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In the present work, calcium diglyceroxide (CaDG) was synthesized by mechanochemical treatment of CaO dispersed in glycerol, and characterized by X-ray diffraction (XRD), thermal analysis (TGA/DTA), infrared spectroscopy (FTIR), and Hammett indicator method for base strength determination. The obtained CaDG was tested as a catalyst in the methanolysis of sunflower oil under different working conditions: catalyst amount, agitation speed, temperature and methanol to oil molar ratio. The main advantage of CaDG used as a catalyst in methanolysis is related to the initial rate of methanolysis. According to many previously reported data in literature the mass transfer resistance controls the overall rate of methanolysis, but it is not observed with CaDG used as catalyst. Recently developed kinetic model that describes the complex methanolysis process was successfully applied for this system and model parameters were determined, supporting the explanation of the physical effect of the CaDG catalyst on the reduction of mass transfer resistance and increasing the rate of methanolysis. The absence of mass transfer rate at the beginning of process is a consequence of the nature of the CaDG, which is adsorbed at the droplet interfaces between methanol and oil leading to the formation of fine dispersion of these two immiscible liquids.

The kinetics of heterogeneous methanolysis of sunflower oil and used vegetable oil were studied at different temperatures, ranging from 60 to 96 degrees C using CaO center dot ZnO as catalyst (2 wt% on the basis of oil) and methanol to oil molar ratio of 10:1. Heterogeneous CaO center dot ZnO catalyst was synthesized by mechanochemical treatment of CaO and ZnO powder mixture with the addition of water necessary for the formation of corresponding mixed hydroxides, and their calcination at 700 degrees C in air. It was shown that kinetics of overall process could be described as pseudo-first order reaction. For the sunflower oil methanolysis at 60 and 70 degrees C, the rate of process at the beginning of biodiesel synthesis was limited by triglycerides mass transfer to the catalyst surface, and after that it is governed by the rate of chemical reaction at catalyst surface. At higher temperatures the influence of mass transfer resistance is almost negligible implying that the rate of chemical reaction determines the overall kinetic of biodiesel synthesis. In the case of used vegetable oil, the influence of mass transfer resistance was not observed either at higher or lower temperature. The kinetic model that describes the whole process well was proposed, and it comprises both the triglycerides mass transfer and chemical reaction controlled regime. The overall volumetric mass transfer coefficient was defined, assuming that it depends on the conversion of triglycerides.

A difficulty of biodiesel synthesis based on alkaline catalysts obviously exists if free fatty acids (FFAs) content in vegetable oil is above 0.5 wt.%. In this study, the ferric sulfate supported on silica (Fe-2(SO4)(3)/SiO2) was synthesized, activated (at different temperature: 120-600 degrees C) and tested for heterogeneous esterification of FFA (oleic acid) present in sunflower oil (5 wt.%). The catalyst samples were characterized by BET, TG/DTG, XRD and FTIR analyses. Obtained results showed that catalyst activated at 500 degrees C for 2 h in air atmosphere gave the maximal conversion of oleic acid (similar to 97%). Repeated use of catalyst without additional catalyst treatment or re-activation indicated that catalyst posses desired stability and activity. A pseudo-homogeneous kinetic model was proposed with good agreement between calculated and experimental data.

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.

Analysis of several different schemes for industrial FAME production at higher pressure and temperature (catalytic or non-catalytic synthesis) was realized with the aim to find the best route to reduce the energy consumption (EC) and to improve the life cycle energy efficiency. Obtained results indicated that the EC (MJ/kg FAME) mainly depends on degree of conversion of triglycerides being almost 25% smaller if degree of conversion increase from 97 mass% to complete conversion. Further significant decrease of EC might be obtained at subcritical conditions but only after substantial decrease of methanol to oil molar ratio (from 42 to 15) which requires use of appropriate catalyst. On account of that, the kinetics of heterogeneous catalyzed methanolysis of triglycerides was analyzed using data published in literature (CaO) as well as own experimental data (K2CO3/Al-O-Si) with a goal to obtain reliable kinetic rate constant which might be used for process simulation. This study shows that if heterogeneous process of biodiesel synthesis is realized at subcritical conditions then further decrease of EC is possible.

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.

Isolation of carrot fruit (Daucus carrota L., cultivar "Chanteney") essential oil by supercritical carbon dioxide was investigated from the pretreatment of herbaceous matrix and extraction conditions to the chemical composition of obtained extract and its antimicrobial activity. The qualitative and quantitative analyses of the supercritical extract, as well as of the essential oil obtained by hydrodistillation, were done by GC/FID and GC/MS methods. Antimicrobial properties of both samples were investigated against ten species of microorganisms. Experimental results showed that the particle size had no influence on the extraction process. The highest yield was obtained at 40 degrees C and 10 MPa. The main component of the supercritical extract, as well as of the essential oil was carotol. The supercritical extract was characterized by the presence of heavier molecular weight compounds, while some lighter compounds, e.g. pinenes, were not detected. The supercritical extract and the essential oil were the most effective against Gram-positive bacteria.

Isolation of carrot fruit (Daucus carrota L., cultivar Chanteney) essential oil by supercritical carbon dioxide was investigated from the pretreatment of herbaceous matrix and extraction conditions to the chemical composition of obtained extract and its antimicrobial activity. The qualitative and quantitative analyses of the supercritical extract, as well as of the essential oil obtained by hydrodistillation, were done by GC/FID and GC/MS methods. Antimicrobial properties of both samples were investigated against ten species of microorganisms. Experimental results showed that the particle size had no influence on the extraction process. The highest yield was obtained at 40 degrees C and 10 MPa. The main component of the supercritical extract, as well as of the essential oil was carotol. The supercritical extract was characterized by the presence of heavier molecular weight compounds, while some lighter compounds, e.g. pinenes, were not detected. The supercritical extract and the essential oil were the most effective against Gram-positive bacteria.