Hydrogenation of dimethyl oxalate to ethylene glycol on a Cu/SiO₂/cordierite monolithic catalyst: Enhanced internal mass transfer and stability

Abstract

in Wiley Online Library (wileyonlinelibrary.com).The design and application of a Cu/SiO 2 -based monolithic catalyst for hydrogenation of dimethyl oxalate (DMO) to ethylene glycol (EG) is presented. The catalyst was dip-coated on cordierite with highly dispersed Cu/SiO 2 slurry prepared by ammonia evaporation method. This structure guarantees high dispersion of copper species within the mesopores of silica matrix in the form of copper phyllosilicate. The catalyst is low cost, stable, and exhibits high activity in the reaction of hydrogenation of DMO, achieving a 100% conversion of DMO and more than 95% selectivity to EG. Notably, STY EG over the monolith is significantly enhanced compared to the packed bed Cu/SiO 2 catalysts in both forms of pellet and cylinder. It is primarily due to the relatively short diffusive pathway of the thin wash-coat layer and high efficiency of the active phase derived from the monolithic catalyst. Theoretical results indicated that the internal mass transfer is dominated on the catalysts of pellet and cylinders. Moreover, the monolithic catalyst possessed excellent thermal stability compared to the pellet catalyst, which is attributed to the regular channel structure, uniform distribution of flow. Catalytic activity testsOur catalytic reactivity system (monolithic fixed-bed MRCS8004B System) (shown in Figure 1) consists of a continuous-flow stainless steel reactor (15 mm i.d. and 350 mm length) inside a horizontal furnace with a temperature controller. The gas distributor has been equipped at the entrance of the reactor to ensure a uniform gas distribution. The monolithic Cu/SiO 2 catalysts were placed in the middle of the (a) scheme of monolith catalyst, (b) SEM images of a monolith channel, and (c) cross-sectional cordierite monolith wash-coated with Cu/SiO2 catalyst, and (d) TEM image of calcined wash-coat layer.

Solvent feedstock effect: the insights into the deactivation mechanism of Cu/SiO2 catalysts for hydrogenation of dimethyl oxalate to ethylene glycol

“…4 A kind of Cu/SiO 2 /Cordierite monolithic catalyst was also studied by Ma et al, 5 and their results showed that the regular channel structure and the uniform distribution of flow of the monolithic catalyst were responsible for the improved thermal stability. Modification with boron on the surface of the Cu/SiO 2 catalysts shows great enhancement in the catalytic stability on account of maintaining the balance of Cu 0 and Cu + distribution and the retarding surface transmigration of copper nanoparticles.…”

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

“…Much higher selectivity of PDO (∼30%) was obtained when using xylitol as a feedstock . Similar problems also exist in EG synthesis through catalytic hydrogenation of coal‐based dimethyl oxalate, which has been commercialized in China in recent years …”

An environmentally benign and low-cost approach to synthesis of thermally stable industrial catalyst Cu/SiO2 for the hydrogenation of dimethyl oxalate to ethylene glycol

“…The reaction generating ethylene glycol (EG) occurs in two major steps [6,7], having as an intermediary methyl glycolate (MG): (AEH) method [15] and copper-phyllosilicate core-sheath nanoreactor using hydrothermal methods [16]. This research is aimed at designing a method that can be scaled up for synthesis of Cu/SiO 2 as an industrial catalyst for dimethyl oxalate (DMO) hydrogenation to ethylene glycol (EG).…”