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Reakcija benzo (b)tiofen 1,1-dioksida i benzonitril oksida
No full textReakcijama 1,3-dipolarne cikloadicije reagiraju dipol i dipolarofil uz nastanak peteročlanog prstena kao produkta. Oksidacijom benzo(b)tiofena, uz ledenu octenu kiselinu i vodikov peroksid, priređen je benzo(b)tiofen 1,1-dioksid, koji u 1,3-dipolarnim cikloadicijama reagira kao dipolarofil. (E)-Benzaldoksim se dobio iz benzaldehida, natrijeva hidroksida i hidroksilamin hidroklorida, a u reakcijama 1,3-dipolarne cikloadicije se koristi kao prekursor 1,3-dipola. U ovom se radu pokušala provesti 1,3-dipolarna cikloadicija korištenjem benzo(b)tiofen 1,1-dioksida kao dipolarofila te benzaldoksima iz kojeg smo očekivali stvaranje 1,3-dipola (benzonitril-oksida). Cilj je bio i usporediti odvijanje ove poznate reakcije u klasičnim uvjetima s onima u mikrovalnoj pećnici. Neočekivano, glavni produkt ovih reakcija je najvjerojatnije nastao konjugiranom adicijom umjesto 1,3-dipolarnom cikloadicijom. U radu su ponuđena objašnjenja za dobivene rezultate.Reactions of 1,3-dipolar cycloadditions are those where dipole and dipolarophile react together to give a 5-membered ring as a product. In this work 1,3-dipolar cycloaddition reactions between benzo(b)thiophene 1,1-dioxide and (E)-benzaldoxime have been attempted. Oxidation of benzo(b)thiophene with glacial acetic acid and hydrogen peroxide gave benzo(b)thiophene 1,1 -dioxide, which in 1,3-dipolar cycloaddition reacts as dipolarophile. (E)-Benzaldoxime was obtained from benzaldehide, sodium hydroxide and hydroxylamine hydrochloride and in reactions of 1,3-dipolar cycloaddition is used to generate 1,3-dipole. The aim of this work was also to compare known 1,3- cycloaddition reactions between these reagents by using standard conditions with those using microwave irradiation. Unexpectedly, the main product of these reactions most possibly formed by conjugated addition instead of 1,3-dipolar cycloaddition. Some explanations of the obtained results are presented in this work
Sinteza kompleksnih spojeva s ugljikohidratima
No full textKompleksni spojevi građeni su od složenih iona ili molekula koje nazivamo kompleksima, nazivaju se još koordinacijski spojevi. Prema teoriji koordinacije atomi, posebno atomi metala, premda su već ušli u kemijski spoj, mogu vezati ili koordinirati atome, ione ili molekule u određenom broju i prostornom razmještaju te tako tvore kompleksne spojeve. Stvaranje kompleksa s ugljikohidratima, točnije šećerima, moguće je s njihovim funkcionalnim skupinama. Schiffove baze pokazuju jako dobre koordinacijske sposobnosti te je to svojstvo iskorišteno u sintezi kompleksnih spojeva s prijelaznim metalima. Shiffove baze su organski spojevi koji imaju dvostruku vezu ugljik-dušik. Rezultati u ovom radu su obrađeni infracrvenom spektroskopijom. Infracrvena spektroskopija temelji se na apsorpciji infracrvenog zračenja od molekula istraživane tvari. Pri tome se apsorpcijom zračenja u infracrvenom području elektromagnetskog spektra pobuđuju molekulske vibracije i molekulske rotacije.Complexes compounds are built of complex ions or molecules, also called coordination compounds. According to the theory of coordination atoms, especially of metal atoms, even though they have already entered the chemical compound can bind or coordinate atoms, ions or molecules in a number and spatial distribution, thus forming complex compounds. Creating a complex with carbohydrate, specifically sugars, it is possible with their functional groups. Schiff bases show very good coordination skills, and this characteristic is used in the synthesis of complex compounds with transition metals. Shiff bases are organic compounds that have a double bond of carbon-nitrogen. The results in this paper are analyzed using infrared spectroscopy. Infrared spectroscopy is based on the absorption of infrared radiation by molecules investigated substances. In doing so, the absorption of radiation in the infrared regions of the electromagnetic spectrum excite molecular vibrations and molecular rotation
Analitika ionskih tenzida
