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In acidic Shiina esterification, Lewis acid catalysts are used, while nucleophilic catalysts are used for Shiina esterification under basic conditions. Shiina esterification using Lewis acid catalyst. In the acidic reaction, 4-trifluoromethylbenzoic anhydride (TFBA) is mainly used as a dehydration condensation agent.
The Yamaguchi esterification is the chemical reaction of an aliphatic carboxylic acid and 2,4,6-trichlorobenzoyl chloride (TCBC, Yamaguchi reagent) to form a mixed anhydride which, upon reaction with an alcohol in the presence of stoichiometric amount of DMAP, produces the desired ester. It was first reported by Masaru Yamaguchi et al. in 1979 ...
The natural esterification that takes place in wines and other alcoholic beverages during the aging process is an example of acid-catalysed esterification. Over time, the acidity of the acetic acid and tannins in an aging wine will catalytically protonate other organic acids (including acetic acid itself), encouraging ethanol to react as a ...
Shiina macrolactonization using Lewis acid catalyst. In the acidic reaction, 4-trifluoromethylbenzoic anhydride (TFBA) is mainly used as a dehydration condensation agent. First, the Lewis acid catalyst activates the TFBA, and then a carboxyl group in seco acid reacts with the activated
2-Methyl-6-nitrobenzoic anhydride is an organic acid anhydride also known as the Shiina reagent, [1] [2] having a structure wherein carboxylic acids undergo intermolecular dehydration condensation. It was developed in 2002 by Prof. Isamu Shiina (Tokyo University of Science, Japan). [3] The compound is often abbreviated MNBA.
The classic example of a dehydration reaction is the Fischer esterification, which involves treating a carboxylic acid with an alcohol to give an ester RCO 2 H + R′OH ⇌ RCO 2 R′ + H 2 O. Often such reactions require the presence of a dehydrating agent, i.e. a substance that reacts with water.
Many acids can function as sources for the protons. Acid used for acid catalysis include hydrofluoric acid (in the alkylation process), phosphoric acid, toluenesulfonic acid, polystyrene sulfonate, heteropoly acids, zeolites. Strong acids catalyze the hydrolysis and transesterification of esters, e.g. for processing fats into biodiesel. In ...
The reaction mechanism is described as follows: . With amines, the reaction proceeds without problems to the corresponding amides because amines are more nucleophilic.If the esterification is slow, a side-reaction occurs, diminishing the final yield or complicating purification of the product.