Meri
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Process for the manufacture ethylbenzene?
If this topic has all ready been discussed, please forgive my ignorance.
__________
Are there is any way to make,from benzene,or any other source?
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Chemosynthesis
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Friedel Crafts
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Tom Yorke
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maybe
convert cinnamaldehyde to the carboxylic acid, decarboxylate to ethyl benzene, not sure why you'd want it though but hey. I haven't tried that but I
don't think there's anything controversial about the concept, idk what happens with the double bond
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Loptr
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My first thought was FC alkylation of benzene with ethyl bromide, but the ethylbenzene would be more reactive than the original benzene, and would
react further leading to over alkylation.
What about FC acylation of benzene with acetyl chloride, which would then be followed up with a reduction of the carbonyl with zinc(hg) and HCl?
[Edited on 11-6-2015 by Loptr]
EDIT: No answer needed. I found this exact reaction online and confirmed it. Clemmensen reduction 
[Edited on 11-6-2015 by Loptr]
EDIT: Or you could just start with my product, acetophenone, and follow with a Clemmensen reduction.
[Edited on 11-6-2015 by Loptr]
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Praxichys
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Start from styrene, since it is easy to manufacture from common plastic items. Hydrogenate gently.
http://www.researchgate.net/profile/Antoine_Fecant/publicati...
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Loptr
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That would be the most straightforward method! You just need to reduce that double bond.
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Praxichys
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True, but the hydrogenation will have a small ethylcyclohexane, ethylcyclohexene, ethylcyclohexadiene impurity which will be very close in BP and
difficult to separate. The acylation/reduction is cleaner but requires a lot more expense in reagents. It depends on the purity required for the final
application.
A wolf-kishner reduction would also work on acetophenone, which reacts ketones with hydrazine to form the hydrazone, then cleaves the hydazone as
nitrogen and water using KOH. It servers as the basic analogue to the acidic clemmensen.
[Edited on 11-6-2015 by Praxichys]
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Tom Yorke
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my way seems easiest but whatever
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Loptr
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Is this a competition? I must have missed that. What are the prizes? 
EDIT: I just checked your reaction and you would end up with styrene! And then you go on to say you don't know what would need to be done with the
double bond, so you left off where Praxichys began... yeah, your way seems easier when you don't have to deal with the double bond.
[Edited on 11-6-2015 by Loptr]
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Chemosynthesis
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Quote: Originally posted by Loptr  |
My first thought was FC alkylation of benzene with ethyl bromide, but the ethylbenzene would be more reactive than the original benzene, and would
react further leading to over alkylation.
What about FC acylation of benzene with acetyl chloride, which would then be followed up with a reduction of the carbonyl with zinc(hg) and HCl?
[Edited on 11-6-2015 by Loptr]
EDIT: No answer needed. I found this exact reaction online and confirmed it. Clemmensen reduction
[Edited on 11-6-2015 by Loptr]
EDIT: Or you could just start with my product, acetophenone, and follow with a Clemmensen reduction.
[Edited on 11-6-2015 by Loptr] |
This is what I would look at for lab scale. The simple alkylation used to be an industrial procedure but I am not sure how well that would downscale.
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Magpie
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Vogel (forum library) shows a method using chlorobenzene, sodium, and ethyl bromide. Indicated yield is 44%.
The single most important condition for a successful synthesis is good mixing - Nicodem
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Tom Yorke
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EDIT: I just checked your reaction and you would end up with styrene! And then you go on to say you don't know what would need to be done with the
double bond, so you left off where Praxichys began... yeah, your way seems easier when you don't have to deal with the double bond.
sweet, thanks for checking that out, I had a bad feeling about that thing. now I know why that's not used to get ethylbenenzene, bio-styrene is pretty
awesome though.
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UC235
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| Quote: Originally posted by Praxichys | | True, but the hydrogenation will have a small ethylcyclohexane, ethylcyclohexene, ethylcyclohexadiene impurity which will be very close in BP and
difficult to separate. The acylation/reduction is cleaner but requires a lot more expense in reagents. It depends on the purity required for the final
application. |
No you wouldn't. Pd/C is not capable of reducing an aromatic ring easily as far as I know, but an aryl conjugated terminal alkene should be an
extremely easy target.
