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1. A method for forming low-aromatic high-octane product streams comprising:
isomerizing a feedstock stream with a C6 cyclic content to form an isomerization effluent; separating, from the isomerization effluent, a heavy stream comprising C4 and heavier hydrocarbons and a stream comprising hydrogen and C3 and lighter boiling hydrocarbons; deisohexanizing or deisoheptanizing the heavy stream and forming an overhead stream comprising light gases and butane, an upper sidecut stream comprising normal pentane, methylbutane, and dimethylbutanes, a lower sidecut stream comprising normal hexane and monomethylpentanes, and a cycloalkane-rich stream; admixing hydrogen with the cycloalkane-rich stream to form a second isomerization feed consisting essentially of hydrogen and the cycloalkane-rich stream; and isomerizing the second isomerization feed at equilibrium conditions favoring formation of cyclopentanes over cyclohexanes, wherein isomerizing the second isomerization feed occurs at a temperature of at least about 200° C.
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