No full textPripremljen je ionsko-izmjenjivački kompleks iz natrijeva dodecilsulfata i cetilpiridinijeva klorida. Kompleks je korišten pri izradi membrane koja je tada korištena kao senzorski materijal u ionsko-selektivnoj elektrodi. Napravljena su mjerenja kako bi se odredile odzivne karakteristike elektrode na korištene tenzide.A new ion-exchange complex was prepared from sodium dodecylsulfate and cetylpiridinium chloride. The complex was used in the preparation of the membrane which was used as the sensor material in ion-selective electrode. Measurements were made to determine the response characteristics of the electrode to surfactants used in the experiment
Cobalt (II) Complexes with 4-hydroxy-quinolin-2-carboxylic Acid
No full textKompleksni spojevi prijelaznih metala, pa tako i kobalta, od iznimne su biološke važnosti. Mnogi enzimi u svojim aktivnim mjestima sadrže metalne ione i funkcije tih enzima mogu biti, djelomično ili potpuno, inhibirane djelovanjem organskih liganada.[8] U ovom diplomskom radu istražene su reakcije soli kobalta (II) s 4-hidroksi-kinolin-2- karboksilnom kiselinom. Cilj je bio pronaći optimalne uvjete priprave kompleksa s obzirom na pH reakcijskog medija, vrstu otapala, te otkriti stehiometrijski omjer metala i liganda i na koji se način ligand veže na centralni metalni ion. Reakcije su izvedene u nekoliko otapala: vodi, etanolu, pirimidinu i DMF-u. Pripravljeni su sljedeći spojevi: [Co(C10H7NO3)2(H2O)2]·H2O, [Co(C10H7NO3)2(DMF)2] i [Co(C10H7NO3)2(py)2]. Dobiveni spojevi identificirani su kemijskom analizom, infracrvenom spektroskopijom i termičkom analizom (TGA/DTA).Complexes with transition metals, including cobalt are very important in biochemistry. Large number of enzymes contain metal ion in their active site and function of those enzymes can be partialy or entirely inhibited by organic ligands.[8] In this graduation thesis, the ractions of cobalt (II) salts with 4-hydroxy-quinolin-2-carboxylic acid were investigated. The goal was to find optimal conditions for preparing complexes, considering pH of reaction and type of solvent. It was important to discover stoichiometric ratio of metal and type of bonding between ligand and central metal ion. Reactions were carried out in water, ethanol, pyrimidine and DMF. Following compounds were isolated: [Co(C10H7NO3)2(H2O)2]·H2O, [Co(C10H7NO3)2(DMF)2] and [Co(C10H7NO3)2(py)2]. The complexes were characterized by chemical analysis, IR spectroscopy and thermal analysis (TGA/DTA)
Dugotrajne promjene u koncentracijama polutanata u zraku - istraživanje skrivenih ciklusa
No full textSvrha ovog rada bila je pronalaženje nevidljivih ciklusa u koncentracijama onečišćivača i vrijednostima praćenih meteoroloških parametara na području Slavonskog Broda. Istovremeno su istraženi mogući utjecaji meteoroloških parametara na prostornu i vremensku dinamiku tih onečišćivača. Na temelju mjerenja onečišćujućih tvari na mjernoj postaji u Slavonskom Brodu provedena je Fourierova analiza kvalitete zraka u 2010. godini. Analiza je obuhvatila sljedeće onečišćivače: H2S, O3, NO2. SO2 i lebdeće čestice (PM2.5). Provedena je i Fourierova analiza podataka satnih koncentracija meteoroloških parametara:temperature, relativne vlage i brzine vjetra. Pored uobičajenih,rezultati provedene Fourierove analize ukazali su na postojanje zajedničkih varijacija među onečišćivačima, ali i postojanje zajedničke periodičnosti između koncentracija nekih onečišćivača i praćenih meteoroloških parametara.The purpose of this paper was to analyze pollutant concentration in urban and industrial aria of Slavonski Brod so as determine correlation with meteorological parameters. Due to results of pollution measurements, Fourier analysis was applied to these time series. H2S, O3, NO2. SO2 and PM2.5 particles were measured in 2010. During that time hourly concentration of pollutants were measured and their cycles were observed. This paper confirms the existence of common peaks in the period region which most probably are connected to meteorological influences
Kemija u raspravi izvješća Osječke realne gimnazije (Jovan Jovanić, 1878./79.)
