It is possible to use straight water from start instead of vinegar but this is unfavorable as the reaction of water and ketene is rather slow and ketene would escape
Will H2SO4 assist in the reaction of ketene with H2O or must it be acetic acid?
e( i*pi)+1=0
(Hive Addict)
02-22-04 03:41
No 490287
Why use that when vinegar could be used? Vinegar is easier to get and cheap.
BTW for the ethanol oxidiser.. Why not use chromic acid to make if from ethanol. Easier to get and less suspicion in purchase.
(Stranger)
02-22-04 04:25
No 490306
the black shit works. add dh2o, mix well, let stand and seperate, blow off excess dh2o.
ive used the black shit for hcl generation and it works great. i tried it to convert PI and KI into HI which was subsequently oxidized into I2. it seemed to work ok but sublime your I2 just to be safe and insure cleanliness
(Hive Bee)
02-22-04 04:46
No 490315
to start with is what would drive one to synthesise ketene....
If sulfuric acid will promote the reaction between ketene and water then the acetic acid/anhydride produced would easily distil from this cleanly, that is why I asked. I just wonder about possible reaction with the other gases - CO and ethene.
e( i*pi)+1=0
(Stranger)
02-22-04 04:52
No 490319
we did these oxidations of EtOH in lab class. the products from Cr+6 and KMnO4 are very dependent on amts and conditions, but any acetCHO can be recycled. spose you knew like almost everyone else, but others are watching and a look at the archives show a lot of bees who dont read the books. one thing ive only seen in one book is the dry dist of Cu acetate giving pure GAA, @250 300C.
the real reason for posting-somewhere in Kirk-Othmer they talk about the acetone/ketene thing. their example reactor gives not only ketene and CH4, but also AcOH, Ac2O, and unreacted acetone. this from the vapor spending 1 sec. in reaction zone. most of the ketene reacted with the AcOH in the hot(150C) condenser, giving Ac2O and AcOH mix. unreacted acetone is dist. off, then whats left is dist. 3X over Ca acetate giving Ac2O and residue of diketene polymer catalyzed by the Ca acetate.
compare this to the other reports of variable success and products. some tweaking(of the app.) may be necessary. have any bees had the same success as vogel? i'll just stick to the hot acid KMnO4 till someone does.
(Wonderful Personality)
02-22-04 05:41
No 490327
You can recover your acetone either by adding another scrubber filled with cold water where you bubble the acetone in AFTER the water/acetic acid. This will hold the acetone back which can bne separated from the water lateron. The further outlet should be directed by an nozzle into the flame of an propane burner - thats the safe way to do this if you cannot run the shit down the drain by an aspirator. Ketene is poisonous - period. After the scrubber there will be only tiny amounts to burn - no real problem.
"Is decomposed by" is a fine sentence - it says nothing about how fast this happens. Mostly this says it happens very, very slow as the fast variation would be "reacts vigorously"
Ketene reacts very slowly with cold water.
Ketene reacts slowly with acetic acid in the cold. (this is not important here as the ketene comes fucking hot outa the tube...)
Acetic anhydride reacts slowly with cold water.
Praesodynium, you may look at Rhodiums page for "ketene" to understand the reaction mechanism. Ever heard of the difference between mineral acids and organic acids?
Turden, so you SERIOUSLY go to build this, PM me.
(Hive Bee)
02-22-04 05:50
No 490329
Org - Wonderful input. thanks
I don't know what you're implying but I plan on starting to assemble parts tomorrow
(Stranger)
02-25-04 07:59
No 490953
Im not sure if anyone can benefit from this info but I'll post it anyway, for reference sake.
Swim, recently paid AUD$69.95 for 2.5Lt AR 98% GAA, from an allied chem supplier. GAA is not rare here, but it is not the easiest to buy..if it werent for an old friend's advice I would be making my own via sodium acetate
I'm a diamond that is tired, of all the faces i've aquired.
