To meet the global demand for shorter-chain hydrocarbons, heavier fractions obtained from the fractional distillation of crude oil are converted into more useful fuels and chemical feedstocks through industrial cracking.
Which statement regarding these industrial cracking processes is correct?
Thermal cracking is conducted at high pressures and temperatures, primarily yielding a high proportion of branched-chain alkanes and aromatic hydrocarbons.
Catalytic cracking operates at lower temperatures and pressures than thermal cracking, using a zeolite catalyst to produce branched alkanes and cycloalkanes.
Unlike fractional distillation, cracking is a physical separation process that utilizes thermal energy to separate structural isomers without breaking covalent bonds.
The catalytic cracking of long-chain alkanes proceeds via a free-radical intermediate mechanism, which is highly selective for producing ethene.