Common electrophilic substitution reactions are

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Common electrophilicsubstitution reactions arehalogenation, FriedelCraft’s reaction etc.Halogenation reactionof ethers: Aromaticethers undergohalogenation, forexample, bromination,when we add a halogen inthe presence or absenceof a catalyst.Friedel Craft’s reactionof ethers: Aromaticethers undergo FriedelCraft’s reaction forexample addition of alkylor acyl group when weintroduce it to an alkyl oracyl halide in thepresence of a Lewis acidas catalyst.Reactions of EtherEthers are relatively unreactivecompounds. The ether linkage isquite stable towards bases,oxidizing agents, and reducingagents. Therefore, we mustremember that with respect to theether linkage, ethers undergo justone kind of reaction. It is cleavageby acids :R-O-R’ + HXR-X + R’-OHR’ ¾XReactivity of HX : HI > HBr > HClCleavage takes place only underquite extreme conditions, like inconcentrated acids (usually HI orHBr) and high temperatures. Adialkyl ether produces, initially, analkyl halide and an alcohol. Thisalcohol may react further and forma second mole of alkyl halide. Forexample :The oxygen of an ether is basic,similar to the oxygen of an alcohol.The initial reaction between anether and an acid is no doubt, theformation of the protonated ether.Cleavage, then, involves thenucleophilic attack by a halide ionon this protonated ether, with thedisplacement of the weakly basicalcohol molecule.Such a reaction usually occursmuch more readily as compared tothe displacement of the stronglybasic alkoxide ion from the neutralether.Reactions of Ether Due to anAlkyl GroupCombustion :Ethers arehighly inflammable andthey form extremelyexplosive mixtures withair giving CO2and water.C2H5O C2H5+ 6O24CO2+ 5H2OHalogenation:The alkylgroup undergoessubstitution reaction withchlorine or bromine. Theresultant product ishalogenated ether inabsence of sunlight.
However, in presence ofsunlight, it substitutes alltheCH3CH2OCH2CH3CH3CHCIOCHCICH3(α α’-dichlorodiethyl ether)CH3CH2OCH2CH3C2CI2OC2CI5(Perchloro diethylether)2) Reaction of Ether Due toEthereal OxygenEthers behave as Lewis basesbecause of the presence of twolone pairs of electrons on theoxygen atom. Therefore, they formsalts with strong acids. Theoxonium salts are soluble in acidsolution.Ethers also form coordinationcomplexes with Lewis acids like BF3,AICI3, RMgX etc. Therefore, e canderive the fact that ethers are verygood solvents for Grignardreagents.3) Formation of PeroxidesEthers form peroxide linkage withoxygen when we expose them toair or ozonized oxygen in presenceof sunlight or ultraviolet light.These peroxides are highlypoisonous in nature. They are oilyliquids and decompose violentlyeven at low concentrations.

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halogenated ether

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