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U ovom radu provedena je sinteza 45 polimernih aditiva na osnovi metil ili benzil metakrilata uz oktadecil, dodecil te 2-(tert-butilamino) etil metakrilat. Cilj rada bio je istražiti utjecaj različitih omjera navedenih monomera na sniženje tecišta dizelskog goriva bez drugih aditiva, smjese dizela i 10 vol. % biodizela te čistog biodizela. Polimeri su sintetizirani radikalskom polimerizacijom u otopini toluena uz 50 mas. % monomera uz Peroxan PO 70 kao inicijator. Sintetiziranim polimerima provjerila se čistoća (uspješnost uklanjanja zaostalih monomera) metodom infracrvene spektroskopije s Fourierovom transformacijom. Metodom 1H nuklearne magnetske rezonancije potvrđena je struktura polimernim aditivima. Toplinska svojstva ispitala su se metodom diferencijalne pretražne kalorimetrije. Formulacijama polimernih aditiva udjela 2000 ppm po masi u dizelu, smjesi B10 i B100 ispitana su niskotemperaturna svojstva radi utvrđivanja utjecaja različitih omjera komonomera u polimeru. Metodom diferencijalne pretražne kalorimetrije ispitan je utjecaj polimernih aditiva na temperaturu kristalizacije aditiviranih goriva te na promjenu entalpije kristalizacije. Kako bi se utvrdio utjecaj polimernih aditiva na temperaturu tecišta formulacija goriva, provedeno je mjerenje temperatura tecišta smjesa automatskom metodom po ASTM D5950. Naposlijetku se promatrao utjecaj aditiva na morfologiju i veličinu kristala n-parafina pomoću mikroskopa s polarizacijom dok se smjesa hladila postoljem s hlađenjem. Radom je utvrđeno da se najveće sniženje temperature tecišta postiže polimernim aditivima s najvećim udjelom dodecil metakrilata i najmanjim udjelom metil i benzil metakrilata. Ovi polimeri snizili su temperaturu tecišta s -18 °C neaditiviranog dizelskog goriva na -45 °C. Isti polimerni aditivi pokazali su najveće sniženje tecišta i u formulaciji B10 goriva gdje je tecište sniženo s -18 °C na -48 °C. Pripremljena je i smjesa funkcionalnog polimernog aditiva masenog udjela 2000 ppm u B100 gorivu te je toj formulaciji ispitano tecište. Toj formulaciji tecište se smanjilo s -6 °C (čisto B100 gorivo) na -12 °C. U radu nije utvrđen značajan utjecaj na tecište dizelskog goriva aditiviranim polimerom s komonomerom s aminskim članom. Utjecaj aminske skupine TBAEMA vidljiv je u promjeni morfologije kristala n-parafina u vidu smanjenja veličine kristala što može doprinijeti snižavanju temperature filtrabilnosti. In this work, the synthesis of 45 polymer additives based on methyl or benzyl methacrylate with octadecyl, dodecyl and 2-(tert-butylamino) ethyl methacrylate was carried out. The aim of the work was to investigate the influence of different proportions of the above monomers on the lowering of the pour point temperature of diesel fuel without additives, mixture of diesel and biodiesel (FAME) B10 and pure biodiesel B100. The polymers were synthesized in a toluene solution containing 50 mass percent of the monomer and with Peroxan PO 70 as initiator at 96 °C. The synthesized polymers were checked for purity (from residual monomers) by infrared spectroscopy with Fourier transformation. Thermal properties were tested by differential scanning calorimetry. Polymer additive mixtures of 2000 ppm mass in diesel, B10 and B100 were prepared to determine the influence of different comonomer contents in the polymer on the lowtemperature properties. Differential scanning calorimetry was used to investigate the influence of polymer additives on the crystallization temperature of the fuel formulations and on the enthalpy of crystallization. To determine the influence of polymer additives on the pour point temperature of fuel formulations, the pour point temperature of the mixtures was measured using the ASTM D5950 automated method. Finally, the effect of additives on the morphology and size of n-paraffin crystals was observed using a microscope with polarization while the mixture was cooled with a cooling stage. It was found that the greatest decrease in the pour point was achieved by the polymers with the highest proportion of dodecyl methacrylate and the lowest proportion of methyl and benzyl methacrylate. These polymers were able to lower the pour point from -18 °C in nonadditivated diesel fuel to -45 °C. These polymer additives showed the best effect in lowering the pour point in the formulation of B10 fuel, where the pour point was lowered from -18 °C to -48 °C. The formulations of the polymer additive in B100 fuel showed a decrease in pour point from -6 °C to -12 °C. The influence of the amine group TBAEMA can be seen in the change in the morphology of the n-paraffin crystals in the form of a decrease in crystal size, which may contribute to the lowering of the cold filter plugging point. In this work, no significant influence on the pour point of diesel fuel by the additive polymer with a comonomer containing an amine group was found.

