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Unlike acid-catalyzed ester hydrolysis, it is not an equilibrium reaction and proceeds to completion. Hydroxide ion attacks the carbonyl carbon to give a tetrahedral intermediate, which then expels an alkoxide ion. The resulting carboxylic acid quickly protonates the alkoxide ion to give a carboxylate ion and an alcohol. [1]
The final step in the reduction of carboxylic acids and esters is hydrolysis of the aluminium alcoxide. [8] Esters (and amides) are more easily reduced than the parent carboxylic acids. Their reduction affords alcohols and amines, respectively. [9] The idealized equation for the reduction of an ester by lithium aluminium hydride is:
The Bouveault–Blanc reduction is a chemical reaction in which an ester is reduced to primary alcohols using absolute ethanol and sodium metal. [1] It was first reported by Louis Bouveault and Gustave Louis Blanc in 1903. [2] [3] [4] Bouveault and Blanc demonstrated the reduction of ethyl oleate and n-butyl oleate to oleyl alcohol. [5]
The hydroxide anion adds to the carbonyl group of the ester. The immediate product is called an orthoester. Saponification part I. Expulsion of the alkoxide generates a carboxylic acid: Saponification part II. The alkoxide ion is a strong base so the proton is transferred from the carboxylic acid to the alkoxide ion, creating an alcohol:
The reaction mechanism for this reaction has several steps: Proton transfer from acid catalyst to carbonyl oxygen increases electrophilicity of carbonyl carbon. The carbonyl carbon is then attacked by the nucleophilic oxygen atom of the alcohol; Proton transfer from the oxonium ion to a second molecule of the alcohol gives an activated complex
In the Tishchenko reaction, the base used is an alkoxide rather than hydroxide, and the product is an ester rather than the separate alcohol and carboxylate groups. After the nucleophilic base attacks an aldehyde, the resulting new oxygen anion attacks another aldehyde to give a hemiacetal linkage between two of the formerly aldehyde-containing ...
Alcohol oxidation is a collection of oxidation reactions in organic chemistry that convert alcohols to aldehydes, ketones, carboxylic acids, and esters. The reaction mainly applies to primary and secondary alcohols. Secondary alcohols form ketones, while primary alcohols form aldehydes or carboxylic acids. [1] A variety of oxidants can be used.
In organic chemistry, an ortho ester is a functional group containing three alkoxy groups attached to one carbon atom, i.e. with the general formula RC(OR') 3. Orthoesters may be considered as products of exhaustive alkylation of unstable orthocarboxylic acids and it is from these that the name 'ortho ester' is derived.