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Priprava kiralnih derivata cinhonidina na [2]paraciklo(5,8)kinolinofanu kao organokatalizatora u stereoselektivnim sintezama
Full text linkThe aim of this thesis was to synthesize chiral cinchonoid analogues, [2](5,8)quinolinophane and quinoline organocatalysts that could be used in stereoselective syntheses. The presence of the quinoline system makes the molecule of quinolinophane a great "building block" for the synthesis of chiral cinchona analogues as potential organocatalysts. In other words, it would be sufficient to introduce into the molecule a tertiary amino group and a chiral carbon bounded to a hydroxyl group to obtain a molecule that has all the elements of chirality as the natural cinchonoids. The only difference lies in the fact that a central chirality associated with quinuclidine ring of cinchonoids is replaced by the planar chirality associated with the system "quinolinophane". In addition, the quinolinophane constitutes a chiral "building block" of extreme versatility. In fact, through simple transformations, it is possible to obtain different structural combinations in which the determined elements for the asymmetric induction (the tertiary amino group, the hydroxylated chiral carbon and the planar chirality system) can be differently assembled.
With that in mind, the scope was to determine contribution of planar and central chirality of (R)-[2]paracyclo[2](5,8)quinolinophane derivatives exhibiting both type of chirality to the asymmetric induction (Figure 1). For sake of comparison envisaged was to prepare also some chiral (S)- and (R)-trifluoromethylsulfoxyamide derived from 4-bromoquinoline.Cilj ovog rada bio je sintetizirati kiralne analoge cinhonoidina, [2]paraciklo(5,8)kinolinofane i kinolinske organokatalizatore koji bi se mogli koristiti u stereoselektivnim sintezama. Zbog prisutnosti kinolinskog sustava molekula kinolinofana je izvrstan building block za sintezu kiralnih cinchona analoga kao potencijalnih organokatalizatora. Drugim riječima, dovoljno je uvesti u molekulu tercijarnu amino skupinu i kiralni ugljik vezan na hidroksilnu skupinu, čime se dobije molekula koja ima sve elemente kiralnosti kao prirodni cinchonoidi. Jedina razlika je u tome što je centralna kiralnost povezana s kinuklidinskim prstenom cinchonoida zamjenjena planarnom kiralnošću kinolinofanskog sustava. Nadalje, kinolinofan predstavlja kiralni building block izuzetne raznovrsnosti. U stvari, jednostavnim transformacijama moguće je dobiti različite strukturne kombinacije u kojoj su utvrđeni elementi za asimetričnu indukciju (tercijarna amino skupina, hidroksilirani kiralni ugljik, planarni kiralni sustav).
Imajući to na umu, opseg je utvrditi doprinos planarne i središnje kiralnosti (R)-[2]paraciklo[2](5,8)kinolinofanskih derivata koji pokazuju oba tipa kiralnosti u asimetričnoj indukciji (Slika 1). Radi usporedbe pripremljeni su i kiralni (S)- i (R)-trifluorometilsulfoksiamidi izvedeni iz 4-bromkinolina
The synthesis of gold nanoparticles via microemulsion method
Full text linkNanočestice zlata (AuNČ) sintetizirane su u mikroemulzijskom sustavu Triton X-100/voda/cikloheksan/1-pentanol pri čemu su kod sinteze mijenjani redukcijski uvjeti u mikroemulziji. Istraživane su tri mikroemulzijske sinteze; (i) sinteza AuNČ u mikroemulziji kod jakih redukcijskih uvjeta (dodatak NaBH4), (ii) sinteza AuNČ u mikroemulziji γ-zračenjem (radiolitička sinteza uz umjereno jake redukcijske uvjete) i (iii) sinteza AuNČ u mikroemulziji kod oksidacijskih uvjeta (dodatak vodene otopine NaOH). Sve sinteze odvijale su se na sobnoj temperaturi. Postupak sinteze započinje pripravom dviju mikroemulzija, A i B, od kojih Mikroemulzija A sadrži ione zlata (Au3+), dok Mikroemulzija B sadrži redukcijsko ili oksidacijsko sredstvo. Kada se Mikroemulzije A i B pomiješaju nastaje Mikroemulzija AB gdje dolazi do reakcije između mikroemulzijskih agregata, a time i do redukcije Au3+ iona u Au0 i nastajanja nanočestica zlata. Kada je u mikroemulziji B korišteno jako redukcijsko sredstvo NaBH4, prosječna veličina kristala zlata iznosi 11,7 nm što je utvrđeno iz proširenja difrakcijskih maksimuma. Prosječna veličina čestica na rubovima čestičnih agregata za isti uzorak mjerena elektronskom mikroskopijom iznosila je 7 ± 2 nm. Kod radiolitičke sinteze Au3+ ioni u mikroemulziji