Biodizel je ester masnih kiselina koji se najčešće sintetizira reakcijom transesterifikacije triglicerida (biljna ulja i životinjske masti) s alkoholom u prisustvu katalizatora. Proizvodnjom od otpadnog ulja, eliminiraju se dodatni troškovi uzgoja biljaka uljarica, štede se plodne površine i voda, izbjegava se kompeticija s hranom što može dovesti do rasta cijena i nedostatka hrane (jestiva biljna ulja) te se smanjuje nastanak otpada u prehrambenom sektoru. Struktura molekule biodizela ovisi o sirovinama od kojih se sintetizira. Masne kiseline triglicerida uglavnom su ravnolančane, stoga molekula alkohola određuje hoće li ester biti razgranat ili ravnolančan. Oblik molekule je odlučujuć za neka svojstva dizelskog goriva. Primjerice, duže ravnolančane molekule povećat će vrijednost cetanskog broja, dok će razgranati esteri sniziti tecište što će omogućiti rad pri nižim temperaturama. Cetanski broj je primarni indikator kvalitete goriva korištenog u kompresijskim motorima s unutarnjim izgaranjem. Neki biodizeli pokazuju visoke vrijednost cetanskog broja, no dokazano je kako su dulji ugljikovodični lanci u molekulama estera proporcionalno povezani s vrijednosti cetanskog broja. U tu svrhu istražuju se sinteze s višim alkoholima poput 1-heksanola. U ovom radu ispitivani su utjecaji reakcijskih parametara na iskorištenje reakcije transesterifikacije otpadnog ulja s heksanolom. Pratio se utjecaj molarnog omjera alkohol/ulje, utjecaj masenog udjela lužnatog katalizatora KOH, utjecaj reakcijskog vremena i temperature. Iskorištenje se određivalo iz 1H NMR spektra integriranjem površine pojedinih signala. Eksperimentalnim dijelom rada utvrđeno je da se najveće iskorištenje dobiva pri temperaturi od 60 °C. Veće iskorištenje reakcija je imala s molarnim omjerom alkohol/ulje 12:1. Veći suvišak alkohola ovu je ravnotežnu reakciju pomaknuo više prema produktima. Maseni udio katalizatora od w(KOH) = 3 % dao je veća iskorištenja reakcije u odnosu na w(KOH) = 1 %. Visoka iskorištenja reakcije dobila su se već nakon 2 minute, no do 15. minute iskorištenje se u prosjeku još povisilo za 1,59 % i doseglo svoj maksimum. Eksperimentalno je pokazano da na iskorištenje najviše utječu parametri maseni udio katalizatora te molarni omjer alkohol/ulje. Biodiesel fuel is a fatty acid alkyl ester, commonly synthesized via transesterification of triglycerides (vegetable oils and animal fats) with an alcohol, in a presence of a catalyst. Production of biodiesel fuel from waste vegetable oil eliminates additional costs of growing oilseed plants as a raw material, reduces the amount of waste in the food sector, preserves fertile land area and water, eliminates direct competition with food which could otherwise potentially lead to price increase and shortages of edible vegetable oils. The structure of the biodiesel molecule depends on the feedstock from which it's synthesized. The triglyceride’s fatty acids have mainly straight hydrocarbon chains, so the alcohol molecule determines if the ester will be straight-chained or branched. The molecule structure is determinant for some diesel fuel properties. For example, longer straight-chained molecules will have higher cetane number values, while branched ones will have lower pour point values and, therefore, engines will be able to perform at lower temperatures. Cetane number is the prime indicator of the fuel quality used in the internal combustion compression engines. Some biodiesel fuels show high cetane number values. It has been proven that longer hydrocarbon chains in the ester molecules are proportionately related to the cetane number value, therefore, synthesis with higher alcohols are being tested, such as 1-Hexanol. In this research, the influence of reaction parameters on the transesterification process of waste vegetable oil with 1-Hexanol was examined. The influence of the alcohol/oil molar ratio, the influence of the mass fraction of the alkaline catalyst KOH, the influence of the reaction time and temperature were monitored. The conversion was calculated from 1H NMR spectra by integrating the surface areas of specific signals. The experimental part of the research established that 60 °C is the best temperature out of given three in the reaction. 12:1 alcohol to oil molar ratio had a higher conversion because greater excess of an alcohol shifted this reversible chemical reaction more towards the products. The catalyst mass fraction of w(KOH) = 3 % gave higher reaction yields than the 1 % one. High conversions of the reaction were obtained after only 2 minutes, but by the 15th minute the conversion increased by approximately 1.59 % and reached its near maximum. It was experimentally shown that the parameters that have the greatest effect on conversion are the mass fraction of the catalyst and the alcohol to oil molar ratio.

Proizvodnja biodizela, neotrovnog kapljevitog goriva koje svoju sve širu primjenu pronalazi kao zamjena ili dodatak dizelu fosilnog podrijetla, u zadnje vrijeme privlači sve veću pozornost. Jedan od najpoznatijih i najznačajnijih reakcijskih puteva sinteze biodizela, reakcija transesterifikacije, predmet je brojnih istraživanja pa je tako analizirana i u okviru ovog rada. Kao jedan od novih reaktorskih sustava za proizvodnju biodizela transesterifikacijom sve veći interes i primjenu pronalaze mikroreaktori. Za provedbu reakcije transesterifikacije u mikroreaktorima, kao i u ostalim reakcijskim sustavima, potrebno je odrediti optimalne reakcijske uvjete potrebne kako bi se dobili iskorištenja te udjeli metilnih estera masnih kiselina u skladu s odgovarajućim standardima. Kao polazna sirovina u proizvodnji biodizela najčešće se koriste različita ulja i masti prirodnog podrijetla, a kao rezultat procesa transesterifikacije dobiva se produkt koji sadrži komponente koje je potrebno odvojiti kako bi se dobio biodizel čistoće u skladu s odgovarajućim standardima. U okviru ovog rada, a u svrhu proizvodnje biodizela koji zadovoljava standarde, razvijen je integrirani mikrosustav u kojemu je prvo provedena reakcija transesterifikacije u mikroreaktoru, a zatim pročišćavanje biodizela u serijski povezanom mikrosustavu. Pročišćavanje je provedeno u mikroekstraktoru s niskotemperaturnim eutektičkim otapalom koje iz biodizela uklanja zaostale reaktante i dobiveni glicerol pri čemu se dobiva biodizel visoke čistoće. Enzim lipaza, koji je korišten za provedbu reakcije transesterifikacije u mikroreaktoru, imobiliziran je na magnetske nanočestice što je omogućilo njegovo zadržavanje u mikroreaktoru i posljedično olakšalo proces pročišćavanja biodizela u serijski povezanom mikrosustavu te proces učinilo ekonomski opravdanim. Inaktivacija enzima metanolom, drugim reaktantom u procesu transesterifikacije koji se u pravilu dodaje u suvišku, jedan je od osnovnih izazova provedbe procesa transesterifikacije katalizirane enzimima. Kao jedno od procesnih rješenja ovog izazova primijenjen je mikroreaktorski sustav u kojemu su kao ulazne procesne struje korišteni čisti metanol te emulzija ulja i enzima pri čemu je proizveden biodizel uz iskorištenje od 94 % uz vrijeme zadržavanja, 𝜏 = 20 min. Dodatno je razvijen i integrirani sustav spajanjem mikroreaktora s mikroekstraktorom pri čemu je proizveden biodizel uz iskorištenje od 94 % za vrijeme zadržavanja, 𝜏 = 20 min, te uz udio glicerola od 0,019 % (w/w). The production of biodiesel, a non-toxic liquid fuel that has been increasingly used as a replacement or addition to diesel of fossil origin, has recently attracted an increasing attention. One of the best known and most important reaction pathways of biodiesel synthesis, the transesterification reaction, is the subject of numerous studies and was analyzed in this paper. As one of the new reactor systems for biodiesel production by transesterification, microreactors have increased interest and application. To demonstrate transerterification reaction in microreactors, as well as in other reaction systems, it is necessary to determine the optimal reaction conditions needed in order to obtain yields and content of fatty acid methyl esters in accordance with relevant standards. As a starting material in the production of biodiesel, various oils and fats of natural origin are commonly used, and as a result of the transesterification process, a product is obtained that contains components that need to be separated in order to obtain the purity of biodiesel in accordance with relevant standards. Purpose of this work was biodiesel production of purity defined by relevant quality standards. An integrated microsystem was developed in which the transesterification reaction was firstly carried out in the microreactor leading to the purification of biodiesel in a microsystem connected in series. Purification was performed in a microextractor using a deep eutectic solvent that removes residual reactants and produced glycerol where in the same time biodiesel of high purity is obtained. Lipase, which was used to carry out the transesterification reaction was immobilized on magnetic nanoparticles, which enabled enzyme retention in a microreactor and consequently facilitated the process of purification of biodiesel integrated microsystem and made the process economically sustainable. Inactivation of the enzyme by methanol, another reactant in the transesterification process which is generally added in excess, is one of the primary challenges of enzyme-catalyzed transesterification processes. As one of the possible process solutions, a microreactor system was used in which pure methanol and emulsion of oil and enzyme were used as process inlets where biodiesel was produced with a yield of 94 % for the retention time of 𝜏 = 20 min. Additionally, an integrated system was developed by combining the microreactor with a microextractor. In this system biodiesel was produced with a yield of 94 % for the retention time of 𝜏 = 20 min, and with glycerol content of 0,019 % (w/w).

