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Approximatively determination of cations and anions present in particulate matter
No full textLebdeće čestice su složena mješavina različitih organskih i anorganskih tvari. Njihovi utjecaji na okoliš ovise o fizičkim i kemijskim svojstvima, vremenu života i brojnosti. Lebdeće čestice se dijele prema veličini u tri frakcije ukupnih lebdećih čestica. Postoje dva izvora prirodni i antropogeni i oni određuju njihove kemijske sastave.Rad uključuje i eksperimentalni dio u kojem se uzorkovao zrak kako bi se dokazala prisutnost određenih iona u atmosferi. Zrak je uzorkovan u aparaturu vakuum pumpom preko papira za filtriranje ''plava vrpca''. Nakon propuštanja zraka oko 8 sati, filter papir narezan je na komadiće i dodavane su otopine kemikalija kako bi se dokazala prisutnost kationa i aniona. Rezultat istraživanja je prisutnost pojedinih iona u atmosferi.Particulate matters are complex compound of various organic and inorganic substances. Their effect on the environment depend upon physical and chemical properties, time of life (durability) and number. Particulate matters can be divided by size into three fractions. There are two sources natural and anthropogenic and they influence their chemical composition. In this study we have conducted experiments to prove presence of specific ions in atmosphere. Measurements were performed by sampling air through apparatus with filter paper blue ribbon. After sampling air for approximately 8 hours, filter paper is sliced into portions and solution of chemicals are added to prove presences of cations and anions. The result indicate potential presence of particular ions in the atmosphere
Characterization of surfactant coated wire electrode with carbon nanotubes
No full textTenzidi su bifunkcionalni organski spojevi koji se sastoje od hidrofilnog i hidrofobnog dijela. Glavna karakteristika im je smanjivanje površinske napetosti, a zbog svojih drugih svojstava su široku primjenu pronašli u proizvodima za čišćenje. S obzirom na naboj hidrofilnog dijela ih dijelimo na kationske, anionske, neionske i amfoterne (amfolitske). Nanočestice su čestice kojima je jedna dimenzija manja od 100 nanometara. Budući da imaju izvanredna svojstva pronalaze vrlo široku primjenu, a jedna od njih je izrada elektrokemijskih senzora. Vrlo je važno određivanje koncentracije tenzida zbog čega su danas razvijene brojne metode od kojih se najčešće upotrebljava potenciometrijska titracija. U potenciometrijskim titracijama se kao elektrokemijski senzori koriste ion selektivne elektrode. Najjednostavnija ion selektivna elektroda je elektroda na presvučenoj žici (coated wire). Za poboljšavanje karakteristika elektrode na presvučenoj žici koriste se ugljikove nanočestice. Eksperimentalnim mjerenjima je utvrđen odziv MWCNT coated wire tenzidne elektrode na kationske i anionske tenzide, te su odrađene titracije upotrebom MWCNT coated wire tenzidne elektrode i ispitan je utjecaj interferenata na istu.Surfactants are bifunctional organic compounds which contain hydrophilic and hydrophobic part. Main characteristic is lowering surface tension but they are widely used in detergents because of their other properties. Considering the charge od hydrophilic part they are classified as cationic, anionic, nonionic and amphoteric (ampholytic).Nanoparticles are particles with one dimensionsmallerthan 100 nanometers.They are widely used because of their extraordinary properties and one of the usage is constructing electrochemical sensors. It is very important to determine concentration of surfactants and because of that many methods are developed. One of the most common method is potentiometric titration. We use ion selective electrode as electrochemical sensor in potentiometric titration. One of the simplest ion selective electrode is coated wire electrode. We use nanoparticles in production of coated wire electrodes for improving their characteristic. In experimental measurements response of MWCNT coated wire surfactant electrode on cationic and anionic surfactants is determined. Using coated wire electrode we performed potentiometric titrations and examined influence of intereferents
Characterization of surfactant coated wire electrode with carbon nanotubes
