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OTC replacement for performic ? (Page 1)
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Author Topic: OTC replacement for performic ?
ChemHack
Member posted 12-11-1999 11:27 PM
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Peracid oxidation of Isosafrole
Well, performic works but peracetic doesn't. Why?
Hmmmm. Formic acid is about 10 times stronger than acetic acid. Maybe thats why? I dunno.
Well, if that is the only reason then perhaps one could chloronate their acetic acid. ChloroAcetic acid is 10 times stronger than formic acid even. So could one prepare a nice peracid with ChloroAcetic and H2O2 ?
I don't have a good chloroacetic acid synth. Supposedly just running Cl2 through GAA in the sunlight will do the trick. The Merck suggests using a small amount of sulfur or iodine as a catalyst...maybe this lets you avoid the sunlight?
Thats pretty OTC if you are careful enough to properly contain the Chlorine gas.
Another thing, if you just want a stronger acid then you don't really need to worry if you end up with Mono-, Di-, or even Tri- clorinated acid because the more chlorine that adds to the acetic, the stronger of an acid it becomes.
Thoughts?
CHEM GUY
Member posted 12-11-1999 11:32 PM
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Acetic acid with H2O2 will work for epoxidation of an alkene, but as you state it might need some help in turning the epoxy into a ketone.
But this is easily remedied by adding a lewis acid and heat. Lithium Iodide is discussed in a patent on Rho's page, but I think any lewis acid will work, given sufficent time and heat.
ChemHack
Member posted 12-11-1999 11:49 PM
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From Merck:
Peracetic Acid. Liquid, acrid odor. Explodes violently on heating to 110C. Freely soluable in water, alcohol, ether, H2SO4. Stable in dilute aqueous solution. Strong oxidizing agent.
I don't know how much I want to heat this stuff...violent explosions are not my thing
CHEM GUY
Member posted 12-11-1999 11:54 PM
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Performic acid does the same thing, so does H2O2. What the Merck is talking about is PURE peracetic acid, which you most definitly won't have if you know what's good for you.
ChemHack
Member posted 12-12-1999 12:43 AM
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Yeah, I just read the patent. The heat used is not to go above 90C and preferably between 60 and 75C so explosion moves down on the list of concerns.
But man, this patent is nothing near an OTC replacement for performic. Check out the catalyst they use! The catalyst is made by reacting Aliquat336 with tungstic acid, phosphoric acid, and hydrogen peroxide.
OK, well you can get weak phosporic acid OTC and obviously you can get H2O2 OTC. You might even get lucky and figure out how to extract some OTC cleaning product to get a quaternary ammonium salt that is close enought to Aliquat336 to work in this rxn. But where do you get tungstic acid?
Then there is the Lithium Iodide. I suppose you might be able to get this from batteries? The freaks in the meth forum probably know.
ChemHack
Member posted 12-12-1999 12:55 AM
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Patent law requires that a new procedure to be patented my be a novel and non-obvious deviation from the state-of-the-art*.
*State-Of-The-Art in patent law literally means the way things are currently and normally done. We tend to misuse this term, especially with consumer electronics, to mean the newest best available.
This patent lists as its very first advantage over the state of the art the fact that internal olefins (isosafrole) are not commercially available. The fact they they have to be "prepared" is presented as a drawback to the state of the art.
Now, the funny thing is that the procedure in this patent still requires an isomerization. The difference is that the isomerization occurs after the epoxide is formed. Oh yeah, and instead of using something cheap and easy like KOH or NaOH, this isomerization requires Lithium Iodide.
Cherrie Baby
Member posted 12-12-1999 09:22 AM
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I think that peracetic will work but...
mixing H2O2 with formic gives performic quichly. mixing H2O2 with acetic does not. The peracetic you use should be prepared before-hand. Perbenzoic was often used for this reaction [in ancient times when chemists did epoxidations with this method].
Question (to the hive).
In theory it it possible to form the epoxide and diol by reacting isosafrole with persulphate. Has anyone done this?
This isn't such a silly question - persulphate is easy to get because it is used for etching printed circuit boards in electronics - and the residue isn't nearly as nasty as formic/performic nor is it volatile.
