Abstract: The catalytic performance of the PdCl2-CuCl2/Li-Al-O catalyst, with palladium as the active component and porous lithium alumina spinel (Li-Al-O) as the support, for vapor-phase synthesis of diethyl carbonate (DEC) from CO and ethyl nitrite was studied in a continuous fixed-bed reactor at low pressure. The Li-Al-O spinel support was synthesized by impregnation of γ-Al2O3(2-3 mm) with aqueous LiNO3 solution. Under the mild reaction conditions of 5%CO-20%EtONO-75%N2, GHSV=2500h-1, 0.3 MPa, and 110 ℃, the CO conversion was 40% and the space time yield of DEC was 418 g/(L•h). The perfectly close-packed spinel structure could be obtained because of the lithium ions that entered the vacancy of γ-Al2O3. The Li-Al-O catalyst support had no strong acid sites, and the catalyst had stable palladium chloride, both of which were favorable for the DEC synthesis reaction.

Key words: diethyl carbonate, carbon monoxide, ethyl nitrite, palladium chloride, copper chloride, alumina, Li-Al-O spinel, supported catalyst