Ograničene količine fosilnih goriva i njihov nepovoljan utjecaj na klimatske promjene potaknuli su znanstvenike na traženje alternativnih izvora energije. Kao jedno od boljih rješenja tog problema pokazao se biodizel. Reakcija transesterifikacije temeljna je reakcija kojom se proizvodi biodizel. Reakcijom alkohola i triglicerida, koji su glavni sastojak masti i ulja, uz prisutnost katalizatora nastaju esteri masnih kiselina. Osim jestivih, nejestivih i otpadnih ulja koja mogu biti korištena prilikom sinteze biodizela, izbor alkohola također je prilično širok. Najviše je istražena sinteza biodizela iz metanola i etanola, ali u novije doba interes su privukli i određeni viši alkoholi. Odabrani alkohol u ovom radu je izopentanol koji reagira sa suncokretovim uljem uz prisutnost bazičnog katalizatora, kalijevog hidroksida. Pratio se utjecaj četiri reakcijska parametra na iskorištenje reakcije transesterifikacije, a to su: reakcijsko vrijeme, molarni omjer alkohola i ulja, maseni udio katalizatora i temperatura reakcije. Reakcijsko vrijeme bilo je u rasponu od 0,5 do 2,5 h, molarni omjer alkohola i ulja od 4:1 do 10:1, maseni udio katalizatora od 1 do 3 % i temperatura reakcije od 40 do 80 ˚C . Uz pomoć programskog paketa Design Expert 11 napravljen je Box-Behnkenov plan koji sadrži 29 pokusa. Iako se najčešće primjenjuje kao kvalitativna metoda, 1H NMR spektroskopija korištena je za kvantitativnu analizu tj. određivanje iskorištenja reakcije. Analizirani su brojni grafički prikazi kojima se potvrđuje ili negira poklapanje eksperimentalnih podataka s modelom dobivenim uz pomoć programskog paketa Design Expert 11. Cilj rada bio je osim određivanja utjecaja reakcijskih parametara na iskorištenje reakcije, pronaći optimalne uvjete za sintezu izopentilnih estera masnih kiselina. Programski paket nudi opciju optimiranja i ovisno o željama postavlja se maksimalna i minimalna važnost određenog reakcijskog parametra, a kao rezultat dobivaju se uvjeti sinteze i predviđeno iskorištenje koje prema HRN ISO 14214 treba minimalno iznositi 95 %. Optimiranjem procesa pokazalo se da je maksimalno moguće iskorištenje uz minimalan iznos ostalih reakcijskih parametara 98,56 %. Ukoliko se želi postići navedeno iskorištenje, potrebno je reakciju transesterifikacije provoditi 2,43 h pri temperaturi od 78,64 ˚C uz omjer alkohola i ulja 8,86:1 te maseni udio katalizatora od 2,57 %. Limited amounts of fossil fuels and their adverse effects on climate change have prompted scientists to look for alternative energy sources. Biodiesel is proven to be one of the solutions for this problem. Fundamental reaction that produces biodiesel is the transesterification reaction. Esters of fatty acids are formed in the reaction between alcohol and triglycerides, which are the main constituents of fats and oils, in the presence of catalysts. In addition to edible, inedible and waste oils that can be used in biodiesel synthesis, the choice of alcohol is also quite wide. The synthesis of biodiesel from methanol and ethanol has been the most researched, but recently certain higher alcohols have also attracted interest. The alcohol of choice in this work is isopentanol which reacts with sunflower oil in the presence of a basic catalyst, potassium hydroxide. The influence of four reaction parameters on the yield of the transesterification reaction was monitored, namely: reaction time, molar ratio of alcohol and oil, mass fraction of catalyst and reaction temperature. The reaction time ranged from 0.5 to 2.5 h, the molar ratio of alcohol and oil from 4: 1 to 10: 1, the mass fraction of catalyst from 1 to 3 % and the reaction temperature from 40 to 80 ˚C. With the help of the Design Expert 11 software package, a Box-Behnken plan, containing 29 experiments, was created. Although it is most often used as a qualitative method, 1H NMR spectroscopy was used for quantitative analysis, i.e. to determine the yield of the reaction. Numerous graphical representations were analyzed which confirm or deny the coincidence of the experimental data with the model obtained with the help of the Design Expert 11 software package. In addition to determining the influence of reaction parameters on the reaction yield, the aim of this work was to find optimal conditions for the synthesis of isopentyl fatty acid esters. The software package offers the option of optimization and, depending on the wishes, the maximum and minimum importance of a certain reaction parameter is set, and as a result the synthesis conditions and predicted yield are obtained, which according to HRN ISO 14214 should be at least 95 %. By optimizing the process, it was shown that the maximum possible yield with a minimum amount of other reaction parameters is 98.56 %. If the desired yield is to be achieved, the transesterification reaction must be carried out for 2.43 h at a temperature of 78.64 ˚C with an alcohol to oil ratio of 8.86: 1 and a catalyst mass fraction of 2.57 %.

