Chapter 3, Problem 17P

Interpretation Introduction

Interpretation: Various products formed from the pyrolysis of propane with regard to only $\text{C – C}$ bond cleavage as initial step should be written.

Concept introduction: Long-chain petroleum hydrocarbons can be broken down unless highly elevated temperatures are used. At extremely elevated temperature the $\text{C–C}$ bond and $\text{C – H}$ undergoes homolytic cleavage. This process generates radicals and is essentially the first step of pyrolysis. If no oxygen is available the radical formed in initial phase may recombine with one another and result in variety of alkanes. For example, the pyrolysis of hexane occurs via homolytic fission of either ${\text{C}}_1{\text{–C}}_2$ or ${\text{C}}_2{\text{–C}}_3$ or ${\text{C}}_3{\text{–C}}_4$ . The radicals generated undergo combinations as illustrated below:

  

Thus the products have new covalent bonds formed as results of electrons contributed from different atoms.