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Predict the major product of acid-catalysed dehydration of (i) 1-methylcyclohexanol and (ii) butan-1-ol. |
Answer» Solution :(i) Acid-catalysed dehydration of 1-methylcyclohexanol can, in principle, give two produces, VIZ., I and II. But since product (I) is more highly substituted, THEREFORE, according to Saytzeff rule, it is the major  (ii) Acid-catalysed dehydration of butan-1-ol produces but-2-ene as the major product and but-1-ene as the minor product. the reason being the dehydration of alcohols occurs through carbocation intermediates. now butan-1-ol being a `1^(@)` alcohol upon PROTONATION and elimination of `H_(2)O` first gives a `1^(@)` carbocation (I) which being less stable rearrages to FORM the more stable `2^(@)` carbocation (II). this can then lose a proton in two different ways to form either but-2-ene or but-1-ene. Since buut-2-ene is more stable, therefore, according to Sayyttzeff rule, this is the major product. 
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