No full textTenzidi su bifunkcionalni organski spojevi koji se sastoje od hidrofilnog i hidrofobnog dijela. Glavna karakteristika im je smanjivanje površinske napetosti, a zbog svojih drugih svojstava su široku primjenu pronašli u proizvodima za čišćenje. S obzirom na naboj hidrofilnog dijela ih dijelimo na kationske, anionske, neionske i amfoterne (amfolitske). Nanočestice su čestice kojima je jedna dimenzija manja od 100 nanometara. Budući da imaju izvanredna svojstva pronalaze vrlo široku primjenu, a jedna od njih je izrada elektrokemijskih senzora. Vrlo je važno određivanje koncentracije tenzida zbog čega su danas razvijene brojne metode od kojih se najčešće upotrebljava potenciometrijska titracija. U potenciometrijskim titracijama se kao elektrokemijski senzori koriste ion selektivne elektrode. Najjednostavnija ion selektivna elektroda je elektroda na presvučenoj žici (coated wire). Za poboljšavanje karakteristika elektrode na presvučenoj žici koriste se ugljikove nanočestice. Eksperimentalnim mjerenjima je utvrđen odziv MWCNT coated wire tenzidne elektrode na kationske i anionske tenzide, te su odrađene titracije upotrebom MWCNT coated wire tenzidne elektrode i ispitan je utjecaj interferenata na istu.Surfactants are bifunctional organic compounds which contain hydrophilic and hydrophobic part. Main characteristic is lowering surface tension but they are widely used in detergents because of their other properties. Considering the charge od hydrophilic part they are classified as cationic, anionic, nonionic and amphoteric (ampholytic).Nanoparticles are particles with one dimensionsmallerthan 100 nanometers.They are widely used because of their extraordinary properties and one of the usage is constructing electrochemical sensors. It is very important to determine concentration of surfactants and because of that many methods are developed. One of the most common method is potentiometric titration. We use ion selective electrode as electrochemical sensor in potentiometric titration. One of the simplest ion selective electrode is coated wire electrode. We use nanoparticles in production of coated wire electrodes for improving their characteristic. In experimental measurements response of MWCNT coated wire surfactant electrode on cationic and anionic surfactants is determined. Using coated wire electrode we performed potentiometric titrations and examined influence of intereferents
Synthesis of quaternary ammonium salts of triazole with potential cytotoxic activities
No full textKvaterni amonijevi kationi jesu poliatomski pozitivno nabijeni ioni strukture NR4+, gdje R predstavlja alkilnu ili arilnu skupinu. Zadatak ovog rada bio je provesti reakciju između alkil halogenida, odnosno u našem slučaju korišten je 1-bromooktadekan, i heterocikla 1H-1,2,4- triazola s ciljem dobivanja kvaterne amonijeve soli. Triazoli su skupina heterocikličkih spojeva molekularne formule C2H3N3 sačinjenih od peteročlanog prstena u kojem se nalaze dva atoma ugljika i tri atoma dušika. Dobivenu kvaternu amonijevu sol smo okarakterizirali 1H i 13C NMR spektrima,masenim spektrom i IR spektrom te pretpostavili njezinu moguću primjenu kao antifungalno sredstvo.Quaternary ammonium cations are polyatomic positively charged ions of the structure NR4+, where R represents alkyl or aryl group. The aim of this study was to perform a reactionbetween an alkyl halide, in our case was used 1-bromooktadekan, and heterocyclic 1H-1,2,4-triazole to get a quaternary ammonium salt. Triazoles are a group of heterocyclic compoundsof the molecular formula C2H3N3 composed of a five-membered ring containing two carbonatoms and three nitrogen atoms. The resulting quaternary ammonium salt, we characterizedwith the 1H and 13C NMR spectra, mass spectra and infrared spectra and assumed its possibleapplication as an antifungal agent
Qualitative analisys photochemical pollution in urban areas of Croatia
No full textOzon je sekundarni plin koji nastaje fotokemijskim procesima iz prirodnih ili antropogenih izvora.Troposferski ozon se smatra onečišćivačem i ima štetan učinak na ljudsko zdravlje i okoliš. Gradovi u Hrvatskoj razlikuju se u geografskom položaju, naseljenosti i emisiji prekursora pa tako i koncentracije ozona variraju. U radu su korišteni satni prosjeci koncentracija ozona mjerenih tijekom 2014. i 2015. godine. Na svim promatranim mjernim postajama koncentracija ozona značajno pozitivno korelira s temperaturom zraka. Atmosferski tlak, vidljivost te smjer i brzina vjetra manje pridonose pojavi ozona, osim na mjernoj postaji Zagreb gdje vidljivost gotovo