Sciencemadness Discussion Board - Need help about Nitrostyrene synthesis

Need help about Nitrostyrene synthesis

gordonL - 29-7-2013 at 00:08

Hello want some help about Nitrostyrene synthesis

I'm trying to synthese Nitrostyrene by this method
100 ml benzaldehyde + 200 Nitromethane + 20 gr. ammonium acetate + 50-60 ml. glacial acetic acid
refluxed on water bath for 5 hours on 70 degrees
the mixture have verry dark color like a dark caramel
after that I put 180 ml warm water
but nothing happens, no yellow crystals - nothing, just two layers

What could be the problem?

Thanks

DrSchnufflez - 29-7-2013 at 00:36

The nitrostyrene is most likely dissolved in the excess nitromethane.
Have you tried evaporating/ distil long off the excess nitromethane?

gordonL - 29-7-2013 at 02:55

Quote: Originally posted by DrSchnufflez

The nitrostyrene is most likely dissolved in the excess nitromethane.
Have you tried evaporating/ distil long off the excess nitromethane?

Nope. I don't

what should be the ratio between benzaldehyde and nitromethane? 1:1? And one more thing. Do I have to use acetec acid?

bfesser - 29-7-2013 at 04:49

Why are you not following the <em>Org. Syn.</em> <a href="http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0413" target="_blank">procedure</a> <img src="../scipics/_ext.png" />‽

gordonL - 29-7-2013 at 09:02

Quote: Originally posted by bfesser

Why are you not following the <em>Org. Syn.</em> <a href="http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0413" target="_blank">procedure</a> <img src="../scipics/_ext.png" />‽

hot synthese is easier for me.

[Edited on 29-7-2013 by gordonL]

solo - 29-7-2013 at 10:27

...did you try a google search,....solo

https://www.google.com.mx/search?q=preparation+of+nitrostyre...

fficial&client=firefox-a&gws_rd=cr

.....here is an interesting one....,

http://www.erowid.org/archive/rhodium/chemistry/nitrostyrene...

[Edited on 29-7-2013 by solo]

gordonL - 30-7-2013 at 10:02

All the same

0.22 mol Nitromethane, 20 mol Benzaldehyde, ammonium acetate 7.8 gr., 50 ml GAA

here's the result mixed with 1l. ice cold water

http://anonym.to/?http://i.imgur.com/qCngB3X.jpg

Organikum - 30-7-2013 at 15:59

Yep, the acetic acid fucks it up.

Ammonium actate is not a very good catalyst for its not active enough and so requirers to high temperatures. Also it tends to form byproducts which cannot be removed easily going throgh a lot of possible following reactions.

Basically any primary amine will do the job though. Some of them are available OTC in common products IIRC.

An example:
10ml benzaldehyde are added whilst stirring to 11ml nitromethane or nitroethane (both reacts the same) in the cold which contains 2ml cyclohexylamine which was neutralized by GAA until acidic (Can be done best in the nitromethane as solvent - slowly, stirring, cold).

Thats rapidly heated to about 65°C in a microwave or an oilbath until slight discoloration occurs, then its put aside to cool down to RT (color gets more intense) and then in the fridge for some hours. Scratching with a glassrod or so you have much better some seed crystals induce crystallisation (It mostly crystallized already just so, or when taken out of the fridge, a nice view!). Back in the fridge for an hour and then filtered at the pump (preferably, gravity filtration will do but get an aspirator, really). The filtercake is washed down with a small amount of ice-cold alcohol (EtOH, IPA...), this adds to the soup and then....
Then the heating - cooling - crystallisation etc. cycle is repeated two times more (it gets darker each time - no problem) and maybe even a third time.

Overall one ends up with beautiful crystals which usually are perfect after just a waterwash (must do! removes catalyst). Recrystallisation from IPA makes it even better. The first 2 goes are best of course.

Yields are excellent.
And I really mean it.

Less is more. Water does not interfere. Boiling is polymerisation madness. The formation of the styrene is hindered by styrene, is this removed it ges on and on and on.....

To prove I am not sucking this from my fingertips....

[Edited on 31-7-2013 by Organikum]

gordonL - 30-7-2013 at 23:47

Organikum, I thik you're right. I should try with some amine - cyclohexylamine, butylamine, propylamine.

Just one more question. Approximately how much GAA you use?

batsman - 31-7-2013 at 03:46

I am reading Pihkal, and in it there are many many different compounds, (nitrostyrene, nitroethane among others) that he have written without any directions on how to make them. At least not that i have found yet.

One thing that i like is that Shulgin have synthesis explaination on the making on a small yields. Some are as little as 0,5 g, maybe less. I don´t mean that his reactions are bad, just that he make small amounts each time. But if one would want to scale up on one of his recipes, and make 1 gram instead. Is it possible to just double the amounts of compounds from the start, for example? Or do i mess up the mole counting then?

The orgsyn.org link was really cool. I have been wondering about the nitrostyrene recipe.

I couldn´t find anything on nitroethane. Which synth is the best, and easiest to do in order to yield nitroethane?

