Development of Sulfonated Carbon Catalyst for Epoxidation of Vernonia Oil

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Addis Ababa University


A biochar-based catalyst was successfully prepared by sulfonation of pyrolysis char with high concentration (>96%) sulphuric acid. Three biochar-based catalysts with pyrolysis supports at three different temperatures (400, 450 and 500oC) were prepared and compared for different characteristics of the catalyst. Further investigations on the biochar based catalyst were conducted to determine the effect of preparation protocol on the above properties of the catalyst. Two established preparation techniques (i.e. preparation protocol with ultrasound sonication and preparation protocol with magnetic stirring method) have been utilized to increase the acid density of sulfonic group (SO3H) during sulfonation. The sulfonated catalysts were characterized using the following analyses: bulk density, elemental analysis, total acid density, Fourier Transform Infra-Red (FT-IR) spectroscopy, and X-Ray Diffraction (XRD) spectroscopy. The catalyst supported on biochar pyrolysis at 500oC with ultrasound sonication (C-SO3H-500u) resulted the maximum, sulfur content and total acid density (4.10 mmol/g). Thus, from the prepared catalyst, catalyst prepared at 500oC (C-SO3H-500u) was selected based on the above characterization and thus further evidence on the morphological structure (SEM) and stability (TGA) of the catalyst was performed. The selected (C-SO3H-500u) catalyst was studied for its activity to catalyze Epoxidation of vernonia oil using peroxyformic acid. Design-Expert 7.0.0 three-level-three-factor BBD was applied for experimental design and statistical analysis of results. A total of 15 experiments were conducted at conditions of reaction temperature 65, 75 and 85oC, molar ratio of hydrogen per oxide to oil 1.5, 2.5 and 3.5 and 2, 4 and 6 %wt of catalyst loading. From the analysis of experimental results the interaction effects were studied and the optimal epoxidation reaction process conditions, which will maximize the percentage of conversion, were found to be 65oC reaction temperature, 2.36:1 molar ratio of hydrogen per oxide to oil and 6 %wt, catalyst loading which gave 51.45% percentage of conversion. The yield of epoxidized vernonia oil were determined by identifying the structure and composition of vernonia oil, in comparison to epoxidized vernonia oil using NMR spectroscopy. Keywords: Bamboo; Sulfonated carbon catalyst; Vernonia galamensis; Epoxidation; Epoxidized vernonia oil



Bamboo; Sulfonated carbon catalyst; Vernonia galamensis; Epoxidation; Epoxidized vernonia oil