(Wonderful Personality)
04-24-04 21:38
No 502713
Production of acetic acid:
This post might be of interest for the acetic acid lacking bees:
Post 502712 (Organikum: "Rhodium wrote: Re: If you do not remove the...", Stimulants)
Oxidation of EtOH to acetic acid using ferrous acetate (FeSO4 should work too) and H2O2. It wont get much easier I guess.
(Hive Bee)
04-25-04 15:32
No 502841
SWIM has tried bubbling ketene into 500 ml GAA over the last 2 weeks. Standard ketene gas set up, bubbled gas for at least 10 hours, yield acetic anhydride mixture bp over 130 Deg less than 70g, total waste of time IMHO.
(Wonderful Personality)
04-25-04 18:23
No 502882
What is a "Standard ketene gas set up" ? Could you please elaborate?
thanks
ORG
(Hive Bee)
04-26-04 05:32
No 503032
Oxidation of Ethanol by Hydrogen Peroxide in a Modular Microreactor System
M. Krauta, A.Nagelb, K. Schuberta
a) Institute for Micro Process Engineering
Karlsruhe Research Center
Hermann-von-Helmholtz-Platz 1
76344 Eggenstein-Leopoldshafen
Germany
b) Bayer AG
Process Technology/Reaction Engineering
51386 Leverkusen
Germany
Klaus.Schubert@IMVT.FZK.DE
WWW.FZK.DE/IMVT
Prepared for presentation at the 2002 AIChE Spring National Meeting (IMRET 6 - 6th International Conference on Microreaction Technology), March 10-14, New Orleans, LA
Proposed topic: TBa05: Poster Session Microreactors as Tools in Chemical Research
Abstract
The iron(III)-catalyzed oxidation of ethanol by hydrogen peroxide to acetic acid is a highly exothermic reaction that was intensively studied by Hafke [1]. This makes it an ideal test reaction for microstructured reactors. Experiments were performed in a newly built test stand planned for a throughput of up to 10 kg/h, temperatures of up to 180 °C, and pressures of up to 10 bar.
We developed a modular microreactor system for this chemical reaction, which is parametrically sensitive and strongly exothermic. The modules consist of a micromixer and microreactors. The reactors are built as cross-flow devices. The reaction passage consists of 169 channels with cross-sections of 150 µm x 200 µm and lengths of 6 cm. The other passage, through which the reaction heat is removed, has 1960 channels with cross-sections of 150 µm x 200 µm and lengths of 1.8 cm each. The modules are flanged together, as a result of which a small dead volume is obtained between the modules. This prevents an uncontrollable temperature rise in this space. The complete microreactor system is built up by combining the micromixer and four reactor modules. The temperatures can be adjusted for each of the modules individually.
In a typical experiment, 1.2 l/h ethanol and 3.1 l/h hydrogen peroxide solution (30%) plus 50 ml/h of an acidic aqueous solution of Fe(NO3)3 serving as a catalyst were fed into the microreactor system. The temperatures in the four reactor modules were adjusted to 70 °C, 105 °C, 105 °C, and 20 °C respectively. The yield was 99.3% acetic acid with a complete conversion of both ethanol and hydrogen peroxide, thereby generating about 3.8 kW of heat. The steady state was achieved and the temperature was kept within narrow boundaries for each of the modules.
Thus, it has been shown that a highly exothermic fast liquid phase reaction can be performed isothermally in microstructured reactors.
References:
[1] C. Hafke, PhD thesis, Universität Stuttgart 1972.
http://www.aiche.org/conferences/techpro
"Canada is exporting to us the crack of marijuana and it is a dangerous problem." ONDCP
(Hive Bee)
04-26-04 10:25
No 503082
Org,
ketene was produced ad nauseum (as posted by others here before) by using a controlled red hot element in the vapour phase of refluxing acetone.
That is, 2 neck flask, one had the condenser with ice cold water running through it, the other heating element.
The heating element was from an electrical radiant heater, had a resistance of 55 Ohms and was voltage controlled via light dimmer so that it glowed red hot in the flask.
The top of the condenser was attached to another condenser (with ice cold water running through it) leading down to another 2 neck flask serving as an acetone trap. The 2nd neck of this trap flask was attached to a bubbler set up so that the gasses were bubbled through GAA and finally exhausted to a propane burner.
There was no doubt ketene was produced (nasty stuff indeed)as well as the by product methane (which was burnt off in the burner).
Used about 5L acetone and well over 10 hours in total. used sodium acetate method to try to seperate GAA from the anhydride, over all yield very dissapointing in relation to how much effort was put in.
Resorted to making acetic anhydride from sodium acetate, bromine, and sulphur, which proved much much better, faster, easier and cheaper due to the fact SWIM blew up 3 expensive light dimmers in the process, not to mention slight fire issues.
Nothing like seeing a 2 foot flame of burning acetone vapours coming out the side neck of a flask.
Abacus
(Wonderful Personality)
04-26-04 11:45
No 503090
ketene was produced ad nauseum (as posted by others here before) by using a controlled red hot element in the vapour phase of refluxing acetone.
Now I understand. This method is known to be ineffective and hazardous. If one cannot get his hands on a original ketene-lamp this setup should be avoided. Also the setup as described by VOGEL 3rd Ed. doesnt work well. If one reads the text it shows up that the claimed yields refer to the original ketene-lamp and not to the inferior setup depicted in the book.
I know it doesnt help shit, but abacus you are not the first and will not be the last to fall for this. 
There are two proven working ways to accomplish the thermolysis of acetone to ketene in acceptable yields:
- the first is to use an about 70 cm long and about 2 cm inner diameter tube preferable made from porcelain/ceramics and filled with broken porcelain,
- the second is to use a coppertube of about 1 meter length and about 3 mm inner diameter - all details are described in the Patent GB425973
Rapid cooling down to below 500°C after the actual "hot spot" is the key. The second method has higher throughput the first one is more resistant against polymerization.
The second method was done by myself, the first claimed functional by persons I trust in this. As both work it is a question of meterials available and personal taste. If one decides to go for the second setup I advise to read the named patent several times, to redo the calculations and to make sure to have really understood everything whats told there. Who reads it once and thinks he knows now how it is done WILL fail.
I myself prefer the coppertube as the small inner diameter prevents any flameback and provides more security when running the device overnight or even longer.
hope this helps
ORG
(Hive Bee)
04-26-04 14:35
No 503101
As I stated, there was NO doubt ketene was being produced
Also, if it wasn't working, how can you explain the constant flammmable gas that was the by-product? ie methane?????
(Wonderful Personality)
04-26-04 15:34
No 503119
Sorry, I never told it doesnt work at all - I only told it is ineffective and hazardous - both is described in your first post.
- There was not very much ketene produced - just enough to get 70 gram AA in 10 hours what you told to be not satisfying at all.
- Flames out of the flask as described are to be called hazardous after my definition.
Please dont interpret things into my post I have not written.
Thanks.
ORG
(Stoni's sexual toy)
04-26-04 15:37
No 503120
How come the yield was so low? Maybe the shit didn't get absorbed into the acetic acid and got burned with the methane?
BUSH/CHENEY 2004! After all, it ain't my country!
(Wonderful Personality)
04-26-04 15:54
No 503124
The only ketene lamp "design" which I can remember posted here is the one of HYPO which doesnt even include an condensor for recondensing the acetone which wasnt pyryolized - if this is the way it was done the yield is absolutely ok.
The original ketene-lamp was the work of life of a german chemist (Ott? - dunno now) and was never reached by others. I would love to see a picture or better drawing of this device. I have seen one from a russian ketene lamp which micht be a exact copy of the original but I am not sure on this.