Zbog sve manjih rezervi fosilnih goriva, a sve većih zahtjeva za energijom, svijet se okreće procesima pretvorbe biomase u tekuća goriva. Jedno od tih goriva je biodizel, alkilni ester masnih kiselina čijim izgaranjem nastaje manje stakleničkih plinova. Biodizel se najčešće dobiva reakcijom transesterifikacije triglicerida iz biljnih ulja ili životinjskih masti i alkohola, najčešće metanola. Nedostatak biodizela naspram mineralnog dizela je niža toplinska vrijednost i loša niskotemperaturna svojstva. Jestiva ulja su rafinirana i imaju manji sadržaj slobodnih masnih kiselina pa se reakcija transesterifikacije provodi uz bazični katalizator te tako ne dolazi do stvaranja sapuna u velikoj mjeri. Propanol i viši alkoholi u odnosu na metanol i etanol imaju određene prednosti poput bolje mješljivosti s dizelom, veće hidrofobnosti, cetanskog broja i toplinske vrijednosti. U ovom radu sintetizirani su propilni esteri masnih kiselina reakcijom transesterifikacije triglicerida iz suncokretovog ulja i propanola uz bazični katalizator (KOH). Kako bi se ispitala molekulska međudjelovanja i njihov utjecaj na primjenska svojstva pripremljene su mješavine osnovnih komponenata, dizela, biodizela i propanola. Primjenska svojstva koja su ispitana normiranim metodama su viskoznost, gustoća, točka filtrabilnosti i mazivost. Mješavine su dodatno karakterizirane infracrvenom spektroskopijom s Fourierovom transformacijom (FTIR), diferencijalnom pretražnom kalorimetrijom (DSC) te mjerenjem površinske napetosti, kontaktnog kuta i indeksa refrakcije. 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.

Biodizel je ekološki prihvatljiva i održiva zamjena za petrokemijski dizel. Prema kemijskom sastavu biodizel obuhvaća monoalkilne estere masnih kiselina i jednostavnih alkohola. Sirovine za proizvodnju biodizela čine razna biljna i otpadna ulja poput suncokretovog, repičinog ulja te ulja kikirikija i soje, dok su od alkohola za sada najzastupljeniji metanol i etanol. U posljednje vrijeme istražuje se mogućnost korištenja i drugih alkohola poput butanola, izobutanoal i pentanola kao sirovina za proizvodnju biodizela. Biodizel se proizvodi reakcijom transesterifikacije ulja s alkoholom. U ovom radu obrađen je utjecaj četiri reakcijska parametra na bazno kataliziranu transesterifikaciju suncokretova ulja s izobutanolom uz kalijev hidroksid kao katalizator. Parametri čiji utjecaj je određivan su: vrijeme reakcije (1 - 3 h) , temperatura (40 - 80 °C), molarni omjer alkohola i ulja (6:1 - 12:1) te maseni udio katalizatora (1 - 3 %). Pomoću programskog paketa Desin-Expert 11 napravljen je Box-Behnkenov plan 28 pokusa. Rezultat svakog pokusa je iskorištenje reakcije. Iskorištenje je određeno pomoću 1H NMR analize reakcijske smjese. Na temelju eksperimentalnih rezultata napravljen je model ovisnosti iskorištenja o reakcijskim parametrima. Dobivenim modelom napravljena su tri slučaja optimizacije. Optimalni uvjeti za jedan od slučajeva su: vrijeme reakcije od 1 sat pri temperaturi od 71,98 uz omjer izobutnola i ulja 10,17:1 sa 1,72 % KOH katalizatora. Previđeno iskorištenje iznosi 99,69 %. Biodiesel is ecologically acceptable a sustainable substitute for petrochemical diesel. By its chemical composition biodiesel is a mixture of monoalkyl esters of fatty acid and simple alcohols. Biodiesel is produced from different waste and cooking oils such as sunflower, castor, peanut and soybean oils. Nowadays, most used alcohols are methanol and ethanol. In recent times, other alcohols, such as butanol, isobutanol and pentanol, are being investigated for biodiesel production. Biodiesel is produced by the reaction of transesterifiction of oil with alcohol. In this paper, the influence of four reaction parameters on base catalysed transesterificaton of sunflower oil with isobutanol was studied. Potassium hydroxide was used as catalyst. Reaction parameters were: reaction time (1 - 3 h), temperature (40 - 80 °C), molar ratio of alcohol and oil (6:1 - 12:1) and mass percentage of catalyst (1 - 3 %). Using Desin-Experst software a Box-Behnken plan with 28 experiments was made. Result of every experiment was the biodiesel yield which was determined by 1H NMR spectroscopic analysis. Based on the experimental results, a model of the dependence that takes into account the yield on the reaction parameters was made. Using the model three optimisation cases were made. Optimal reaction parameters for one of those cases were: 1 h of reaction time at 71.98 °C using 10,17:1 ratio of isobutanol and oil and 1.72 % of KOH catalyst. The estimated yield was 99.69%.

U suvremenom svijetu zbog rastućih problema s okolišem dolazi do potrebe za korištenjem obnovljivih izvora energije u svakodnevnom životu i industriji. Zbog toga se nad klasičnim izvorima energije dobivenim iz fosilnih izvora nadmeće biodizel, koji se sintetizira reakcijom transesterifikacije alkohola i masti/ulja biljnog ili životinjskog porijekla, uz prisutnost katalizatora. U ovom diplomskom radu ispitan je utjecaj reakcijskih parametara na iskorištenje reakcije između propanola i suncokretovog ulja, uz KOH kao katalizator. Ispitano je četiri parametra: temperatura reakcije, vrijeme provedbe reakcije, maseni udio katalizatora i molarni omjer propanol:suncokretovo ulje. Najveće postignuto iskorištenje iznosilo je 99,79 % pri temperaturi od 60 °C, razdoblju od 2 h, masenom udjelu katalizatora od 1 mas. %, te omjeru propanol:ulje u iznosu od 10:1. Dizajniranju eksperimenta prethodila su 3 preliminarna pokusa, gdje su vrijednosti temperature bile od 40 do 80 °C, vremena od 1 do 3 h, omjera propanol:ulje od 6:1 do 10:1 i masenog udjela katalizatora od 1 do 3 mas. %. Planiranje eksperimenta i statistička obrada provedeni su u programskom paketu Design Expert. Nakon provedenih eksperimenata, provedena je optimizacija procesa transesterifikacije, s ciljem postizanja iskorištenja većeg od 95 %. Zbog toga se težilo što kraćem vremenu reakcije, nižoj temperaturi, manjem omjeru propanola i suncokretovog ulja, te manjem masenom udjelu katalizatora. Ovisno o tome kolika je zadana važnost pojedinog cilja (1-5), dobiveno je tri slučaja s različitim optimalnim uvjetima. Odabrani optimalni uvjeti iznosili su: temperatura 40,00 °C, vrijeme 2,42 h, omjer propanol:ulje 9,53:1, maseni udio katalizatora 1 mas. % pri čemu predviđeno iskorištenje iznosi 96,81 %. SUMMARY In the modern world, due to growing environmental problems, there is a need to use renewable energy sources in everyday life and industry. Therefore, biodiesel, which is obtained by the transesterification reaction of alcohol and fats/oils of vegetable or animal origin, with the presence of a catalyst, competes over classical energy sources obtained from fossil sources. In this thesis, the influence of reaction parameters on the yield of the reaction between propanol and sunflower oil, with KOH as a catalyst, was investigated. Four parameters were examined: reaction temperature, time of reaction, mass fraction of catalyst and molar ratio of propanol:sunflower oil. The highest conversion of 99.79 % is achieved at the temperature of 60 °C, reaction time of 2 hours, propanol:oil ratio in the amount of 10:1 and the mass fraction of catalyst 1 wt. %. The design of the experiment was preceded by 3 preliminary experiments, where the temperature values were from 40 to 80 °C, time from 1 to 3 hours, propanol:oil ratio from 6:1 to 10:1 and a mass fraction of catalyst from 1 to 3 wt. %. Experiment planning and processing statistics were performed in the Design Expert software package. After the experiments, the optimization of the transesterification process was made, with the aim of achieving the highest possible conversion. Therefore, we strived for the shortest possible reaction time, lower temperatures, lower ratio of propanol and sunflower oil, and lower mass fraction of catalyst. Depending on the given importance of each goal (1-5), three cases with different optimal conditions were obtained. The selected optimal conditions were: temperature 40,00 °C, time 2,42 h, propanol:oil ratio 9,53:1, mass fraction of catalyst 1 wt. %, where the predicted yield is 96,81 %.

