Author Topic: propionic anhydride (Read 1361 times)

poisoninthestain · « **Reply #20 on:** February 07, 2010, 05:02:14 PM »

I would recommend not decomposing NaHSO4 over a propane flame with glass unless the glass is considerably thick + good heat control. I have only used reagent grade bisulfate for this which didn't really fume so much but then again took longer than 10-15 minutes to harder up, after which point the glass started to crack so it was stopped prematurely.

After the glass was removed I noticed a green solid residue on the outside of the glass where the cracking had occured like Vesp had mentioned. The still molten contents of the glass jar appeared oily and within 5-10 minutes(it was very cold outside) the whole molten liquid was rock hard...so hard that when I tried to scrape it out the bottom of the glass jar fell off(made things a helluva lot easier) which appeared as sparkling off-white crystals. I'll take a MP as I feel not all is the pyrosulfate. Also, I believe in order for SO3 to get kicked off in reasonable amounts you'd need a wee bit H2SO4 otherwise the pyrosulfate won't crack into SO3 and sodium sulfate.

hypnos · « **Reply #21 on:** February 08, 2010, 01:07:54 AM »

apparently you can get sodium pyrosulphite/ate from home brewing suppliers OTC no problems,, which would save a bit of time and energy in this process-i havent bought any myself yet,,but when i was UTSE to learn a bit more about it,,i got several home brewing suppliers offering it for sale,,and at less than $30au for a kg,,sounds ok..unless i am mistaken-which is always a possibilty

poisoninthestain · « **Reply #22 on:** February 13, 2010, 09:21:14 PM »

...used a steel/aluminum measuring cup this time over a propane flame...no estimate on temp...NaHSO4 first turned to white/clear liquid in under a minute with slight-to moderate evolution of not so dense fumes(presumably just H2O vapor), then it stayed in that molten state for another ~5-6 minutes with some more fumes but nothing copious...took it off for 4 minutes and the whole mess was solid HARD white crystals(bear in mind this was performed outside and it's freezing)...heat was then reapplied which caused the white crystals from prior to turn yellow emitting a lot of fumes(kinda dense), then finally the yellow molten liquid turned green while fuming...said fuck it...took it off the heat and within a minute in the outside cold it was a solid lime green rock...i'm going to regulate temps next time obviously but shit!...yellow green solid? Confused. Perhaps a MP test is in store.

Vesp · « **Reply #23 on:** February 13, 2010, 09:50:19 PM »

The green/yellowish color is possible from it reacting with the metal container and having this be some sort of sulfate of iron, nickel, or copper.
Should take its mass before and after, making sure it is anhydrous NaHSO4 before massing it the first time. That would help tell you how much NaHSO4 is left, and how much turned into the anhydride salt or whatever.

poisoninthestain · « **Reply #24 on:** February 13, 2010, 10:15:36 PM »

Good point. That's what I thought originally but was just hoping for someone else to save me the time of running a few MP tests...but I just finished taking a MP of the yellow and the green which turned out to be spot on for nickel sulfate and nickel (II) oxide respectively. Next time I'll just have to use pyrex, period.

Vesp · « **Reply #25 on:** February 13, 2010, 10:20:48 PM »

I've had great luck with using a porcealin dish - it didn't break, or seem to react. I also am sure it can get much hotter then pyrex with out having any problems.

Sedit · « **Reply #26 on:** February 15, 2010, 05:18:34 AM »

I got the same results poison and the green is more then likely due to Nickle leaching out the the stainless steal. I achieve this same leaching with almost all acid work when dealing with SS. Nickle salts are toxic to various degrees so take care and just toss that shit out and use a ceramic bowl next time.

student · « **Reply #27 on:** June 13, 2010, 04:10:46 PM »

Has this worked out for the others who have tried it?

Quote from: hypnos on February 08, 2010, 01:07:54 AM

apparently you can get sodium pyrosulphite/ate from home brewing suppliers OTC no problems,, which would save a bit of time and energy in this process-i havent bought any myself yet,,but when i was UTSE to learn a bit more about it,,i got several home brewing suppliers offering it for sale,,and at less than $30au for a kg,,sounds ok..unless i am mistaken-which is always a possibilty

hmmm can't seem to find pyrosulphate, is sulphite interchangeable?

Vesp · « **Reply #28 on:** June 13, 2010, 08:47:39 PM »

I didn't catch that, I doubt you can find pyrosulphate at any place besides a chem store -- I can't imagine what use it would have for everyday people.

I think the pyrosulfate has to be made by the decomposition/dehydration of sodium bisulfate, which is OTC. Best done in a porcelain crucible/evaporating dish IMO.

Quote

Has this worked out for the others who have tried it?

I have never done it. :/ I have made Na2S2O7 before though - I assume if the carboxylate salt were anhydrous, it would easily react to produce an anhydride.

