Sciencemadness Discussion Board

Nitropropene Problem

tom_servo - 14-4-2012 at 18:44

While following the write up for 3,4-Methylenedioxyphenyl-2-Nitropropene From Piperonal, Nitroethane & NaOH a problem has came up. This has been successfully accomplished before, but this time regular filtration was used prior to recrystallization in IPA. Now in a sep funnel there is top layer clear yellow oily layer which is flamable and smells like IPA, then a yellow layer holding the product with a slimy consistancy. Not sure if it is excess liquid from the previous step since it was not vacuum filtered or if the IPA was not anhydrous enough. A little back ground on the IPA, was the polar brand, similar to ISO-Heet which btw the iso-heet brand now has a yellow tint to it, anyone else notice that?
The IPA was added into a container with Damp Rid and shaken and allowed to settle multiple times over a 3 hours period in attempt to make as near anhydrous as possible.

Can anyone please offer a solution as to how to pull the MDP2NP product from this solution? Initially the idea of distillation seemed obvious, however there is a worry about decomposition.
Then the idea of heating the IPA which would allow the MDP2NP to become soluble in the IPA but would that be enough to pull it out of the Meoh/HCL/NaOH or h20 layer that it is currently in?

DDTea - 14-4-2012 at 21:36

It sounds like you're drying your solvents in a very difficult way. It shouldn't take 3 hours. See this video. Skip to ~14:35 or so. http://ocw.mit.edu/resources/res-5-0001-digital-lab-techniqu...

I'm confused with what you are trying to do: are you trying to extract your product into isopropyl alcohol from an aqueous mixture? Isopropyl alcohol, water, and MeOH are all completely miscible with one another--this will never work. You want to use something immiscible such as ethyl acetate, toluene, or dichloromethane. But if you're trying to extract from an aqueous phase anyway, why would you even bother drying your extraction solvent?

How can you have an HCl/NaOH layer? A mixture cannot be both acidic and basic. What is the pH that you are aiming for with this extraction?

tom_servo - 14-4-2012 at 21:57

Ok, the isopropyl alcohol was dried prior to the reaction.
What needs to be done now is to obtain the 3,4-Methylenedioxylphenyl-2-Nitropropene.
This is the procedure that was followed.
Quote:

15g of piperonal was dissolved in 40ml of methanol under stirring in a 250ml Erlenmeyer flask. When all of the piperonal had dissolved, 7.1g nitroethane was added to the solution. The flask was put in a ice/salt-bath with magnetic stirring, and when the temperature of the solution had dropped to 0°C, an ice-cold solution of 4g of NaOH in 20ml H2O was added at such a rate that the temperature never rose above 10°C. A white precipitate formed at the bottom of the flask during this addition, which was broken up with a glass rod. The stirring was continued for another hour, while the temperature of the solution was never allowed to rise above 5°C, and at the end of this time, 100 ml of ice-cold H2O was added to the solution, which caused even more precipitation of white solid. The whole slurry was poured into 100 ml of ice-cold 2M HCl solution in a 500ml Erlenmeyer flask, which was gently swirled, and there was a slight bubbling and fizzing, with the color of the solution shifting from white to blue to green to yellow in under a minute. Quite spectacular! When the fizzing had subsided, the solution was once again placed in in an ice-bath with magnetic stirring. When the temperature had dropped to about 5°C, the solution was clear with yellow granules of crude product at the bottom. The granules were filtered with suction, and recrystallized from IPA.

The last steps are where things went awry. The granules were filtered, not with suction. When attempting to recrystalize with the warm IPA product initially was mixed in and as cooled it began to form properly but there was more of a sludge of yellow instead of yeallow crystals with a little IPA then it was put into a sep funnel to set over night and see if there were multiple layers, now there is a top layer that is yellow tinted and looks almost like an oil and is flamable and smells like IPA. The bottom layer is the sludge-like product, which is assumed to be mixed with something else.
At this point it shouldn't be a liquid.

DDTea - 15-4-2012 at 07:20

Thank you for clarifying. It sounds as if your desired product oiled out of solution instead of recrystallized. Here's some background on that from: http://www.chem.wisc.edu/areas/organic/orglab/tech/oilout.ht...