U novije vrijeme sve se više zaliha fosilnih goriva nekontrolirano iscrpljuje, a različiti ekonomski, gospodarski i politički interesi suverenih država, samo su dodatni faktori koji su utjecali na sve veća ulaganja u istraživanja alternativnih goriva u svrhu povećanja ekološke svijesti. Biogoriva, osobito biodizel, ističu se kao prikladno rješenje koje odgovara zahtjevima globalnog tržišta, održivog razvoja i postizanja zadanih ušteda. Biodizel se definira kao metilni ili etilni ester viših masnih kiselina proizveden raznim procesima među kojima se ističu mikroemulzifikacija, piroliza i transesterifikacija. Potonji proces je ujedno i najrašireniji zbog visoke učinkovitosti, manjih proizvodnih troškova i velike brzine reakcije. Kao sirovine za proizvodnju biodizela transesterifikacijom koristi se široki spektar proizvoda poput jestivih i/ili otpadnih ulja i masti te alge i jantrofa koji poboljšavaju svojstva biorazgradivosti i netoksičnosti, a biodizel proizveden iz ovih sirovina odlikuju niže emisije stakleničkih plinova. Stoga se biodizel proizveden transesterifikacijom iz ovih izvora smatra i ekološki prihvatljivim. Kako bi se odvila reakcija transesterifikacije između ulja/masti i alkohola, najčešće metanola, potreban je katalizator. Uporaba enzima tj biokatalizatora, posebice enzima lipaze porijeklom iz Thermomyces lanuginosus, pokazala se obećavajućom jer su enzimi specifični, kataliziraju reakcije u kojim sudjeluju brojni supstrati, selektivni su, posjeduju visoku aktivnost u blagim eksperimentalnim uvjetima čime njihova primjena rezultira manjom potrošnjom energije u odnosu na kiselo ili bazno katalizirane reakcije transesterifikacije. Učinkovitosti procesa transesterifikacije može pridonijeti i upotreba mikroreaktorskih sustava, odnosno reaktora u mikroskopskom mjerilu. U usporedbi s makroskopskim reaktorskim sustavima, primjena mikroreaktora omogućuje bolji prijenos tvari i topline, što je posljedica velikog omjera površine i volumena samog mikroreaktora, za provedbu reakcije potrebne su manje količine reaktanata i katalizatora što rezultira i manjom količinom otpadnih struja, a samim time i manjim utroškom energije. Povoljnija hidrodinamika sustava, laminaran tok i učinkovito miješanje procesnih struja vode k povećanju brzine kemijske reakcije. U ovom radu provedena je transesterifikacija otpadnog jestivog ulja uz enzim lipazu u mikroreaktoru širine kanala 500 μm s dva ulaza i dva izlaza, a praćene su veličine značajne za uspješnu provedbu procesa (konverzija, vrijeme zadržavanja i aktivnost enzima). Maksimalna konverzija X = 32,28 % postignuta je pri najdužem retencijskom vremenu (τ = 30,63 min) za sustav u kojemu je transesterifikacija otpadnog ulja provedena uz komercijalni enzim suspendiran u puferu. In recent years, more and more fossil fuel stocks have been uncontrollably depleted and the differing economic and political interests of sovereign countries are merely additional factors that have led to increasing investment in alternative fuel research with the purpose of increasing environmental awareness. Biofuels, especially biodiesel, stand out as a suitable solution that meets the demands of the global market, sustainable development as well as achieving the set savings. Biodiesel is defined as the methyl or ethyl ester of higher fatty acids produced through various processes such as microemulsification, pyrolysis and transesterification. Tranesterification is the most widespread due to its high efficiency, lower production costs and high reaction speed. As a raw material, it offers a wide range of products such as edible and / or waste oils and fats as well as algae and amber, which improve biodegradability, non-toxicity and lower greenhouse gas emissions. Therefore, biodiesel is produced by transesterification from these sources and is environmentally friendly. In order to carry out the transesterification reaction between oil / fat and alcohol, most commonly methanol, a catalyst is required. The use of enzymes, i.e. biocatalysts, especially lipases from Thermomyces lanuginosus, has proven to be very promising as they are very specific with the recognition of numerous substrates, selective and they show high activity in mild experimental conditions, which reduces energy consumption relative to acidic or base catalyzed reactions. The efficiency of the process is also contributed by the microreactor system, i.e. the microscopic scale reactors. Comparing micro- and macroscopic systems, microreactors enable better mass and heat transfer, which is due to the large surface-to-volume ratio of the microreactor itself, requires less reactants and catalysts to effect the reaction, resulting in less waste streams and, over time, lower energy consumption. It is also noticed that more favorable hydrodynamics of the system, laminar flow and effective mixing of currents are increasing the rate of chemical reaction. In this work the transesterification of waste edible oil with lipase enzyme in a 500 μm channel microreactor with two inputs and two outputs was carried. The sizes important for successful process implementation (conversion, retention time, enzyme activity) were monitored as well. A maximum conversion of X = 32.28% was achieved at the longest retention time (τ = 30.63 min) for a system in which transesterification of waste oils was carried out with a commercial enzyme suspended in buffer.

