How did thermal cracking and catalytic cracking expand the petrochemical industry?

Thermal and catalytic cracking were pivotal in the expansion of the petrochemical industry by transforming crude oil refining into a source of essential chemical raw materials.1

Thermal Cracking

The development of thermal cracking in 1913 provided the industry's primary impetus. While initially intended to increase gasoline production, the process generated gaseous by-products—including ethylene, propylene, and butylene—that were recognized in the 1920s and 1930s as valuable chemical feedstocks. These olefins became the building blocks for a vast array of products, such as synthetic rubber and plastics.123

Catalytic Cracking

The introduction of catalytic cracking in 1937 further expanded the industry by allowing for more efficient production of high-quality products under less severe conditions than thermal methods. Catalytic cracking units became significant sources of propylene and butylene, which are critical for polymerization and alkylation processes. By providing a steady supply of these reactive hydrocarbons, both technologies enabled the transition from simple fuel refining to the complex manufacturing of modern chemical goods, including solvents, fertilizers, and synthetic fibers.143