Study On The Oxidative Carbonylation Of Propanol To Dipropyl Carbonate

Dipropyl carbonate (DPC) is one of the important carbonate as an"environmentally benign chemistry". DPC is found to be diesel fuel additive as traditional additive replacement for its competitive chemical properties. The synthesis of DPC by vapor phase direct oxidative carbonylation of propanol was evaluated as"green technology"route with mild condition, unharmful byproduct and high atomic economy.It was carried out based on the system of the CuCl2-PdCl2/AC loaded Wacker type catalyst in this paper. The effect of various promoters and alkali treatment was evaluated. The significant variety on the catalyst activities was closely related with the KCl promoter and KOH treatment. The optimum reaction temperature lies in 433K under 0.6MPa pressure. The conversion of propanol reached above 24.3% and the selectivity of DPC was 93.6% and the STY of DPC was 396gDPC/(Lcat·h).XPS, SEM and BET analysis show that the competitive adsorption between KCl and the active component made the better dispersion of CuCl2 and PdCl2 on the surface of activated carbon. The deactivation of catalysts can be ascribed to the leaching of Cl species. XPS and XRD analysis show that the mixture of two kinds of crystals which are crystallineα-Cu2(OH)3Cl andγ-Cu2(OH)3Cl appear after the alkali treatment to the catalyst. The addition of KCl promoter to the CuCl2-PdCl2 /AC catalyst favors formation of crystallineγ-Cu2(OH)3Cl, which plays a more important role in the DPC synthesis.The influence of alkali pre-treatment for activeted carbon supports on the catalytic performance was mainly studied. The conversion of propanol and the STY of DPC are selectively increased to 26.1% and 451.2g DPC/(Lcat·h) without any decrease of the selectivity of DPC. From FT-IR analysis, the activity of catalyst was found to be improved by KOH pre-treatments for the increased surface oxygen-containing groups, especially C-O bond and C=O bond. BET and ICP-AES analysis show that the increase of surface area of catalyst due to alkali pre-treatment and it is favorable for the loading of CuCl2 and PdCl2.