Search

Abstract 5-Na/ZnO loaded SBA-15 has been prepared by one-pot method in atmospheric conditions (without employing hydrothermal treatment) and following wet impregnation method. The prepared catalyst was characterised by using several techniques viz., BET method for determination of surface area, FE-SEM for morphology of catalyst, XPS study to determine the oxidation state of constituent elements. The catalyst was utilised for transesterification from virgin cotton seed oil and the catalyst activity was dependant on its basic strength. Under optimal reaction conditions of catalyst amount 12 wt%, methanol to oil molar ratio of 24:1 at reaction temperature of 65 °C, the prepared catalyst yielded > 98% fatty acid methyl ester in 4 h of reaction duration. The catalyst was able to yield conversion level as good as ∼74% even in 5th cycle after regeneration. Leaching of < 5 ppm metal content was observed, in 4th and 5th cycle, which was within the ASTM specified limitations. The thermodynamic parameters for the reaction, viz. , activation energy E a , ΔH‡, ΔS‡, ΔG‡ were calculated as 77.3 kJ mol−1, 74.2 kJ mol−1, -0.064 kJ mol−1 and, + 93.2 kJ mol−1 respectively. Graphical abstract Image 1 Highlights • Synthesis of SBA-15 and impregnation of 5-Na/ZnO was performed in single step. • In situ method of synthesis saved lot of time and energy consumption compared to 2-step synthesis. • Prepared catalyst was employed for biodiesel production and reused for 5 consecutive runs. • The catalyst activity was found to be a function of its basic strength. [ABSTRACT FROM AUTHOR]

Present work demonstrates an easy route by sol-gel method, without using any template, for the synthesis of flower shaped tungsten (W) supported TiO 2 /SiO 2 catalyst for the triglyceride transesterification. The structure of the catalyst was established by powder X-ray diffraction and surface morphology and particle size by field emission scanning and high resolution transmission electron microscopy studies, respectively. The oxidation state of tungsten by X-ray photoelectron spectroscopy was found to be +6. Under the optimized reaction conditions of 5 wt% of 20-W/TiO 2 /SiO 2 -700 catalyst, 30:1 methanol to oil molar ratio and 65 °C reaction temperature, more than 98% fatty acid ethyl ester yield was obtained in 4 h. The kinetic and thermodynamic parameter of the reaction was also evaluated following the pseudo-first order equation. The catalyst was recycled in four consecutive runs and total metal contents in biodiesel was observed <5 ppm to maintain the stability of the catalyst. [ABSTRACT FROM AUTHOR]