bili su reducirani γ-zračenjem. Redukcijska svojstva γ-zračenja bila su podešena propuhivanjem mikroemulzije plinovitim dušikom. Mikroemulzije koje nisu bile propuhane dušikom sadržavale su otopljeni kisik, a time i slabije redukcijske uvjete. γ-zračenjem mikroemulzija zasićenih kisikom dobivene su relativno veće nanočestice zlata (~12 nm) u odnosu na iste uvjete kod dušikom zasićenih mikroemulzija gdje su dobivene nanočestice prosječne veličine čestica 7-10 nm koje su nakon centrifugiranja djelomično agregirale u velike nanočestice promjera oko 150 nm. Dobivene velike nanočestice zlata posjeduju tiksotropna svojstva. Kod mikroemulzijske sinteze na sobnoj temperaturi kod oksidacijskih uvjeta u kiselom području (pH 7, jači oksidacijski uvjeti), nastaju dobro dispergirane nanočestice zlata promjera oko 12 nm. Sinteza nanočestica zlata u mikroemulziji kod alkalnog pH, ali ne i kod kiselog pH, može se objasniti oksidacijom alkoholnih skupina (-C-OH) u karbonilne skupine (>C=O) uz pomoć katalitičkog djelovanja hidroksilnih iona i zlata. Paralelno s katalitičkom oksidacijom alkoholnih skupina u mikroemulziji, ioni zlata (Au3+) reduciraju se u elementarno zlato (Au0) uz nastajanje nanočestica zlata.The gold nanoparticles (AuNPs) were synthesized in a microemulsion Triton X-100/water/cyclohexane/1-pentanol using various reducing agents. Basically, three microemulsion syntheses were studied; (i) the microemulsion synthesis of AuNPs using strong chemical reducing agent (NaBH4), (ii) the microemulsion synthesis of AuNPs using γ-irradiation (radiolytical synthesis at moderate reducing conditions) and (iii) the microemulsion synthesis of AuNPs at oxidising conditions (with the addition of NaOH aqueous solution). The syntheses were performed at room temperature. As the first step, Microemulsion A containing Au3+ ions and Microemulsion B containing reducing or oxidising agent were prepared separately. Then, the Microemulsion B was rapidly poured into Microemulsion A. While obtaining Microemulsion AB, a collision, coalescence and exchange of content between the microemulsion aggregates occurred. As a consequence the Au3+ ions were reduced to Au0 and the gold nanoparticles formed. When the strong chemical reducing agent NaBH4 was used in the microemulsion, the gold nanoparticles of 11,7 nm in size were obtained as determined on the basis of XRD line broadening. The mean particle size at the edges of aggregates for the same sample as measured by electron microscopy was 7 ± 2 nm. In the next experiments the aureate (Au3+) ions in microemulsions were reduced using γ-irradiation. The reducing power of γ-irradiation was tuned by bubbling microemulsions with nitrogen gas. The microemulsions that were not bubbled contained dissolved oxygen and thus more oxidizing conditions in comparison to the nitrogen saturated microemulsions. Basically, the γ-irradiated oxygen-saturated microemulsions produced relatively larger gold nanoparticles (~12 nm) in comparison to the γ-irradiated nitrogen-saturated microemulsions (7-10 nm), which under isolation by centrifugation aggregated in huge nanoparticles of about 150 nm in size. These gold nanoparticles possessed thixotropic properties. In addition, the microemulsion synthesis of gold nanoparticles under oxidising condition was investigated. The microemulsion stirred at room temperature and at pH 7 (oxidising conditions) the well-dispersed gold nanoparticles of 12 nm in size as measured using TEM were formed. Microemulsion synthesis of gold nanoparticles in the alkaline range, but not at an acidic pH, could be explained by the oxidation of alcoholic groups (-C-OH) into carboxylic groups (>C=O) due to the catalytic action of hydroxyl ions and gold. In parallel with the catalytic oxidation of alcohol groups in microemulsion, the Au3+ ions reduced to Au0 with subsequently formation of gold nanoparticles
Modelling of granulation processes
Full text linkOvaj rad je svojevrsni studij i sažet pregled postojećih pristupa modeliranja procesa granuliranja. Sagledani su modeli uvećanja procesa granuliranja odnosno procedure koje se provode s ciljem pravilnog odabira onih makroskopskih svojstava koja će u granulatoru većih dimenzija (pilot i/ili komercijalnom) rezultirati željenim svojstvima kolektiva granula, istovjetnim onima već dobivenim u malim (laboratorijskim) granulatorima.
