Due to the reduction of fossil fuel reserves and increasing energy demand, the world is heading towards conversion processes from biomass to liquid fuels. One of these alternative fuels is biodiesel, defined as fatty acid alkyl ester, whose combustion results in fewer greenhouse gases. The most common method for biodiesel synthesis is transesterification of triglycerides from vegetable oils or animal fat and alcohol, mostly methanol. A disadvantage of biodiesel in opposition to mineral diesel fuel is lower heating value and poor cold flow properties. Edible oils are refined and have lower content of free fatty acids, so the reaction of transesterification is carried out in the presence of alkaline catalyst so the formation of soap will not occur to a large extent. Propanol and higher alcohols are advantageous over methanol and ethanol due to their blending capabilities, hydrophobic properties, cetane number and heating value. In this thesis, fatty acid propyl esters were synthesized by the transesterification reaction od tryglycerides from edible sunflower oil and propanol in the presence of potassium hydroxide as a catalyst. Mixtures of basic components, diesel, biodiesel, and propanol, were prepared so the effect of molecular interactions on the application properties could be examined. The properties that were examined by standardized methods are viscosity, density, cold flow plugging point and lubricity. Mixtures were additionally characterized by infrared spectroscopy with Fourier transformations (FTIR), differential scanning calorimetry (DSC) and surface tension, contact angle and refractive index were also measured.