JOURNAL OF APPLIED CHEMISTRY
Year:2018 | Volume:13 | Issue:46|Papers Count:25

Flavonoids are the most abundant bioactive polyphenolic compounds having a plant origin and the most important property of them is their antioxidant activity. Since the knowledge of the solubility of bioactive materials in various solvents is very important for pharmaceutical researches and industrial applications, in this work, the solubility of natural flavonoid quercetin has been measured quantitatively. This study has been performed in binary solvent mixtures containing water and 2-propanol (0-100% v/v), at constant temperature 25 ° C by using the saturation technique. From solubility data, the preferential solvation parameters of this flavonoid were determined by the reverse Kirkwood-Buff integral method in different compositions of the solvent mixture studied. The results show that the flavonoid solubility increases with increasing percentage of organic solvent and also in high compositions of the organic solvent, solvation extent of this compound become more than water-rich region. Finally, the results obtained have been discussed based on solvent-solute interactions.

In the present study, carbon ceramic electrode prepared using sol-gel method was modified by multi-walled carbon nanotubes (MWCNT) and the ionic liquid (IL) nanocomposite. The electrode modifying process was performed by depositing the MWCNT/IL suspension on the electrode surface. Electrochemical studies revealed that the IL/MWCNT nanocomposite modified carbon ceramic electrode exhibited high electrocatalysis properties for oxidation of morphine and phenylephrine with respect to the MWCNT/CCE and bare CCE. The obtained results from present study indicate that IL/MWCNT nanocomposite modified carbon ceramic electrode can be applied as an appropriate sensor for the measurement of morphine and phenylephrine using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The linear dynamic ranges and limits of detection for two compounds were obtained. Moreover simultaneous determination of morphine and phenylephrine is possible using this modified electrode and they can be determined without others interferences.

Development of wastewater treatment methods has become a hot research topic. The advanced oxidation processes (AOPs) have attracted much attention as a method for degrading a wide range of non-biodegradable and harmful organic pollutants into less toxic compounds. In this work, TMU-16 a two-fold interpenetrated mesoporous MOF as a heterogeneous catalyst was employed to photodegradation of Eriochrome Black T under UV irradiation from aqueous solution. Some parameters such as pH, catalyst amount and dye concentration which affect the efficiency of the degradation were studied. From kinetic studies, the degradation producer is the pseudo-first-order. The detection of hydroxyl radicals with probe molecule and perform degradation in the absence of O2 molecules revealed that degradation occurred by mediated these radicals. The results shown, that TMU-16 should be effective photocatalyst for dyes degradation.

Triaryl cyanurates are important chemicals used in various fields such as polymer, dyes and pharmaceuticals. In this research, synthesis of some triaryl cyanurates derivatives on smectite clays such as montmorillonites K10 and KSF, hectorite and bentonite as green, recyclable and heterogeneous catalysts using grinding method without any organic solvents has been evaluated. This present method is superior since it is eco-friendly, advantageous over previously described methods in yield, requires no special apparatus, there is simplicity of operation, and is non-hazardous, simple and convenient. In addition, the simple experimental and product isolation procedures combined with the easy recovery and reuse of these worthwhile natural clays play an important role in development of the clean and environmentally friendly strategy in this new and benign method.

Substituted isobenzofuran-1(3H)-ones and imidzoles are useful building blocks in organic synthesis due to their structural importance, chemical stability and relative accessibility. Furthermore, such structures are of important and biologically active heterocycles and they are widely present in many bioactive compounds and synthetic drugs. In this paper, a novel, one-pot and efficient procedure are introduced for the preparation of some new derivative of these compounds. At first, some of 3a, 8a-dihydroxyindeno[1, 2-d]imidazole-8(3H)-one derivatives were synthesized from the reaction of trichloroacetonitrile, amines and ninhydrin in ethanol. Then their corresponding isobenzofuran-1(3H)-ones were prepared by the one-pot oxidation of the synthesized diols using lead tetraacetate in acetic acid. Reaction well worked for various amine derivatives and final products were characterized using their IR, 1H-NMR and 13C-NMR spectra.