K.C. Nicolaou
Member posted 12-12-1999 04:48 PM
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Cherrie Baby - As far as I know, persulfate is not a good epoxidizing agent by itself. However, under slightly basic conditions(pH 7.5-8.0), persulfate reacts with acetone to form dimethyldioxirane(three membered cyclic peroxide with both oxygens bonded to what used to be the carbonyl carbon of acetone), which is a very good epoxidizing reagent. I am looking into that as an epoxidation system for asarone and there is a thread under my name in the chemistry discourse about it. Persulfate is VERY easy to get. You can either make persulfuric acid from sulfuric acid and H2O2, or you can buy Oxone, which is a Dupont trade name for a mixture of 2KHSO5/KHSO4/K2SO4, at any home depot or pool supply place as a non-chlorine pool shock. The main difficulty with most dimethyldioxirane methods is that you can only use fairly dilute solutions(~.15M) of the reagent, so I am looking into some alternative procedures using a two-phase CHCl3/water system that generates the dimethyldioxirane in-situ. That procedure requires a PTC though, and you're still talking about having a total volume of ~2L to oxidize 100g asarone.
ChemHack
Member posted 12-12-1999 05:13 PM
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So will chloroacetic form a peracid?
If so, is it a good epoxidizing agent ?
ChemHack
Member posted 12-12-1999 05:58 PM
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Cherrie Baby: You mention that peracetic, in contrast to performic, does not form quickly by the simple addition of hydrogen peroxide to the acid.
Can you tell us how it is formed? Is it just a matter of pre-mixing them and waiting for some period of time? Will it not degrade on stading? Is some catalytic ummph needed to do it this way? H2SO4?
The Merck says that a 50% solution may be obtained from acetic anhydride, H2O2, and sulfuric acid.
I may be off the deep end here but could acetic anhydride be formed from acetic acid the same way that ethyl ether is formed from ethanol?
To wit:
CH3CH2-OH + H2SO4 --> CH3CH2-HSO4 + H2O
CH3CH2-OH + CH3CH2-HSO4 --> CH3CH2-O-CH3CH2
Well, thats complicated by the fact that at higher temps side reactions will become more pervasivie and increase the amount of acetalyhyde and ethylene that come out, not to mention sulfur dioxide gas, yuck!
So what I'm getting at is the question of whether sulfuric acid can do the same thing for acetic acid that it does for ethanol and turn CH3CHO-OH into CH3CHO-O-CH3CHO? If so then what temperature would give the optimum yield of the anhydride? The Ethyl Ether rxn yields the most at temps that are HIGHER than the 110 "violent explosion" temp of peracetic so I guess you'd want to form the anhydride first and then form the peracid. Diluting it wouldnt really be an option to lower the explosion point because, at least in the ether formation process, you need to use very concentrated H2SO4.
OK, now I know Im way off on a tangent so I will go back to my original question:
How does one go about making peracetic acid?
K.C. Nicolaou
Member posted 12-12-1999 08:31 PM
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Chemhack - My understanding of the way that peracetic/performic acids are formed in-situ from the regular acids is that the peracids are formed by exchange of OH with OOH in the following process(please excuse my crappy drawings and note that all of the crap to the right of C is bonded to that carbon)
R-C(=O)-OH + H(+) -> [R-C(=O(+)H)-OH <-> R-C+(OH)2]
R-C+(OH)2 + HOOH --(-H+)-> R-C(OOH)(OH)2
R-C(OOH)(OH)2 --(-H2O)-> R-C(=O)-OOH
As you can see by looking at the role of H+ in this process, the reaction is acid catalyzed. Since formic acid is much stronger of an acid than acetic is, it is more able to perform the catalytic function itself, while acetic acid is less able to do so. So, one would assume that adding a catalytic amount of H2SO4(or another strong lewis acid) would allow you to form peracetic acid from acetic acid and H2O2. It would also probably help to prepare the peracetic acid well ahead of time to give the peracid lots of time to form. I would guess that H2O2, excess acetic acid, and a couple of drops of H2SO4, stirred overnight at room temp would do the trick.
As to your other questions:
Perchloroacetic acid - I don't think you realize what's involved in making that from acetic acid. Remember, a mole of any gas at RT and 1 atm is ~22L, so to make 100g of the perchloro acid, you'd have to generate >22L of Cl2. Not very easy or safe. I have no idea if there is another way to make it than is less nasty or if its peracid is any good as an epoxidizing reagent, but I'm positive that it would be easier to just make formic instead.
Acetic anhydride - No, H2SO4 will not dehydrate it. SO3 gas will, but then you're talking about using large amounts of a very nasty gas again.
ChemHack
Member posted 12-13-1999 12:58 AM
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More speculation on my part but it doesnt seem Shulgin uses all the formic acid in his #109 synth to form the peracid.
There is only 0.2 mol of substrate but >2.5mol of acid. There isnt even enough H2O2 to make peracid out of all that acid. So why is it there?
1. solvent
2. H+ donor
3. Because it smells nice
Ok, well it isn't #3. My point is that it doesn't really seem like one would need to chlorinate ALL of the acetic acid, just enough of it for the rxn.
ChemHack
Member posted 12-14-1999 08:42 AM
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So I evaporated a little iodine tinture in the oven, scraped it into some GAA, and bubbled it with Chlorine gas. I used a blacklight on it just in case for that sunlight thingy.
Damn, Chlorine gas sucks.
I dont think any chloroacetic was created, just Cl2 suspended in the acid...
CHEM GUY
Member posted 12-14-1999 12:13 PM
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Fromic acid is too easy to obtain for you to be going thru all this shit...
If all else fails make it...
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HOW TO MAKE SODIUM FORMATE AND CHLOROFORM FROM ETHANOL
4 C2H5OH + 8 Ca(OCl)2 --> 2 CHCl3 + 3 Ca(O[CO]H)2 + 5 CaCl2 + 8 H2O
2 C2H5OH + 4 Na(OCl) --> CHCl3 + 3 Na(O[CO]H) + NaCl + 4 H2O
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Then evaporate the solvent and gas with HCl and poof! formic acid with water and NaCl in it which won't do a dam thing to the synthesis you are trying to run.
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Everything in this post is for informational purposes only, and is not intended to facilitate illegal activity. I've done nothing illegal and nor should you.
Rhodium
Administrator posted 12-14-1999 12:59 PM
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Chemhack: The excess Formic acid is used partly as a solvent and partly to drive the equilibrium towards the formation of peracetic acid.
Chemguy: Too much water will prevent the isosafrole from dissolving in the formic acid solution.
egotrip
Junior Member posted 12-14-1999 02:04 PM
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An astounding revelation supplied by The Complete Book Of Ecstacy reveals THE
friggin replacement for all this mess.
Chlorine gas bubbled thru isosafrole in DCM
at >Oc gives about a 70 percent yield of the dicloro derivative.
This, refluxed w/ 15% KOH gives
MDP2P in 65% yield.
Blammo.
Rhodium
Administrator posted 12-14-1999 02:56 PM
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Ok that this method doesn't use formic acid, but it employs a highly toxic gas instead and gives less yield than the performic. Even with the figures you are quoting, the yield will be at most (0.65*0.7)*100 = 45%
ChemHack
Member posted 12-14-1999 04:12 PM
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Recently having the pleasure of breathing both Chlorine gas and hot vaporized formic acid, my vote for nastiest goes to....
Chlorine!
But just barely.
ChemGuy: Yeah, I know about that method of home formic production but I just pour in a bit of dilute H2SO4 and distill off the azeotrope. Gassing prolly takes almost as long as distilling anyhow.
Rhodium: Is there an certain concentration required for this rxn to be a success? If there was too much water in the acid why not just add more acetone?
Rhodium
Administrator posted 12-14-1999 05:23 PM
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I don't know how dilute you can go, or if very much acetone will interfere with the reaction, but the more dilute the solution, the more labor will be required in the workup. I think it is impractical enough as it is.
ChemHack
Member posted 12-15-1999 06:19 AM
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Oh, yeah, the reason Im looking for another way to do it is that I had a bad experience making formic that way.
It all started when I got tired of evaporating all the water out of the sodium formate. I thought to myself, "Self, You are just gonna add more water in the form of dilute H2SO4 anyhow, why worry about getting it all dry?"
