Friedel-Crafts Reaction

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Friedel-Crafts reaction

[frē¦del ′krafs rē‚ak·shən]
(organic chemistry)
A substitution reaction, catalyzed by aluminum chloride in which an alkyl (R‒) or an acyl (RCO‒) group replaces a hydrogen atom of an aromatic nucleus to produce hydrocarbon or a ketone.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Friedel-Crafts Reaction

 

a method of alkylating and acylating aromatic compounds in the presence of acidic catalysts, such as AlCl3, BF3, ZnCl2, FeCl3, mineral acids, oxides, and cation-exchange resins. The alkylating agents used are alkyl ha-lides, olefins, alcohols, and esters. The acylating agents include carboxylic acids and their acid halides and their anhydrides.

The Friedel-Crafts reaction is a typical electrophilic substitution reaction in the aromatic nucleus; the role of the catalyst amounts to the generation of an attacking particle—an alkyl or acyl cation.

Examples are given below of the interaction of benzene with the ethyl chloride and the acid chloride of acetic acid:

Friedel-Crafts alkylation is used in industry to produce high-octane fuels, antioxidants, surfactants, perfumes, ethylbenzene (starting material in styrene manufacture), and other important products, such as cumene and thymol. Friedel-Crafts acylation is a basic method of synthesizing aromatic and aliphatic-aromatic ketones, many of which are intermediate products in the manufacture of pharmaceuticals and various dyes, such as Michler’s ketone.

The Friedel-Crafts reaction was discovered by C. Friedel and J. Crafts in 1877–78.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Maggi, "Use of solid catalysts in Friedel-Crafts acylation reactions," Chemical Reviews, vol.
Recently, we reported the synthesis of novel poly(aryl ether ketone)s containing amide linkages in main chains by the electrophilic Friedel-Crafts acylation copolycondensation, the copolymers obtained with low content of amide linkages had not only much higher [T.sub.g]s than the conventional PEEK and PEKK due to the existence of intermolecular hydrogen bonding, but also moderate [T.sub.m]s, which are suitable for melt processing, but the resistance to organic solvents and the thermal stability decreased with the incorporation of amide linkages [38-42].
1,4-Bis(4-phenoxybenzoyl)naphthalene (BPOBN) was prepared by the Friedel-Crafts acylation reaction of 1,4-naphthalenedicarboxylic acid dichloride with excess diphenyl ether in 1,2-dichloroethane (DCE) as shown in Scheme 1.
Yang, Friedel-Crafts Acylation of Indoles in Acidic Imidazolium Chloroaluminate Ionic Liquid at room Temperature, Tetrahedron Lett., 43, 5793 (2002).
Advances in Friedel-Crafts acylation reactions; catalytic and green processes.
The Friedel-Crafts acylation reaction is of interest to organic chemists in academia and industry.
Chemical properties related to unsaturated centres: Hydrogenation; Oxidation through reaction with oxygen; Biological oxidation; Other oxidation reactions; Halogenation; Stereomutation; Metathesis; Double bond migration and cyclisation; Dimerisation (dimer acids, isostearic acid, estolides, Guerbet alcohols and acids); Neighbouring group participation; Friedel-Crafts acylation and related reactions.
Recently, we described the preparation of novel polyfaryl ether ketone)s containing amide linkages in main chains by the electrophilic Friedel-Crafts acylation copolycondensation, the resulting copolymers with low content of amide linkages had not only much higher [T.sub.g]s than the conventional PEEK and PEKK due to the existence of intermolecular hydrogen bonding, but also moderate [T.sub.m]s, which are suitable for melt processing, but the resistance to organic solvents and the thermal decomposition temperature ([T.sub.d]) decreased with the introduction of amide linkages [23-26].
It is well known that premature polymer precipitation from initially homogeneous solution in Friedel-Crafts acylation polycondensation synthesis prevents further macromolecular chain growth reactions and produces polymer of undesirably low molecular weight and of poor thermal stability.
It is generally accepted that premature polymer precipitation from initially homogeneous solution in Friedel-Crafts acylation polycondensation synthesis prevents further macromolecular chain growth reactions and produces polymer of undesirably low molecular weight and of poor thermal stability.
Figure 1 shows the Friedel-Crafts acylation reaction scheme used to prepare the amine-functionalized graphenes in this work.
The polymer was synthesized by using Friedel-Crafts acylation of polystyrene with benzoyl chloride, and was characterized by different instrumentations.