U današnje vrijeme sve se više suočavamo s posljedicama dugogodišnjeg negativnog utjecaja na okoliš. Povećanjem ljudske populacije raste potreba za energijom odnosno fosilnim gorivima koja se većinom dobivaju iz neobnovljivih izvora energije. Zbog toga su se kao alternativa fosilnim gorivima razvila tekuća biogoriva koja se dobivaju iz obnovljivih izvora energije. Najrašireniju primjenu među biogorivima našao je biodizel. Biodizel dobiven procesom transesterifikacije iz biljnih ulja ili životinjskih masti, sadrži veliki udio glicerola, kojeg je potrebno odvojiti kako bi se zadovoljile direktive Europske unije. Posebno je kao proces pročišćavanja biodizela zanimljiva kapljevinska ekstrakcija pomoću selektivnog otapala. Kao selektivno otapalo najviše se koriste organska otapala koja su toksična, a time i ekološki neprihvatljiva. Stoga se kao njihova zamjena razvijaju zelena otapala, koja su obnovljiva, ne hlapiva, jednostavna za upotrebu te su kemijski i fizički stabilna. Posljednja dva desetljeća veliku pozornost u zelenoj kemiji privukla su eutektička otapala, koja su svoju primjenu pronašla i u procesima pročišćavanja biodizela. U ovome radu provedeno je pročišćavanje biodizela s eutektičkim otapalima u tri tipa mikroekstraktora, iste konfiguracije ali različite širine (250 μm, 350 μm, 500 μm) i volumena (4,15 μL, 5,81 μL, 8,30 μL) mikrokanala. Biodizel korišten u ovom radu je dobiven transesterifikacijom iz svježeg suncokretova ulja uz komercijalni enzim lipazu. Za potrebe provedbe procesa ekstrakcije u mikroekstraktorima sintetizirana su eutektička otapala kolin klorid/glicerol (u molarnim omjerima 1:2,0; 1:2,5; 1:3,0) i kolin klorid/glicerol/voda (u molarnim omjerima 1:1:0,5; 1:1:1,0; 1:1:2,0). Prije provedbe procesa ekstrakcije ovim eutektičkim otapalima su izmjereni gustoća, viskoznost, pH-vrijednost i vodljivost. Ekstrakcija eutektičkim otapalima u mikroekstraktorima pokazala se kao vrlo učinkovita, relativno jeftina i za okoliš prihvatljiva metoda pročišćavanja biodizela. Nowadays we are facing more and more with the repercussions of a long-term negative influence on the environment. With an increase of human's population, there is also growing need for energy, i.e. fossil fuels which are mainly produced from non-renewable energy sources. Due to that, fluid biofuel produced from renewable energy sources appeared as a sort of alternative. Biodiesel has found the broadest use among the other biofuels. Biodiesel is produced by the transesterification from biooils or animal fat and it contains large amount of glycerol which must be separated in order to satisfy the directives of the European Union. Specially interesting as a biodiesel purification process is a liquid extraction with a selective solvent. As a selective solvent, there can be used mostly organic solvents which are known to be toxic and therefore ecologically unacceptable. As a result, green solvents have been developed as their replacement. Green solvents are renewable, non-volatile, chemically and physically stable and easy to use. During the last two decades, deep eutectic solvents, which found their application in the process of biodiesel refining, have received huge attention in the green chemistry. In this thesis biodiesel refining with deep eutectic solvents was carried out in three types of microextractor, with the same configuration but different width (250 μm, 350 μm, 500 μm) and volume (4,15 μL, 5,81 μL, 8,30 μL) of microchannels. Biodiesel used in this study was produced by the transesterification of the fresh sunflower's oil with the commercial enzyme lipase. Different deep eutectic solvents such as choline chloride/glycerol (in molar ratio 1:2,0; 1:2,5; 1:3,0) and choline chloride/glycerol/water (in molar ratio 1:1:0,5; 1:1:1,0; 1:1:2,0) were synthesised and used for extraction in microextractors. Before extraction process density, viscosity, pH value and conductivity of all syntesised deep eutectic solvents were measured. Extraction in microextractors by deep eutectic solvents is very effective, inexpensive and environmentally acceptable for biodiesel purification.

Rastuća svijest o klimatskim promjenama potakla je znanstvenike na razvoj obnovljivih energetskih izvora kako bi zaštitili Zemlju, nas i buduće naraštaje života. Jedan od glavnih problema opasnih klimatskih promjena su staklenički plinovi nastali kao posljedica sve većeg broja prijevoznih sredstava. Emisija stakleničkih plinova po kilometru putovanja osobnim vozilom u porastu je za 13% u posljednjem desetljeću. Rješenje za izgaranje dizela i benzina u prijevoznim sredstvima je biorazgradiva, netoksična i ekološki prihvatljiva alternativa – biodizel. Za proizvodnju visoko kvalitetnog biodizela potrebno je ukloniti nečistoće, vodu i metale iz masti i ulja, sirovina za dobivanje biodizela. U ovom eksperimentalnom radu cilj je bio smanjiti koncentraciju metala u otpadnim životinjskim mastima i otpadnim jestivim uljima metodom ekstrakcije niskotemperaturnim eutektičkim otapalima pri temperaturi 60 °C tijekom dva sata kako bi se dobila što kvalitetnija sirovina za dobivanje biodizela. Na temelju dobivenih rezultata odabrano je najučinkovitije otapalo za ekstrakciju metala iz otpadnih životinjskih masti i otpadnih jestivih ulja. Increasing awareness of Earth's climate change inspires scientists to find renewable energy sources to protect the Earth, us and the future generations of life. One of the major problems of dangerous climate change is greenhouse gases as a consequence of an increasing number of vehicles. The greenhouse gas emissions per kilometer by passenger car increased 13% in the last decade. The solution for diesel and gasoline combustion in transportation is a biodegradable, non-toxic and ecologically acceptable alternative – biodiesel. In order to achieve high quality biodiesel, it is necessary to remove impurities, water and metals from fats and oils, raw material for obtaining biodiesel. In this experimental work, the aim was to reduce the concentration of metals in animal waste fats and edible waste oils by extracting the metals with low-temperature eutectic solvents at 60 °C for two hours to get the best quality raw material for obtaining biodiesel. Based on the obtained results, the most efficient solvent for the extraction of metals from waste animal fat and waste edible oils was selected.

