“aldol reaction”的概念、定义、翻译、参考文献-科学参考

aldol reaction

Chemistry

A reaction of aldehydes of the type
${2 RCH}_{2} CHO ⇌ {RCH}_{2} CH (OH) CHRCHO$
where R is a hydrocarbon group. The resulting compound is a hydroxy-aldehyde, i.e. an aldehyde-alcohol or aldol, containing alcohol (–OH) and aldehyde (–CHO) groups on adjacent carbon atoms. The reaction is base-catalysed, the first step being the formation of a carbanion of the type RHC-CHO, which adds to the carbonyl group of the other aldehyde molecule. For the carbanion to form, the aldehyde must have a hydrogen atom on the carbon next to the carbonyl group.
Aldols can be further converted to other products; in particular, they are a source of unsaturated aldehydes. For example, the reaction of ethanal gives 3-hydroxybutenal (acetaldol):
${2 CH}_{3} CHO ⇌ {CH}_{3} {CH (OH) CH}_{2} CHO$
This can be further dehydrated to 2-butenal (crotonaldehyde):
${CH}_{3} {CH (OH) CH}_{2} CHO \to H_{2} O + {CH}_{3} CH : CHCHO$

单词	aldol reaction
释义	aldol reaction Chemistry A reaction of aldehydes of the type ${2 RCH}_{2} CHO ⇌ {RCH}_{2} CH (OH) CHRCHO$ where R is a hydrocarbon group. The resulting compound is a hydroxy-aldehyde, i.e. an aldehyde-alcohol or aldol, containing alcohol (–OH) and aldehyde (–CHO) groups on adjacent carbon atoms. The reaction is base-catalysed, the first step being the formation of a carbanion of the type RHC-CHO, which adds to the carbonyl group of the other aldehyde molecule. For the carbanion to form, the aldehyde must have a hydrogen atom on the carbon next to the carbonyl group. Aldols can be further converted to other products; in particular, they are a source of unsaturated aldehydes. For example, the reaction of ethanal gives 3-hydroxybutenal (acetaldol): ${2 CH}_{3} CHO ⇌ {CH}_{3} {CH (OH) CH}_{2} CHO$ This can be further dehydrated to 2-butenal (crotonaldehyde): ${CH}_{3} {CH (OH) CH}_{2} CHO \to H_{2} O + {CH}_{3} CH : CHCHO$
随便看	von Kármán, Theodore (1881–1963) von Laue, Max von Laue, Max Theodor Felix von Mises distribution von Mises, Richard Martin Edler (1883–1953) Vonnegut, Bernard Von Neumann, John Von Neumann, John (1903–57) von Neumann, John (1903–57) von Neumann machine von Neumann universe von Ohain, Hans Joachim Pabst von Thünen models von Wright, Georg Henrik (1916–2003) von Zeipel theorem Voortrekkers V operation VOR Voronoi diagram Voronoi, Georgy Fedoseevich (1868–1908) Voronoi polygon Voronoi polyhedron Vorster, John (1915–83) vortal vortex