Reversible Selectivity Modulation of Gasoline and Diesel by a Facile Metal-Salt-Modified Fischer-Tropsch Synthesis Strategy

摘要

It has long been known that inorganic additives enhance the product selectivity in organic catalytic transformations. However, the potential of this facile approach in the industrially significant Fischer-Tropsch synthesis (FTS) has not been well explored. Herein, after examining the promotion effects of a diversified range of metal sulfates on product distribution over an active and recyclable Ru/P25 catalyst in the aqueous-phase, low-temperature FTS, we show that whereas enhancing the selectivity to diesel is a general feature for most metal sulfates, nickel sulfate is unique in enhancing the selectivity to gasoline. Moreover, this strategy enables the reversible boosting of the selectivity to gasoline or diesel with ease and thus provides access to a FTS process with unprecedented versatility. Probe reactions and theoretical studies point to the scenario that metal sulfates modify the reaction pathway by affecting the stability of the endogenous alpha-olefins, which hence alters the probability of chain growth and product distribution.