Which nonhydrocarbon group forms the largest share of compounds in petroleum?

• A. Nitrogen compounds
• B. Sulfur compounds
• C. Oxygenates
• D. Halogenated hydrocarbons

Answer: (B)

Sulfur-containing compounds are the most common nonhydrocarbon species in crude oil. In most petroleum samples, the amount of sulfur is higher than that of nitrogen- or oxygen-containing compounds, while halogenated hydrocarbons occur only in trace amounts. This makes sulfur compounds the largest share of nonhydrocarbon groups. Practically, this drives desulfurization needs in refining and explains why sulfur compounds influence catalytic processing and emissions, more so than nitrogen or oxygenates or halogenated hydrocarbons.