摘要 |
Unleaded blend compositions, as well as formulated gasolines containing them have a Motor Octane Number (MON) of at least 80 comprising either: (i) component (a) at least 5% (by volume of the total composition) of at least one hydrocarbon having the following formula I <?in-line-formulae description="In-line Formulae" end="lead"?>R-CH2-CH(CH3)-C(CH3)2-CH3 I<?in-line-formulae description="In-line Formulae" end="tail"?> wherein R is hydrogen or methyl, especially triptane, or (ii) at least 2% of component (a'), which is at least one branched chain alkane of MON value of at least 90 and of boiling point 15-160° C. or a substantially aliphatic hydrocarbon refinery stream, of MON value of at least 85, at least 70% in total of said stream being branched chain alkanes, said stream being obtainable or obtained by distillation from a refinery material as a cut having Initial Boiling Point of at least 15° C. and Final Boiling Point of at most 160° C., said Boiling Points being measured according to ASTMD2892, or (iii) at least 10% of component (a''), which is at least one branched chain alkane of 8-12 carbons with at least 4 methyl or ethyl branches The components (a), (a') and (a'') give rise to reduced emissions to the composition or gasoline on combustion.
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