If a catalyst is used as well it is known as catalytic cracking. It is known as hydrocracking if the catalytic process is conducted in a hydrogen atmosphere. Cracking causes molecular decomposition and recombination to produce a range of more useful base chemicals. A process based on the difference in boiling points of the liquids in the mixture to be separated. Successive vaporisation and condensation of crude oil in a fractionating column will separate out the lighter products, leaving a residue of fuel oil or bitumen.
Distillation is carried out in such a way as to avoid any cracking.
It is the basic process that takes place in an oil refinery. While the extra pairs of electrons give the bond more energy they also make it more chemically reactive. Elastomer A polymer with the properties of rubber. Polymers that can be formulated as elastomers are polyurethane, butyl rubber, silicones and specially treated ethylene-propylene copolymers. Ethylene An olefin consisting of two carbon atoms and four hydrogen atoms, a very important base chemical in the chemical and plastics industries.