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The new type of catalyst for fatty acid methyl esters (FAME or biodiesel) synthesis with K2CO3 as active component on alumina/silica support was synthesized using sol-gel method. Corresponding catalyst (xerogel) was prepared by 12 h drying the wet gel in air at 300 degrees C, 600 degrees C or 1000 degrees C at atmospheric pressure. The catalysts activity in the methanolysis of sunflower oil was compared to the activity of the pure K2CO3. The effects of various reaction variables on the yield of FAME were investigated. It was found that the temperature of 120 degrees C and methanol to oil molar ratio of 15: 1, are optimal conditions for FAME synthesis with synthesized catalyst. Repeated use of same amount of catalyst indicated that effect of potassium leaching obviously existed leading to decrease of catalyst activity.

The new type of catalyst for fatty acid methyl esters (FAME or biodiesel) synthesis with K2CO3 as active component on alumina/silica support was synthesized using sol-gel method. Corresponding catalyst (xerogel) was prepared by 12 h drying the wet gel in air at 300 °C, 600 °C or 1000 °C at atmospheric pressure. The catalysts activity in the methanolysis of sunflower oil was compared to the activity of the pure K2CO3. The effects of various reaction variables on the yield of FAME were investigated. It was found that the temperature of 120 °C and methanol to oil molar ratio of 15:1, are optimal conditions for FAME synthesis with synthesized catalyst. Repeated use of same amount of catalyst indicated that effect of potassium leaching obviously existed leading to decrease of catalyst activity.

The sunflower oil methanolysis was studied in a stirred reactor at different agitation speeds. The measurements of drop size, drop size distribution and the conversion degree demonstrate the effects of the agitation speed in both non-reaction (methanol/sunflower oil) and reaction (methanol/KOH/sunflower oil) systems. Drop size distributions were found to become narrower and shift to smaller sizes with increasing agitation speed as well as with the progress of the methanolysis reaction at a constant agitation speed. During the methanolysis reaction, the Sauter-mean drop diameter stays constant in the initial slow reaction region, rapidly decreases during the fast reaction period and finally reaches the equilibrium level. Due to the fact that the interfacial area increases, one can conclude that the rate of reaction occurring at the interface will also be enhanced progressively. The "autocatalytic" behavior of the methanolysis reaction is explained by this "self-enhancement" of the interfacial area, due to intensive drop breakage process.