Synthesis of Dimethyl Ether via CO₂ Hydrogenation: Effect of the Drying Technique of Alumina on Properties and Performance of Alumina-Supported Copper Catalysts

Abstract

Thermal treatment during catalyst preparation is one of the important factors affecting the characteristics and performance of a catalyst. To improve the catalytic performance of an alumina-supported copper catalyst prepared by an impregnation method for dimethyl ether (DME) synthesis from CO 2 , the effects of the use of hot air and infrared drying as well as calcination at 600 and 900°C to prepare alumina supports were investigated. Infrared drying could shorten the required drying time by 75% when compared with hot air drying. Infrared drying could also help maintain the pore size and pore volume of the supports, leading to their larger surface areas. Different drying techniques were additionally noted to result in different sizes and shapes of the pores as well as to different copper distributions and intensities of acid sites of the catalyst. An increase in the calcination temperature resulted in a decrease in the surface area of the supports because of particle aggregation. The drying technique exhibited a more significant effect than calcination temperature on the spacetime yield of DME. A catalyst utilizing the support prepared by infrared drying and then calcined at 600°C exhibited the highest yield of DME (40.9 g DME kg cat −1 h −1 ) at a reaction temperature of 300°C. Stability of the optimal catalyst, when monitored over a 24 h period, was noted to be excellent.

From Mobile Phones to Catalysts: E-Waste-Derived Heterogeneous Copper Catalysts for Hydrogenation Reactions

“…The beneficial effect of γ-alumina as a support for copper nanoparticles is in agreement with our previous observations for ligand-free copper catalysts . Copper-based catalysts supported on γ-alumina have been reported in the past, though they were not used for N-heterocycle hydrogenation; instead, their activity was mainly demonstrated on hydrogenation of biomass, CO 2 , and NOs. − Under the same reaction conditions, other materials showed very low activity (Table , entries 1–5). When the temperature and hydrogen pressure were increased to 140 °C and 50 bar, respectively, the conversion improved to 88% using 60 mg of Cu-iKat, giving a clean reaction profile (Table , entry 7).…”

Effect of the Structure of Highly Porous Silica Extracted from Sugarcane Bagasse Fly Ash on Aflatoxin B1 Adsorption

“…Figure shows the NH 3 -TPD profiles of the synthesized silica and bentonite. The NH 3 desorption peaks were distributed in the ranges of 100–200 °C (weak acid sites) and 400–800 °C (strong acid sites) . All of the synthesized porous silica only showed the intensities of the weak acid sites.…”

“…Temperature-Programmed Desorption Using Ammonia as a Probe Molecule (NH 3 -TPD). 33 Experiments were conducted using a TPDRO apparatus (Thermo Scientific, TPDRO 1100, Waltham, MA) to investigate the acidic property of porous silica. 0.2 g of a sample was pretreated by passing He (30 mL/min) at a heating rate of 10 °C/min until 400 °C was reached; such a temperature was maintained for 60 min.…”

“…7 Bentonite showed higher AFB1 adsorption capability than the synthesized silica, although the former had a smaller surface area. This is because of the high intensity of the surface acid sites 33 and the highly negatively charged surface of bentonite. 34 2.6.…”

CO2 to dimethyl ether (DME): structural and functional insights of hybrid catalysts

“…133 The Cu/Al 2 O 3 catalyst prepared by infrared drying followed by calcination at 600 °C displays a respectable DME yield (40.9 g DME kg cat −1 h) at 300 °C. Owing to less shrinkage during…”