Dodatno, razmatrani su pristupi kojima se danas modeliraju procesi fizičke pretvorbe tvari granuliranjem. Pri razmatranju modela za simuliranje odziva partikulskog procesa granuliranja posebna pažnja usmjerena je k primjeni mehanističkog pristupa konceptom populacijske bilance.
Proces fizičke pretvorbe nanostrukturirane tvari TiO2 u kolektiv pogodnijeg stanja disperznosti modeliran je mehanističkim pristupom, primjenom populacijske bilance. Pristup modeliranja populacijskom bilancom u ovome radu podrazumijeva ispitivanje mogućnosti primjene 1-D populacijske bilance u diskretiziranom obliku te Size-Independent Kernel (SIK) modela koalescencije u predviđanju stvarnih promjena u svojstvu partikulskog sustava (raspodjeli veličina čestica) tijekom procesa granuliranja. Modeliranje procesa granuliranja ostvareno je primjenom sekvencijalne procedure. Dobiveni rezultati uspoređeni su s onima dobivenim prethodnim istraživanjem, ostvarenim primjenom nesekvencijalne procedure modeliranja.
Primijenjeni pristup može ukazati na zastupljenost pojedinih mehanizama u procesu granuliranja. Metodom optimizacije, očitovanom u minimiziranju ukupne sume kvadrata odstupanja, procijenjen je karakterističan procesni parametar, konstanta brzine koalescencije. Time je, za sekvencijalan pristup, kvantificirana kinetika fizičke pretvorbe nanostrukturirane tvari TiO2 u stohastičkom okruženju fluidiziranog sloja.This thesis is a kind of study and concise overview of present approaches for modelling granulation processes. Scrutinized are models for scaling the granulation process, in fact the procedures that are lead for the purpose of right selection of the macroscopic properties for the operation of a larger scale granulator (pilot and/or commercial) that will result in targeted collective attributes, identical to those that are gained in a small scale granulators (laboratory ones).
Additionally, considered are approaches that are nowadays modelling tools for processes of physical conversion of substance by granulation. In analyzing the models for simulating the outcome of the particulate process of granulation, focus is given to the usage of mechanistic approach by concept of population balance.
Process of physical conversion of TiO2 nanostructured substance in a collective of a more appropriate dispersity state is modelled with mechanistic approach using population balance. In this thesis, modelling approach implies testing the applicability of a 1-D discretized population balance with Size-Independent Kernel (SIK) coalescence model for simulating real changes of the property of particulate system (particle size distribution) during granulation process. Modelling of the granulation process is carried out using sequential procedure. Attained results are compared with those of a previous research, brought by using non-sequential modelling procedure.
