Extrusion of Cu/ZnO catalysts for the single-stage gas-phase processing of dimethyl maleate to tetrahydrofuran

Abstract

Bifunctional catalysts consisting of copper, zinc oxide, and γ -alumina have been produced by means of extrusion. The effects of formulation and forming conditions on morphology, pore texture, and copper surface area are discussed. These extruded catalysts have been employed in the fixed-bed gas-phase conversion of dimethyl maleate at temperatures between 453 and 493 K and space velocities ranging from 0.2 to 2.4 h −1 . Copper catalyzes the hydrogenation and hydrogenolysis reactions yielding γ -butyrolactone, and 1,4-butanediol. γ -Alumina provides weakly acidic sites which promote the subsequent dehydration of 1,4-butanediol to tetrahydrofuran. Coupled products are methanol and water. Through choice of composition and pore texture of the extrudates it is possible to achieve tetrahydrofuran yields of 100% (basis the C 4 -products) at a low pressure (2.5 MPa) in a single stage.

Synthesis of Tetrahydropyran from Tetrahydrofurfuryl Alcohol over Cu–Zno/Al2O3 under a Gaseous-Phase Condition

“…The surface areas (S BET ) of the calcined catalysts increased monotonically from 196.4 to 261.7 m 2 ·g −1 with the increase in the content of γ-Al 2 O 3 , though they were generally lower than that of γ-Al 2 O 3 (A 0-0-01 ) ( Table 1). This is consistent with the study by Kraushaar-Czarnetzki et al [34]. …”

“…The Cu-ZnO/Al 2 O 3 catalysts were prepared by means of the precipitation-extrusion method [34]. γ-Al 2 O 3 produced from boehmite (>400 mesh and 26% m/m water, Shandong Aluminum Corp., Zibo, China), Cu(NO 3 ) 2 ·3H 2 O (Sinopharm Chemical Reagent Co., Ltd., Shanghai, China), and Zn(NO 3 ) 2 ·6H 2 O (purchased from Sinopharm Chemical Reagent Co., Ltd., Shanghai, China) were dissolved in water with a final total metal concentration of 1.4 M. Aqueous Na 2 CO 3 (0.3 M) was used as a precipitating agent.…”

“…Among non-noble metals, copper-based catalysts were widely used in hydrogenation and hydrogenolysis reactions due to their good catalytic performance and low cost. Müller et al [34] found that dimethyl succinate could be completely converted to THF over CuO-ZnO/Al 2 O 3 at 220/Allely MPa. Guo et al [35] also reported that a selectivity of THF as high as 94% could be obtained over Cu-B/Al 2 O 3 during the hydrogenolysis of dimethylsuccinate.…”

Vapour phase hydrogenolysis of biomass-derived diethyl succinate to tetrahydrofuran over CuOZnO/solid acid bifunctional catalysts

“…The selectivity of BDO increased linearly at the expense of GBL with increasing pressure, which suggests the presence of reversible inter-conversion between GBL and BDO. 15,18,19 At 1.0 MPa, the selectivity of THF was improved to 12.0%, and no enhancement was found at higher pressures. The above results indicate that the co-precipitated CuO-ZnO is a promising catalyst for the hydrogenolysis of DES.…”

“…17 the cyclo-dehydration of BDO to THF has been weakly catalyzed by CuO-ZnO catalyst with a low selectivity to the target THF (Scheme 1). 16 -18 Müller et al 19 reported that dimethyl succinate was completely converted to THF over CuO-ZnO/Al 2 O 3 at 220…”