Exploring the Promotional Effects of K, Sr, and Mg on the Catalytic Stability of Red Mud for the Synthesis of Glycerol Carbonate from Renewable Glycerol

Abstract

The focus of this study was to utilize red mud (RM), an aluminum industry waste, for the preparation of various catalysts for the synthesis of glycerol carbonate (GC) from glycerol (GL). A series of catalysts were prepared by doping potassium, strontium, and magnesium on the surface of RM, and their effect on the stability of RM based catalysts was examined. From preliminary studies, K-doped RM catalysts were found to have better activity as well as stability than the Sr-and Mg-doped RM catalysts for the transesterification of GL. The RK-30%-800 catalyst prepared by 30% K loading and calcination at 800 °C produced the highest activity and stability compared to other K-doped catalysts. The better activity of the RK-30% catalyst was due to the presence of the maximum surface concentration of active K 2 O, which was confirmed from the XRD analysis. The surface concentration of K 2 O contributed significantly to the increased basic properties of the catalyst, which was quite evident from the acid−base titration, CO 2 -temperature programmed desorption (CO 2 -TPD), and Hammett indicator test. A probable mechanism of the GL transesterification process by using the RK-30%-800 catalyst was proposed. Moreover, effect of the presence of impurities on the catalytic activity, the reaction kinetics, reusability study, and deactivation mechanism were studied in detail here.

Green synthesis of glycerol carbonate via transesterification of glycerol using mechanochemically prepared sodium aluminate catalysts

“…Layered double hydroxides have also been widely reported for the reaction [27][28][29] . Catalysts for the reaction can also be prepared from a variety of waste sources such as oil palm ash 30 , steel slag 27,31 and red mud 32,33 .…”

Glycerol carbonate synthesis via transesterification of enriched glycerol and dimethyl carbonate using a Li-incorporated MCM-41 framework

“…Likewise, evaluation of the impact of K, Sr, and Mg on the catalytic stability of red mud in GC synthesis revealed that a 30 wt% K loading and calcination at 800 °C resulted in the most favorable catalytic performance due to the maximal surface concentration of active K 2 O. 28 The synthesis process of glycerol carbonate is known for its high energy consumption and signicant costs, necessitating optimization through the application of appropriate statistical tools. Specically, the identication of optimal reaction parameters to maximize glycerol carbonate yield is crucial.…”

“…The catalyst's surface contains basic sites responsible for initiating the transesterification process. Catalysts functionalized with metals, such as potassium (K), 28,29 sodium (Na), 30 Li, 6,29 magnesium (Mg), 28,29 strontium (Sr), 28 and zirconium, 22 exhibit an enhanced performance in GC production.…”

Synthesis of Glycerol Carbonate from Glycerol and Dimethyl Carbonate Catalyzed by Solid Base Catalyst Derived from Waste Carbide Slag

“…In addition to catalytic performance, separation efficiency, and environmental friendliness, the cost of the catalyst preparation is also a key factor that should be considered. Ionic liquids [34,35] and biological enzymes [36,37] as new green catalysts have attracted great attention. However, the complex preparation process and relatively high preparation cost seriously limit the application of these catalysts in the industrial field.…”