The Kinetic investigations and modeling of potassium iodide and hydrogen peroxide reaction in acidic medium

Ispitivanje kinetike i modeliranje reakcije izmeĊu kalijum-jodida i vodonik-peroksida izvršeno je u kiseloj sredini (pH= 3,03) na sobnoj temperaturi. Korišćenjem EPR spin trap tehnike i upotrebom spinskih hvataĉa BMPO i DEPMPO, u ovom radu, su detektovane reaktivne kiseoniĉne radikalske vrste (HO• i HOO•) u kalijum-jodid – vodonik-peroksid sistemu. Detekcija radikala ĉini dobru osnovu za postavku novog detaljnijeg, radikalskog modela reakcije izmeĊu kalijum-jodida i vodonik-peroksida. Postavljanjem eksperimenta za istovremeno praćenje ĉetiri reakcione vrste, I-, I2, I3- i O2 i konstrukcijom odgovarajućih kinetiĉkih krivih omogućena je provera postuliranog radikalskog modela. Postulirani radikalski model ima neradikalsko jezgro, koga ĉine ĉetiri hemijske jednaĉine (6 reakcija raĉunajući i povratne), literaturno neraskidivo povezane sa ispitivanim sistemom. Radikalski model ima 18 reakcija (12 radikalskih + 6 neradikalskih) od ĉega je ĉak 15 konstanti brzina preuzeto iz literature, a preostale tri su optimizovane u ovom radu. Dobijeni rezultati pokazuju da uvoĊenje radikalskih vrsta u modeliranje reakcije izmeĊu kalijum-jodida i vodonik-peroksida znaĉajno povećava slaganje eksperimentalnih i simuliranih kinetiĉkih krivih, prvenstveno za kiseonik. Iako na poĉetku prisutne u maloj koncentraciji, reaktivne vrste radikala mogu da iniciraju i povezuju razliĉite reakcione puteve i time utiĉu na tok reakcije. U reakciji izmeĊu kalijum-jodida i vodonik-peroksida u kiseloj sredini na sobnoj temperaturi, doprinos slobodnih radikala se direktno ogleda u koliĉini izdvojenog kiseonika (jodne vrste se solidno simuliraju i neradikalskim modelom, tj. neradikalskim jezgrom). UvoĊenje radikalskih reakcija omogućuje detaljniji uvid u odvijanje ispitivanog procesa i njegovu kontrolu, a budući da je ispitivana reakcija deo mnogo sloţenijih sistema otvaraju se novi pravci u modeliranju njihove kinetike.The investigation and modeling of reaction between potassium iodide and hydrogen peroxide is performed at room temperature in acidic medium (pH= 3,03). Reactive oxygen species (HO• and HOO•) were directly detected in iodide-hydrogen peroxide reaction system by using EPR spin-trap technique with BMPO and DEPMO spin trap. Free radical detection is the most important part in this dissertation because it gives good starting point for new radical model of the reaction between potassium iodide and hydrogen peroxide. The postulated radical model was successfully tested by using experimental monitoring for reaction species I-, I2, I3- and O2, and by the construction of the kinetic curves for these species. Postulated radical model has non-radical core formed from four chemical reactions which are strongly connected with the investigated system as well as with literature. The radical model has 18 reactions and the values of rate constants for 15 of them were obtained from the literature, but the values of rate constants for other 3 reactions were estimated by optimization process during simulations in this dissertation. The experimentally obtained results demonstrate that introduction of radical species in the modelling of potassium iodide – hydrogen peroxide reaction significantly increases agreement between experimental and simulated results for oxygen (iodine species are well simulated without radicals). While free radicals are present in small amount at the begging of the reaction, their concentration as well as their influence on the reaction course can be significantly increased trough radical loops and propagation steps. In the reaction between potassium iodide and hydrogen peroxide in acidic medium at room temperature, the contribution of radical species can be noticed by the amount of the created oxygen (simulation of the iodine species can be performed very well by the non-radical model or in other words non-radical core). The introduction of the radical reactions provid detailed insight into the investigated process and its control, furthermore the analyzed reaction represents one part of the very complex chemical systems and new directions in modeling are opened

Highly-efficient N-arylation of imidazole catalyzed by Cu(II) complexes with quaternary ammonium-functionalized 2-acetylpyridine acylhydrazone

The reaction of (E)-N,N,N-trimethyl-2-oxo-2-(2-(1-(pyridin-2-yl)ethylidene)hydrazinyl)ethan-1-aminium-chloride (HLCl) with copper(II) perchlorate led to mononuclear [CuLCl]ClO 4 complex (1). The same reaction with excess of sodium azide gives dinuclear azido double end-on bridged Cu(II) complex [Cu 2 L 2 (μ- 1,1 -N 3 ) 2 ](ClO 4 ) 2 (2). In both complexes hydrazone ligand is NNO coordinated in monodeprotonated formally neutral zwitter-ionic form. Complexes were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray crystallography. Variable‐temperature magnetic susceptibility measurements for dinuclear Cu(II) complex showed intra-dimer ferromagnetic coupling between Cu(II) ions (J = 7.4 cm −1 ). DFT-BS calculations provided explanation for magnetic properties of dinuclear Cu(II) complex. Both complexes were shown to highly efficiently catalyze the N-arylation of imidazole and benzimidazole with electron-poor or electron-rich aryl iodides, under user-friendly and sustainable conditions.This is the peer-reviewed version of the following article: Milenković, M. R.; Papastavrou, A. T.; Radanović, D.; Pevec, A.; Jagličić, Z.; Zlatar, M.; Gruden, M.; Vougioukalakis, G. C.; Turel, I.; Anđelković, K.; et al. Highly-Efficient N-Arylation of Imidazole Catalyzed by Cu(II) Complexes with Quaternary Ammonium-Functionalized 2-Acetylpyridine Acylhydrazone. Polyhedron 2019, 165, 22–30. [https://doi.org/10.1016/j.poly.2019.03.001]Supplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3006

