Esterification of palmitic acid with methanol over tungsten oxide supported on zirconia solid acid catalysts: effect of method of preparation of the catalyst on its structural stability and reactivity

Ramu, S.; Lingaiah, N.; Devi, B.L.A. Prabhavathi; Prasad, R. B. N.; Suryanarayana, I.; Prasad, P. S. Sai

doi:10.1016/j.apcata.2004.08.002

Cited by 133 publications

(54 citation statements)

References 15 publications

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“…Ramu et al also reported that the catalytic activity has a direct relationship with the fraction of tetragonal phases. 19 Furthermore, the catalytic activity increases with the enhancement of strontium sulfate loading. Nevertheless, the fraction of tetragonal phases and activity of the catalyst reduces with enhancement of further strontia loading up to 25 mol.…”

Section: Resultsmentioning

confidence: 99%

Preparation of Supported Nanosized Sulfated Zirconia by Strontia and Assessment of Its Activities in the Esterification of Oleic Acid

Nayebzadeh

Saghatoleslami

Maskooki³

et al. 2014

Chem.Biochem.Eng.Q.

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The aim of this study was to examine a new nanocatalyst of SrO/S-ZrO 2 in esterification reaction and the optimum value of strontia loading over the sulfated zirconia. The sulfated zirconia was supported with different molar ratios of strontia in the range of 0.0-0.30, using the solvent-free method. The samples were characterized using XRD, FT-IR, BET and TEM analysis and their activity were investigated in esterification reaction of oleic acid. The findings of this study revealed that 25 mol % SrO/S-ZrO 2 had the highest yield in the esterification reaction. It was also concluded that strontia-supported sulfated zirconia could improve the low reusability of the catalyst. Furthermore, 95 % conversion was also obtained at optimized conditions (i.e., 100 °C, 2 wt. % of catalyst, 6:1 molar ratio of methanol/oleic acid and for a period of 30 minutes).

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Section: Resultsmentioning

confidence: 99%

Preparation of Supported Nanosized Sulfated Zirconia by Strontia and Assessment of Its Activities in the Esterification of Oleic Acid

Nayebzadeh

Saghatoleslami

Maskooki³

et al. 2014

Chem.Biochem.Eng.Q.

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“…Subsequently, the calcium-glycerol complex formed in the reaction of CaO with glycerol functioned as the main catalyst in transesterification. Under optimal reaction conditions (0.1 Impregnation + Calcination (WO3) -500 °C 98 Ramu et al (2004) g CaO, 3.9 g methanol, 15 g oil, and 1.5 h activation time at room temperature), the methyl ester was obtained in approximately 90 % yield within 3 h at 60ºC. Wang and Yang (2007) showed that Nano-MgO had higher catalytic activity in the supercritical/subcritical temperatures.…”

Section: Precipitation Methodsmentioning

confidence: 99%

“…The catalyst was active for both transesterification and esterification reactions although the reaction time was relatively long. On the other hand, Ramu et al (2004) evaluated the effect of calcinations temperature on the catalytic performance of ZrO 2 /WO 3 2" as well as the effect of amount of WO 3 loading on the zirconium oxide for the esterification of palmitic acid with methanol and discovered that the catalyst which was calcined at 500°C had the most activity. This activity was attributed to the formation of tetragonal phase of ZrO 2 .…”

Section: Calcination (Thermal Treatment)mentioning

confidence: 99%

Biodiesel production using solid metal oxide catalysts

Refaat

2010

Int. J. Environ. Sci. Technol.

248

154

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Biodiesel production is worthy of continued study and optimization of production procedures due to its environmentally beneficial attributes and its renewable nature. Heterogeneous transesterification is considered to be a green process. The process requires neither catalyst recovery nor aqueous treatment steps and very high yields of methyl esters can be obtained, close to the theoretical value. However, heterogeneously catalyzed transesterification generally requires more severe operating conditions, and the performance of heterogeneous catalysts is generally lower than that of the commonly used homogeneous catalysts. Heterogeneous catalysis for biodiesel production has been extensively investigated in the last few years. Many metal oxides have been studied for the transesterification process of oils; these include alkali earth metal oxides, transition metal oxides, mixed metal oxides and supported metal oxides. The use of solid metal oxides as catalysts in oil transesterification is well established, accordingly, researchers' attempts are now focused on how to attain the highest catalyst activity. Catalyst activity is a function of its specific surface area, base strength and base site concentration. High specific surface area, strong base strength and high concentration of base sites are characteristics of an active transesterification catalyst. This review provides a brief overview of the different metal oxides frequently used in the process of transesterification of oils for the production of biodiesel with special reference to the various methods of catalyst preparation and catalyst characterization. Reaction conditions and catalyst leaching analysis are also highlighted. Finally, concluding remarks regarding catalyst selection and catalyst preparation steps are provided.

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“…The activity of WO 3 2− / ZrO 2 was attributed to the formation of tetragonal phase of ZrO 2 . Beyond 500 °C the tetragonal phase transferred to the monoclinic phase which caused a decrease in the activity (Ramu et al, 2004). However, the transesterification reaction catalyzed by SO 4 2− /ZrO 2 at low temperature is very slow.…”

Section: Solid Acidmentioning

confidence: 99%