So anyway, I put the acid in and guess what, there was still a lot of chloroform or NaOCl dissolved in the water! Jesus shit! Don't wanna breathe that!
purplxd
Member posted 12-15-1999 08:05 AM
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dear K.C.
have read many of your posts with interest.
several deal with peracidic procedure on asarone. it is said that the methylenedioxy
bridge increases the reactivity of the substrate. so does not a methoxy in any position on the benzene ring also increase the reactivity? thus anethole is a good replacement for isosafrole. yes?
then should not asarone be three times more
reactive? is there some other problem with asarone vis a vis the performic method?
thanx
rev drone
Member posted 12-15-1999 10:18 AM
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ChemHack,
Why do you believe peracetic acid doesn't work? I've read a lot of material stating the contrary. I've also seen performic do some evil things when unstable.
rev drone
Member posted 12-15-1999 10:20 AM
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sodium sulfite or bisulfite are nice ways to quench unreacted oxidizing material, in case you hadn't known.
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-the good reverend drone
K.C. Nicolaou
Member posted 12-15-1999 10:16 PM
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purplxd - Oxygens, whether as in a methylenedioxy group or methoxy groups, strongly activate the double bond in asarone/isosafrole towards electrophillic reagents when they are in the ortho or para position. Oxygens in the meta position are weakly deactivating. So yes, asarone is much more reactive than isosafrole, although not exactly 3 times more so. The problem with asarone is that since it is so much more reactive, it(so I have been told, by Osmium and others) undergoes acid-catalyzed polymerization on exposure to formic/performic, resulting in a tarry mess.
Semtex Enigma
Member posted 12-17-1999 07:01 AM
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First off, who said the peracetic doesn't work...?
I could have sworn that Rhodium stated somewhere here on the hive that indeed french chemists from the 1800's used it successfully, or at least they said that it was supposed to work...
Hmmmm, didn't Gyro mention something, hmm maybe I just wasn't paying attention in class that day...
It's enuf to make an explosive puzzle down right frumpy if'n he/she sat and thought about it enuf...
Just too damn bad, would have been a hell of a method for bees looking to get their wings...
Would have even given them newbies practice with that ever so important lab tech, which might'n help them out later on in their travels...
Hmmm, yup, it's just too bad that they went and made Glacial Acetic Acid list I and all, I guess it's better to go with them less "watched" chems...
If'n your not getting the hint, there is nothing wrong(well, ok, if you take the temp above 110C you'll blow up your whole damn ghetto) with the hypothetical peracetic, HYPOTHETICALLY speakin' of course...
ChemHack
Member posted 12-17-1999 11:51 AM
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Dear Explosive Puzzzle,
OK, so I get your hint. Do you generally agree with K.C.'s suggestion on how to create the performic?
quote:
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"I would guess that H2O2, excess acetic acid, and a couple of drops of H2SO4, stirred overnight at room temp would do the trick." - K.C. Nicolaou
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Sure peracetic would be unstable but do you have any idea on how long it takes this stuff to break down?
I might also guess that the polarity of GAA might increase the Acetone requirements for good solvation. Thoughts? Observations?
How about reaction time? Didn't Eleusis translate a french article on peracetic that specified a 48 hour reaction time? Anything you can share in this regard would also be helpful.
Semtex Enigma
Member posted 12-17-1999 06:00 PM
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1) Peracetic ala Rhodium's suggestion, Scaled exactly 5X:
Chemicals
- Peracid:
- 1650ml of Glacial Acetic Acid
- 325ml of 30% H2O2
- 5ml of H2SO4
- Olefin:
- 500ml Acetone
- 325g of Isosafrole
- Solvents:
- 7500ml of Water
- 1500ml of DCM
- 600ml of MeOH
- H2SO4(15%):
- 525g(285ml) of Concentrated H2SO4
- 3215ml of Water
- Wash(s):
- 1250ml of Water
- 1250ml of NaOH 5% solution
- Drying:
-50g of Anhydrous MgSO4
- Distillation:
- 100ml of Cooking oil to prevent scorching
Proceedure
- Mix the peracetic acid chemicals together in an appropreate sized flask(3L+), swirl or stir solution until thouroughly mixed and let stand for 12 hours.
- Combine the olefin chemicals and place into the freezer to chill.
- Bring the peracid solution down to 5C with the help of an ice/salt/water bath. While magnetically stirring this solution sitting in the ice bath, add the now chilled olefin solution to the peracid solution at such a rate that the mixture stays below 40C. After all of the olefin has been added, let the solution stir for 16 hours, letting the ice bath melt away and the solution come to room temperature on it's own.
- After the 16 hours of stirring has elapsed, flood solution, or pour solution into 7500ml cold water and mix thouroughly. After which time one extracts this mixture with 3 X 500ml DCM. The extractions are combined and the solvent removed via distillation to yeild a thick, dark red syrup.
- This syrup is taken up with 600ml MeOH and added to the 3500ml H2SO4 solution and lightly refluxed for two hours. After which the flask is cooled under running water and/or the use of an ice bath, do not proceed until solution has reached room temperature or lower.
- Using a large sepratory funnel or by simply pouring off the acid layer collect the dark bottom layer BEFORE extracting this mixture 3 X 400ml DCM(you did reuse the DCM from the first extraction, didn't you?). Combine the extracts with the dark layer which was first collected and proceed.
- Wash this dark mixture of ketone/solvent with 1250ml of water, then with the 1250ml of the 5% NaOH solution which was made previously. Please note that the seperation with the second wash will be difficult to see, therefor the use of a light is favorable to determine the different layers(similar to the first seperation of a Benzoquinone wacker wash).
- Dry organic phase over/thru 50g of anhydrous MgSO4(made by baking epsom salts at 300C for a couple of hours, let cool, then grinding into a powder) making sure to filter off the MgSO4, and washing the filter cake with a small amount of DCM. The solvent is removed and kept for a later run, the resulting residue is combined with 100ml of vegitable cooking oil and distilled under vac to yeild ketone(>200g).
Of course, that's from memory about a dream SWIM said something about in one of his/her ramblings...
Semtex Enigma
Member posted 12-17-1999 06:09 PM
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Oh yeah, I forgot, some amounts were changed with out a change in yeild. I think SWIM said that the amount of GAA could be reduced to 1500ml and the resulting Oxime can be taken up in 500ml of MeOH and refluxed with 2500ml of H2SO4(15%)(thanks Strikey, baby!!!), instead of the above amounts. Oh, and for BIG extractions and shit, SWIM mentioned something about needing to go to the home brew shop, something about a boy with a car, or a car boy, hmmm, can't really remember, that SWIM always has been a raving lunatic though...
Enjoy...
egotrip
Junior Member posted 12-17-1999 06:30 PM
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Has anyone here heard of generating performic from O2 and formaldehyde?
Is this viable?
Itm seems two guys named Bowen and Tietz(?)
did this in one of the journals...
O2 and formaldehyde are easy to get.
I will try to dig up the ref...
purplxd
Member posted 12-18-1999 09:06 AM
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k.c.
thanks for the clarification
so it's a go for asarone with wacker?
any ideas if nitropropene route ala pugsley better or worse to lead to ketone?
K.C. Nicolaou
Member posted 12-18-1999 01:18 PM
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I'm not down with using the wacker on asarone. You'll get a low yield of a mixture of two compounds with the carbonyl group in the 1 or 2 position and then you'd have to separate them. Not very fun. My feelings about asarone -> TMA-2 chemistry are
R.C.'s method - Good, but lots of steps and not very high yielding. May be better to just reduce the nitro intermediate.
Pugsley's Method - Toxic gases , so no fun there
Asarone -> 2,4,5-trimethoxybenzaldehyde -> nitropropene -> TMA-2 - Nice, but requires nitroethane and LAH/Red-AL/H2 Pd/C.