jednako pridonosi pojavi ozona kao i temperatura zraka. Koncentracija ozona negativno korelira s relativnom vlagom zraka u svim mjernim postajama. U polarnim dijagramima mjerne postaje Dubrovnik može se uočiti kako je koncentracija ozona povezana sa sjevernim, sjeveroistočnim i istočnim smjerom vjetra. U području grada Zagreba nema značajnog smjera vjetra, jer ozon nastaje na području same mjerne postaje, a tako isto je i u području grada Osijeka. U metodičkom dijelu diplomskog rada obrađena je nastavna jedinica Ozon i ozonski omotač. Obradom nastavne jedinice za 3. razred gimnazije učenici su naučili što je ozon i svojstva ozona te kako nastaje i na koji način naši postupci uništavaju ozonski omotač.Ozone is a secondary gas formed by photochemical reaction from natural or anthropogenic sources.Tropospheric ozone is considered as pollutant and could be harmful to the health of humans, animals or theenvironment. Concentration of ozone varies in Croatian cities due to difference in geographic location,demography and emission of precursors. Hourly averages of ozone concentration measured during the periodof 2014 and 2015 were used in the study. Concentration of ozone significantly correlated with airtemperature in a positive way at all observed stations. Atmospheric pressure, visibility, direction and speed ofwind have less impact on ozone occurrence. The concentration of ozone has shown a negative correlationwith air humidity at all observed points. Polar diagrams obtained at station in Dubrovnik have shown that theincident of ozone is related with north, north-east and east wind. In the area of Zagreb and Osijek, directionof wind is not notable since the ozone is produced in the zone of measuring point.In addition, the thesis contributes to teacher methodologie showing how a lesson like. Ozone and ozonelayer could be thought in a high school. Chemistry of ozone, its features, genesis, impact to the environmentand human influence to ozone layer has been presented. Teacher preparation including appropriatestoichiometric calculations and class experiments has been appended
Hidrophilically modified silicones as dispersants in low permittivity solvents
No full textCilj i svrha ovoga rada je ispitati utjecaj dodatka hidrofilno modificiranih silikona male molarne mase na svojstva suspenzija nanočestica i ZnO u otapalima niske permitivnosti. Korišteni su hidrofilno modificirani silikoni različitih proizvođača, Elkay®Silicones, Xiameter® Dow Corning. Silikoni su karakterizirani mjerenjem viskoznosti u tri otapala različite permitivnosti: u DMSO, etanolu i heksanu. Akustičkom spektroskopijom ispitivan je utjecaj dodatka različite količine silikona na svojstva suspenzija kao što je veličina čestica i zeta-potencijal, a adsorpcija na površini nanočestica testirana je termogravimetrijski. Rezultati istraţivanja potvrđuju mogućnost korištenja hidrofilno modificiranih silikona u disperznim sustavima s otapalima visoke polarnosti. Metodički dio rada sadrži pripremu za nastavnu jedinicu pod naslovom "Osnovna svojstva fluida". Nastavni sat zamišljen je kao kombinacija frontalnog i grupnog rada uz izvođenje pokusa.The aim of this work is to examine the influence of the small molecular weight hydrophilically modified silicones on the properties of the nanoparticle and ZnO suspensions. The silicones of two different manufacturers, Elkay® Silicones, Dow Corning® Performance Products were used. They were characterized by viscosity measurements in the three different permittivity solvent: DMSO, ethanol and hexane. Acoustic spectroscopy was used to examine the influence of silicone addition on the suspension properties (particle size, zeta-potential), and the absorption onto the nanoparticles was tested by thermogravimetry. The results confirm the potential use of hydrophilically modified silicones in dispersed systems containing solvents of high polarity. Methodical part of the work includes preparation for teaching unit entitled "Basic properties of fluids". Lesson is designed as a combination of teacher`s frontal talk and group student`s work with experimentation
Synthesis and Characterization of Porous Macrocyclic Schiff Bases
