Question

Question: Free-radical chlorination of hexane gives very poor yields of 1 clorohexyane, while cyclohexane can be converted to chlorocyclohexane in good yield.

(a)How do you account for this difference?

(b) What ratio of reactants (cyclohexane and chlorine)

Short answer

Answer

(a) There are twelveequivalent protons attached to the secondary carbon atom, and only sixprotonsareattached to the primary carbons in hexene. The desired product with cyclohexane is more likely to occur.

(b) Cyclohexane should be used in excess to the synthesis of chlorocyclohexane.

Step-by-step solution

Free radicals

An atom or group of atoms containing odd or unpaired electronsis known as the free radical. The unpaired electron is represented by a single unpaired dot in the formula. Free radicals are electrically neutral. They are highly reactive species formed by homolytic fission of a covalent bond.

Steps involved in a free radical chain reaction

In a free-radical chain reaction, free radicals are generally created in the initiation steps. A free radical and a reactant is combined to yield a product and another free radical in the propagation steps. Lastly, the number of free radicals generally decreases in the termination steps.

Explanation

(hexane) (poor yield)

(cyclohexane) chlorocyclohexane (good yield)

(a) There are twelveequivalent protons attached to the secondary carbon atom, and only sixprotonsareattached to the primary carbons in hexene. The desired product with cyclohexane is more likely to occur.

(b)Cyclohexane should be used in excess for the synthesis of chlorocyclohexane.