My proposed dimethyldioxirane method - only two steps, very few suspicious chems, should be very high yielding if done right, but not proven, yet...
psychokitty
Member posted 12-19-1999 09:47 PM
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ChemHack: One of my earliest threads covered this problem. Potassium peroxymonosulfate (oxone; pool bleach) is the way to go. In a JOC article that I don't have on hand, potassium peroxymonosulfate is used to either epoxidize or hydroxylate (depending on the pH) B-methylstyrene, better known as propenylbenzene. The reaction was performed in a biphasic mixture: water containing the oxidation salt was one phase, while the other was the alkene. No solvent was used. In my opinion, to get the reaction to work for ring substituted propenylbenzenes, heat may have to be applied. The method however, is definitely OTC all the way. To find the thread with the reference use the search engine (the username is 'psychokitty' and the keyword is 'peroxymonosulfate').
Hope I've been of some help.
--PK
equarius
Member posted 12-20-1999 01:26 AM
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Semtex: wow! and thank you.
K.C. Nicolaou
Member posted 12-20-1999 11:47 AM
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Psychokitty - Was there acetone present in that rxn? All of the peroxymonosulfate epoxidations I have seen generate dimethyldioxirane in-situ from peroxymonosulfate and acetone, which then acts as the epoxidizing reagent. I have seen references where peroxymonosulfuric acid is used alone as an epoxidizing reagent, but the high acidity under those conditions would be a real problem.
ChemHack
Member posted 12-20-1999 12:26 PM
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OK, dreaming of the Semtex Enigma process at a 1/20th scale.
In the dream, the smooth solution is clear reddish-orange at the 3 hour mark.
Other than the scale down the only difference so far is that the reactants were cooled a bit more before the addition and were not put into the ice until the temp reached 35C. This didnt really take very long at all considering that the acid started at -5C instead of 5C as Semtex specifies. The ice bath quickly stablized the temp which dropped slowly down down down to about 15C. Color seems to change more slowly when it is cold. Considering pulling it out to see if it will go back above room temp on its own...
ChemHack
Member posted 12-20-1999 12:27 PM
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Maybe dream of the Psychokitty version next time...
psychokitty
Member posted 12-20-1999 01:29 PM
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No acetone was used. Just water (quite a bit actually), the oxidizing salt, and the alkene ONLY. The article can be found in JOC 56, p.7022, 1991. It indicates that co-solvents and even PTC catalysts do not affect the reaction advantageously. Just stirring and in some cases, heat, were required. Looks promising to me. I did mention in the original thread, however, that some soot might need to be removed from the water solution before the reaction is commenced. It seems harmless, but makes the solution cloudy. Letting the solution sit for about 12 hours, maybe less, allows the soot to settle. Decantation might work for it's removal. Or filtration.
Questions?
--PK
ChemHack
Member posted 12-20-1999 02:06 PM
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quote:
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Color seems to change more slowly when it is cold. Considering pulling it out [of cold bath] to see if it will go back above room temp on its own...
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Dreamed that it was pulled out of the ice bath and off the stirrer and it came up to room temp.
The temp then climbed to 2C above room temp but got no warmer. Checked with 2 different thermometers, same result. Seems to be holding steady at this temp. Perhaps air cooled by the room? If so the rxn must be proceeding very slowly.
Color changed much more quickly once it was taken out of cold bath. Now it is fully that same clear red color that you get with most other techniques (performic, O2 Wacker, HBr, etc..)
The color is not an indication of success, just a common color that you get when you destroy a little (iso)safrole by whatever technique. Therefore, I cannot say if the epoxidation goes quicker at higher temps but it does appear that one of the side reactions (the one that causes the red) does go faster at higher temps.
It is now 5 hours since the dream began, the bath no longer contains any ice, just cold water. Since solution is smooth (no layers) and temp is not hard to control, the stirrer is not really that important and its use will be discontinued. Back into the cold water for the rxn flask.
Semtex Enigma
Member posted 12-20-1999 03:28 PM
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PK: That method you propose, sounds VERY interesting!!! Please keep us advised if you get a synth written up for that, or just email me if you wish. Good work!!!
Chemhack: Ok it seems as though everything is going well for you, but why on earth would you stop stirring? It might not make a difference, but if it does then you may perhaps look negitivly upon the method, which INDEED works. Please keep us advised as to your progress. And one not even need use a bath(ice or water) if you can keep the temp below 40, as long as that happens you should be fine. Good luck!!!
