Question

b) Write the action of Cu on the following: i) Propanol ii) 2-methyl propanol​

Answer 1

Answer:

I)Alcohols are oxidised by passing their vapours over heated copper. 1° alcohols are oxidised to aldehydes ii) 2° to ketones while 3° alcohols undergo dehydration to form alkenes.

Answer 2

Explanation:

i). The gas phase reactions between Cu+ and 2-propanol have been investigated using density functional theory at the B3LYP/6-311+G(d) and B3LYP/6-311++G(d,p) levels of theories. Seven reaction pathways have been studied. Of all reaction paths, the mechanism involving an electrophile-induced one step syn elimination of H2O has the lowest energy barrier. Dehydration also occurs via the intermediate corresponding to C−O insertion of Cu+. On the H2 elimination channel, reaction begins with C−H insertion of Cu+, followed by hydrogen migrations to form H2−Cu+−acetone or the H2−Cu+−2-propenol intermediates. Our results show that the reaction with copper cation insertion into the H−OCH(CH3)2 bond is unlikely, for its activation energy is 24.5 kcal/mol higher than those of the reactants (Cu+ and 2-propanol). The mechanism involving C−C insertion of Cu+ is also energetically unfavorable. The predicted potential energy surface of reaction and relative energies of the fragmentation products are consistent with available gas phase experiments.

ii). Alcohols, Phenols and Ethers

2-methyl propan-2-ol undergo dehydration with Cu at 573 K resulting in 2- methyl propene