Supplementary data for article: Milenković, M. R.; Papastavrou, A. T.; Radanović, D. D.; Pevec, A.; Jagličić, Z.; Zlatar, M.; Gruden, M.; Vougioukalakis, G. C.; Turel, I.; Anđelković, K. K.; et al. Highly-Efficient N-Arylation of Imidazole Catalyzed by Cu(II) Complexes with Quaternary Ammonium-Functionalized 2-Acetylpyridine Acylhydrazone. Polyhedron 2019, 165, 22–30. https://doi.org/10.1016/j.poly.2019.03.001

Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/2865]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2858]Supplementary material for: [https://www.sciencedirect.com/science/article/pii/S0277538719301664?via%3Dihub

Supplementary data for article: Milenković, M. R.; Papastavrou, A. T.; Radanović, D. D.; Pevec, A.; Jagličić, Z.; Zlatar, M.; Gruden, M.; Vougioukalakis, G. C.; Turel, I.; Anđelković, K. K.; et al. Highly-Efficient N-Arylation of Imidazole Catalyzed by Cu(II) Complexes with Quaternary Ammonium-Functionalized 2-Acetylpyridine Acylhydrazone. Polyhedron 2019, 165, 22–30. https://doi.org/10.1016/j.poly.2019.03.001

Related to accepted version: [http://cherry.chem.bg.ac.rs/handle/123456789/2865]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2858]Supplementary material for: [https://www.sciencedirect.com/science/article/pii/S0277538719301664?via%3Dihub

Influence of temperature and dopant concentration on structural, morphological and optical properties of nanometric Ce1-xErxO2-delta (x=0.05-0.20) as a pigment

Ceramic pigments based on cerium oxide were synthesized by self-propagating room temperature method and their color properties were assessed from the viewpoint of potential environmentally nontoxic pink pigments. Thermal stabilities of the pigments were examined at 600, 900 and 1200 degrees C. According to X-ray powder diffraction and Raman spectroscopy results, all obtained pigments were singlephase solid solutions of cerium oxide, independent of the concentration of dopants. The X-ray analysis showed that the crystallites were of nanometric dimensions, as recorded and by transmission electron microscopy analysis. Color characteristics of solid solutions, which depended on concentration erbium ions and calcination temperature, and their position in the chromaticity diagram were studied by ultraviolet visible spectrophotometry, which confirmed potential application of environmentally friendly pigments of desired color. The color efficiency of pigments was also evaluated by calorimetric analysis.Accepted version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3174

Regularity of Intermittent Bursts in Briggs Symbol of the Klingon Empire Rauscher Oscillating Systems with Phenol

The intermittency or intermittent bursting as the type of dynamic state when two qualitatively different behaviors replace one another randomly during the course of the reaction, although all the control parameters remain constant, is found in the Briggs Symbol of the Klingon Empire Rauscher oscillating system moderated by a very small amount of phenol. Within a range of phenol concentrations, the oscillation amplitude is diminished considerably, and after oscillations cease, they repeat intermittently, giving several bursts of oscillations. For the concentrations used here, the range of phenol concentrations where intermittent bursting oscillations occur in a closed reactor is ca. 1.8x10(-5) to 3.6x10(-5) M. Bursting also occurs in an open reactor and can be sustained indefinitely at 5.53x10(-5) M concentration. The intermittent bursting behavior is robust, and can be achieved at a variety of conditions

Influence of temperature and dopant concentration on structural, morphological and optical properties of nanometric Ce 1−x Er x O 2−δ ( x = 0.05–0.20) as a pigment

Ceramic pigments based on cerium oxide were synthesized by self-propagating room temperature method and their color properties were assessed from the viewpoint of potential environmentally nontoxic pink pigments. Thermal stabilities of the pigments were examined at 600, 900 and 1200 degrees C. According to X-ray powder diffraction and Raman spectroscopy results, all obtained pigments were singlephase solid solutions of cerium oxide, independent of the concentration of dopants. The X-ray analysis showed that the crystallites were of nanometric dimensions, as recorded and by transmission electron microscopy analysis. Color characteristics of solid solutions, which depended on concentration erbium ions and calcination temperature, and their position in the chromaticity diagram were studied by ultraviolet visible spectrophotometry, which confirmed potential application of environmentally friendly pigments of desired color. The color efficiency of pigments was also evaluated by calorimetric analysis.Accepted version: [http://cer.ihtm.bg.ac.rs/handle/123456789/3174