No full textU 19. stoljeću se znalo veoma malo o organskoj kemiji jer se ona tek razvila početkom 19. stoljeća u Europi, a krajem istog stoljeća u Hrvatskoj. Tadašnji pogledi na neke kemijske procese su bili dosta jednostavni i nisu bili toliko proučeni kao u današnje vrijeme. Jovanić je 1879. godine napisao izvješće čiji cilj je bio da objasni svoje viĎenje nekih temeljnih prirodnih raspadnih organskih procesa koji bi mogli zanimati ne samo znanstvenike već i svakog čovjeka kojeg imalo zanima kako nastaje vino, pivo, kako uskiselit mlijeko i neke druge namirnice i što je najpotrebnije bilo, kako očuvati namirnice od propadanja, truljenja, gnjiljenja, oksidacije. Kroz analizu Jovanićeve rasprave mogla sam si jasno predočiti sliku tadašnjeg društva, tadašnjeg viĎenja temeljnih prirodnih pojava, a i zaključiti da se današnje viĎenje istih nije uvelike promijenilo.In early 19th century little was known about organic chemistry because it just started to develop in Europe, but at the end of the same century in Croatia. Then they looked on chemical processes in a simpler way. In 1879. Jovanić has written a report in which he explained some of basic nature processes and his main focus was decomposition of organic mater. He used knowledge of his time and applied it on some every day processes that was commonly known and used in food preservation but nobody completely understood what is beyond, what processes occur and keep organic mater form decay. He explained processes of decay, fermentation and oxidation through examples from every day life, such as process of making beer, vine and cheese, and he used new ways of looking on things because organic chemistry started to develop around the time he wrote his report. Thru this analysis of Jovanić report I have got a fragment of that time and seen how they looked on different natural phenomena which don't differ so much from one we have today
Spectrophotometric study of starch-triiodide system
No full textŠkrob je polisaharid pohranjen u biljkama kao rezervna hrana. Po kemijskom sastavu on je smjesa dvaju polimera D-glukoze, amiloze i amilopektina. Kada se otopini škroba doda otopina joda u kalijevom jodidu (otopina trijodida I3- ili Lugolova otopina) nastaje intenzivno modro ili, rjeđe, smeđe obojenje. To obojenje posljedica je nastajanja kompleksa škroba i trijodidnog iona. Koncentracija kompleksa, a samim time i koncentracija škroba može se odrediti spektrofotometrijski mjerenjem apsorbancije danog uzorka. Omjer amiloze i amilopektina varira ovisno o vrsti škroba. Kompleks s trijodidom čine obje komponente škroba, amiloza tvori jaki tamnoplavi, a amilopektin slabi smeđi kompleks. U istraživanju je pokazano kako se apsorpcijski spektri amiloza - trijodid kompleksa mogu uzeti kao parametar za određivanje botaničkog porijekla škroba. Uočene su razlike između različitih vrsta škroba u samom intenzitetu obojenja pri nastanku kompleksa, apsorpcijskom maksimumu te pomaku apsorpcijskog maksimuma u odnosu na reprezentativni uzorak.Starch is a polysaccharide stored in plants as a food reserve. According to its chemical composition it is a mixture of two D-glucose polymers, amylose and amylopectin. When a solution of iodine in potassium iodide (triiodide solution I3- or Lugol solution) is added to a starch solution, intensive dark blue or, rarely, brown coloration appears. This coloration is a result of yielded starch-triiodide complex. Concentration of this complex and thus the concentration of starch can be determined spectrophotometricaly by measuring the absorbance of the given sample. Volume fraction of amylose and amylopectin varies depending on the starch type. Both starch components yield complex with triiodide, amylose yields strong dark blue and amylopectin weak brown complex. Therefore the absorption spectra of amylose-triiodide complex can be taken as a parameter for determination of botanical origin of starch, as presented in this research. Noted differences between various starch types are in the intensity of coloration due to complex formation, maximum wavelength of absorbance and the shift of maximum wavelength of absorbance when compared to representative sample
The application of microchip electrophoresis in determination of the organic substances
No full textRad ne sadrži sažetak
Determination of Amino Acids by Electrophoresis on a Microchip
