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AlCl 3 is a common Lewis-acid catalyst for Friedel-Crafts reactions, both acylations and alkylations. [14] Important products are detergents and ethylbenzene . These types of reactions are the major use for aluminium chloride, for example, in the preparation of anthraquinone (used in the dyestuffs industry) from benzene and phosgene . [ 12 ]
A typical Lewis acid catalyst is aluminium trichloride. Because, however, the product ketone forms a rather stable complex with Lewis acids such as AlCl 3, a stoichiometric amount or more of the "catalyst" must generally be employed, unlike the case of the Friedel–Crafts alkylation, in which the catalyst is constantly regenerated. [13]
Aniline (from Portuguese anil 'indigo shrub', and -ine indicating a derived substance) [6] is an organic compound with the formula C 6 H 5 NH 2. Consisting of a phenyl group ( −C 6 H 5 ) attached to an amino group ( −NH 2 ), aniline is the simplest aromatic amine .
The Gattermann reaction (also known as the Gattermann formylation and the Gattermann salicylaldehyde synthesis) is a chemical reaction in which aromatic compounds are formylated by a mixture of hydrogen cyanide (HCN) and hydrogen chloride (HCl) in the presence of a Lewis acid catalyst such as aluminium chloride (AlCl 3). [1]
Two common modes of Lewis acid catalysis in reactions with polar mechanisms. In reactions with polar mechanisms, Lewis acid catalysis often involves binding of the catalyst to Lewis basic heteroatoms and withdrawing electron density, which in turn facilitates heterolytic bond cleavage (in the case of Friedel-Crafts reaction) or directly activates the substrate toward nucleophilic attack (in ...
Scheme 4 depicts this 4 component reaction with the ethyl ester of glyoxylic acid, 3,4-dihydro-2H-pyran, aniline and ethanol with lewis acid scandium(III) triflate and molecular sieves. Scheme 4 Four component Povarov reaction. In order to clarify the role of the lewis acid, a solid scandium nitrogen bond is drawn.
The most common Lewis bases are anions. The strength of Lewis basicity correlates with the pK a of the parent acid: acids with high pK a 's give good Lewis bases. As usual, a weaker acid has a stronger conjugate base. Examples of Lewis bases based on the general definition of electron pair donor include: simple anions, such as H − and F −
Chlorobenzene is manufactured by chlorination of benzene in the presence of a catalytic amount of Lewis acid such as ferric chloride, sulfur dichloride, and aluminium chloride: [6] Industrially the reaction is conducted as a continuous process to minimize the formation of dichlorobenzenes .