Selective conversion of glycerol to lactic acid using nickel supported on calcium oxide and magnesium oxide
| dc.contributor.author | Muhammad Hazim Yaacob | |
| dc.date.accessioned | 2021-11-02T08:35:57Z | |
| dc.date.available | 2021-11-02T08:35:57Z | |
| dc.date.issued | 2018-08-01 | |
| dc.description.abstract | The rapid increase of biodiesel production worldwide generates an excess of crude glycerol as the primary co-product which negatively affect the price of glycerol in the market. In order to sustain the glycerol industry, the development of value-added chemicals from glycerol is necessary. Among them, lactic acid has received a considerable attention due to its numerous applications in the food, cosmetic and pharmaceutical industries. In this study, glycerol was upgraded to lactic acid through a base catalyzed reaction. Different types of catalyst (MgO, CaO, NiO, NiO/MgO and NiO/CaO) were used in this reaction. Among these catalysts, NiO/CaO showed high activity and was selected for the following study. NiO/CaO catalysts were synthesized with different molar ratios of Ni/Ca (0.25, 0.43 and 0.67) and calcination temperatures (800, 900 and 1000°C). In addition, the physicochemical properties of these catalysts were characterized by nitrogen adsorption, temperature programmed desorption of carbon dioxide (CO2-TPD), scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). Effects of reaction conditions such as reaction time (30-160 min), reaction temperature (280-300°C) and catalyst loading (10-20 wt. %) were also studied to identify the best reaction conditions obtain high lactic acid yield. It was found that NiO/CaO catalyst demonstrated the highest activity at a Ni/Ca ratio of 0.43 and calcined at 900°C. Furthermore, this catalyst was found to be excellent to be used in this reaction as it possessed the high amount basicity of 11.28 mmol/g. Thus, the increase in the total basicity of the catalyst might have favored its glycerol conversion to lactic acid. 93.2% of glycerol was converted to give 41.3% yield of lactic. Besides, this catalyst was reusable up to two cycles with a reduction in glycerol conversion from 89.3% to 78.0%. This could be due to leaching of calcium from the catalyst into glycerol. Nevertheless, high yield of lactic acid up to 28.7% could still be obtained after two catalytic cycles. A kinetic model for the glycerol concentration in glycerol conversion using 0.43NiO/CaO-900 as catalyst is also developed. This model could well describe the actual reaction occurring in the reactor in a temperature range of 280-300°C. Therefore, it appeared that CaO/NiO catalyst is a potential catalyst for lactic acid production from glycerol. | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/14335 | |
| dc.language.iso | en | en_US |
| dc.title | Selective conversion of glycerol to lactic acid using nickel supported on calcium oxide and magnesium oxide | en_US |
| dc.type | Thesis | en_US |
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