roamingnome
Hazard to Others
Posts: 363
Registered: 9-9-2006
Member Is Offline
Mood: No Mood
|
|
Benzene --> benzaldehyde
"Efficient synthesis of benzaldehyde by direct carbonylation of benzene in ionic liquids"
Catalysis Letters
Volume 107, Numbers 1-2, 123-125,
Please view Table 1 entry 6 on page 124
As good scientists that these men are, they preformed an experiment where they used AlCl3 alone with Carbon Monoxide and Benzene to achieve a 40%
yield benzaldehyde
This appears to be an excellent approach for any experimenter.
remarkable if it can be confirmed.
Thank you for you time
Attachment: AlCl3.pdf (166kB)
This file has been downloaded 1550 times
|
|
|
spirocycle
Hazard to Others
Posts: 197
Registered: 29-9-2010
Member Is Offline
Mood: No Mood
|
|
how to get clean monoxide easily is the next question
also it says that they achieved | Quote: | with relatively high yield (up to 91%) and selectivity
(ca. 96%). |
[Edited on 28-10-2010 by spirocycle]
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
A) There are existing threads on the general topic. Please attempt to find existing threads before starting new ones that make researching a topic
more difficult.
B) 40 kg/cm2 CO pressure is not terrible, but not something many amateurs might not be able to do.
C) Best yields were with the highest AlCl3:ionic liquid ratios, with straight AlCl3 you need 1/2 mole AlCl3 per mole benzene. The AlCl3 complexes
with the aldehyde, the traditional method of handling this is hydrolysis of the complex which results in the destruction of the chloride. Anhydrous
AlCl3 of high quality is something not really easy to come by; some amateur attempts have had difficulty in obtaining the needed quality.
This general reaction, using AlCl3 or other metal halides, has been done before; there are examples in the patent records I believe; because of that I
would not be surprised if the work referenced is correct or nearly so. It's just the difficulty of the two and a half bar dry CO pressure, plus large
amounts of good grade AlCl3, that make it appear less accessible than the chlorination of toluene followed by fractionation and hydrolysis.
|
|
|
spirocycle
Hazard to Others
Posts: 197
Registered: 29-9-2010
Member Is Offline
Mood: No Mood
|
|
http://pubs.acs.org/doi/pdf/10.1021/cr980032t
this is the link to how they prepared their ionic liquid, if someone has access
|
|
|
RiP057
Harmless
Posts: 29
Registered: 26-10-2010
Member Is Offline
Mood: No Mood
|
|
I thought vilsmeier hack was the way to go to make benzaldehydes???
simple DMF/POCl3 reaction with a reflux
|
|
|
mnick12
Hazard to Others
Posts: 404
Registered: 30-12-2009
Location: In the lab w/ Dr. Evil
Member Is Offline
Mood: devious
|
|
Well the vilsmeier-Haack reactions is often used for creating aldehydes, but it is not economic especially for a simple aldehyde like benzaldehyde
phosphorus oxychloride is quite expensive and not readily aquired.
|
|
|
Sandmeyer
National Hazard
Posts: 784
Registered: 9-1-2005
Location: Internet
Member Is Offline
Mood: abbastanza bene
|
|
Quote: Originally posted by mnick12  | | Well the vilsmeier-Haack reactions is often used for creating aldehydes, but it is not economic especially for a simple aldehyde like benzaldehyde
phosphorus oxychloride is quite expensive and not readily aquired. |
I don't think that is the reason, in fact Vilsmeier normally only works on electron rich aromatics hence formylation of benzene will not work this
way.
|
|
|
Methyl.Magic
Hazard to Others
Posts: 139
Registered: 14-5-2007
Member Is Offline
Mood: No Mood
|
|
Benzene and CO :
If you are not dead by CO, cancer will take care of your death.
|
|
|
RiP057
Harmless
Posts: 29
Registered: 26-10-2010
Member Is Offline
Mood: No Mood
|
|
benzene will readily undergo the vilsmeier hack just like it will undergo chlorination iodination nitration all of the above prefer electron donating
substituents but will react with benzene easily just maybe longer reaction time....
POCl3 however is not easily gotten if you are an amateur chemist.... it is readily available from chem supplies just expensive to ship as it must be
drop shipped, but if you buy any amount it is usually a substantial amount and unless you are making kilo quantities of benzaldehyde for unsavory
purposes it does the job just fine and you arent exposing yourself to CO at what I heard was 2.5 ATM.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
My Organic Chem professor died last year at
age 92. When I took his class in the 1970's he liked to joke about all the asbestos filters he stirred up in beakers from asbestos powder, and how
he washed organic tars off his hands daily with benzene as a graduate student. Just say'n.
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
OTOH one of my chem profs recounted how many of his profs and fellow students that went into research (pure & applied) that died of cancer and
various organ failures in middle age - rates far above the average for the population there. Asbestos isn't that much of a risk to workers in the
field (or in the field pre-1970) especially compared to some of the other stuff.
|
|
|
roamingnome
Hazard to Others
Posts: 363
Registered: 9-9-2006
Member Is Offline
Mood: No Mood
|
|
Your right
all the reagents are toxic and take preparation.
CO can be made with Zn powder CaCo3
For AlCl3 your probably making Chlorine gas anyway so chlorinate toluene
Benzene seems to have a nice boiling point to work with but will benzaldehyde form azeotropes during work up anyway?
Hydrogenation of benzoic acid with H2 gas at 360 C over ZnO again seems friendly.
Ozonenation of styrene in methanol followed by hydrogen and lindlar's catalyst takes apparatus but doesn't it all.
And that Mn salt
Im just trying to put all the cards on the table
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
| Quote: Originally posted by RiP057 | | benzene will readily undergo the vilsmeier hack just like it will undergo chlorination iodination nitration all of the above prefer electron donating
substituents but will react with benzene easily just maybe longer reaction time.... |
When claiming things that seemingly make no sense, it is always good sense to provide a reference. So, please provide a reference describing a
Vilsmeier–Haack formylation of benzene!
|
|
|
RiP057
Harmless
Posts: 29
Registered: 26-10-2010
Member Is Offline
Mood: No Mood
|
|
will do going to do a search on beilstein after I shower.... I figure most people have access to something like that, but then again I guess most
dont
|
|
|
RiP057
Harmless
Posts: 29
Registered: 26-10-2010
Member Is Offline
Mood: No Mood
|
|
it would seem I am talking out of my arse, but in this journal article it was accomplished
Tetrahedron yr:1990 vol:46 iss:16 pg:5633 -5648
however the use of n-Bu-Li and t-BuOK were used to deprotonate the benzene ring... this article focuses on making deuterated benzaldehydes.... so I
guess its done with extra reagents, but everyone else uses CO....
although this article uses hydrogen cyanide if you really want to kill yourself
Journal of the Chemical Society yr:1932 pg:2793 -2797
I guess in my past I worked on heterocycles which usually always have extra electron to push the reaction, and in my theoretical mind the reaction
should be able to be accomplished just that the energy barrier for it is higher than what is supplied by the reflux.... then again just cause I cant
find a reference doesnt mean it cant be done.... I guess you could try it for yourself and find out 
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
