In order to study the effect of support structure on hydrogenolysis of spirulina polysaccharide, series of platinum catalysts supported by different silica-based zeolites were synthesized. The catalysts were characterized by a combination of N2 adsorption-desorption, X-ray diffraction (XRD) and transmission electron microscope (TEM), which suggested that Pt/K-10, Pt/Beta, Pt/ZSM-5 and Pt/Y possessed significantly different structure—specific surface area, pores configuration, crystalline structure and so forth. To further investigate the role of the above structural differences, thorough tests as pyridine-infrared radiation (Py-IR), CO adsorption, NH3 temperature-programmed desorption and inductive coupled plasma (ICP) were conducted, which showed that the above catalysts exhibited different properties on Brφnsted/Lewis acidity (32.8-79.5 μmol/g), the dispersion of Pt (15.0-35.4%) and the loss of Pt (3.9 to 0.5 wt% during five cycles of reuse). Finally, hydrogenolysis experiments of spirulina polysaccharide were carried out and properties of the spirulina polysaccharide were tested. The number-average molecular weight (Mn) of this spirulina polysaccharide was 63240 and it was composed of glucose, xylose, rhamnose and their polymers according to the data from gel chromatography (GPC), elemental analysis (EA) and high performance liquid chromatography (HPLC). The reaction results showed that the performance (activity and stability) of these catalysts and distributions of product polyols (ethylene glycol, butanediol, etc.) were significantly different and strongly influenced by catalytic acidity, Pt dispersion and the loss of Pt. Our study indicated that support structure of catalysts influenced the catalytic performance and distribution of polyols by altering the acidity of catalyst, the dispersion of Pt and the loss of Pt during reuse, which ultimately affected the catalytic acid sites and hydrogenation sites.

Effect of catalytic structure on hydrogenolysis of microalgae (spirulina sp.) polysaccharide into polyols over zeolites-supported Platinum catalysts

254th National Meeting (2017)

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