In the present work, Polyethylene-Rhodamine B composites at various concentration of Rhodamine B dye in 200 µ m thickness were fabricated. Various influencing concepts like radiation time and concentration on photodegradtion of Rhodamine B in solid state was investigated. The oxidation was studied by FT-IR spectroscopy and it was shown that the oxidation products consisting carbonyl group are obtained. All samples exhibited significant changes in color with exposure conditions. Results indicated that the photodegradation efficiency was increased by rising radiation intensity, dye concentration and time of exposure. Also, it was showed that the photodegradation kinetics obeys a first-order kinetic model.

Role of water vapor in propane selective oxidation to acrylic acid over Mo1V0. 3Te0. 23Nb0. 12Ox has been investigated using kinetic study. The catalyst was produced by slurry method and two sets of experiments have been designed: reactions in the presence and absence of water vapor. Experimental data were obtained under different operating conditions in a tubular fixed bed reactor. Power law and Mars-Van Krevelen (MVK) models for the predictions the catalytic performance were employed using the genetic algorithm. The reaction orders obtained by the power law model determined that gas phase oxygen concentration has considerable effects on catalytic performance in wet condition. Contrary to dry ones which reveal that changing oxygen concentration has negligible effects on catalytic performance. MVK results indicate that in the presence of water vapor, lattice oxygen production is the rate determining step. Therefore dependency on gas phase oxygen concentration is expectable. While at dry conditions the activation energy of hydrocarbon is higher than that of oxygen. Therefore lattice oxygen is always available and independent of gas phase oxygen. Presence of water induces some structural modifications: improvement the crystallinity, decreasing production of non-selective sites (MoO3) and enhanced presence of the M1 phase. As a results, water vapor limits lattice oxygen availability through improvement of catalyst structure leading to better acrylic acid selectivity.

The density (d) and speed of sound (u) for systems containing{cefazolin sodium+ ionic liquid (1-octyl-3-methyl imidazolium bromide, [OMIm] Br) + H2O} and {ceftriaxone sodium+ ionic liquid (1-octyl-3-methyl imidazolium bromide, [OMIm] Br) + H2O}have been measured at T = 298. 15 K. The measured data have been applied to calculate, standardpartial molar volume( ), apparent molar isentropic compressibility (Kφ ), transfer volume (∆ _tr V_φ ^0), transfer compressibility (∆ _tr K_φ ^0)and hydration number (nH), and used to discussvarious solute-solvent interactions. The transfer quantities are positive and increase with molalities of ionic liquid which indicate the dominance of hydrophilic-hydrophilic interactions between the ionic liquid and drugs molecules and dehydration effect of ionic liquid on the solutions.

In this research, the degradation of C. I. Reactive Green 19 (RG19) from aqueous solution has been studied by the ozonation under UV irradiation (O3/UV) in recirculating mode. Mineralization efficiency was compared using the O3 and O3/UV processes, which was 78. 54% and 91. 03% after 70 min for 100 mg/L of the dye, respectively. Then, the effect of experimental parameters on the O3/UV process including initial RG19 concentration, ozone mass flow rate and initial pH on the COD removal was studied. The obtained results revealed that the COD removal increases by enhancement of ozone amount and decreasing of the DR23 concentration; the mineralization process was performed efficiently at the basic condition (pH= 10) due to the production of extra hydroxyl radicals from ozone molecules. The pseudo-first order kinetic was observed for the dye mineralization and electrical energy per order decreases using the O3/UV process indicating adequate synergistic effect of the photolysis and ozonation. Eventually, central composite design (CCD) approach was properly applied for prediction of the COD removal with appropriate performance (R2 = 99%) and optimization of the process.