Upotreba fosilnih izvora energije uzrokuje brojne negativne učinke na okoliš. Zbog navedenog problema, čovječanstvo se okreće prema drugim izvorima. Biodizel, kao alternativno motorno gorivo, proizvodi se iz bioloških izvora. Popularnost je stekao zbog smanjenja štetnih utjecaja na okoliš, obnovljivih izvora sirovina, biorazgradivosti i netoksičnosti. Također, proizvodnja biodizela je ekonomski prihvatljiva jer se može proizvoditi iz otpada koji se ne može koristiti u ljudskoj prehrani. U ovom radu dan je pregled procesa obrade otpadnih životinjskih masti u cilju dobivanja što kvalitetnije sirovine za proizvodnju biodizela. Uzorci su podvrgnuti procesima ekstrakcije i adsorpcije kako bi se iz njih uklonile nečistoće, odnosno smanjio sadržaj slobodnih masnih kiselina i koncentracija prisutnih metala. Ispitivanjima je utvrđeno kako je niskotemperaturno eutektičko otapalo kalijev karbonat:etilen glikol (molni omjer, 1:10) pogodno za snižavanje sadržaja slobodnih masnih kiselina iz sirovina životinjskog podrijetla te kako sastav polazne sirovine, odnosno sadržaj slobodnih masnih kiselina i koncentracija metala, utječe na učinkovitost adsorpcije i samim time na izbor adsorbensa. The use of fossil energy sources causes numerous negative environmental impacts. Because of this problem, mankind is turning to utilization of other resources. Biodiesel, as an alternative motor fuel, is derived from biological sources. It has gained popularity due to reduced environmental impacts, accessibility of renewable raw materials, biodegradability and non-toxicity. Furthermore, production of biodisel is economically viable because it is often produced from waste that cannot be used for human consumption. This paper presents an overview of animal waste processing in order to obtain high quality raw materials for biodiesel production. Samples were subjected to extraction and adsorption processes to remove impurities, reduce the content of free fatty acids and concentration of metals. Studies have shown that deep eutectic solvent potassium carbonate:ethylene glycol (molar ratio, 1:10) is suitable for lowering the free fatty acids content of animal fat and the way in which the composition of the starting material, ie the content of free fatty acids and the concentration of metals, affects the adsorption efficiency and hence the choice of adsorbent.

U novije vrijeme sve je veći naglasak na biodizelu kao alternativnom, ekološki prihvatljivom gorivu. Ono što biodizel razlikuje od konvencionalnog dizela jest odsutnost sumpora, smanjen udio čađe i ugljikova monoksida u ispušnim plinovima te općenito manje ostalih tvari štetnih po okoliš. Biodizel se danas proizvodi pirolizom, mikroemulzifikacijom, a najčešće se kao proizvodni proces primjenjuje transesterifikacija. Transesterifikacijom otpadnih ulja i masti može se dobiti biodizel bolje kvalitete uz niže proizvodne troškove. Uporabom enzima kao katalizatora u procesu transesterifikacije ostvaruje se čitav niz prednosti u odnosu na klasičnu industrijsku proizvodnju biodizela kataliziranu kemijskim katalizatorima. Na učinkovitost procesa znatno utječe i primjena mikroreaktorskih sustava koji u usporedbi s klasičnim makroreaktorima omogućuju bolji prijenos tvari i topline, kraća vremena zadržavanja, manje količine potrebnih reagensa i katalizatora, manje otpadnih procesnih struja, kompaktnost i jednostavnost dizajna, laminarni tok procesnih struja, učinkovitije miješanje, kraći difuzijski put molekula, lakšu kontrolu procesa, te smanjenu potrošnju energije. U ovom radu provedena je transesterifikacija masnih kiselina iz jestivog i korištenog suncokretovog ulja uz enzim lipazu kao katalizator u mikroreaktoru promjera cijevi 1 mm i duljine 30 cm. Kao alkoholna faza korišten je metanol uz dodatak emulgatora SDS (natrijev dodecil-sulfat) koji se u pokusima pokazao najboljim za miješanje faza reakcijskog sustava. Proces je proveden za različite protoke komponenata reakcijske smjese, pri temperaturi 40 °C, a konverzija od 93 % postignuta je za vrijeme zadržavanja 80 min korištenjem jestivog ulja te 95 % korištenjem otpadnog ulja kao supstrata za vrijeme zadržavanja od 40 min. Ista konverzija, u kotlastom makroreaktoru postignuta je tek nakon 22 h. Kako prisustvo glicerola u biodizelu smanjuje njegovu kvalitetu razvijen je sustav od dvije serijski spojene mikroprocesne jedinice, mikroreaktora za proizvodnju biodizela i mikroseparatora za kontinuiranu separaciju glicerola uz primjenu kolin korid etilenglikola kao ekstraktne faze. Analizom biodizela nakon ekstrakcije glicerola utvrđeno je da je glicerol u potpunosti uklonjen iz biodizela. Biodiesel is recently being explored as an alternative fuel with eco-friendly properties. What differs biodiesel from conventional diesel is the absence of sulphur, less soot, carbon monoxide in exhaust gasses and generally less matters that are hazard for the environment. Biodiesel is today being produced by pyrolysis, microemulsification and transesterification. By using waste cooking oil, it is possible to conduct low-cost production process with good fuel properties. Enzymes as biocatalysts in the process of transesterification show series of advantages compared to the usage of classic industrial catalysts. Microreaction systems also show many advantages in biodiesel production, as they enable better heat and matter transfer, shorter retention time, less raw materials and catalysts, less waste products, laminar flow, better mixing, better molecular diffusion, less energy consumption, easier process control and, finally, they are compact and simple by design. Transesterification of fatty acids from edible and waste cooking oil was conducted in this work. Enzyme lipase was used as a catalyst in a microreactor with tube diameter of 1 mm and length of 30 cm. Methanol was used as alcohol phase, and SDS (sodium dodecyl sulfate) as an emulsifier for stabilizing the two phases. The process was conducted at the temperature of 40 ºC, and the conversion of 93% was achieved with the retention time of 80 min for edible oil and 95% for retention time of 40 min for waste cooking oil, respectively. Equal conversion in a batch macroreactor was achieved after 22 h. To continuously separate glycerol from the biodiesel, a system of two microprocess units was developed. Microreactor was used for biotransformation and microseparator was used for extraction of glycerol where choline chloride ethylenglycol was used as the extract phase. By analyzing biodiesel after the separation of glycerol, it is shown that all of glycerol was successfully removed.

