Effect of In-Situ Dehydration on Activity and Stability of Cu–Ni–K2O/Diatomite as Catalyst for Direct Synthesis of Dimethyl Carbonate

Abstract

An in-situ dehydrating system built in a continuous flow fixed-bed bubbling reactor for direct synthesis of dimethyl carbonate (DMC) was designed. 3A molecular sieve (MS) was selected as the ideal dehydrating agent and the water trapping efficiency was studied. The effect of dehydrating agent/catalyst ratio, the dehydrating temperature and pressure, as well as the space velocity on the direct DMC synthesis catalyzed by K2O-promoted Cu–Ni was further investigated. These results demonstrated that 3A MS could effectively dehydrate the reaction system at the optimal conditions of 120 °C and 1.0 MPa with gas space velocity (GHSV) of 600 h−1, thereby greatly shifting the reaction equilibrium toward high DMC yield. Higher DMC yield of 13% was achieved compared with undehydrated reaction. Moreover, the catalyst can be highly stabilized by 3A MS dehydration with stable performs over 22 h.

A Review of Catalysts for Synthesis of Dimethyl Carbonate

“…The above findings indicate that by loading active metal species on the carrier surface, catalysts with acid-base bifunctionality are obtained, which can adsorb both activated methanol and CO 2 , thus generating more of the target product DMC. An in-situ dehydration system for the direct synthesis of dimethyl carbonate (DMC) was formed by combining a supported catalyst with a 3A molecular sieve [90]. Compared with the conventional reaction, the selectivity of DMC remained above 88% at 13 h and decreased to 78% at 22 h under the condition of in-situ dehydration.…”

From ‘Gift’ to gift: producing organic solvents from CO2

“…The authors further investigated the highly active K 2 O-promoted Cu-Ni catalyzed direct DMC synthesis with 3 Å molecular sieves (MS) as a dehydrating agent. 169 The developed in situ dehydrating system enabled higher methanol conversion and selectivity by shifting the reaction equilibrium to a high DMC yield. Recently, a novel Cu x Ni y @POP-PPh 3 catalyst was synthesized and used in direct DMC synthesis by Chen, Ye and coworkers.…”

Catalytic, Photocatalytic, and Electrocatalytic Processes for the Valorization of CO2

“…Finally, the synthesis of dimethylcarbonate (DMC) was investigated by Han et al [30,31]. Different alkali metals were added to Cu-Ni/diatomite catalysts to synthesize DMC from CO 2 and methanol, thanks to their strong electron-donating ability.…”

“…86% selectivity to DMC [31]. Furthermore, the same authors investigated the effect of dehydration using 3A molecular sieves to shift the equilibrium and to improve the stability of a K 2 O-promoted Cu-Ni catalyst [30]. An improved yield of DMC by 13% was obtained with respect to the undehydrated base case and stable performance for 22 h.…”