The described tubes are much simpler and cheaper and give good results. The approach to homebuild a balanced system like the ketene-lamp is bound to fail if one doesnt have the plans and an glassblower by hand. This does by no way say it doesnt work at all - but the famous yield and throughput cant be reached.
(Hive Bee)
04-27-04 13:50
No 503295
Osmium, the ketene dissolved in the GAA which caused the GAA solution to heat up, which was cooled periodically while dismantling to replace the used acetone with fresh acetone.
No traces of ketene gas seemed to pass through the GAA. This was tested by periodically stopping burning the flammable by product, methane, and carefully sniff tested (not really recommended) for traces of obnoxious ketene gas.
I did work, but as Org has mentioned the set up used proved to be ineffective. I dont know why, coz heaps of methane was produced, but in any case SWIM wont be trying that experiment again.
(Hive Bee)
04-27-04 23:37
No 503374
>and carefully sniff tested (not really recommended) for traces of obnoxious ketene gas.
Wow, do you understand just how poisonous that stuff is?
"Canada is exporting to us the crack of marijuana and it is a dangerous problem." ONDCP
(Moderator)
04-29-04 04:47
No 503663
(Rated as: excellent)
Hypo's design wasn't intended to produce liters of acetic anhydride, so abacus's results aren't very surprising. As far as pictures, the pages from Vogel's 3rd Edition concerning the keten lamp:
The commercial keten lamps for sale, primarily in Europe, are based on the design of H Stage, published in Chem Ztg 97 67 (1973)
Hershburg's modifciations of Hurd's design:
Another design of possible interest from Ind Eng Chem 38 53-7 (1938) that has been used for liquid phase pyrolysis of acetone to produce keten:
Chemistry is our Covalent Bond
(Hive Addict)
04-29-04 09:33
No 503697
(Rated as: good idea!)
i think i never could explain the setup correctly. that's what it looked like:
the 2nd condensor improved yield, because there wasn't that ugly middle
fraction. if one has the equipment for a ketene lamp, distillation should be easy.
i really don't see why 1l/week wouldn't be doable this way. if that is
too inefficient -> bummer. there's still the S2Cl2 methods.
http://www.animalyawns.com
(Chief Bee)
04-29-04 17:53
No 503765
Check out these patents: Post 259042 (PolytheneSam: "concentrating carboxylic acids", Methods Discourse)
According to one of them it is possible to vacuum distill out the water from 80% acetic acid by the addition of a bunch of sodium acetate to the distillation flask...
The Hive - Clandestine Chemists Without Borders
(Hive Bee)
05-03-04 02:07
No 504460
SWID recently mixed 300mL of 40% acetic acid and 650mL of 91% IPA. With the stirrer on high, a large quantity of sodium chloride was added until there was an undissolved layer on the bottom of the erlyenmeyer. There was no biphasic layers visible. This was left (stoppered) in the fridge overnight. The next day, there was still no layers visible.
Because of previous posts, SWID is somewhat confused. Is there supposed to be a biphasic seperation or not? How else could one isolate the AA/IPA mix? Should SWID add more IPA or water to effect seperation?
Ok, 3 quick questions.
Drug Chemists are Ta to a good Sm.
(Moderator)
06-20-04 01:56
No 514328
(Rated as: good read)
The article by H Stage, mentioned in Post 503663 (lugh: "Hypo's design wasn't intended to produce ...", Chemicals & Equipment); Chem Ztg 97 67 (1973)
Chemistry is our Covalent Bond
(Hive Bee)
06-20-04 04:49
No 514355
Org, why don't the ketene lamps perform adequately?
There are nichrome wires with insulating coatings.
Ceramic, glass.
With superfine wires, your going to have problems maintaining heat without insulation.
If the wires aren't arranged thoughtfully, I'd also invisage failure.
I found tables of various nichrome wire gauges and types, relating amperage across them to gain specific temperatures.
I'm sort of stuck choosing the gauge and type of nichrome (fine insulated or thicker uninsulated etc), and the electrical components required to adjust the temperature of the chosen wire.