This study examined the feasibility of using stem of sour cherry as available low cost adsorbent for Brilliant Green dye (BG) adsorption from aqueous solution. Adsorption studies were conducted on a batch process by observing the effects of pH, contact time, dye concentration of BG, amounts of adsorbents and temperature. Maximum color removal was observed at pH=7. The equilibrium data was analyzed by the Freundlich, Langmuir and Temkin isotherms. The maximum adsorption capacity was found to be 9. 32 mg/g. The pseudo-second-order kinetics was the best model. Thermodynamic parameters, such as standard Gibbs free energy changes (㠀–â ˆ†G㠀—^0), standard enthalpy changes (㠀–â ˆ†H㠀—^0) and standard entropy changes (㠀–â ˆ†S㠀—^0) were computed to predict the nature of adsorption process. This study examined the feasibility of using stem of sour cherry as available low cost adsorbent for Brilliant Green dye (BG) adsorption from aqueous solution. Adsorption studies were conducted on a batch process by observing the effects of pH, contact time, dye concentration of BG, amounts of adsorbents and temperature. Maximum color removal was observed at pH=7. The equilibrium data was analyzed by the Freundlich, Langmuir and Temkin isotherms. The maximum adsorption capacity was found to be 9. 32 mg/g. The pseudo-second-order kinetics was the best model. Thermodynamic parameters, such as standard Gibbs free energy changes (㠀–â ˆ†G㠀—^0), standard enthalpy changes (㠀–â ˆ†H㠀—^0) and standard entropy changes (㠀–â ˆ†S㠀—^0) were computed to predict the nature of adsorption process.

The electronic and structural properties of Agn (n=2-10) nano clusters and their interaction with carbon monoxide have been investigated using DFT. The average equilibrium Ag-Ag distance and binding energy per atom of clusters increase with cluster size and close to the experimental values of bulk material. The smallest HOMO-LUMO energy gap (Δ EH-L) is related to the Ag3 cluster indicating more reactivity of this cluster compared to the other clusters. The most stable adsorption modes of CO are adsorption from carbon end to the one atom of the cluster. The maximum CO adsorption energy was observed for the Ag3 cluster because of the more reactivity of this cluster. The NBO calculations revealed that for CO adsorption, charge density has been transferred from s and p orbitals of the oxygen atom to the p orbital of sliver atom of the cluster. The Wiberg bond indexes were also calculated according to the NBO calculations

In this work, a new application of nano zinc oxide in Baeyer-Villiger oxidation of ketones with hydrogen peroxide has been introduced. The capability of nano zinc oxide as a heterogeneous catalyst on the basis of of its very small size and large surface area can improve and also promote the Baeyer-Villiger oxidation process. The synthesized nano zinc oxide was characterized by scanning electron microscopy (SEM) and FT-IR. It was found that H2O2/ZnO system showed good efficiency in Baeyer-Villiger oxidation of alicyclic, aliphatic and aromatic ketones to either esters or lactones. The effects of reaction conditions, such as amount of catalyst, reaction temperature, reaction time and different solvents on the catalytic performance of nano ZnO were also investigated. Notably, the process has advantages such as mild reaction conditions, simple operation and good product yield. To the best of our knowledge, use of H2O2/ZnO system in Baeyer-Villiger reactions has never been reported. It should be pointed out that, H2O2 as an environmentally benign oxidant, produces water as the safest by-product.

Absorption of toluene vapors from atmospheric air through surface absorption of adsorbents based on gas phase extraction was obtained. In experimental study, through pilot simulator, toluene vapors absorption and absorbents efficiency in the dynamic and static system was examined by nano graphene and graphene oxide (NG and GO). The effect of different parameters on toluene absorption by NG and GO such as: absorption capacity, temperature desorption, contact time and repeatability, the amount of sorbents and recovery adsorption were investigated. According to discovered findings, capacity and efficiency of absorption by absorbents depend to kind of absorbent, mass of absorbent, toluene density, temperature, air flow rate and contact time. The toluene concentration in air was determined by gas chromatography spectrometer with flame ionization detector (GC-FID). The mean of absorption recovery (AR) and the absorption capacity (AC) for nano graphene absorbent was higher than graphene oxide, respectively (ARNG: 97. 3% > ARGO: 23. 5%; ACNG: 285. 2 mg/g > ACNGO: 67. 3 mg/g).