No full textMakrocikli su cikličke molekule koje se sastoje od najmanje 9 atoma u prstenu od kojih barem jedan mora biti donor elektronskog para. Makrocikli su otkriveni sredinom 20. stoljeća i od tada predstavljaju važan dio raznih polja istraživanja, kako u kemiji, tako i u biologiji i medicini. Makrocikličke Schiffove baze, zbog relativno jednostavne primjene i sinteze, su sve više zastupljene u istraživanjima. Sastavni su dio makrocikličke kemije koja je vrlo popularna i sve više se razvija. Tijekom nekoliko posljednjih desetljeća, znanstvenici su uspješno proučavali različite vrste čvrstih materijala koji mogu selektivno vezati plinovite vrste. Među ovim materijalima postoji veliki interes za makrocikle koji imaju poroznu strukturu, a u koju se mogu ugraditi molekule nekog plina. U ovome radu opisane su sinteze dviju novih makrocikličkih Schiffovih baza od benzaldehida i diamina. Svi dobiveni produkti okarakterizirani su infracrvenom (FT-IR) spektroskopijom i termičkim metodama (TGADSC). Rentgenskom strukturnom analizom utvrđeno je da prilikom slaganja molekula u kristal kod spoja 1,6,20,25 - tetraaza-2,5:8,9:17,18:21,24:27,28:36,37 - heksabenzo-10,16,29,35 - tetraoksa - ciklooktatriakonta - 1,6,20,25 - tetraen (p-D1) nastaju šupljine. U nastale šupljine mogu se ugraditi različite plinovite vrste. Termičkom analizom određen je udio pojedinih plinova koji se adsorbiraju u šupljikavu strukturu spoja. Analizom spojeva s ugrađenim I2, NO2, Br2, CO2 i SO2 određeni su host/guest omjeri: I2 (1,5:1), NO2 (1:3), Br2 (2:1), CO2 (1:2,5) i SO2 (2:1). Dobiveni rezultati su pokazali da prilikom adsorpcije plinova ne dolazi do promjene u molekulskoj strukturi spoja. Također, opisan je i metodički dio koji sadrži napisanu pripremu za nastavni sat za srednju školu na temu "Onečišćenje i zaštita zraka". Nastavni je sat osmišljen u vidu eksperimentalnog dokazivanja svojstava plinova koji onečišćuju zrak (NOx, SO2 i CO2). Uz navedene pokuse, pripremljeni su pripadajući radni listići kako bi učenici kemijskim zakonitostima objasnili pojave u pokusima.Macrocycles are cyclic molecules of at least 9 atoms in the ring, one of which is electron donor atom. Macrocycles were discovered in mid 20th century and have been an important part of various fields of research, in chemistry, biology and in medicine. Macrocyclic Schiff bases are lately more and more presented in scientific studies due to the simplicity of their application and preparation. They are a part of macrocyclic chemistry that is very popular and is being furthermore developed. In the past few decades, scientists have successfully studied various types of solid materials that can selectively bind gaseous species. Among these materials, there is a great interest in macrocycles that can form porous structures and subsequently bind gaseous species. In this thesis, the synthesis and characterization of two new macrocyclic Schiff bases from benzaldehydes and diamines are described. All products were characterized by infrared spectroscopy (FT-IR) and thermal methods (TGA-DSC). The X-ray structural analysis of 1,6,20,25 - tetraaza - 2,5:8,9:17,18:21,24:27,28:36,37 - heksabenzo-10,16,29,35 - tetraoksa - ciklooktatriakonta - 1,6,20,25 - tetraen (p-D1) showed a presence of a nanometar sized voids in the crystal structure. As a result, gaseous species can be adsorbed into the voids. The ratio of adsorbed gaseous species in hollow structure of a product was determined by thermal analysis. Analysis of compound (p-D1) with adsorbed I2, NO2, Br2, CO2 and SO2 gave information on host/guest ratio: I2 (1,5:1), NO2 (1:3), Br2 (2:1), CO2 (1:2,5) and SO2 (2:1). Obtained results have demonstrated that there is no change in the molecular structure of compound during the adsorption of gaseous species. This thesis also contains a part with teaching methods on high school level including printed preparation for lesson on "Pollution and protection of air". The lesson is designed in form of an experimental demonstration of properties of air pollutant gases (NOx, SO2 and CO2). Corresponding working papers are included in order for students to explain the phenomena seen in given experiments
Green Synthesis of Organic Compounds
No full text"Zelena" kemija definirana je kao kemija koja osmišljava kemijske produkte i procese koji ne štete okolišu zamjenjujudi ih obnovljivim izvorima i novijim pristupom sintezama te na taj način sprečava najstajanje onečišdenja. "Zelena" kemija bazira se na 12 načela u kojima je katalizator naveden kao jedan od najvažnijih alata za provedbu "zelenih" procesa. Ovaj rad se usredotočuje na primjere sintetskih procesa u organskoj kemiji u kojima se koriste novi "zeleni" pristupi, čime je minimaliziran nastanak otpada i nusprodukata. Ovi primjeri obuhvadaju cijeli niz trendova "zelene" kemije kao što su: biokataliza, kataliza, upotreba alternativnih sirovina i reakcijskih medija te njihovu primjenu u osnovnim organskim reakcijama (oksidacija, nitriranje, sulfoniranje, alkiliranje).Green chemistry is defined as the design, development, and implementation of chemical products or processes, which reduce or eliminate the use of generation of hazardous and toxic substances, as well as replace non-renewable feedstocks with renewable materials. Green chemistry is based on d "The 12 Principles of Green Chemistry". These principles identify catalysis as one of the most important tools for implementing green chemistry. This paper focuses on the examples of the synthetic unit processes, which demonstrate the procedures that have been effectively implemented to accomplish several of green chemistry principles simultaneously. Wastes and byproducts can be minimised or avoided by developing these cleaner synthesis routes. These examples encompass the full range of green chemistry trends such as catalysis, biocatalysis and use of alternative feedstocks, solvents, reagents etc. in basic organic reactions as oxidation, nitration, alkylation etc
Solution and refinement of Crystal Structures
No full textCilj ovog rada je pobliţe upoznati metode rješavanja i utočnjavanja kristalnih struktura na primjeru dinuklearnog bakrovog kompleksa s acetatnim i metoksi ligandima, Cu2[(μ- CH3COO)2(CH3O)2]. Uvedeni su ključni pojmovi iz područja rentgenske difrakcije i kristalografije, te je kratko opisan korišteni softver kao što je WinGX, Ortep3, ShelX, Mercury bez kojeg ovaj rad ne bi bio moguć. Detaljno su opisane duljine veza, kutevi, intermolekularne interakcije, te geometrija kompleksa. U ovom radu se moţe vidjeti kako se pouzdano moţe odrediti struktura kristalizirane molekule te brojne karakteristike molekule, uz korištenje i osnovno poznavanje navedenog softvera, te teorije difrakcije i kristalografije.The goal of this thesis is to learn the methods for solution and refinement of crystal structures, on a dinuclear copper complex with acetate and methoxy ligands, Cu2[(μ- CH3COO)2(CH3O)2]. Key terms have been introduced from the fields of Roentgen diffraction and crystallography, and the software used, without which this thesis would not be possible, like WinGX, Ortep3, ShelX and Mercury, was also shortly described. Bond lengths, angles, intermolecular interactions, and the geometry of the complex were thoroughly described. In the thesis, one can easily see that a structure of a crystallized molecule, and its numerous properties can be reliably determined, with the usage and basic understanding of mentioned software, and the theory of diffraction and crystallography
Electrochemical Caracterization of a Schiff Base Complex with Copper
No full textSintetiziran je kompleks bakra sa Schiffovom bazom (1E)-1-N-{[4-(4-{[(E)-N-(2- aminofenil) karboksiimidoil] fenoksi} butoksi) fenil] metiliden} benzen-1,2- diaminom, S36; te ispitan pomoću cikličke voltametrije. Ovom metodom su se pratili oksidacijski i redukcijski procesi ispitivanog kompleksa. Utvrđeno je da se radi o kvazireverzibilnom oksido-redukcijskom procesu oksidacije Cu+ iona u Cu2+ ion, te redukcije Cu2+ iona u Cu+ ion. Dobiveni rezultati očitani su iz cikličkih voltamograma koji su snimljeni na elektrodi od staklastog ugljika u otopinama kompleksa bakra sa S36 u rasponu potencijala od -1,0 V do 0,55 V u odnosu na Ag/Ag+ elektrodu u nevodenom mediju (kao otapalo korišten je N,N- dimetilformamid) uz brzinu promjene potencijala od 25 mV s-1 do 300 mV s-1.Copper complex with Schiff base (1E)-1-N-{[4-(4-{[(E)-N-(2-aminophenyl) carboxyimidoyl] phenoxy} butoxy) phenyl] methylidene} benzene-1,2-diamine, S36 is synthesized and tested using cyclic voltammetry. Oxidation and reduction processes of the investigated complex were followed by this method. It has been found that quasi-reversible oxidation process of Cu+ to Cu2+ ion, and reduction process of Cu2+ to Cu+ ion occur. The results are obtained from cyclic voltammograms which were recorded on a glassy carbon electrode in solutions of the copper complex with S36 in a potential range from -1.0 V to 0.55 V vs. Ag / Ag + electrode in non-aqueous media (N , N-dimethylformamide was used as a solvent) at scan rates from 25 mV s-1 to 300 mV s-1