Britannica
Sources used in this answer
How are acids used as catalysts in petroleum refining?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
catalysis
Nanoparticles of a gold-palladium (yellow-blue) alloy supported on acid-treated carbon (gray) directly catalyzing hydrogen peroxide formation from hydrogen (white) and oxygen (red) while shutting off unwanted hydrogen peroxide decomposition.
In petroleum refining, acids serve as essential catalysts to convert light hydrocarbons into high-octane gasoline components through several key processes.12
Primary Acid-Catalyzed Processes
- Polymerization: Light olefins, such as propylene and butylene, are combined to form larger molecules. This process typically utilizes phosphoric acid supported on porous pellets.1
- Alkylation: This process combines an olefin with an isoparaffin (usually isobutane) to produce high-quality blending components like isooctane. Industry standards rely on two primary acid systems:
- Sulfuric acid: Used at low temperatures (2–7 °C), requiring refrigeration to manage the heat generated by the reaction.1
- Hydrofluoric acid: Allows for higher operating temperatures, eliminating the need for refrigeration. Because this substance is highly toxic and corrosive, its use requires stringent safety protocols.1
- Isomerization: Acids such as aluminum chloride are used to rearrange straight-chain hydrocarbons into branched-chain structures to improve fuel quality.23
- Cracking: High-molecular-weight hydrocarbons are decomposed into smaller molecules using alumina-silica catalysts, which function as Brønsted-Lowry acids.2