Kako bi se unaprijedila proizvodnja biodizela s ekonomskog i ekološkog gledišta potrebno je istražiti primjenu novih katalizatora, ekološki prihvatljivijih i ekonomski isplativijih sirovina te optimirati proces s istima. Konvencionalni katalizatori poput NaOH i KOH kada se primjenjuju na biljna ulja s većim sadržajem slobodnih masnih kiselina i vode dovode do saponifikacije koja bitno otežava separaciju produkata i povećava proizvodnju otpadne vode. U isto vrijeme primjena biljnih ulja (posebice jestivih) negativno utječe na tržište hrane te smanjuje količinu iskoristivih poljoprivrednih površina. Osim toga, najčešće korišteni alkohol za transesterifikaciju, metanol, proizvodi se iz neobnovljivih izvora (povećava emisiju stakleničkih plinova) i toksičan je. Iz tih razloga u ovom radu ispitana je aktivnost novog gvanidinskog katalizatora N,N',N''-tris(3-dimetilamino)propil gvanidina (GV3) uz kojeg ne dolazi do saponifikacije, a kao sirovine korištene su otpadno restoransko ulje i niži alkoholi, metanol, etanol, n-butanol i i-butanol. Ovdje je posebice zanimljiva sirovina etanol kojeg je moguće proizvesti iz obnovljivih izvora (bioetanol). Shodno tome provedeno je modeliranje i optimizacija šaržnog procesa proizvodnje etilnih estera višemasnih kiselina (FAEE) transesterifikacijom otpadnih ulja s etanolom pomoću GV3 za najvažnije procesne parametre (maseni udio katalizatora, molarni omjer etanola i otpadnog ulja, temperatura i vrijeme provedbe reakcije) metodom planiranja pokusa s faktorskim centralno kompozitnim planom. Kao rezultat razvijen je vjerodostojan empirijski matematički model. Pomoću metode odzivnih površina (RSM) utvrđeni su optimalni uvjeti procesa za zadane ciljeve. Ciljevi optimiranja bili su postizanje maksimalne konverzije uz minimalan udio katalizatora i minimalnu temperaturu s omjerom reaktanata što bližim stehiometrijskom te što kraćem vremenu. Ovisno o zadanoj važnosti pojedinog cilja dobiveni su različiti optimalni uvjeti od kojih su odabrani: maseni udio katalizatora od 1,72 mas. %; molarni omjer etanola i otpadnog ulja od 5,35:1; temperatura od 40 °C i vrijeme od 40 min s predviđenom konverzijom od 91,44 %. In order to improve the production of biodiesel from an economic and environmental point of view, it is necessary to research the application of new catalysts, environmentally friendlier and cost-effective raw materials and their process optimization. Conventional catalysts, i.e. NaOH and KOH, when applied to vegetable oils with higher content of free fatty acids and water, usually lead to saponification. The resulting soap makes the separation of products difficult and thus increase waste water production. Furthermore, the use of edible vegetable oils has a negative impact on the food market by reducing the quantity of available farmland and increasing the price of food. Methanol is the most commonly used alcohol for transesterification. But it is toxic and produced from non-renewable sources, increasing greenhouse gas emissions. For this reason, the activity of the new guanidine catalyst N,N',N''-tris(3-dimethylaminopropyl)-guanidine (GV3) for the tansesterification of waste oil with various lower alcohols (methanol, ethanol, n-butanol and i-butanol) were examined. Ethanol is particularly interesting as a raw material because it can be produced from renewable sources, i.e. bioethanol. The process optimization with ethanol and waste oil was carried out for the most important process parameters (mass fraction of the catalyst, the molar ratio of ethanol and waste oil, reaction temperature and time) in accordance with the factorial central composite design of experiments. As result the significant empirical mathematical model was developed. Using Response Surface Methodology (RSM) optimal conditions were determined for the tested parameters. The goals of the optimization were to maximize the conversion, minimize the mass fraction of catalyst, at the lowest temperature and the shortest reaction time with the molar ratio of ethanol and waste oil closer to stechiometric. Depending on the importance given to a individual goal, different optimal conditions were calculated. The chosen optimal conditions were: the catalyst mass fraction of 1.72 wt.%; the molar ratio of ethanol and the waste oil 5.35:1; reaction time of 80 min at 40 °C with the calculated conversion of 91.44 %.

Zbog rastuće potrebe za energijom odnosno gorivom i zbog sve strožih zakona zaštite okoliša u svrhu smanjenja emisije stakleničkih plinova i ispunjavanja obveza Kyoto protokola, uz neobnovljive izvore energije (fosilna goriva) sve više se počinju razvijati i koristiti obnovljiva ili alternativna goriva kao biodizel. Biodizel se proizvodi od biljnih ulja, recikliranog otpadnog jestivog ulja ili životinjske masti, procesom transesterifikacije, pri čemu kao sporedni produkt nastaje glicerol. Za njegovu široku upotrebu u uobičajenim dizel-motorima potrebno je iz njega izdvojiti glicerol u skladu sa standardiziranim normama za biodizel EN14214 i ASTM D6751 (max. 0,02 % m/m). U ovom je radu istražena mogućnost ekstrakcije zaostalog glicerola iz biodizela sintetiziranih iz jestivih ulja. Biodizeli su sintetizirani iz suncokretovog, biljnog, sojinog, kikiriki, maslinovog i bućinog ulja. Kao selektivno otapalo korištena je eutektička smjesa kolin klorid/etilen glikol. Eksperimentalno su određene gustoća, viskoznost, koeficijent toplinske vodljivosti i ogrjevne vrijednosti biodizela i uspoređene sa svojstvima komercijalnog dizela. FTIR spektri biodizela nakon ekstrakcije ne pokazuju prisutnost glicerola i preklapaju se s FTIR spektrom komercijalnog biodizela. Due to the growing demand for energy and fuel, and because of increasingly stringent environmental laws to reduce greenhouse gas emissions and fulfill the obligations of the Kyoto Protocol, beside the non-renewable energy sources (fossil fuels), the renewable or alternative fuels like biodiesel are increasingly developed and used. Biodiesel is made from vegetable oils, recycled used cooking oil or animal fats, through the process of transesterification, whereby as a by-product the glycerol is produced. For the wide use of biodiesel in conventional diesel engines, it is necessary to isolate glycerol from him according to standardized norms for biodiesel EN14214 and ASTM D6751 (max. 0.02% m / m). In this work, the possibility to extract residual glycerol from biodiesel synthesized from edible oils was investigated. Biodiesels were synthesized from sunflower, vegetable, soybean, peanut, olive and pumpkin oil. As a selective solvent the deep eutectic solvent made of choline chloride / ethylene glycol was used. Density, viscosity, thermal conductivity and calorific values of biodiesel were experimental determined and compared with the properties of commercial diesel. FTIR spectrum of biodiesel after extraction do not show the presence of glycerol and overlap with the FTIR spectrum of commercial biodiesel.