Sciencemadness Discussion Board
Not logged in [Login ]
Go To Bottom

Printable Version  
Author: Subject: Process for the manufacture ethylbenzene?
Meri
Harmless
*




Posts: 16
Registered: 7-6-2015
Member Is Offline

Mood: No Mood

[*] posted on 10-6-2015 at 14:55
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?
View user's profile View All Posts By User
Chemosynthesis
International Hazard
*****




Posts: 1071
Registered: 26-9-2013
Member Is Offline

Mood: No Mood

[*] posted on 10-6-2015 at 16:20


Friedel Crafts
View user's profile View All Posts By User
Tom Yorke
Harmless
*




Posts: 3
Registered: 10-6-2015
Member Is Offline

Mood: No Mood

[*] posted on 10-6-2015 at 20:12
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
View user's profile View All Posts By User
Loptr
International Hazard
*****




Posts: 1298
Registered: 20-5-2014
Location: USA
Member Is Offline

Mood: Grateful

[*] posted on 11-6-2015 at 05:34


Quote: Originally posted by Chemosynthesis  
Friedel Crafts


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 :P

[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]
View user's profile View All Posts By User
Praxichys
International Hazard
*****




Posts: 1022
Registered: 31-7-2013
Location: Detroit, Michigan, USA
Member Is Offline

Mood: Coprecipitated

[*] posted on 11-6-2015 at 05:51


Start from styrene, since it is easy to manufacture from common plastic items. Hydrogenate gently.

http://www.researchgate.net/profile/Antoine_Fecant/publicati...




View user's profile Visit user's homepage View All Posts By User
Loptr
International Hazard
*****




Posts: 1298
Registered: 20-5-2014
Location: USA
Member Is Offline

Mood: Grateful

[*] posted on 11-6-2015 at 05:55


Quote: Originally posted by Praxichys  
Start from styrene, since it is easy to manufacture from common plastic items. Hydrogenate gently.

http://www.researchgate.net/profile/Antoine_Fecant/publicati...


That would be the most straightforward method! You just need to reduce that double bond.
View user's profile View All Posts By User
Praxichys
International Hazard
*****




Posts: 1022
Registered: 31-7-2013
Location: Detroit, Michigan, USA
Member Is Offline

Mood: Coprecipitated

[*] posted on 11-6-2015 at 06:03


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]




View user's profile Visit user's homepage View All Posts By User
Tom Yorke
Harmless
*




Posts: 3
Registered: 10-6-2015
Member Is Offline

Mood: No Mood

[*] posted on 11-6-2015 at 08:18


my way seems easiest but whatever
View user's profile View All Posts By User
Loptr
International Hazard
*****




Posts: 1298
Registered: 20-5-2014
Location: USA
Member Is Offline

Mood: Grateful

[*] posted on 11-6-2015 at 09:06


Quote: Originally posted by Tom Yorke  
my way seems easiest but whatever


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. :P


[Edited on 11-6-2015 by Loptr]
View user's profile View All Posts By User
Chemosynthesis
International Hazard
*****




Posts: 1071
Registered: 26-9-2013
Member Is Offline

Mood: No Mood

[*] posted on 11-6-2015 at 09:33


Quote: Originally posted by Loptr  
Quote: Originally posted by Chemosynthesis  
Friedel Crafts


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 :P

[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.
View user's profile View All Posts By User
Magpie
lab constructor
*****




Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline

Mood: Chemistry: the subtle science.

[*] posted on 11-6-2015 at 13:08


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
View user's profile View All Posts By User
Tom Yorke
Harmless
*




Posts: 3
Registered: 10-6-2015
Member Is Offline

Mood: No Mood

[*] posted on 11-6-2015 at 14:10


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. :P

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.
View user's profile View All Posts By User
UC235
International Hazard
*****




Posts: 506
Registered: 28-12-2014
Member Is Offline

Mood: No Mood

[*] posted on 11-6-2015 at 18:16


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.
View user's profile View All Posts By User
CuReUS
International Hazard
*****




Posts: 928
Registered: 9-9-2014
Member Is Offline

Mood: No Mood

[*] posted on 12-6-2015 at 05:18


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 :D)
View user's profile View All Posts By User
Loptr
International Hazard
*****




Posts: 1298
Registered: 20-5-2014
Location: USA
Member Is Offline

Mood: Grateful

[*] posted on 12-6-2015 at 06:15


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]
View user's profile View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2169
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 12-6-2015 at 15:23


Quote: Originally posted by Loptr  
the hydrogenation also seems to have a costly barrier to entry


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.




"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
Loptr
International Hazard
*****




Posts: 1298
Registered: 20-5-2014
Location: USA
Member Is Offline

Mood: Grateful

[*] posted on 12-6-2015 at 15:41


Quote: Originally posted by S.C. Wack  
Quote: Originally posted by Loptr  
the hydrogenation also seems to have a costly barrier to entry


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...
View user's profile View All Posts By User
CuReUS
International Hazard
*****




Posts: 928
Registered: 9-9-2014
Member Is Offline

Mood: No Mood

[*] posted on 13-6-2015 at 01:14


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]
View user's profile View All Posts By User
zed
International Hazard
*****




Posts: 1881
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline

Mood: Semi-repentant Sith Lord

[*] posted on 16-6-2015 at 14:21


Pt, H2, STP.
View user's profile View All Posts By User
CuReUS
International Hazard
*****




Posts: 928
Registered: 9-9-2014
Member Is Offline

Mood: No Mood

[*] posted on 24-6-2015 at 09:29


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
View user's profile View All Posts By User
S.C. Wack
bibliomaster
*****




Posts: 2169
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline

Mood: Enhanced

[*] posted on 24-6-2015 at 13:45


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]




"You're going to be all right, kid...Everything's under control." Yossarian, to Snowden
View user's profile Visit user's homepage View All Posts By User
zed
International Hazard
*****




Posts: 1881
Registered: 6-9-2008
Location: Great State of Jefferson, City of Portland
Member Is Offline

Mood: Semi-repentant Sith Lord

[*] posted on 27-6-2015 at 15:19


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]
View user's profile View All Posts By User

  Go To Top