Quote:

Sometimes, during cooling for crystallization, the product separates not as crystals but as a liquid, an "oil". This shows up first as a cloudiness or opalescence, and then as visible droplets. An oil is undesirable because it is often an excellent solvent for impurities. When, or if, the oil finally freezes, the impurities that have dissolved in the oil will remain in the crystals. If the first traces of oil can be caused to solidify by the addition of seed crystals, by vigorous stirring or swirling of the mixture, or by scratching the walls of the flask with a stirring rod, the remainder of the product will usually separate as crystals if the rate of cooling is not too great. If oiling out cannot be prevented-that is, if most of the product separates as an oil before it can be caused to solidify-you can hope that recrystallization of the solidified oil will give a better result, you can try a different solvent, or, probably best, you can purify the product by another method before attempting to recrystallize it.

tom_servo - 15-4-2012 at 09:54

so first shake the shit out of it? lol

Organikum - 16-4-2012 at 04:13

Put it in the freezer and decant the IPA etc. Then wash the sludge with lukewarm tapwater, yep shake the hell out of it. Decant water. Hit the rest with icecold brine and crystals will result. Recrystallize from a real suitable organic solvent, benzene, toluene, ethylacetate, hot/cold.

Never understood the recrystallisation from IPA with P2NPs thats pretty shitty for the purpose, Great for ephedrine and meth though.

Nevermind
/ORG

Amy Winehouse - 16-4-2012 at 13:38

Your IPA had too much water but never fear, just pour the oil into a pyrex dish and pipette methanol droplets into the thin oil layer and you will see little crystals form, filter these out and rextalize. I'm not really sure why this works so well but it does, maybe the methanol absorbs the water along with all the other trash

tom_servo - 17-4-2012 at 12:47

seperated ran the amalgam having a hell of a time extracting oil from this mess.
Damn shamed there is no DCM to use

Amy Winehouse - 18-4-2012 at 00:55

No ether or toluene?

tom_servo - 18-4-2012 at 09:21

sure dont. could probly head up to menards for some toulene though

tom_servo - 18-4-2012 at 09:25

ended up putting everything but the sludge from the amalgam back into a flask and started separating.
first a clear liquid that smelled like a mixture of methanol and acetic acid?? 60-70c
then a clear layer that smelled like IPA ~80 - 85c
then a sweet but watered down smelling(if that makes sense) layer clear also ~85 - 101c
all that is left is a brown sludge that smells sweet, maybe caramelized salt? not sure what that is.
the sweet clear liquid was put in the freezer over night and turn to solid ice.
Trying to figure out the next move

turd - 18-4-2012 at 12:28

Sorry, the whole thing sounds like a case of GIGO.

Your best bet is to do an acid/base extraction and vacuum distill the freebase.

It's hard to tell from your not-very-coherent writing what you actually did and since nobody can read minds it will be impossible to help you.

tom_servo - 18-4-2012 at 12:45

Sorry for my "not-very-coherent writing" i guess.
here is what the entire procedure was since you asked.
initially from piperonal
Quote:

15g of piperonal was dissolved in 40ml of methanol under stirring in a 250ml Erlenmeyer flask. When all of the piperonal had dissolved, 7.1g nitroethane was added to the solution. The flask was put in a ice/salt-bath with magnetic stirring, and when the temperature of the solution had dropped to 0°C, an ice-cold solution of 4g of NaOH in 20ml H2O was added at such a rate that the temperature never rose above 10°C. A white precipitate formed at the bottom of the flask during this addition, which was broken up with a glass rod. The stirring was continued for another hour, while the temperature of the solution was never allowed to rise above 5°C, and at the end of this time, 100 ml of ice-cold H2O was added to the solution, which caused even more precipitation of white solid. The whole slurry was poured into 100 ml of ice-cold 2M HCl solution in a 500ml Erlenmeyer flask, which was gently swirled, and there was a slight bubbling and fizzing, with the color of the solution shifting from white to blue to green to yellow in under a minute. Quite spectacular! When the fizzing had subsided, the solution was once again placed in in an ice-bath with magnetic stirring. When the temperature had dropped to about 5°C, the solution was clear with yellow granules of crude product at the bottom.


So far smooth sailing,
No vacuum available since both pumps I've scavenged dont seem to work. anyways, gravity filtered over night and part of the day. still a little wet and proceeded to attempt to recrystalize using hot IPA, everything turned to a sludge. ended up letting as much evaporate as possible then continued on to do an aluminum amalgam as stated in the attached file.
that went without issue. Then while trying to separate out (without DCM) ended up screwing the whole deal up, tried separating the then 3 layers (amalgam nasty looking junk on the bottom, yellow layer with medium thickness, small dark brown tinted layer on top) wasn't sure if the yellow layer had it but figured it would, so i tried using brine to separate layers further and it worked, light milky yellow layer and darker clear yellow. added small amount of IPA and sulfuric acid some cloudy crystals came out in both, filtered them, tried recrystalizing them and turned to sludge. when dried more like granules than crystals. both tasted like salt.
threw all that was lidui-esk back together in a 1L flask and started distilling and got the results posted previously.

