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Disertační práce se zabývá procesem ethanolýzy řepkového oleje. Ten sestává z vlastní reakce řepkového oleje s ethanolem za alkalické katalýzy, neutralizace přebytečného katalyzátoru pomocí oxidu uhličitého, odstraněním přebytečného ethanolu za sníženého tlaku a vyšší teploty a separace reakční směsi na glycerolovou a esterovou fázi. Statistickými metodami je zkoumán vliv reakčních podmínek na reakční proces. Zjišťuje se také vliv podmínek separace na kvalitu i kvantitu esterové fáze. Separační proces je dále zkoumán z hlediska distribuce látek mezi obě vznikající fáze. Je zkoumán i vliv existence meziproduktů ethanolýzy na separaci. Jsou také zjišťovány některé korelace mezi kvantitativními a kvalitativními veličinami esterové fáze., Dissertation thesis deals with a process of rapessed oil ethanolysis. The process consists of the alkaline-catalyzed reaction of rapeseed oil ant ethanol, a neutralization of an excessive catalyst with the help op carbon dioxide, a removal of excessive thanol at low pressure and high temperature and a separatioon of the reaction mixture into ester and glycerol phases. Effects of reaction conditions on the reaction process are ivestigated with the help of statistical methods. Effects of separation conditions on the quantity and quality of ester phase are investigated too. The separation is also researched from the point of view of a substance distribution between the both originating phases. It is also investigated what effect an existence of intermediate products has on the separation. Finally, some correlations among quantitative and qualitative variables are found out., Fakulta chemicko-technologická, Dokončená práce s úspěšnou obhajobou

Many samples of rapeseed oil ethyl ester were prepared by alkaline-catalyzed transesterification at various conditions (reaction time, temperature, amount of catalyst, the molar ratio of ethanol to oil, the rotations of a disperser and the purification by water). The concentrations of the key impurities for biodiesel quality (the concentrations of monoglycerides, diglycerides, triglycerides, free glycerol, ethanol, free fatty acids, water) and some qualitative parameters (flash point, carbon residue, kinematics viscosity at 40 °C) were determined and then the relationships among them were found out. The relationships were characterized by the linear or non-linear statistical models. The found models enable the better understanding of the significance of the qualitative parameters and estimate them from the concentrations of impurities. The temperature dependence was also measured in the case of the viscosity of ethyl ester and used rapeseed oil.

Various effects on the separation of raw reaction mixture after the ethanolysis of rapeseed oil were investigated. Water addition, initial temperature of separation, centrifugation, ionic compound addition and time effects affecting concentrations of potassium, free glycerol and yield of the ester phase were found out. Centrifugation has the most positive effect. Finally, correlation between concentrations of potassium and free glycerol was found out.

The alkaline-catalyzed (KOH) ethanolysis of rapeseed oil with the help of a mechanical disperser was researched in this study. The effects of chosen reaction conditions (independent variables: the reaction temperature and time, the amount of catalyst, the molar ratio ethanol to oil and the rotation frequency of the disperser) on the ethanolysis process and ways for the improvement of the transesterification and separation process were studied. The transesterification of oil, the separation of the ester phase from the glycerol phase and qualitative properties of the ester phase were monitored by many dependent variables (e.g. the yield of the ester phase, the weight concentration of glycerides, the content of potassium ions etc). The measured data was analyzed by multi-linear regression with the help of many statistical tests (significance of parameters, exclusion of outliers etc.). The created mathematical models describing the relations between the independent and dependent variables were verified by several independent experiments.

The distribution of ethyl esters, triglycerides, diglycerides, monoglycerides and glycerol between the ester and glycerol phase was investigated after the ethanolysis of rapeseed oil at various reaction conditions. The determination of these substances in the ester and glycerol phases was carried out by the GC method. The amount of ethyl esters in the glycerol phase was unexpectedly high and therefore the possibility of the reduction of this amount was investigated. The distribution coefficients and the weight distributions of each investigated substance were calculated and compared mutually. The distribution coefficients between the ester and glycerol phase increase in this sequence: glycerol, monoglycerides, diglycerides, ethyl esters and triglycerides. Soaps and monoglycerides in the reaction mixture cause a worse separation of ethyl esters from the reaction mixture. The existence of a non-separable reaction mixture was observed also, and its composition was determined.

Byl studován vliv různých veličin na transesterifikaci řepkového oleje ethanolem s cílem navrhnout vhodné reakční podmínky. Dále se zkoumala separace po transesterifikaci za účelem zvýšení výtěžku a kvality produktu., Katedra fyzikální chemie, Dokončená práce s úspěšnou obhajobou