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What is Fischer esterification? |
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Answer» Solution :When a carboxylic acid is HEATED with an ALCOHOL in the presence of concentrated sulphuric acid or dry hydrogen chloride gas, an ester is obtained. The reaction is called Fischer esterification. This is reversible reaction and the formation of ester is favoured USING excess of alcohol in the presence of conc. `H_(2)SO_(4)`. Here, concentrated sulphuric acid acts as dehydrating agent. `underset("carboxylic acid alchol")(R - overset(O)overset(||)C- OH + HO-R) overset(H^(+))hArr underset("ester")(R-overset(O)overset(||)(C)-O-R+H_(2)O+)` e.g., `underset("acetic acid")(CH_(3)) - overset(O)overset(||)(C) - OH + H underset("ethyl alchol")-O C_(2)H_(5) underset(Delta)overset(conc. H_(2)SO_(4))to underset("ethyl ACETATE")(CH_(3)-overset(O)overset(||)(C) -OC_(2)H_(5) +H_(2)O)` `underset("propionic acid")(CH_(3)-CH_(2))-overset(O)overset(||)(C) - OH+ CH_(3) - OH underset(Delta)overset(conc.H_(2)SO_(4))to underset("methyl propiobate")(CH_(3)-CH_(2))- overset(O)overset(||)(C) - OCH_(3) + H_(2)O` |
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