[Edited on 18-4-2012 by tom_servo]

Attachment: Amphetamine_sulphate_synthesis.pdf (796kB)
This file has been downloaded 19133 times

tom_servo - 18-4-2012 at 17:16

DCM is distilling currently

DrNoiZeZ - 19-4-2012 at 04:06

I am sorry but it is a little bit difficult to understand what you really did, everyone here wants to help, but...

First I think you should get a vacuum (good or bad but a vacuum) and DCM will help a lot.

Then, as I can see, you tried to reduce the NPP with AL/Hg after triing recristalize it from IPA (not a good choice) without success and I really cant understand what is that sludge you say. If the recristalization did not work you should get an oil (red or orange) and not a sludge (the sludge was red or orange?). So, I it is possible that your NPP was very contaminated.

Then you made the reduction and got 3 layers. The layer that is important is the IPA at the top (if the pH of the second layer was 12 or more, did you checked it?). You should separated that layer and then extract the two others with toluene, ether, dcm or even IPA (not a good choice) two or more times (did you do that?).
After that, all that matters are the organic fases that you must perform an a/b extraction as Turd said ( if you don't know or understand why you should learn it because it is VERY important for your purposes). Only then you should try to crystalize it and the product, as many amine salts, has to have a bitter taste and not salty. There is the possibility that you have only Al2(SO4)3 ( the melting point can be helpfull).
It can be frustrating but only go to next step on a synthesis after having certain that what you get is the product you want and it is pure, otherwise, very often, a storm will come and you will be lost amidst it (poetic... very poetic)
Good synthesis.

[Edited on 19-4-2012 by DrNoiZeZ]

[Edited on 19-4-2012 by DrNoiZeZ]

[Edited on 19-4-2012 by DrNoiZeZ]

[Edited on 19-4-2012 by DrNoiZeZ]

tom_servo - 20-4-2012 at 06:00

Picking up a PH tester this weekend.
Lack of knowledge got everything messed up.
Pooled it all back together and will be distilling everything again.
At no point was any oil recognizable btw

bosshead - 23-4-2012 at 03:10

First Hi to all,
this my first reply, o I ' m goin'crazy because I followed 3or 4 time the Amph sulph synth like Attachment: Amphetamine_sulphate_synthesis.pdf (796kB) and one time like
http://www.scribd.com/doc/41010414/Amphetamine-Synthesis-Ice...
and the steps are (I think) perfect but when I arrive at last step (dropping IPA+H2SO4 in the reddish extract)my arms fall off because instead of a beaker full of crystals, a low white pink layer is formed, with saline taste and smell vaguely similar to the original product I do wrong?
perhaps my NP is not good, but I have carefully followed the directions of rhodium archive you can help me?
many thanks to all

DrNoiZeZ - 23-4-2012 at 05:30

To Tom_servo: A Ph tester is a good beginning indeed. I think you should try all again. Forget the past, sometimes it is better. I don´t know if the method using NaOH is a good choice to make the NPP if your aldheide is benzaldehyde, I never did it but sometimes the NaOH method does not work or the yields are too low.
So it would be better if you try again making the NPP (with care) and your goal will be to make the NPP as a yellow/ orange cristaline powder (there are some NPP that just don't cristalize at all) and after that recristalize it from methanol. Only after that you can run a reduction with good chance to do a successfull synthesis. The method followed by Bosshead is probably better but requires more equipament and buthylamine. Try to find information about the NPP you should obtain (its collour, mp).
It is important to know that the amine (some more others not so much) will only cristalize on a anhydrous media, so it is important to dry the solvent well and use the acid (HCl, H2SO4, you name it) with little or no water and drop it slow if you put too much water the salt may not cristalize at all.

Good synthesis

PS. I do not endorse to taste the products of a synthesis to avaliate it. You dont know what you got and it can be dangerous, as well to make substances that are illicit and potencially dangerous. Try to keep your mind open and use this place to learn chemistry

[Edited on 23-4-2012 by DrNoiZeZ]

Nicodem - 23-4-2012 at 12:12

Since this thread is headed to techniques discussion and poses no scientific value, I think it is time to close it before it ends up being just another worthless drug cook thread.