Organikum - 31-7-2013 at 07:40

Quote: Originally posted by gordonL

Organikum, I thik you're right. I should try with some amine - cyclohexylamine, butylamine, propylamine.

Just one more question. Approximately how much GAA you use?

As an example:
10ml B-dehyde + 11ml Nitro + 2ml cyclo + 1,6ml GAA

Can be used for nitromethane and ethane, the different density compensated by the molecular weight.

@ Batsman: Shulgin is great but not all methods he uses are great. His nitrocondensations are an example for this. I know he would have not the slightest problem admitting this and congratulating everybody who found something better. He is a great man. I very much hope I am not the only one here to donate for his care now after his stroke.

Sensitive compounds can be prepared with benzoic acid instead acetic acid. Works very well from what I know.

The linked OrgSyn works btw. really good for ancient stuff. Better then sodium actate.

You can scale up from 0,5g to 1g without issues, thats in range. Scaling up from 1mmol to 1 mol is something completely different though.
The by me described method was tested from 5g to 300g and works in this range guaranteed. I woould not go bigger but use more flasks instead, say 3x300g Erlenmeyers instead of 1x1000g, put them together in the micro or oilbath with some distance, its on the heattransfer.

/ORG

[Edited on 31-7-2013 by Organikum]

bfesser - 31-7-2013 at 08:07

Well, of course the <em>Org. Syn.</em> procedure works. The journal publishes established and tested procedures, only. It's often the first place I look, and why I shared the link.

Quote:

<div align="center"><img src="http://www.orgsyn.org/Organic%20Syntheses%20Website_files/oslogo_withwords.gif" width="350" /></div>
Since 1921, <em>Organic Syntheses</em> has provided the chemistry community with detailed, reliable, and carefully checked procedures for the synthesis of organic compounds. Some procedures describe practical methods for the preparation of specific compounds of interest, while other procedures illustrate important synthetic methods with general utility. Each procedure is written in considerably more detail as compared to typical experimental procedures in other journals, and each reaction and all characterization data has been carefully "checked" for reproducibility in the laboratory of a member of the Board of Editors. <img src="../scipics/_ext.png" />

</a>

:(

gordonL - 23-8-2013 at 06:50

Even with cyclo, result is the same

Organikum - 25-8-2013 at 10:59

Without details on ratios and temperatures and what was used in which amoiunts in what order, fuck what do you expect? Brainreading?

I suspect you are still boiling the holy shit outa it or using masses of acid.
Probably both.

The very most OrgSyn recipes work.
Does not say thats the best way to do it. Some water has run down the rivers since 1925.

Hey janitor, shouldn´t you be supervising the cleansing of the restrooms at the moment?
Cats away, mice dancing on the table.....

/ORG

[Edited on 25-8-2013 by Organikum]

gordonL - 25-8-2013 at 11:30

Quote: Originally posted by Organikum

Without details on ratios and temperatures and what was used in which amoiunts in what order, fuck what do you expect? Brainreading?

I suspect you are still boiling the holy shit outa it or using masses of acid.
Probably both.

The very most OrgSyn recipes work.
Does not say thats the best way to do it. Some water has run down the rivers since 1925.

Hey janitor, shouldn´t you be supervising the cleansing of the restrooms at the moment?
Cats away, mice dancing on the table.....

/ORG

[Edited on 25-8-2013 by Organikum]

hey hey, calm down

I used your proportions 22 ml nitromethane, 20 ml benzaldehyde, 4 ml cyclo and 3.2 ml GAA in this order

I didnt put it on microwave, but on reflux for 1 hour @ 85 degrees

starman - 25-8-2013 at 20:16

Well if you were expecting a crystalline product and it oiled out on you. Have you read anything on laboratory technique?
Jeez.Direct recystallisation maybe? Methanol,ethanol or isopropanol possibly suitable.

organichem - 14-11-2013 at 05:54

Well, I found a very interesting/promising article - but I've no access to it:
Ambiphilic Dual Activation Role of a Task-Specific Ionic Liquid: 2-Hydroxyethylammonium Formate as a Recyclable Promoter and Medium for the Green Synthesis of β-Nitrostyrenes
Some abstract can be found on organic-chemistry.org

Agricola - 14-11-2013 at 11:56

Quote: Originally posted by organichem

Well, I found a very interesting/promising article - but I've no access to it:
Ambiphilic Dual Activation Role of a Task-Specific Ionic Liquid: 2-Hydroxyethylammonium Formate as a Recyclable Promoter and Medium for the Green Synthesis of β-Nitrostyrenes
Some abstract can be found on organic-chemistry.org

The paper is attached to this message.

Attachment: nitrostyrenes_alizadeh2010.pdf (1MB)
This file has been downloaded 1094 times

Organikum - 14-11-2013 at 12:23

Quote: Originally posted by gordonL

Quote: Originally posted by Organikum

hey hey, calm down

I used your proportions 22 ml nitromethane, 20 ml benzaldehyde, 4 ml cyclo and 3.2 ml GAA in this order

I didnt put it on microwave, but on reflux for 1 hour @ 85 degrees

To long to hot as said.

Hit it in the sep-funnel with ice-cold brine.
Either it crashes out or if not separate and then it will.

