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Fischer esterification is an acyl substitution reaction based on the electrophilicity of the carbonyl carbon and the nucleophilicity of an alcohol. Carboxylic acids tend to be deprotonated by nucleophiles, which gives an unreactive carboxylate.
A common method for preparing isobutyl acetate is Fischer esterification, where precursors isobutyl alcohol and acetic acid are heated in the presence of a strong acid. Isobutyl acetate has three isomers: n-butyl acetate, tert-butyl acetate, and sec-butyl acetate, which are also common solvents.
The classic synthesis is the Fischer esterification, which involves treating a carboxylic acid with an alcohol in the presence of a dehydrating agent: RCO 2 H + R'OH ⇌ RCO 2 R' + H 2 O. The equilibrium constant for such reactions is about 5 for typical esters, e.g., ethyl acetate. [15] The reaction is slow in the absence of a catalyst.
Fischer glycosidation (or Fischer glycosylation) refers to the formation of a glycoside by the reaction of an aldose or ketose with an alcohol in the presence of an acid catalyst. The reaction is named after the German chemist, Emil Fischer, winner of the Nobel Prize in chemistry, 1902, who developed this method between 1893 and 1895. [1] [2] [3]
In acid-catalyzed Fischer esterification, the proton binds to oxygens and functions as a Lewis acid to activate the ester carbonyl (top row) as an electrophile, and converts the hydroxyl into the good leaving group water (bottom left). Both lower the kinetic barrier and speed up the attainment of chemical equilibrium.
The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester RCO 2 H + R′OH ⇌ RCO 2 R′ + H 2 O. Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water.
Hermann Emil Louis Fischer FRS FRSE FCS (German pronunciation: [ˈeːmiːl ˈfɪʃɐ] ⓘ; 9 October 1852 – 15 July 1919) was a German chemist and 1902 recipient of the Nobel Prize in Chemistry. He discovered the Fischer esterification. He also developed the Fischer projection, a symbolic way of drawing asymmetric carbon atoms. He also ...
Acyl compounds react with nucleophiles via an addition mechanism: the nucleophile attacks the carbonyl carbon, forming a tetrahedral intermediate. This reaction can be accelerated by acidic conditions, which make the carbonyl more electrophilic , or basic conditions, which provide a more anionic and therefore more reactive nucleophile.