No full textElektroforeza na mikročipu uspješno je upotrebljena u ovom radu za separaciju i kvantifikaciju β-alanina i L-histidina, pojedinačno i u smjesi. Za ispitivanja je korišten ureĎaj za elektroforezu na mikročipu sa kapacitivno spregnutim, beskontaktnim, konduktometrijskim detektorom, C4D, koji radi na frekvenciji od 4 MHz. Separacija je provedena na polimetil-metakrilatnom (PMMA) mikročipu, duljine separacijskog kanala 75 mm. Kao pufer korištena je 0,5 M octena kiseline, pH = 2,5. Primijenjeni napon injektiranja bio je 0,80 kV, a napon separacije 3,80 kV. Ustanovljen je linearni odziv C4D detektora za β-alanin u području od 2,5 x 10-5 M do 7,5 x 10-5 M (R2 = 0,9990) i za L histidin u području 1,5 x 10-5 M do 5 x 10-5 M (R2 = 0,9538) sa granicom detekcije ispod 1 mg/L. C4D detektor pokazao je i linearni odziv za smjesu β-alanina i L-histidina u području od 2,5 x 10-5 M do 7,5 x 10-5 M u odnosu na alanin i histidin (R2 = 0,9926 i 0,9640, respektivno). Točnost odreĎivanja pojedinačnih aminokiselina, kao i njihov sadrţaj u smjesi, testirani su metodom poznatog dodatka.Microchip electrophoresis (MCE) was successfully used in these investigations for separation and quantification of β-alanine and L-histidine, both single and in a mixture. A microchip electrophoresis device equipped with capacitively-coupled contactless conductivity detector (C4D) operating at 4 MHz was used for the investigations. The separation was carried out on a polymethyl-metacrylate (PMMA) chip with the separation channel length of 75 mm. Acetic acid solution of the concentration 0,5 M was used as a buffer (pH = 2,5). The applied injection voltage was 0,80 kV and the separation voltage was 3,80 kV. A linear relationship between C4D detector response and β-alanine concentration was assessed in the range 2,5 x 10-5 M - 7,5 x 10-5 M (R2 = 0,9990), and in the range of 1,5 x 10-5 M - 5 x 10-5 M (R2 = 0,9538) for L-histidine, with a detection limit below 1 mg/L. C4D detector exhibited a linear relationship toward the mixture of β-alanine and L-histidine in the range of 2,5 x 10-5 M - 7,5 x 10-5 M related to β-alanine and L histidine particularly (R2 = 0,9926 and 0,9640, respectively). The accuracy of determination for single aminoacids, and their content in a mixture, were tested by known addition method
Sinteza i IR spektroskopska analiza aspirina i paracetamola
No full textCilj rada je sintetizirati organske spojeve acetilsalicilnu kiselinu i acetaminofen i okarakterizirati ih snimanjem njihovih IR spektara. Ova tema je izabrana radi boljeg upoznavanja povijesti, načina dobivanja i karakteristika dvaju najpoznatijih farmaceutskih proizvoda današnjice - aspirina i paracetamola,te korištenja IR spektroskopije kao instrumentalne analize koja se, među ostalim, često primjenjuje u analizi poznatih organskih spojeva. Oba spoja dobivena su reakcijama esterifikacije. Aspirin® je dobiven reakcijom acetatnog anhidrida i salicilne kiseline uz mineralnu kiselinu kao katalizator. Paracetamol je dobiven reakcijom acetatnog anhidrida i p-aminofenola, također u kiseloj sredini. Mehanizam takvih reakcija je nukleofilna adicija-eliminacija. Eksperimentalno iskorištenje za aspirin je 50.5%, a za paracetamol 36.3%. Snimljeni su IR spektri dobivenih spojeva te je uočeno dobro preklapanje sa literaturnim spektrima. Ovim radom se dokazalo da su aspirin i paracetamol lijekovi koje je lako dobiti iz jeftinih sirovina, a zbog svojih svojstava, sigurni za upotrebu kod većine ljudi (iznimka su osobe s ozbiljnim gastrointestinalnim tegobama).The aim of this work is to synthesise organic compounds, acetylsalicylic acid and paracetamol and to characterize them by infrared spectroscopy. This topic is chosen to understand better the history, methods for synthesis and characteristics of two of the most famous contemporary drugs - aspirin and paracetamol, and to apply IR spectroscopy as an important instrumental method that can be used in analysis of known organic compounds. Both compounds were prepared through esterification reactions. Aspirin® is obtained from the reaction of acetic anhydride with salicylic acid and mineral acid as a catalyst. Paracetamol is obtained from the reaction of acetic anhydride with p-aminophenol, also with mineral acid as catalyst. Mechanism of both reactions is described as nucleofilic addition-elimination. The obtained yield for aspirin is 51%, and for paracetamol 36%. IR spectra of obtained compounds were recorded and they are in accordance with literature spectra. It was proved that aspirin and paracetamol are drugs that can be easily obtained from cheap chemicals, and it is known that due to their properties most people can safely use them (excluding people with serious gastrointestinal difficulties)