15546-08-4Relevant articles and documents
Cu-Mn composite oxides: Highly efficient and reusable acid-base catalysts for the carbonylation reaction of glycerol with urea
Luo, Wei,Sun, Lei,Yang, Yue,Chen, Yanqiu,Zhou, Zhou,Liu, Junhua,Wang, Fang
, p. 6468 - 6477 (2018)
A series of Cu-Mn composite oxides were prepared by co-precipitation. Interestingly, catalysts with varied Cu/Mn molar ratios showed different catalytic performances for glycerol carbonylation. The physicochemical properties of the catalysts are characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) spectroscopy, temperature-programmed desorption (TPD) of CO2 and NH3 and temperature-programmed reduction (H2-TPR) technology. The results showed that the Cu1.4Mn1.6O4 crystal phase is the active component of the catalysts for the carbonylation of glycerol, this phase can effectively provide Mn4+ and lattice oxygen (O2-), and the existence of the Mn4+-O2- Lewis acid-base pair can promote the formation of glycerol carbonate. Various reaction parameters, such as reaction temperature, time, the molar ratio of glycerol to urea and the amount of catalysts, are studied. Under optimizing reaction conditions, the conversion of glycerol is 91.0% with 99.1% glycerol carbonate selectivity.
Synthesis of glycerol carbonate from glycerol and urea with gold-based catalysts
Hammond, Ceri,Lopez-Sanchez, Jose A.,Hasbi Ab Rahim, Mohd,Dimitratos, Nikolaos,Jenkins, Robert L.,Carley, Albert F.,He, Qian,Kiely, Christopher J.,Knight, David W.,Hutchings, Graham J.
, p. 3927 - 3937 (2011)
The reaction of glycerol with urea to form glycerol carbonate is mostly reported in the patent literature and to date there have been very few fundamental studies of the reaction mechanism. Furthermore, most previous studies have involved homogeneous catalysts whereas the identification of heterogeneous catalysts for this reaction would be highly beneficial. This is a very attractive reaction that utilises two inexpensive and readily available raw materials in a chemical cycle that overall, results in the chemical fixation of CO2. This reaction also provides a route to up-grade waste glycerol produced in large quantities during the production of biodiesel. Previous reports are largely based on the utilisation of high concentrations of metal sulfates or oxides, which suffer from low intrinsic activity and selectivity. We have identified heterogeneous catalysts based on gallium, zinc, and gold supported on a range of oxides and the zeolite ZSM-5, which facilitate this reaction. The addition of each component to ZSM-5 leads to an increase in the reaction yield towards glycerol carbonate, but supported gold catalysts display the highest activity. For gold-based catalysts, MgO is the support of choice. Catalysts have been characterised by XRD, TEM, STEM and XPS, and the reaction has been studied with time-on-line analysis of products via a combination of FT-IR spectroscopy, HPLC, 13C NMR and GC-MS analysis to evaluate the reaction pathway. Our proposed mechanism suggests that glycerol carbonate forms via the cyclization of a 2,3-dihydroxypropyl carbamate and that a subsequent reaction of glycerol carbonate with urea yields the carbamate of glycerol carbonate. Stability and reactivity studies indicate that consecutive reactions of glycerol carbonate can limit the selectivity achieved and reaction conditions can be selected to avoid this. The effect of the catalyst in the proposed mechanism is discussed.
