Talk:Friedel–Crafts reaction

message: This article could perhaps do with a more thorough mechanism, explaining the action of the AlCl3? Sorry I can't do this myself, but my TeX skills are sorely lacking -- Tom
— Preceding unsigned comment added by 81.178.141.153 (talk) 20:29, 12 June 2005 (UTC)
thread_title:  Mechanism 

message: One of the reactions shown is the addition of a methyl group to a benzene.  The mechanism for this addition involves the loss of the halogen from the alkyl halide and the formation of a carbocation.  The methyl carbocation is far too unstable to allow for the addition of a methyl substituent to benzene through the Friedel-Crafts reaction.  Furthermore, the reaction would not occur with even a primary alkyl halide (such as the addition of an ethyl group, as shown later in the article) as primary carbocations are also much too unstable to allow for addition.  --Ian
— Preceding unsigned comment added by Asian Fury (talk • contribs) 06:01, 5 December 2005 (UTC)
thread_title:  Problem with methyl example 

message: No, methyl groups and primary alkyl halides CAN react in Friedel-Crafts alkylation. In the case of secondary and tertiary halides, the carboation is formed by the removal of the halogen ion by the Lewis Acid. However, because methyl and primary carbocations are NOT stable as you stated, the halide  instead forms a Lewis acid-base complex with the acid, and this acts as the electrophile in this case:
CH3CH2-Cl + AlCl3 -> CH3CH2-Cl(+)-Al(-)-Cl3. I'll add this later to the main article, with some fancy drawings.
Jhum101 18:40, 23 February 2006 (UTC)
thread_title:  Stability of carbocations 

message: The article references making 2,4,6-triethylbenzene. However, not only is this wrongly named, it does not form as such. The foot-note lists an abstract for 1,3,5-Tris(aminomethyl)-2,4,6-triethylbenzene, but this is a different molecule, and the abstract doesn't even mention friedel-crafts. I'll fix this later, and add a new section on the limitations of friedel crafts reactions (specifically, polyalkylation, reactivity, and the para/ortho substitution.)
Jhum101 18:40, 23 February 2006 (UTC)
replies: text: Actually, for successive alkylations on a benzene ring, steric control is more the rule than the exception.  Ortho para direction is only true for electrophilic aromatic substitution reactions that are essentially irreversible. Alsosaid1987 (talk) 14:56, 29 August 2018 (UTC)
thread_title: Wrong molecule used for reference

message: The reason for lack of rearrangement of the carbocation electrophile in FC Acylation is "there are no carbocation rearrangements as an aromatic carbocation is very stable compared to alkyl carbocations."  This is just wrong - the carbocation isn't aromatic.  The reason is the resonance stabilisation where the empty shell of the Carbon interacts with the lone pairs of electrons on the oxygen in the acyl group.  This should be changed, no?
--DapBot 00:32, 15 June 2006 (UTC)
thread_title: Stability of electrophile in FC acylation

message: According to the mechanism, you start and end with the same compound (benzene) and lose the R group somewhere along the way. Also, as mentioned previously the mechanism does not directly involve an alkyl carbocation as an intermediate. It would be good if someone could edit the mechanism to rectify these things.--Joe
— Preceding unsigned comment added by Jtfletcher (talk • contribs) 22:37, 10 April 2007 (UTC)
thread_title: Errors in alkylation mechanism

message: anyone?
I could easily make a general acylation mechanism using software on my own computer however bringing the necessary files into the article is assuredly not my area of expertise  — Preceding unsigned comment added by Isntitbull (talk • contribs) 02:45, 10 April 2012 (UTC)
thread_title: Does anyone have a acylation mechanism?

message: The article mentioned 'Reaction conditions are similar to the Friedel-Crafts alkylation mentioned above' in the Friedel-Crafts acylation section.
Many different sources give different conditions for this reaction, and I'm interested to know why, and what are the true conditions.
Crazyjoe 7 12:32, 24 June 2007 (UTC)
thread_title:  Reaction conditions 

message: The image and description of the Friedel-Crafts dealkylation reaction portray an alkylation, not a dealkylation.
* Incorrect: the text with the image clearly states that the product forms by a series of alkylations and dealkylations. V8rik 17:06, 12 July 2007 (UTC)
thread_title:  Error in Friedel-Crafts dealkylation section 

message: Sorry, but "drugfuture.com" links point to an illegal copy of the Merck index. I have already contacted Merck about the issue.
213.188.227.119 (talk) 15:08, 29 November 2007 (UTC)
thread_title:  drugfuture.com 

message: the helicene article talk about Friedel-Crafts cyclization... what's that?  —Preceding unsigned comment added by 72.70.182.227 (talk) 15:33, 16 June 2008 (UTC)
thread_title:  F-C cyclization 

message: I do not think, that the "catalyst" is regenerated. Most Friedel-Crafts acylations use stoichiometric amounts of lewis acid. For learning purposes it is not helpful, if people think, catalytic amounts of AlCl3 can be used.
Maybe the full mechanism needs to be rechecked. There are two versions available in common textbooks and I can't judge by myself whether you have chosen the more reliable one. So the main question is, whether AlCl3 is bound to Cl or to O before formation of the acylium ion...
213.188.227.119 (talk) 02:58, 4 January 2012 (UTC)
replies: text: Good question, but yes the catalyst is regenerated.  The evolved HCl should not diminish its activity, but yes if one is acylating the resulting ketone would be a better Lewis base than the acyl chloride and slow it.  But I have not seen that it kills it.  The more grevious problems with the page are the depiction of FeX4- as square planar (probably a bitetrahedral dimer Fe2X7-) and the naked carbocation. Nice point overall because many so-called catalysts are not very catalytic. --Smokefoot (talk) 03:10, 4 January 2012 (UTC)
thread_title:  Friedel–Crafts acylation 

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thread_title:  Blacklisted Links Found on [[Friedel–Crafts reaction]] 

message: The FC reaction refers to construction of C-C bonds with electrophilic carbon.  I've never seen the FC reaction used to refer to sulfonation or any other C-X bond forming reaction. It's like how people call any 1,4-addition a Michael reaction these days. If there's agreement on this issue, I move to delete this section, or merge this into the article on electrophilic aromatic substitution. Btw, is there an easy way to transfer text from one article to another? Alsosaid1987 (talk) 14:52, 29 August 2018 (UTC)
replies: text: Question: Why is sulfonation listed here? Ans: because well-intentioned editors thought that RSO2Cl etc + ArH is an example of Friedel-Crafts repertoire without checking sacred tomes.  In any case, I moved the offending section to sulfones and sulfoxides.--Smokefoot (talk) 17:29, 29 August 2018 (UTC)
thread_title:  Why is sulfonation listed here? 

message: This compound is found to be unstable at room temperature. Chlorine is a good leaving group and the hydrogen left is very acidic. The hydrogen also donates it's electron and forms HCl. In the first place, we create HCOCl by simply putting HCl and CO under high pressure. At normal conditions they go back to their constituents according to Le Chatelier's principle. 2405:201:C02C:E107:1060:510C:702:D018 (talk) 18:04, 19 February 2023 (UTC)
thread_title:  Why formyl chloride is unstable?