Aldol Reaction
The aldol reaction, or aldol condensation, is a reaction between two open chain (aliphatic) aldehyde molecules to produce a compound called a beta hydroxyaldehyde (an aldol). This reaction is an example of a polymerization reaction and it occurs only with those compounds containing the CH2CHO functional group.
An aldol is both an aldehyde and an alcohol at the same time, meaning that it possesses both -COH (aldehyde) and -OH (alcohol) functional groups. Aldols can be produced by reacting an aldehyde with a range of alkaline condensing reagents (for example, sodium ethanoate or dilute sodium hydroxide)in the presence of a catalyst (frequently potassium cyanide) at low temperatures.Aldehydes with a closed ring structure (aromatic aldehydes) undergo a similar reaction called the Cannizzaro reaction. [This reaction is named for Italian chemist Stanislao Cannizzaro (1826-1910) who discovered it in the nineteenth century.]
The product of this reaction is capable of losing water quite easily; this then returns to the starting point of unsaturated aldehydes. Aliphatic ketones (ketones with an open chain structure) react in a similar manner. This reaction can take place between aldehydes or between ketones and it can also take place between aldehydes and ketones. When a ketone is involved the resultant product is a beta hydroxyketone.
The simplest aldol—CH3CHOHCH2CHO—is produced from ethanal. This is the first stage in the manufacture of 1-butanol which is an important solvent for resins and lacquers. The United States produces some 40,000 metric tons of 1-butanol annually.
This is the complete article, containing 239 words
(approx. 1 page at 300 words per page).