In this article, magnesium oxide (MgO) nanoparticles coated onto sawdust (SD) and its application as an efficient sorbent for removal of methylene blue dye has been reported. The introduced Nanocomposite was prepared through co-precipitation by addition of sawdust which has been previously soaked in magnesium sulfate solution into a NaOH solution. Adsorption studies was carried out in both batch and column systems. For determination of optimum dye removal conditions, the effect of parameters such as pH, initial dye concentration, sorbent dosage, contact time, and temperature were investigated in a batch adsorption system. The results indicated that SD/MgO nanocomposite is able for uptaking of methylene blue dye from aqueous solutions successfully. It was found that more than 95% dye removal is happened when 0. 20 g adsorbent was treated with 100 mL of dye solution with initial concentration of 100 mg/L. The treatment of the data was also carried out using both Freundlich and Langmuir adsorption isotherms. Based on regression analysis, it was found that the sorption of methylene blue using nanocomposite of SD/MgO adopt Freundlich isotherm partially better than Langmuir isotherm. Maximum monolayer adsorption capacity has been obtained 59. 17 mg/g. Kinetic studies have also been conducted and it was found that adsorption of methylene blue by SD/MgO follows with the pseudo-second-order kinetic model.

In this study, polyurethane nanofibers were prepared by electrospinning process. An Antibiotic drug, Cefixime trihydrate, was loaded on polyurethane nanofibers. The physical condition and interaction of drug within these nanofibers were studied by FT-IR and SEM. In vitro release studies showed a burst release at the initial stage followed by a sustained release of Cefixime from this system up to 70 h. This burst release can be favorable to reduce the associated surgical site infections, since most of the bacteria are introduced to the surgical site at the time of surgery or in the immediate after the surgery, zero order, first order, Higuchi, Korsmeyere-Peppas equation were utilized to characterize the system.

In this study, different electrochemical methods such as cyclic voltammetry, differential puls voltammetry, chronoamperometry, chronocoulometry and electrochemical impedance spectroscopy were used for electrochemical determination of tramadol using carbon paste electrode modified with V2O5 nanoparticles. A phosphate buffer of pH= 8 was used as a supporting electrolyte. Some parameters such as scan rate, step potential, pulse amplitude were changed to create optimal conditions. Linear calibration curves were obtained in the range of (0. 1 µ M-550 µ M) with a detection limit of 0. 013 µ M. The modified electrode shows good selectivity with respect to tramadol in the presence of some interferences. The modified electrode was successfully used for determination of tramadol in real samples.

In this context, a rapid electrochemical decolorization of aqueous Acid Blue 25 solutions on a batch reactor using a rectifier was studied. The central composite design (CCD) has been chosen to elucidate the combined effect of four process variables; applied potential, pH, electrolyte concentration and temperature. The decolorization percentage (measure of remediation) and the energy efficiency (measure of energy saving) were considered as responses that were optimized simultaneously using desirability function. Under the optimum conditions of applied potential (5 V), pH (2), KCl concentration (0. 1 mol L-1) and temperature (20° C), 100% decolorization percent and 167. 1 mmolkW-1h-1 energy efficiency was predicted, that was close to obtained results (100% and 163. 2± 0. 5 mmolkWh-1).

In the peresent work, tetrakis(p-aminophenyl)porphyrin manganese(III) chloride was attached through an amide bond on multi-wall carbon nanotubes and the prepared catalyst was characterized by different methods. After synthesis and characterization of this catalyst, its catalytic activity was investigated as heterogeneous catalyst in the oxidation of sulfides with sodium periodate. Different sulfides were converted efficiently to their corresponding sulfoxides and solfones by this catalytic system. The oxidation products were sulfone and sulfoxide which isolated and identified. The effect of reaction parameters such as catalyst amount and different solvents on the catalytic activity was also investigated. This catalyst was reused several times without significant loss of its catalytic activity.

Two N-heterocyclic carbene platinum complexes [PtMe2(NHC)], 1 and [Pt(TFA)2(NHC)], 2, in which, NHC = 1, 1′-methylene-3, 3′-bis[(N-(tert-butyl) imidazol-2-ylidene] have been prepared and characterized using NMR spectroscopy and ESI-MASS spectrometry. Reactivity of these complexes toward hydrosilylation of some α , β-unsaturated ketones investigated by NMR spectroscopy. Dimethyl bis-NHC platinum(II) complex shows good performance in comparison with those observed for trifluoroacetate bis-NHC platinum(II) complex, 2 in which higher efficiency and selectivity obtained with dimethyl complex 1 as catalyst. Although, the 1, 2-additon and 1, 4-addition pathways are possible, regiochemistry of the products show a 1, 4-addition is preferred pathway for these reactions.