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CuReUS
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among all the methods mentioned till now,the hydrogenation of styrene seems to be the best approach.I found another paper on that
http://jes.ecsdl.org/content/143/4/L71.abstract
magpie's method is nothing but the wurtz-fittig reaction.In that case,benzyl bromide and methyl iodide could also be coupled using Na.But I have a
better idea,phenylmagnesium bromide +ethyl bromide(kumada coupling)
http://www.organic-chemistry.org/namedreactions/kumada-coupl...
but the best thing to do would be to just buy it.its dirt cheap(the irony is that styrene is made by dehydrogenation of ethylbenzene  )
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Loptr
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| Quote: Originally posted by UC235 | | Quote: Originally posted by Praxichys | | True, but the hydrogenation will have a small ethylcyclohexane, ethylcyclohexene, ethylcyclohexadiene impurity which will be very close in BP and
difficult to separate. The acylation/reduction is cleaner but requires a lot more expense in reagents. It depends on the purity required for the final
application. |
No you wouldn't. Pd/C is not capable of reducing an aromatic ring easily as far as I know, but an aryl conjugated terminal alkene should be an
extremely easy target. |
I found an example on Google Books that shows Pd/C doesn't reduce the aromatic ring, while a rhodium-alumina catalyst does. The example is the
reduction of mandelic acid.
https://books.google.com/books?id=7gPnWf4UDLsC&lpg=PA416...
Personally, I would stick with the acylation. This is possibly because I remember doing it very clearly in college, while the hydrogenation also seems
to have a costly barrier to entry.
[Edited on 12-6-2015 by Loptr]
[Edited on 12-6-2015 by Loptr]
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S.C. Wack
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Ni (without heat) and Cu (reduced from their oxides) are supposed to give quantitative yield at 85 atm. in 3 hr., but then if one would go for that,
why not 94% from polystyrene and U-Ni-B at 350C at the same pressure in less time, ftw, profit, etc.
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Loptr
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| Quote: Originally posted by S.C. Wack |
Ni (without heat) and Cu (reduced from their oxides) are supposed to give quantitative yield at 85 atm. in 3 hr., but then if one would go for that,
why not 94% from polystyrene and U-Ni-B at 350C at the same pressure in less time, ftw, profit, etc. |
I was speaking from the perspective of an equipment poor home chemist.
While it might be less costly for industry to run these sorts of reactions, I am not quite sure how you would go about it exactly in your garage
without metal working abilities. That's just me, though, not to mention that I also have no interest in this product...
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CuReUS
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styrene can be reduced to ethylbenzene using catalytic Ni(see pg 292)
https://books.google.co.in/books?id=DiKGAwAAQBAJ&pg=PA75...
in the same book,on pg 320,is another reduction using Pd/C
styrene can also be reduced to ethylbenzene using H2(1 atm)/Pd at 100'C
but I think the easiest way would be to treat styrene with HCl and then convert the halide to hydrocarbon using Zn/acetic acid
if HI/red P is available,then a one pot reduction could be done
[Edited on 14-6-2015 by CuReUS]
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zed
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Pt, H2, STP.
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CuReUS
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zed,could you give the reference for doing the reduction at STP.
everywhere it says that alkenes are converted to alkanes using Pt,Ni,Pd/H2 at a temperature of 100-300'C
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S.C. Wack
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JOC 31, 3989 (1966). This is where borohydride was used to make the catalyst and hydrogen.
Nickel acetate was substituted for chloroplatinic acid earlier in JACS 85, 1005 (1963); hydrogen absorption 50% in 9 minutes and 100% in 10 minutes
respectively.
[Edited on 24-6-2015 by S.C. Wack]
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zed
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Dr. Brown and friends, ran many such reductions. Active catalysts are prepared by reducing Chloroplatinic Acid with NaBH4, usually in ethanol. An
elegant approach, that produces a very active catalyst.
Thereafter, the hydrogen can come from anywhere. If you have lots of low cost Borohydride, it is an excellent hydrogen source.
Sadly, full procedures are present in Journals, but not on-line.
It's worth a trip to the library to view Dr. Brown's procedures. Since I no longer have the original papers, I'm due for a trip myself.
These are lab procedures that might be quite adaptable to producing ethyl benzene.
[Edited on 27-6-2015 by zed]
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