Isomerization of butane yields gasoline with an unleaded octane number around __________________?
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Answer: C. 70
Explanation
Catalytic isomerization converts straight-chain normal butane into branched isobutane molecules efficiently. Isomerization of butane produces a reaction product yielding an unleaded motor octane number around seventy. Branching the carbon chain increases resistance to engine knock compared to the straight-chain precursor. Isomerism involves molecules sharing identical chemical formulas but possessing different structural arrangements. Normal butane has a straight four-carbon chain, whereas isobutane features a branched carbon skeleton. Chloride-promoted platinum catalysts facilitate butane isomerization reactions at moderate industrial temperatures.
Refineries use isomerization units to upgrade low-octane paraffin streams into valuable gasoline blending stocks. Isobutane produced via isomerization also serves as a critical feedstock for refinery alkylation units. Enhancing gasoline pool octane without adding aromatic compounds helps refiners meet stringent environmental rules. An octane number of forty-five is far too low and represents unbranched heavy paraffinic compounds. Fifty-five falls below the typical octane enhancement achieved through standard catalytic butane isomerization. Ninety represents the higher octane output achieved by isomerizing longer-chain pentane and hexane fractions.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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