Used approach might indicate the contributions of underlying mechanisms in the granulation process. By optimization method, that connotes minimizing the overall sum of squared errors, characteristic process parameter, coalescence rate constant is estimated. Thus, for the sequential approach, kinetic of physical conversion of TiO2 nanostructured substance in a stochastic fluid-bed environment is quantified
Nanofluids based on transformer oils and iron oxide nanopowder
No full textU ovom radu provedena su ispitivanja stabilnosti i primjenskih svojstava nanofluida na osnovi mineralnog transformatorskog ulja i nanočestica Fe3O4. Dosadašnja ispitivanja pokazala su kako dodatkom nanočestica u bazni fluid može doći do poboljšanja toplinske vodljivosti i probojnog napona baznog fluida. Rezultati preliminarnih ispitivanja gdje su upotrijebljene komercijalno dostupne površinski aktivne tvari (oleinska, palmitinska i stearinska kiselina) nisu pokazali zadovoljavajuću stabilnost nanofluida. Stoga su sintetizirane vlastite površinski aktivne tvari na osnovi kopolimera metil-, dodecil-, i dimetilaminoetil-metakrilata. Kopolimeri odabranih sastava sintetizirani su izravno u transformatorskom ulju u izotermnim uvjetima uz diperoksidni inicijator. Određena im je raspodjela molekulskih masa i viskoznost razrijeđenih polimernih otopina. Sintetizirani kopolimeri pokazali su se uspješnima kroz ispitani period od sedam dana gdje je utvrđeno da je raspršeno 22-26 mas. % čestica. Dodatak nanočestica Fe3O4 u transformatorsko ulje uz prisutnu polimernu površinski aktivnu tvar uzrokuje sniženje probojnog napona, međutim, dobivene vrijednosti su i dalje u granicama propisanima odgovarajućom normom.In this paper, main task was to perform investigations of stability and application properties of nanofluids based on mineral transformator oil and Fe3O4 nanoparticles. Previous investigations have shown that the addition of nanoparticles in the base fluid can improve the thermal conductivity and breakdown voltage of the base fluid. Results of preliminary tests where commercially available surfactant (oleic, palmitic and stearic acid) were used have not showed satisfactory stability of nanofluids. Therefore, new surfactants were synthesized based on copolymers of methyl-, dodecyl-, and dimethylaminoethyl-methacrylate. Copolymers of selected compositions were synthesized directly in the transformer oil under isothermal conditions by using bifunctional peroxide initiator. Distribution of molecular mass of polymers were obtained by GPC/SEC method and viscosity of polymer dilute solution by capillary viscometry method. The synthesized copolymers have shown as effective surfactants - it was found that after seven days the 22-26 mass.% of nanoparticles was dispersed. Addition of Fe3O4 nanoparticles in transformer oil along with present polymeric surfactant causes a decrease of the breakdown voltage. However, the obtained values are still within the limits required by corresponding standards
Removal of pharmaceuticals using membrane bioreactors
Full text linkFarmaceutici u ulozi "novih onečišćivala", njihova pojava i mehanizmi transporta u okolišu, razvoj analitičkih i separacijskih metoda za otkrivanje, praćenje i nadzor, ekotoksikološki učinci na žive organizme i ekosustave i tehnologije obrade otpadnih voda, pitke vode i krutog, prvenstveno medicinskog, otpada s ciljem sprječavanja njihovog dospijevanja u prirodne recipijente (vodne sustave, zrak i tlo), a posljedično i u žive sustave, tema su brojnih znanstvenih publikacija objavljenih u posljednjih desetak godina. Zbog svijesti o prisutnosti u okolišu te dokazanih i potencijalnih negativnih učinaka na zdravlje, radi kojih se očekuje postavljanje zakonskih okvira za ograničavanje njihova unosa u okoliš, sve više zaokupljaju pozornost znanstvenika sa različitih područja djelovanja, kao i laika. Novim zakonskim zahtjevima će postrojenja za obradu otpadnih voda biti primorana smanjiti koncentracije na razinu manju od maksimalno dopuštene za pojedine farmaceutske tvari.
Danas korišteni uređaji za obradu otpadnih voda u najvećem broju koriste tehnologiju konvencionalne biološke obrade aktivnim muljem. Ona nije predviđena za uklanjanje aktivnih farmaceutskih tvari.
