Search

The mixed metal oxides S-CaMgAl MO prepared by acidolysis, coprecipitation and calcination under different temperatures from S95 steel slag of Shanghai Baosteel Co., Ltd. were used to catalyze the transesterification of dimethyl carbonate (DMC) and glycerol for synthesizing glycerol carbonate (GC). The catalysts were characterized by EDS, XRD, FT-IR, SEM, CO2-TPD and nitrogen adsorption–desorption isotherms. S-CaMgAl MO calcined at 600 °C had excellent catalytic performance due to the large pore size and proper alkalinity. The effects of reaction temperature, reaction time and the amount of catalyst on transesterification were investigated to obtain the optimal reaction conditions. The glycerol carbonate yield reached 96.2% and the glycerol conversion was 98.3% under the condition of 3 wt% catalyst, 1:3 molar ratio of glycerol and DMC, 75 °C reaction temperature and 90 min reaction time. In addition, the GC yield and glycerol conversion still achieved above 90% after five cycles of S-CaMgAl MO. [ABSTRACT FROM AUTHOR]

β-cyclodextrin derivative intercalated MgAl-hydrotalcites (β-CD-Ca/LDH) was synthesized to convert glycerol into high value-added glycerol carbonate(GC) by transesterification of dimethyl carbonate (DMC) and glycerol in this paper. β-cyclodextrin-metal complexes and β-CD-Ca/LDH was characterized by XRD, FT-IR, SEM, XPS and nitrogen adsorption-desorption. The enrichment of organic reactants in the hydrophobic cavity of β-cyclodextrin improved the collision probability of reactants. The intercalation of β-cyclodextrin-calcium complex (β-CD-Ca) increased the pore size and basic strength of catalyst. The experiment results showed that the glycerol conversion was 93.7% and the GC yield was 91.8% catalyzed by β-CD-Ca/LDH when the molar ratio of DMC and glycerol was 3:1, the catalyst dosage was 4 wt.%, the reaction temperature was 75 °C and the reaction time was 100 min while the glycerol conversion was 49.4% and the GC yield was 48.6% catalyzed by MgAl-LDH under the same conditions. [ABSTRACT FROM AUTHOR]

Ca-Mg-Al hydrotalcites were prepared by coprecipitation from Type S95 steel slag of Shanghai Baosteel Group as supports of ionic liquid in this paper. Five basic ionic liquids [Bmim][CH3COO], [Bmim][HCOO], [Bmim]OH, [Bmim]Br and ChOH were prepared and their catalytic performance on the synthesis of glycerol carbonate by transesterification between dimethyl carbonate and glycerol was investigated. The characterization results indicated that [Bmim]OH is the best ionic liquid (IL) for the transesterification reaction of glycerol carbonate. The hydrotalcites before and after intercalation by ionic liquid were characterized by XRD, FTIR, SEM, EDS and the IL were characterized by FT-IR, 13C-NMR and basicity determination via the Hammett method. The analysis results implied that the dispersion of [Bmim]OH in hydrotalcites reduced the alkali density appropriately and facilitated the generation of glycerol carbonate. The yield of glycerol carbonate and the conversion rate of glycerol reached 95.0% and 96.1%, respectively, when the molar ratio of dimethyl carbonate and glycerol was 3:1, the catalyst dosage was 3 wt%, the reaction temperature was 75 °C and the reaction time was 120 min. The layered structure of hydrotalcites increased the stability of ionic liquid intercalated in carriers, thus the glycerol conversion and the GC yield still remained 91.9% and 90.5% in the fifth reaction cycle. [ABSTRACT FROM AUTHOR]