Publication: Selective conversion of glycerol into lactic acid using sba-15 supported mixed cerium and zirconium oxide catalyst in the absence of base
| datacite.subject.fos | oecd::Engineering and technology::Chemical engineering | |
| dc.contributor.author | Syamima Nasrin, Binti Mohamed | |
| dc.date.accessioned | 2025-11-27T04:16:02Z | |
| dc.date.available | 2025-11-27T04:16:02Z | |
| dc.date.issued | 2024-01-01 | |
| dc.description.abstract | Glycerol surplus has been produced due to the exponential growth of the world's oleochemical and biodiesel industries. Glycerol serves as a valuable raw material for the production of various useful chemicals, one of which is lactic acid. Nevertheless, the literature on the utilization of a mixture of multi-metal mixed oxide catalysts, which have bimetallic characteristics, that could selectively facilitate the catalytic glycerol-to-lactic acid oxidation, is hardly found. Although solid base catalysts have shown their potential, a major challenge arises from the active species’ partial dissolution into glycerol during the reaction. However, the amount of lactic acid generated in terms of yield is often low in existing processes, making it economically unfeasible. The use of mesoporous support could theoretically aid to improve the shape selectivity effect, hence favouring the formation of lactic acid. Due to its uniform and large pore diameters, which are advantageous in catalyzing many types of reactions especially involving viscous medium, the support, SBA-15, has aroused a lot of interest for application in numerous reactions. In the present work, potential mixed oxide catalysts which is cerium and zirconium oxide with different ratio among one another (1:1, 1:2, and 2:1) supported on SBA-15 has been synthesized with a final calcination temperature of 500 ⁰C. All three catalysts were characterized via N2 physisorption analysis, XRD, SEM, EDX, FTIR, TGA, basicity determination by CO2-TPD and Hemmert indicator analysis, determination of ability to absorb O2 by O2-TPD, and redox capability determination by H2-TPR in order to explore the physicochemical properties. The CeZr/SBA-15 catalyst has been used to catalyze the glycerol conversion into lactic acid at the temperature of 250 ⁰C for 2 hours in a modified stirred stainless-steel reactor. The 2:1CeZr/SBA-15 catalyst exhibited the highest catalytic performance among all the three catalysts, with 91.8 % glycerol conversion and 35.1 % yield of lactic acid for a 2-hour reaction at 250 ⁰C. Then, the mesoporous 2:1CeZr/SBA-15 catalyst was synthesized with different metal loadings (5-40 wt.%) and characterized via N2 physisorption analysis, SEM, TEM, EDX, and FTIR. The catalytic activity of the catalysts was eventually correlated with their respective characteristics. Effects of reaction conditions such as catalyst-to-glycerol loading (5-40 wt.%), reaction temperature (240-270 ⁰C), and reaction time (0.5-3 hours) were elucidated. The 10 wt.% 2:1CeZr/SBA-15 catalyst was found to demonstrate the highest activity in the production of lactic acid at 15 wt.% catalyst-to-glycerol ratio at the reaction temperature of 260 ⁰C at 2 hours of reaction. A glycerol conversion of 94.2 % and a lactic acid yield of 45.3 %, was obtained. A reusability test was performed on the best catalyst and the catalyst was found to be reusable with only a marginal decrease in catalytic activity for up to three cycles of reaction. The marginal decrease in catalytic activity was due to the leaching of the catalyst and pore collapse. Obeying a pseudo-second order kinetic model with respect to glycerol, the selective glycerol-to-lactic acid conversion was found to have an activation energy of 165.3 kJ/mol. In short, the 10CeZr/SBA-15 catalyst demonstrated a well-defined structure, and could effectively enhance oxygen release and storage capabilities, by which this improvement could be attributed to the rich basic site distribution and improved synergistic interaction between the Ce1-xZrxO2 compounds. Hence, this catalyst is highly recommended as a viable and alternative solid base catalyst for selective lactic acid synthesis from glycerol. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/23205 | |
| dc.language.iso | en | |
| dc.title | Selective conversion of glycerol into lactic acid using sba-15 supported mixed cerium and zirconium oxide catalyst in the absence of base | |
| dc.type | Resource Types::text::thesis::doctoral thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |