Acylation

The two most powerful tools in the organic chemistry are the alkylation reaction and the second one which is the acylation reaction. Here we are dealing with the Acylation Reaction.

There are various numbers of organic chemical structures and elements, since the carbon can form links to itself by forming chains and also rings. The entire molecules can also be added to each other or other elements, and such is the case with the acylation reaction.

Mechanism of Acylation Reaction

 

The mechanism of this Acylation Reaction is the electrophilic aromatic substitution. In Organic chemistry, the acylation is the process or mechanism of adding an acyl group (RCO-) to a particular compound. This compound which provides the acyl group is called as the acylating agent.

Since these form the strong electrophiles when added with some of the metal catalysts, the acyl halides are widely used as the acylating agents. Consider, for example, the Friedel-Crafts acylation reaction uses the acetyl chloride, CH3COCl, as the acylating agents and the compound called aluminum chloride, AlCl3 as the catalyst for adding ethanol or the acetyl group to the benzene. The following reaction shows the mechanism.

Acylation

An acyl group is the alkyl group which is attached to the carbon-oxygen double bond as shown in below figure. If the letter “R” represents the alkyl group, the acyl group will have the formula RCO-. The process of Acylation is to substitute an acyl group into the reaction. The most widely used acyl group is the CH3CO-. It is called as the ethanoyl group.

Acylation

The Acyl halides and the anhydrides of the carboxylic acids are commonly used as the acylating agents for acylating amines forming amides or also acylate alcohols which form the esters. The alcohols and amines are nucleophiles; this mechanism is a kind of nucleophilic acyl substitution reaction. The Succinic acid is commonly used in various types of acylation reactions. Acylation occurs when two or more salts of succinic acid add to form a single compound.

Acylation process is used in preventing the rearrangement reactions which occur in the process of alkylation. For achieving this, the acylation reaction is usually performed, later the carbonyl group is removed by the Clemmensen reduction reaction or some similar process.

Acylation Reaction – Example

A Simple kind of Acylation reaction Example is given below-

The Acetic acid or the CH3COOH, vinegar which is 5 percent of the acetic acid in water are present in form of their chloride, this is the acetyl chloride, having chemical structure CH3-COCl.

The process of Acylating the benzene with such substance in presence of the catalyst aluminum chloride gives this reaction. It is as shown below-

C6H6 + CH3-COCl + catalyst ? C6H5-CO-CH3 + HCl

The above sequence of reaction explains that one molecule of the benzene and one molecule of the acetyl chloride in presence of some of the aluminum chloride catalyst is said to produce one molecule of the methylphenyl ketone and one molecule of the hydrogen chloride gas. The Ketones are of great importance as compounds offering a variety of reaction paths for the additional synthesis process.


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