/ORG

chemrox - 15-11-2013 at 11:56

I wonder what's going on? I would suggest some practice with less spendy reagents.. just general practice. Anyway I really appreciate the 2HEMF article. I found a prep for it. Or is it 2-HEAF?

Attachment: HEMF_prep.pdf (152kB)
This file has been downloaded 1139 times

[Edited on 15-11-2013 by chemrox]

Organikum - 16-11-2013 at 02:46

Quote: Originally posted by organichem

They are of course just naming prior art which makes their method look good. Albeit its not god at all. 2-HEAF to substrate is >5 to 1, thats not a catalyst - thats a solvent with additional properties.

I propose that th ionic liquid character is just not essential and that for example the acetate instead the formate will work the same if not better, the benzoate will do it also, and if one zaps the whole shebang in the microwave (short) then an ctalytic amount will suffice, say something like 3 to 10 (g or ml just by thumb) and not the insane amount which is used by the authors of the article, which is one of the shady sort which makes me think of lighters and testicles. But there is far worse around nowadays.

@Chemrox: Right, such an easy ionic liquid might come very handy, have not seen something like this up to now. Not stable anough for many interesting uses though, I am afraid, but there might be some gold to discover nevertheless.

/ORG

organichem - 16-11-2013 at 03:52

I was curious if it would work and tried the HEAF-method on a 10 mmol-scale, using anisaldehyde and nitroethane.
My scale has only an accuracy of 0.1 g - so it is definitely just a "over-the-thumb"-method in this 10 mmol range.
I took 1.3 g of anisaldehyde and 0.7 g of nitroethane, mixed it in a small beaker, added approx. 10 mL HEAF and stirred it vigorously on the magnetig stirrer for 70 min. Afterwards I added water to about 50 mL total volume, causing a yellowish precipitate, floating partially on the top - vacuum filtered it, and recrystallized from ca. 5 mL of MeOH.
Filtration yielded 1.4 g of the nitrostyrene corresponding to about 78 %.
Scaling it up and being more accurat could be more efficient though.

[EDIT: little error - it was 2 h 10 min, not only 1 h 10 min]

[Edited on 16-11-2013 by organichem]

organichem - 18-11-2013 at 00:01

Small-scale trial of the Henry-Reaction with 2-HEAF (~10 mmol)

1.3 g anisaldehyde (MW 136, ~9.6 mmol)
0.7 g EtNO2 (MW 75.07, ~9.3 mmol)
10 mLs 2-HEAF

In a 50 mL beaker together with a small magnetig stirbar was added 1.3 g anisaldehyde as well as 0.7 g nitroethane and thereto added 10 mLs of 2-hydroxyethyl ammonium formate The mixture was vigorously stirred and a watchglass placed upon the top of the beaker to prevent squirting. The medium was stirred for 2 h 10 min before the content was diluted to 50 mLs with water. The nitroalkene precipitated was vacuum filtered, washed wit 2 x 25 mLs of water, sucked dry and recrystallized using a little MeOH (about 5 mL). The final product weighed 1.4 g (~7.3 mmol) – ~78 % yield.

Up-scaling the Henry-reaction with 2-HEAF (70 mmol)

10.5 g piperonal (MW 150, 70 mmol)
5.3 g / 5.0 mLs EtNO2 (MW 75, 70 mmol)
70 mL 2-HEAF

The reaction was carried out as described in the 10 mmol-scale reaction despite a 250 mL beaker was used, the time reduced to 90 min and the aldehyde and NE were added to the preheated IL (about 50 °C, to liquefy the solid aldehyde and improve stirring, letting it cool over the reaction time). The IL-filtrate was saved for recycling.
11.6 g (56 mmol) recrystallized nitroalkene – 80 % yield (did not reduce the volume of the mother liquor from the recrystallization that was about 70 mLs of MeOH, could have given a 2nd crop)

Recycling the 2-HEAF:

The collected filtrate of the 2nd condensation reaction was washed with 3 x 30 mL EtOAc, leaving a pale yellow IL which was placed in a 250 mL RBF and evaporated in a rotavap. Because the IL couldn’t be decolorized, I saved it and will try it for the same substrate maybe.

Noshtuba - 16-5-2015 at 10:03

been reading about nitrostyrenes for a while.
I'm slightly confused.
nitrostyrenes are formed by the dehydration of nitroalcohols, according to wikipedia
http://en.wikipedia.org/wiki/Nitroaldol_reaction
but in all these above reactions there doesnt seem to be a dehydrating reagent
am i missing something? What triggers the dehydration to styrene?
any help would be greatly appreciated

[Edited on 16-5-2015 by Noshtuba]

turd - 16-5-2015 at 12:58

Quote: Originally posted by Noshtuba

but in all these above reactions there doesnt seem to be a dehydrating reagent
am i missing something?

It's a simple acid catalyzed dehydration of an alcohol.

See http://www.organic-chemistry.org/namedreactions/knoevenagel-...

Also note the imine intermediate in the case of amine catalyst.

Edit: acid catalyzed of course in AcOH

[Edited on 17-5-2015 by turd]