This paper deals with the liquid-phase oxidation of ethylbenzene (EB) with air to give ethylbenzene hydroperoxide (EBHP), catalysed by bis(acetylacetonate)nickel(II) and tetra-n-butylammonium tetrafluoroborate, in a stirred tank reactor, at atmospheric pressure. This catalytic system offers some advantages over the currently used industrial catalysts, and the use of a quaternary ammonium tetrafluoroborate has not been reported previously for this reaction. The effects of temperature, stirring speed, and catalysts concentration on EB conversion and EBHP selectivity and formation kinetic rate have been studied, and the optimal values found are 125 degrees C (at atmospheric pressure), 1400 rpm and 1.5x10(-4) and 2.0x10(-3) M for bis(acetylacetonate)nickel(II) and tetra-n-butylammonium tetrafluoroborate, respectively.