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Due to the strongly alkaline reaction conditions, aldehydes that have alpha hydrogen atom(s) instead undergo deprotonation there, leading to enolates and possible aldol reactions. Under ideal conditions the reaction produces 50% of both the alcohol and the carboxylic acid (it takes two aldehydes to produce one acid and one alcohol). [5]
Pentaerythritol was first reported in 1891 by German chemist Bernhard Tollens and his student P. Wigand. [5] It may be prepared via a base-catalyzed multiple-addition reaction between acetaldehyde and 3 equivalents of formaldehyde to give pentaerythrose (CAS: 3818-32-4), followed by a Cannizzaro reaction with a fourth equivalent of formaldehyde to give the final product plus formate ion.
Pivaldehyde is an organic compound, more specifically an aldehyde.Shown in the image is a line-angle representation of this organic aldehyde, whose systematic name, 2,2-dimethylpropanal, is based on the longest carbon chain (three carbon atoms), ending in "-al" to indicate the aldehyde functionality, and where another descriptive synonym is trimethylacetaldehyde. [2]
The reaction is named after Russian organic chemist Vyacheslav Tishchenko, who discovered that aluminium alkoxides are effective catalysts for the reaction. [1] [2] [3] In the related Cannizzaro reaction, the base is sodium hydroxide and then the oxidation product is a carboxylic acid and the reduction product is an alcohol.
Usually, the crossed product is the major one. Any traces of the self-aldol product from the aldehyde may be disallowed by first preparing a mixture of a suitable base and the ketone and then adding the aldehyde slowly to the said reaction mixture. Using too concentrated base could lead to a competing Cannizzaro reaction. [12]
The reaction is catalyzed by nucleophiles such as a cyanide or an N-heterocyclic carbene (usually thiazolium salts). The reaction mechanism was proposed in 1903 by A. J. Lapworth . [ 7 ] In the first step in this reaction, the cyanide anion (as sodium cyanide ) reacts with the aldehyde in a nucleophilic addition .
A former surgeon who is accused of abusing hundreds of young patients, often while they were under anaesthetic, is set to go on trial this month in the largest child abuse trial in French history.
In the context of butanol fuel, isobutyraldehyde is of interest as a precursor to isobutanol. E. coli as well as several other organisms has been genetically modified to produce isobutanol. α-Ketoisovalerate, derived from oxidative deamination of valine, is prone to decarboxylation to give isobutyraldehyde, which is susceptible to reduction to the alcohol: [3]