Junlong Liu

Stability Enhancement of H-Mordenite in Dimethyl Ether Carbonylation to Methyl Acetate by Pre-adsorption of Pyridine

The carbonylation of dimethyl ether to methyl acetate over H-mordenite (HMOR) and pyridine-modified HMOR was compared. The catalytic stability of HMOR was improved significantly by pyridine pre-adsorption, and a yield of methyl acetate ∼30% was still obtained after 48 h on stream at 473 K. In situ infrared spectroscopy and ammonia temperature-programmed desorption revealed that pyridine preferentially occupied the acidic sites in 12-membered ring pores but not the acidic sites in 8-membered ring pores. 129Xe NMR studies suggested that the channels of HMOR were blocked by coke in the reaction but those in the pyridine-modified HMOR were not. The acidic sites in the 12-membered ring pores were responsible for the deactivation of HMOR, and the reaction can be directed to occur mainly on the acidic sties in the 8-membered ring pores by the selective adsorption of pyridine in the 12-membered ring pores.

Synthesis and Catalytic Performance of Manganese Oxide Octahedral Molecular Sieve Nanorods for Formaldehyde Oxidation at Low Temperature

Abstract Uniform manganese oxide octahedral molecular sieve (OMS-2) nanorods were synthesized by adding a small quantity of K 2 S 2 O 8 to the solution containing MnSO 4 ·H 2 O and KMnO 4 , and used for complete oxidation of formaldehyde. According to the results of N 2 adsorption and X-ray diffraction, the material is a manganese oxide octahedral molecular sieve with the cryptomelane type structure. TEM observation shows that the diameters of the nanorods range from 15 to 25 nm, and the lengths are 300–400 nm. Complete conversion of HCHO to CO 2 and H 2 O can be achieved at 353 K over OMS-2, and the same conversion is obtained at 373 K on the MnO x powder under the same conditions, which demonstrates that the catalytic activity is closely related to the morphology of the catalysts.

Transfer dehydrogenation of alcohols over ceria-supported Cu, Ir, and Pd catalysts

Abstract Ceria-supported Cu, Ir, and Pd catalysts showed quite promising activity for transfer dehydrogenation of cyclohexanol and 2-octanol to cyclohexanone and 2-octanone, respectively, using styrene as the hydrogen acceptor. The Cu/CeO2 and Pd/CeO2 catalysts were more active than the previously reported Cu and Pd catalysts supported on Al2O3, and the Ir/CeO2 catalyst exhibited extremely high activity. The reactivity of alcohols decreased in the order 2-octanol > cyclohexanol > benzyl alcohol > 1-octanol. The synergistic effect between the metals and CeO2 as well as the effective coupling of dehydrogenation of alcohols and hydrogenation of styrene was responsible for the high catalytic activity.

Exploration of cinnamaldehyde hydrogenation in Co–Pt/γ‐Al2O3 catalytic membrane reactors

The feasibility of Co–Pt/γ‐Al2O3 catalytic membrane reactors for cinnamaldehyde hydrogenation has been explored. The results of hydrogenation in four membrane reactors with different configurations indicate that the effect of the gas transport limitation is more important than the liquid diffusion limitation. The membrane with the catalytic layer situated on the gas side shows the highest activity due to the minimized gas transport limitation.