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Fischer Esterification

Fischer Esterification. NOOR NABEEL BNE SHAMSA. Table of Contents. Objectives Background Reaction and Mechanism Application and recent literature Conclusion references. Objectives. Knowing the reaction application and its recent literature.

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Fischer Esterification

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  1. Fischer Esterification NOOR NABEEL BNE SHAMSA

  2. Table of Contents • Objectives • Background • Reaction and Mechanism • Application and recent literature • Conclusion • references

  3. Objectives • Knowing the reaction application and its recent literature. • To know the Reaction and Mechanism of Fischer Esterification

  4. Background • Fischer esterification or Fischer–Speier esterification is a special type of esterification by refluxing a carboxylic acid and an alcohol in the presence of an acidcatalyst. The reaction was first described by Emil Fischer and Arthur Speier in 1895.[1] Most carboxylic acids are suitable for the reaction, but the alcohol should generally be a primary or secondary alkyl. Tertiary alcohols are prone to elimination, and phenols are usually too unreactive to give useful yields. Commonly used catalysts for a Fischer esterification include sulfuric acid, tosic acid, and Lewis acids such as scandium(III) triflate. For more valuable or sensitive substrates (for example, biomaterials), dicyclohexylcarbodiimide is often used. The reaction is often carried out without a solvent (particularly when a large reagent excess (e.g. of MeOH is used) or in a non-polar solvent (e.g. toluene) to facilitate the Dean-Stark method. Typical reaction times vary from 1–10 hours at temperatures of 60-110°C.

  5. Reaction and Mechanism The Lewis or Brønstedt acid-catalyzed esterification of carboxylic acids with alcohols to give esters is a typical reaction in which the products and reactants are in equilibrium

  6. Mechanism • Addition of a proton (e.g.: p-TsOH, H2SO4) or a Lewis acid leads to a more reactive electrophile. Nucleophilic attack of the alcohol gives a tetrahedral intermediate in which there are two equivalent hydroxyl groups. One of these hydroxyl groups is eliminated after a proton shift (tautomerism) to give water and the ester.

  7. Application and recent literature • Protic Acid Immobilized on Solid Support as an aExtremely Efficient Recyclable Catalyst System for a Direct and Atom Economical Esterification of Carboxylic Acids with AlcoholsA. K. Chakraborti, B. Singh, S. V. Chankeshwara, A. R. Patel, J. Org. Chem., 2009, 74, 5967-5974.

  8. Application and recent literature • FeCl3·6H2O as a Versatile Catalyst for the Esterification of Steroid Alcohols with Fatty AcidsK. Komura, A. Ozaki, N. Ieda, Y. Sugi, Synthesis, 2008, 3407-3410.

  9. references • http://www.organic-chemistry.org/namedreactions/fischer-esterification.shtm • http://www.oppapers.com/essays/Fischer-Esterification-Conclusion/500698 • http://en.wikipedia.org/wiki/Fischer%E2%80%93Speier_esterification • http://www.writework.com/tag/fischer-esterification

  10. Conclusion • The Fischeresterification method is a fundamental and important synthesis process Fischer esterification involves the formation of an ester from a carboxylic acid and an alcohol. The mechanism is an acid promoted acyl substitution, which results in the substitution of an alkoxy group for the hydroxyl portion of the carboxyl group

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