In this research, a novel material namely N,N,N',N'-tetramethylethylenediaminium-N-(silica-n-propyl)-N'-sulfonic acid chloride trifluoroacetate ([TEDSPSCT]) was synthesized, and its structure was characterized using Fourier-transform infrared spectroscopy (FT-IR), energy-dispersive X-ray (EDS), field emission scanning electron microscopy (FE-SEM), thermal gravimetric (TG), differential thermal gravimetric (DTG) and x-ray diffraction (XRD); most of the partcles were in nano-size, and a few of them were in micro-size. Afterward, [TEDSPSCT] was used as effective and recyclable catalyst for the preparation of bis-coumarins via the reaction of 4-hydroxycoumarin (2 equivalents) with arylaldehydes (1 equivalent) under solvent-free conditions; these compounds were obtained in high yields and short reaction times. Moreover, an attractive and logical mechanism based on dual-functionality of the catalyst has been described {this catalyst has both acidic group (SO3H) and weak basic group (trifluoroacetate)}.
In this study, the PTA @ MIL-53 (Fe) heterogeneous catalyst was synthesized to provide a suitable alternative to Lewis acids, including rare-earth metal triflates, AlCl3, and BF3, which have been used as catalysts for Fries rearrangements. This catalyst was synthesized using a mixture of FeCl3.6H2O, and 1, 4-benzenedicarboxylic acid (BDC) and PTA in DMF solvent in the ultrasonic bath. PTA encapsulation in MIL-53 (Fe) was confirmed using XRD, FT-IR, TGA, ICP and SEM techniques. The activity of PTA @ MIL-53 (Fe) catalytic in the Fries rearrangements of O-Acyloxy benzene reaction was investigated under ultrasound illumination and the effect of parameters such as reaction time, amount of catalyst and PTA percent in structure of catalyst on the yield was studied. The results show that increasing of all three parameters lead to increase yield upper than 98 percent.
In this study, nickel oxide nanoparticles was prepared by co-precipitation method and characterized using FT-IR, XRD, VSM and SEM techniques. By Fourier transform infrared FT-IR has proven bond forming of NiO in nickel oxide. . X-ray diffraction (XRD) showed that the single-phase sample had a cubic symmetry with a particle size of 57 nm. Nickel oxide nanoparticles can be prepared as an efficient adsorbent for the removal of food color in aqueous solution. The highest removal percentage of food color, was in pH=7 and it,s concentration was 15 ppm. The obtained experimental data in optimum condition was used to model the behavior of absorption in isotherms equations such as: Langmuir, Freundlich, Langmuir-Freundlich and Toth. An examination of the Langmuer isotherm (R2=0.980) showed that the absorption of food color on the adsorbent surface was monolithic and uniform. The kinetics of adsorption interactions were examined. The obtained results showed that the adsorption data has the most conformity with, pseudo-second-order model.
A simple and low-cost spectrophotometry method was proposed based on resonance Plasmon peak of silver nanoparticles for measurement of metanephrine(MN) drug. This method was based on reducing property of metanephrine and it was founded that this compound reduces silver ions in presence of polyvidone (PVP) as stabilizer compound. In this condition the formed silver nanoparticles show a localized surface plasmon resonance (LSPR) peak of about 423 nm. The resulted nano-particles were analyzed by transmission electron microscope (TEM) technique and nanoparticles size was estimated to be maximum of 200nm. Furthermore, realized that the absorption of solution depends on concentration of metanephrine and the maximum of absorption was found at 〖AgNO〗_3 concentration of 1.53 mM, NaOH concentration of 4.10 mM, 〖NH〗_3 concentration of 2.51 mM and 1.15 ml of PVP. Also, the proposed method showed a good linear relationship than MN concentration in the range of 2.5-20 µM and limit of detection was obtained as 0.6 µM for metanephrine. Finally, this method was used for measuring epinephrine in real samples and the acceptable results were obtained.
In this work electrochemical oxidation of some urazole derivatives (1–6) was studied both experimentally and theoretically. The results indicate that the urazoles are converted to oxidized forms (1ox-6ox) via two electron process. The produced species (1ox-6ox) are unstable and participate in hydrolysis reaction, and ring cleavage happens after electrochemical process. Depending on the substituent that is connected to the urazol ring, the rates of the hydrolysis are different. Because the charge of reaction site and bond order of C1-N1 bond are effective on the hydrolysis rate, using computational study, the effects of the both parameters on the hydrolysis rate were analyzed. It was found that various substituents by affecting on the both parameters change the hydrolysis rate. After drawing diagrams of charge of reaction site and bond order of C1-N1 bonds versus hydrolysis rate, it was shown that there are significant relationship between these parameters and hydrolysis rate. Finally these results were used to estimation of hydrolysis rate of some other urazoles (7-10) without conducting laboratory research.
