Conversion of Straight-Run Naphtha to C5−C6 Alkanes on Co(Ni)/HZSM–5/SO42-—ZrO2 Composite Catalysts

Abstract

The conversion of straight-run naphtha on composite catalytic systems containing HZSM-5 zeolite modified with 0.4 wt % Co or Ni and 15% SZ (10% SO₄^2-/ZrO₂), performed at atmospheric pressure in the interval 140–200°C, was studied. At 140–200°C, the major products of straight-run naphtha conversion are branched C₅−C₆ alkanes. At T ≥ 180°C, the reaction products become enriched in gaseous alkanes. Analysis of the conversion products suggests that the process occurs via formation of a skeleton-isomerized intermediate, followed by its cleavage (disproportionation) at the β- or α-bond. The conversion is influenced by the conditions of the reaction and reduction of the composite catalytic system. On the Co-containing composite catalyst reduced at 380°C, the conversion of C₈₊ components of straight-run naphtha at 180°C, feed space velocity of 2.5 h⁻¹, and H₂/CH = 3 is 76.8%, and the content of C₅−C₆ alkanes consisting to 78% of isoparaffins reaches 61%.