How is sulfuric acid used in petroleum refining?

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A labeled diagram highlights sulfur's position on the periodic table, showing its atomic number 16, symbol S, atomic weight range, electron configuration, and classification as a solid, strongly acidic, orthorhombic nonmetal at room temperature. — sulfur Chemical properties of sulfur.

In petroleum refining, sulfuric acid is primarily utilized in two ways:

Alkylation: Concentrated sulfuric acid (typically 98 percent purity) serves as a catalyst in the alkylation process. This reaction combines light olefins (such as propylene and butylene) with isoparaffins (usually isobutane) to produce high-octane gasoline components, such as isooctane. Because the reaction is exothermic, refrigeration is required to maintain temperatures between 2 and 7 °C (35 to 45 °F).12
Impurity Removal: The acid is also used to remove impurities from fuels and lubricants, including gasoline and kerosene.23

It is important to handle this substance with extreme care, as it is a highly corrosive and dangerous chemical that can cause severe burns upon contact with skin.24