U ovom radu dan je pregled primjene tehnologije obrade otpadnih voda membranskim bioreaktorima s ciljem uklanjanja farmaceutika.Pharmaceuticals are part of a group of chemicals called micropollutants or emerging contaminants. Their occurrence, fate, and effects in environment, development of analytical and separation methods for detection, monitoring and control, ecotoxicological effects on living organisms and ecosystems and wastewater treatment technologies used for their removal are subject of numerous scientific publications published in the last ten years. Because of the cognition of the presence in the environment, and proven and potential adverse health effects, for which is expected to set up the legal framework for limiting their entry into the environment, pharmaceuticals increasingly occupy scientists' attention.
Wastewater treatment plants will be forced to reduce the concentration to a level lower than maximum allowed one by law for certain pharmaceutical substance. Currently, the most used technology for wastewater treatment is conventional activated sludge technology. However, it is not designed to remove active pharmaceutical ingredients.
This work gives an overview of membrane bioreactor technology and its use in removal of pharmaceuticals
Photochemical Approach to New Polycyclic Substrates Suitable for Further Photocatalytic Functionalization
Full text linkNew polycyclic compounds are synthesized by photocycloaddition reactions of methoxy, methyl or phenyl substituted butadiene derivatives 11−14. Mono- and dimethoxy butadiene derivatives 11 and 12 undergo intramolecular [2+2] photocycloaddition giving benzobicyclo[3.2.1]octadiene structures (endo-15, endo,trans-17) as main products. As minor photoproducts tricyclic compounds endo-16 and endo,trans-18 are isolated, respectively, formed by [4+2] photoinduced cycloaddition of the starting molecules. The reaction of compounds 13 and 14 is more selective and only benzobicy-clo[3.2.1]octadienes endo,endo-19 and endo,endo-20 are formed, respectively. New bicy-clo[3.2.1]octadienes with isolated double bond can be suitable substrates for further efficient photo-catalytic oxygenations in course of new functionalized polycycles, potentially new biologically active compounds
Testing durability of shotcrete
No full textMlazni betoni su kompozitni materijali sa vrlo kratkim vremenom vezanja, od svega nekoliko minuta, te se u praksi koriste za sprječavanje prodora vode i stabilizaciju stijena pri izradi tunela. Od uobičajenih cementnih veziva razlikuju se po vrlo kratkom vremena vezanja i nanošenjem na površinu prskanjem u mlazu, tzv. torkretiranjem. U ovome radu istraživana je hidratacija Portland cementa (PC) i Portland cementa uz različite masene dodatke titanil sulfata (TiOSO4) odnosno komercijalnog proizvoda AS 301 kao aditiva za pripravu materijala (mlaznog betona) vrlo kratkog vremena vezanja. Utjecaj aditiva na kinetiku hidratacije praćen je in situ kalorimetrijski, te naknadnom analizom materijala rendgenskom difrakcijom. Pripravljeni materijali s dodatkom aditiva su volumno postojani (nisu skloni pojavi pukotina i pretjeranoj ekspanziji), a vrlo kratko vrijeme vezanja zadovoljava uvjet za ugradnju kompozita direktnim špricanjem. Najbolje tlačne čvrstoće postižu se s dodatkom 2% TiOSO4.Shotcrete are composite materials with very short setting time of only a few minutes, and are used in practice to prevent water penetration and stabilization of rock in the preparation of the tunnel. A further peculiarity of this material, except for a very short time setting, is it's application to the surface by jet spraying, so-called concrete-gunning. In this work, hydration of Portland cement (PC) and Portland cement with various mass additions of titanyl sulfate (TiOSO4) or a comercial product AS 301 as an additive for the preparation of materials (shotcrete) with very short cure times has been investigated. The effect of additives on hydration kinetics was investigated in situ by calorimetry and powder X-ray diffraction of extracted material. The prepared materials have stable volumen evolution (no affinity towards cracking and expansive reactions), and very short setting times and thus satisfies the requirement for composite placement by jet spraying. Best compressive strengths are obtained with 2% of TiOSO4
