نشریه شیمی کاربردی روز
پیاپی 62 (بهار 1401)

In this research, convenientand environmental friendly method has been reported for preparation of double Schiff bases N,N'-bis(2-hydroxybenzylydene)-1,1-diaminoalkane. These compounds have been synthesized through one pot three component reaction of salicylaldehyde, ammonium hydroxide and various aliphatic aldehydes under ultrasonic irradiation and solvent free conditions. All of desire double Schiff bases obtained with excellent yields and short reaction times using this method. The structure of nine products (4a-i), characterized using different spectroscopy data such as: 1H NMR, 13C NMR, FT-IR and Mass spectrometric. With attention to structure of synthetic double Schiff bases, in continuation of research, physicochemical properties of compounds surveyed using Molinsiration calculating server. As a results, all of the synthetic double Schiff bases obey the Lipinski rules of five and exhibit good absorption, permeability and penetration abilities in human body.

In the present study, biocompatible hydrogels based on polyethylene glycol with molecular weights 2000 and 4000 g/mol was synthesized by using click chemistry (Azide – Alkyne coupling). For this Perouse, the precursors were functionalized with azide and alkyne functional groups and then the hydrogels were synthesized by coupling reaction between azide and alkyne groups in the presence of copper sulfate and ascorbate sodium catalyst. Investigation of the morphology of these hydrogels well illustrated their network structure. The study of the swelling behavior of these hydrogels showed that the degree of swelling decreases with decreasing of polyethylene glycol molecular weight. These hydrogels were loaded with 2,4-dichlorophenoxy acetic acid herbicide. The obtained results showed that the rate and amount of herbicide release decrease with decreasing of polyethylene glycol molecular weight. In other words, the release amount of the herbicide decreases from 80% for the hydrogel with polyethylene glycol 4000 to 55% for the hydrogel with polyethylene glycol 2000. Hydrogels showed good stability in neutral buffer medium. It was also observed that drug release in both samples followed a non-Fickian mechanism.

A sensitive, straightforward, and inexpensive dispersive micro solid-phase extraction (DµSPE) coupled with the spectrophotometric method was developed for measuring celecoxib in biological and water samples. For this purpose, a new sorbent (Nickel nanoparticles doped carboxyl graphene oxide) was synthesized using a simple chemical procedure and was utilized to extract celecoxib. The effective factors in the DµSPE procedure were evaluated and optimized by the design of experiment method. Two designs, including the Plackett-Burman design and Box-Behnken design, were applied to screening significant factors and to optimize the significant factors, respectively. The DµSPE- spectrophotometric method was linear in the concentration range of 0.004-3.5 µg mL-1 with an R-squared of 0.9951 for the celecoxib measurement under the optimum conditions. The method showed a low limit of detection of 0.004 µg mL-1 and a suitable enrichment factor of 21.7 for the analyte determination. The relative standard deviation was calculated for five measurements of the standard solution of celecoxib with a concentration of 0.3 µg mL-1 and was 3.2%. Finally, the proposed method was used to analyze real samples such as milk, urine, and tap water samples, indicating that the method is very suitable for measuring celecoxib in real samples with a recovery in the range of 90.3-96.8% with a relative standard deviation lower than 5.1 %. The important advantages of the method are simple and inexpensive procedure, low desorption solvent and sorbent consumption, and without the need for sophisticated and expensive instruments.

Zinc sulfide nanostructures were synthesized by a green, cost-effective, and simple co-precipitation method using the amino acid L-cysteine as a surfactant. After synthesizing and annealing the nanostructures, the obtained samples were characterized by different techniques such as X-ray diffraction (XRD) patterns, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), X-ray energy diffraction (EDX) patterns and ultraviolet-visible(UV) spectroscopy. The results of XRD and FTIR showed that zinc sulfide nanostructures have a hexagonal phase. The results of the UV-vis showed that increasing the annealing temperature led to a decrease, the band-gap energy and increase the size of the nanostructures. The prepared nanostructures were used to investigate the photocatalytic activity. The results showed that with increasing annealing temperature, the photocatalytic efficiency of nanostructures was decreased.

