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Isooctane, for HPLC 99%+ - is an organic compound with the formula (CH3)3CCH2CH(CH3)2. It is one of several isomers of octane (C8H18).
I 1639 (OTTO) Isooctane, for HPLC 99%+ Cas 540-84-1 - used in relatively large proportions to increase the knock resistance of the fuel.