An aliphatic
gasoline component comprising more than 90 wt % of a mixture of trimethyl substituted compounds and monomethyl substituted compounds in a weight ratio of trimethyl to monomethyl compounds of at least 0.03 and wherein the compounds may be paraffins and olefins. The invention is also directed to a process to prepare an aliphatic
gasoline component by (a) contacting a Fischer-Tropsch synthesis product with a catalyst
system comprising a catalyst, which catalyst comprises an acidic matrix and a
large pore molecular sieve in a riser reactor at a temperature of between 450 and 650° C. at a
contact time of between 1 and 10 seconds and at a catalyst to oil ratio of between 2 and 20 k.g / kg, (b) isolating from the product of step (a) a
gasoline fraction and a fraction comprising iso-
butane and
isobutylene; (c) subjecting the iso-
butane and the iso-butylene obtained in step (b) to an
alkylation step to prepare a trimethyl substituted
pentane, and (d) combining the gasoline fraction obtained in step (b) with the product rich in trimethyl substituted
pentane as obtained in step (c).