Saved Bookmarks
| 1. |
Give beta-elimination of given alcohol reaction. (i) Propyl alcohol (ii) Isopropyl alcohol (iii) Cyclo hexanol (iv) tertiary-butyl alcohol. |
|
Answer» SOLUTION :Alcohol treated with conc. `H_(2)SO_(4)`, on dehydration, alkene is formed also known as `beta`-elimination reaction. (i) `underset("Propane-1-ol")underset("(m-propyl-alcohol)")(CH_(3)CH_(2)CH_(2)OH) underset(Delta 443 K)overset("Conc. " H_(2)SO_(4))rarr underset("Propene")(CH_(3)H=CH_(2)+H_(2)O)` (ii)`underset("alcohol")underset("(isopropyl-ol)")underset("propane-2-ol")(CH_(3)CHOHCH_(3))underset(438-443 K)overset(H_(2)SO_(4))rarr underset("Propene")(CH_(3)CH=CH_(2)+H_(2)O)` (III)  (iv) `underset((3^(@)" BUTYL alcohol"))underset("2,2-Dimethyl propane-2-ol")(H_(3)C-underset(OH)underset(|)overset(CH_(3))overset(|)(""^(alpha)C)-overset(beta)(CH_(3)))underset(Delta, 360 K)overset(H_(2)SO_(4))rarr underset("(very easily)")underset("2-Methyl propane")(H_(3)C-overset(CH_(3))overset(|)(C)=CH_(2))` Note : (i) Rate of reaction `3^(@)`-Alcohol `gt 2^(@)`-Alcohol `gt 1^(@)`-Alcohol. (ii) dehydration reaction occurs in PRESENCE of `ZnCl_(2)` or anhydrous `Al_(2)O_(3)`. |
|