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The conversion of ethanol to ethylene is a fundamental example: [3] [4] CH 3 CH 2 OH → H 2 C=CH 2 + H 2 O. The reaction is accelerated by acid catalysts such as sulfuric acid and certain zeolites. These reactions often proceed via carbocation intermediates as shown for the dehydration of cyclohexanol. [5] Some alcohols are prone to dehydration.
In organic chemistry, some dehydration reactions are subject to unfavorable but fast equilibria. One example is the formation of dioxolanes from aldehydes: [9] RCHO + (CH 2 OH) 2 RCH(OCH 2) 2 + H 2 O. Such unfavorable reactions proceed when water is removed by azeotropic distillation.
The reaction may otherwise involve the functional groups of the molecule, and is a versatile class of reactions that can occur in acidic or basic conditions or in the presence of a catalyst. This class of reactions is a vital part of life as it is essential to the formation of peptide bonds between amino acids and to the biosynthesis of fatty ...
Molecular models of the different molecules active in Piranha solution: peroxysulfuric acid (H 2 SO 5) and hydrogen peroxide (H 2 O 2). Piranha solution, also known as piranha etch, is a mixture of sulfuric acid (H 2 SO 4) and hydrogen peroxide (H 2 O 2). The resulting mixture is used to clean organic residues off substrates, for example ...
The carbon snake is a demonstration of the dehydration reaction of sugar by concentrated sulfuric acid. With concentrated sulfuric acid, granulated table sugar ( sucrose ) performs a degradation reaction which changes its form to a black solid-liquid mixture . [ 1 ]
The dehydration of secondary and tertiary alcohols to yield an olefin through a sulfamate ester intermediate is called the Burgess dehydration reaction. [ 13 ] [ 14 ] [ 15 ] The reaction conditions used are typically very mild, giving it some advantage over other dehydration methods for sensitive substrates.
Another useful example is the one pot two-step synthesis of halfordinol, a parent compound for Rutaceae alkaloids. The initial steps follow the Fischer oxazole synthesis, although the acid-catalyzed cyclization occurs in two steps rather than one, which ensures the formation of the di-chloro intermediate , preventing formation of the regioisomer .
An example of the E1cB reaction mechanism in the degradation of a hemiketal under basic conditions. The E1cB elimination reaction is a type of elimination reaction which occurs under basic conditions, where the hydrogen to be removed is relatively acidic, while the leaving group (such as -OH or -OR) is a relatively poor one.