ChemHack
Member posted 12-20-1999 04:08 PM
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Semtex,
The original reason that I dreamed that the stirrer was removed was that I wanted to make sure that the +2C over ambient temp was not being caused by the slight warmth generated by the stirring plate. It was not.
In my dream, I thought about it a little more and decided that stirring wasn't really needed if there was no separation of layers. The atmosphere, or exposure to it, doesn't really play a part in this reaction, right? It isn't like a O2 wacker where it is important that the liquid contact the atmosphere. Also, there isnt really evolution of gas because no hydrogen is being replace or whatnot...an oxygen is adding to a double bond...so there is no issue of freeing bubbles of gas from the liquid to pull the equation to the right.
My dream guess is that the only purpose for stirring is to ensure even cooling so that localized temps do not go above above the criticle level. At 1/20th scale even the air (and perhaps evaporation of acetone) provides enough cooling to keep even the center of the rxn mixture well below the dangerous levels.
This is not to imply that stirring was not required during the addition of the not isosafrole, it was. Just noting that the evolution of heat is much less now at the seven hour mark, that it was within the first 30-60 mins. Because the total volume is only 1/20 of the amount in your procedure, the thermal enertia of this rxn is also much much less. The only reason I can think of to continue stirring would be to prevent the concentration of potentially explosive expoxides of acetone. I don't know if such expoxides are indeed formed in this procedure but if they are, it would again be more important to prevent a big explosion than a little one.
What is the lowest temp that this thing should be run at?
ChemHack
Member posted 12-20-1999 04:15 PM
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Oh, and if it doesn't work, it can be dreamed again with constant stirring. That is the beauty of 1/20th scale batches...
CHEM GUY
Member posted 12-20-1999 04:25 PM
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Here's a reference to the epoxidation of alkenes with FeCl3 and H2O2.
CHemical Reviews, yr 1989, Vol. 89, No 3, page 447.
J. Org. Chem. yr 1985, 50, 1784
ChemHack
Member posted 12-21-1999 09:17 AM
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I woke up before the dream could procede. The next night I dreamed that the 1/20th experiment was continued but that the solution had been sitting for 24 hours instead of 16. Flooding with water at this point leaves a lot of orangish yellow opaque aqueous layer sitting above a clear red organic layer. So far so good.
ChemHack
Member posted 12-21-1999 01:25 PM
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Dreamed that it sat in the water for a few hours, water turned more pinkish and less orangish. Extracted with DCM. Evap solvent. Mmmmm, smells right, time for the boiling acid.
Semtex Enigma
Member posted 12-21-1999 08:57 PM
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The notes that SWIM has stated that the ice bath is usually allowed to melt away on it's own. I'm not so sure that the temp(as long as it's below 40) is that big a deal...
ChemHack
Member posted 12-22-1999 12:35 AM
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Dreamed 5 hours in a boiling bath.
Aqua layer was amazingly free of color.
Started out darker than it finished.
Strange.
Organic layer much darker as expected.
Yield looks about right.
Blacklight action looks good.
Awoke before the distillation.
Perhaps in later dreams.
Semtex Enigma
Member posted 12-22-1999 07:20 PM
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Hang on, are you saying that you refluxed for 5hrs? If that is the case, from what I have heard of the performic in this step, you may get a whole shitload of tar produced, maybe not, hell what do I know...
At any rate, keep us posted, I'm sure your "dreams" will work out VERY positive, cept for that list I chem, GAA...
BTW, if anyone gets credit for this, I think it should be Rhodium. As he proposed this almost a year ago, and Gyro gave SWIM a kick in the ass to get on it when he/she reported success with it. This is NOT a new method, just seems to be one which got lost in the shuffle somehow. Have fun and please remember that the peracetic is explosive, so please try to treat it with some respect(caution)...
Good luck...
ChemHack
Member posted 12-23-1999 03:32 AM
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refluxed with 15% H2SO4 & methanol for 5 hours.
ChemHack
Member posted 12-26-1999 04:56 AM
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I dreamed that reductive amination ala Osmium's Al/Hg was a success.
Thanks Semtex Enigma!
Merry Xmas
Semtex Enigma
Member posted 12-26-1999 04:37 PM
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Good to see you had yourself a nice White Christmas...
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