Degradation of diclofenac in water by UV/TiO2 process
No full textUsprkos činjenici da su farmaceutici namijenjeni u pozitivne svrhe kao što su liječenje i sprječavanje raznih bolesti, danas se smatraju i tzv. novim onečišćivalima. Za sada je zabilježen njihov utjecaj na vodene ekosustave ali ne i na zdravlje ljudi i životinja. Zbog straha od daljnjeg lošeg utjecaja na okoliš Europska komisija revizijom Direktive 2013/39/EU dodaje na tzv. „watch“ listu tvari čiji će se utjecaj pratiti u budućnosti po prvi put farmaceutike, među kojima i diklofenak (DCF) istraživan u ovom radu. Iz tog razloga javila se potreba za pronalaskom metode za obradu otpadnih voda koja bi bila učinkovita ali i ekološki prihvatljiva. Kao najbolje metode pokazale su kemijske metode i to napredni oksidacijski procesi (engl. Advanced Oxidation Processes, AOP). Cilj ovog rada bio je primijeniti UV-A/TiO2 proces za razgradnju DCF-a u vodi i odrediti utjecaj procesnih parametara (pH vrijednosti i koncentracije katalizatora) na učinkovitost obrade. Utjecaj ključnih parametara primijenjenog fotokatalitičkog procesa obrade (pH i koncentracija katalizatora TiO2) na njihovu učinkovitost ispitan je korištenjem kombinacije punog faktorskog plana i metode odzivnih površina (RSM). Utvrđeno je da razgradnja prati kinetiku drugog reda. Maksimalna brzina razgradnje otopine DCF-a iznosi 4,052 M^-1s^-1 i postiže se pri pH 6 i γ(TiO2)=1,3055 g/L a bliska je vrijednosti predviđenoj modelom (4,074 M^-1s^-1). Pokazano je da γ(TiO2) ima značajan utjecaj na brzinu razgradnje u ispitivanom području dok pH nema. Utvrđeno je da se provedbom UV-A/TiO2 procesa na optimalnim uvjetima uz potpunu konverziju DCF-a postiže stupanj mineralizacije > 90%. Usporedbom konverzije i mineralizacije može se zaključiti da razgradnjom DCF-a nastaju brzo mineralizirajući produkti. Učinkovitost postupka pri optimalnim uvjetima uspoređena je s vremenom potrebnim za postizanje referentnih intervala stupnja mineralizacije te su praćene promjene u vrijednosti kemijske i biokemijske potrošnje kisika (KPK i BPK5) te toksičnosti na Vibrio fischeri.Despite the fact that pharmaceuticals are made for positive purposes such as treatment and prevention of various diseases, today they are include in a group of a new pollutants. There is only a record of their impact on aquatic ecosystems so far, but no on human and animal health. Due to fear of further adverse impact on the environment, the European Commission in revision of Directive 2013/39/EU on the so-called "watch" list of substances whose impact will be monitored in the future added for the first time pharmaceuticals, including diclofenac (DCF) which was studied in this paper. Due to this reasons there is a need to find a method to treat the wastewater that would be effective, but also environmentally acceptable. Chemical methods such as advanced oxidation processes have proven to be the best methods. The aim of this study was to apply UV-A/TiO2 process for the degradation of DCF in the water and to determine the influence of process parameters (pH and concentration of catalyst) on the effectiveness of treatment. The impact of key parameters of the applied photocatalytic process (pH and concentration of catalyst TiO2) on their efficiency was tested using a combination of full factorial design and Response Surface Methodology (RSM). It was found that the degradation follows second order kinetics. The maximum rate of the degradation solution DCF is 4,052M^-1s^-1 and it is achieved at pH 6 and γ (TiO2) = 1.3055 g/L which is close to the value of the predicted model (4,074 M^-1s^-1). It is shown that γ(TiO2) has a significant effect on the degradation rate in the test area, while the pH has no effect. It was found that the implementation of UV-A/TiO2 process in optimal conditions with complete conversion of DCF achieves the degree of mineralization > 90%. Comparison of the conversion and mineralization leads to conclusion that the degradation of DCF forms rapidly mineralizing products. The effectiveness of the procedure under optimal conditions was compared to time required to achieve the degree of mineralization of reference intervals and changes in the value of chemical and biochemical oxygen demand (COD and BOD5) and toxicity to Vibrio fischeri has also been monitored