Mn(II)/Pb(II)-exchanged zeolite Y was synthesized and characterized by XRD, EDX, FT-IR and SEM spectroscopies. This is the first application of Mn/Pb-Y in four-component synthesis of spiro[indoline-3, 4'-pyrano[2, 3-c]pyrazole from isatin, malononitrile, ethylacetoacetate and hydrazine hydrate as a heterogeneous acidic catalyst. Short reaction times, high yields of products and simple work-up procedure are the advantages of current method. The catalyst is inexpensive, can be easily prepared and can be recovered and reused. Short reaction times, high yields of products and simple work-up procedure are the advantages of current method. The catalyst is inexpensive, can be easily prepared and can be recovered and reused and reused.

The new [2+2] macrocyclic ligand with N4 donor set, from the [2+2] condensation of benzene-1, 3-dicarboxaldehyde and 2, 2-dimethylpropylenediamine was synthesized by high dilution method and confirmed by IR, 1H NMR, 13C NMR, elemental analysis and crystal structure determination. Resonance data investigation of the compound indicates highly symmetrical structure for the macrocyclic ligand consists of two N2 donor sets. The compound is crystallized in the monoclinic system with space group C2/c. The metric parameters of the molecule show that a twofold axis bisects the macrocycle, passing through the cavity of the macrocycle.

The multicomponent synthesis of 3, 4-dihydropyrimidin-2(1H)-ones/thiones under thermal and solvent free conditions in the presence of a meglumine as efficient catalyst in acetic acid is reported. Presented method is operationally simple and environmentally benign. Availability and low cost dual catalyst system of meglumine/acetic acid, solvent free condition, simple separation of the reaction products, the short reaction time in compared with the time of other reported results (in Biginelli compounds synthesis), together with high yield of products, are the main advantages of mentioned method. Reaction products were identified using determination of the melting point, furier transform infrared (FTIR), nuclear magnetic resonance of hydrogen and carbon (1HNMR and 13CNMR) techniques.

Eight new [NiL1] (1), [CuL1] (2), [CoL1] (3) and [CdL1] (4), [NiL2] (5), [CuL2] (6), [CoL2] (7) and [CdL2] (8) complexes were prepared by the reaction of two new Schiff base ligands and Ni(II), Cu(II), Co(II) and Cd(II) metal ions in equemolar ratios. The ligands, H2L1 and H2L2, were synthesized by reaction of N, N'(2-aminoethyl)(3-aminopropyl)piperazine and 2-hydroxybenzaldehyde or 2-hydroxy-3-methoxy-benzaldehyde while characterized with IR and 1H, 13C NMR spectroscopy. All complexes have been studied with IR and microanalysis. Theoretical calculations of relevant complexes are done by using one of the hybrid density functional theories which is B3LYP method with GEN keyword.

In this work, the electrochemical behaviors of some pharmaceutical sulfonamide derivatives including sulfadiazine (SDZ), sulfathiazole (STZ), sulfaquinoxaline (SQX), sulfacetamide (SAA), and sulfasalazine (SSZ) on carbon paste electrodes (CPEs) modified by carbon and lanthanide nano-materials were studied. Under the optimized conditions, the CPEs containing 5% of the reduced graphene oxide (RGO) decorated ceria (CeO2) nano-composite showed a significant increase in the response current toward sulfadiazine (SDZ) with respect to the other sulfonamide derivatives. A fast Fourier transform-square wave voltammetry (FFT-SWV) was applied in order to reveal the measurement applicability of the proposed electrode for the SDZ determination. The calibration curve result showed the linear range 3-1000 µ M for the sulfadiazine redox. The LOD and LOQ quantities were calculated and compared with other reports in the literature. Furthermore, the SDZ measurement was carried out on some pharmaceutical tablets by the proposed sensor.