Naphtha (petroleum), C 4-12 butane- alkylate, isooctane-rich; Low boiling point modified naphtha (A complex combination of hydrocarbons obtained by alkylation of butanes. It consists predominantly of hydrocarbons having carbon numbers predominantly in the range of C 4 through C 12 , rich in isooctane, and boiling in the range of approximately 35 °C to 210 °C.)