2bfrank · « **Reply #29 on:** June 14, 2010, 05:02:56 AM »

Ive done it a number of times, I eventualy used a shallow fyrpan that has been enamaled. I learnt to only do small amounts, it soon turns into liquid and eventualy turns rock hard. Hes got an old industrial type heating mantle that generates good heat, and it takes a good 6 or so hours. I have also ground this up and used it for the Propanoic anhydride prep without problem. The color if anything has been a slight shade of grey, but when finished it is pretty well white. Very hard to scrape of the pan, as i have to use a chissel. But its been pretty easy allround.

poisoninthestain · « **Reply #30 on:** June 14, 2010, 01:15:27 PM »

6 hours for decomp? I think I heard that somewhere before but I was thinking with adequate heat it should only take 15-20 minutes with a propane flame. Now that I think about it I think it was 2CFrank who said with a mantle the time was very long. I've only attempted this once with and the molten bisulfate leeched some intense nickel among other things out of the container i was using. Plan to experiment with is again sometime soon under the same conditions using a ceramic or porcelain dish.

Goldmember · « **Reply #31 on:** June 15, 2010, 07:23:10 AM »

The green coloration will come if it is heated to high to fast regardless of what vessel is used. A decomposition product I suppose.
This has been noticed in pyrex as well as enamelled vessels.

Why is everyone using propane torches? A stove top hot plate will do the job.

nk40ouvm · « **Reply #32 on:** June 15, 2010, 04:21:21 PM »

Hi jon & ziggy,

Nice to hear you guys got the pyrosulfate method working. Was there an acid fraction in the distillate along with the anhydride? How was the anhydride characterized?

DaMoose · « **Reply #33 on:** June 15, 2010, 06:29:38 PM »

damoose JUST did this over the weekend !

we made the sodium pyrosulfate by dehydrating the sodium bisulfate in a glass pyrex:
we used a stainless grill and layed it over the op of an electric stove element, then placed the pyrext directly atop it..

first the sodium bisulfate melted: we stirred to assist evel melting

Then the water was seen bubblin out, after the bubbles ceased it started to smoke a little: then we removed it from the heat.

It was allowed to cool slowly: it popped out as a whole chunck without too much trouble.

It was used shortly after to make propionic anhydride....

it was first pounded into small chuncks, then coffe ground into a fine powder, in small batches..
In total 3\4 a pound was powdered..

This was evenly mixed with Calcium Propinate( aprox 3\4 lb) an a RBF
It was stoppered and heated at 130C for 2 hours, then the stopper was replaced with a Shortpath distillation tube ( 10 inches of braided tubing hung over the side of the stainless steel pot that held the oil bath ) tube ran into a collection mason jar.

Heat increased to 175C:
this was felt out because the thermometer was in the oil, not the neck of the tube !..

150ml was distilled out quick and easy..

I am told by a jedi knight
that the solid Klunker that remains in the flask can be re-ground and re-distilled for more acid..
I am assuming this is if it is kept water free...

we also made some sodium acetate to be used as a catalyst in a loperamide esterfication
but thats off topic,,, so no discuss in here mmmK !

2bfrank · « **Reply #34 on:** June 15, 2010, 08:14:59 PM »

Quote from: poisoninthestain on June 14, 2010, 01:15:27 PM

6 hours for decomp? I think I heard that somewhere before but I was thinking with adequate heat it should only take 15-20 minutes with a propane flame. Now that I think about it I think it was 2CFrank who said with a mantle the time was very long. I've only attempted this once with and the molten bisulfate leeched some intense nickel among other things out of the container i was using. Plan to experiment with is again sometime soon under the same conditions using a ceramic or porcelain dish.

That was 2bfrank, (good guy, very smart, good looking and a genius in fact.

) a close friend of mine. anyway, I suppose if using a higher heat source will quicken it up, but I just place it on the mantle, and come back to it later that day and its done. easy peazy. each to their own of course.

2bfrank · « **Reply #35 on:** June 15, 2010, 08:42:17 PM »

Quote from: nk40ouvm on June 15, 2010, 04:21:21 PM

Hi jon & ziggy,

Nice to hear you guys got the pyrosulfate method working. Was there an acid fraction in the distillate along with the anhydride? How was the anhydride characterized?

I just posted from memory and deleted, If one cannot be exact then what is the point of posting. I will redo, and record what occured in better detail.

DaMoose · « **Reply #36 on:** June 15, 2010, 11:42:34 PM »

There is room to use the force

2bfrank · « **Reply #37 on:** June 16, 2010, 01:01:23 AM »

DaMoose · « **Reply #38 on:** June 16, 2010, 02:36:59 AM »

Re: 'the force' & 'huh'

" Was there an acid fraction in the distillate along with the anhydride? How was the anhydride characterized "

this it was characterized: it was employed in an esterification that had positive results.

2bfrank · « **Reply #39 on:** June 16, 2010, 07:14:56 AM »

Yes it was used in an esterification reaction and it was succesful, My memoiry is sketchy,and I plan to do it again soon and will give better detail.

Author Topic: propionic anhydride (Read 1361 times)

poisoninthestain

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hypnos

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poisoninthestain

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Vesp

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poisoninthestain

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Vesp

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Sedit

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student

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Vesp

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2bfrank

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poisoninthestain

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Goldmember

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nk40ouvm

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DaMoose

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2bfrank

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2bfrank

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DaMoose

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2bfrank

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DaMoose

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2bfrank

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