The main purpose of this study is the direct synthesis of regular mesoporous polymer with 3-(1-Vinyl imidazolium-3-yl) propane-1-sulfonate (MPIL-PS) ionic liquid units and its use as a catalytic substrate in the esterification of acids and the acylation of alcohols. in this research,Polyvinyl benzene polymer was synthesized with imidazolium units. In the next step, the regular mesoporous polymer (MPIL-PS) was activated with the Propane sultone group, and then the desired catalyst (H2SO4 @ MPIL-PS) was prepared by the interaction of ionic liquid units created on the surface of the polymer with sulfuric acid groups. The synthesized catalyst has the simultaneous advantages of ionic liquids and polymer nanostructured materials. By changing the reaction conditions and reducing the percentage of ionic liquids used in the presence of small amounts of catalyst, this catalyst was used in the reaction of esterification of acids and acylation of alcohols with high yields of products. The resulting catalyst after synthesis, The synthesized catalyst were characterized by various techniques such as nitrogen adsorption-desorption analysis, thermal gravimetric analysis (TGA) and FT-IR spectroscopy. Also, the catalyst recycling test showed that the catalytic system can be recycled up to 5 times with high efficiency without any significant reduction in activity.

Raisin factories face a problem called waste and unusable waste in their industry. Due to the richness of industrial waste in this industry from carbon, in this work, we synthesized activated carbon by chemical method from raisin waste. For the synthesis of activated carbon, a chemical method with a zinc chloride activating agent was used in one to one mass ratio. After the optimization of various parameters such as type of activation agent, the ratio of activating agent, carbonization temperature and carbonization time, the best conditions for activated carbon were obtained. Then, in order to evaluate the efficiency of the synthesized activated carbon, a methylene blue dye removal test as a model was performed. Optimal conditions for the removal of methylene blue dye using the activated carbon including neutral pH, ambient temperature and the amount of adsorbent 0.01 g in 10 mL of solution with a concentration of 20 mg L-1 were obtained. In these conditions, the removal efficiency is more than 99%. The adsorption capacity is about 20 mg g-1 and the reaction kinetics is quasi-second order and according to thermodynamic studies the endothermic reaction is spontaneous and with increasing entropy. The dye adsorption mechanism on the adsorbent also follows the Langmuir isotherm, which indicates the uniformity of the adsorbent surface and the monolayer adsorption. Finally, in order to compare the performance of synthetic activated carbon, the amount of dye removal under optimal conditions was compared with the commercial activated carbon including Merck, Jacobi and activated carbon obtained from the almond shell. The results showed that synthetic activated carbon can compete with commercial samples.

In this study, the photocatalytic performance of ZIF-8, as one of the most important MOFs, was improved by impregnation on the TiO2 nanotubes and was used for hybrid photocatalytic degradation of Methyl Orange from aqueous solutions. The prepared nanostructure was characterized by XRD, TEM, EDX, BET, SEM, and FTIR analyses and their results confirmed the successful fabrication of nanocrystals with spherical morphology. Also, the meso/macro cavity structure with slit-like cavities has been obtained by SEM and BET results. The photocatalytic behaviour of the nanostructure was investigated under UV light irradiation. In order to optimize the degradation process, the effect of various parameters, such as pH, photocatalyst concentration, and the proposed mechanism for dye degradation have been evaluated. The results showed that the methyl orange photodegradation efficiency of 86% was reached using ZIF-8/TiO2 at pH 7 and photocatalyst concentration of 0.5 g/Lit after 60 min under UV irradiation.

In this project, crosslinked Styrene-Co-Maleic anhydride Polymer Catalyst modified with NiSO4 hexahydrate, as an efficient heterogeneous polymer-based nanocatalyst was synthesized in three steps. First, Styrene-Co-Maleic anhydride polymer was synthesized by radical polymerization of styrene in maleic anhydride, then the resulted copolymer was crosslinked with 1,3-phenylenediamine and finally the crosslinked copolymer was modified with NiSO4. This polymer-based nanocatalyst was investigated and identified using Fourier-transform infrared spectroscopy (FT-IR), Energy Dispersive X-Ray (EDX) (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM). In order to investigate the catalytic properties of CPSMA-Ni, the synthesis of various types of 2-amino-4H-chromane derivatives was investigated using the reaction of aldehyde derivatives with malononitrile in the presence of dimedone, resorcinol or naphthols. 2-Amino-4H-Cromans were synthesized with good to excellent efficiency (85%-96%) under mild conditions. This heterogeneous polymeric catalyst has a good performance in the synthesis of chromium derivatives. This catalyst can be recycled without pre-activation and reloaded up to 5 consecutive runs without significant decrease in its efficiency.

One of the main causes of explosions events in high energetic material industry is static electricity. Handling of energetic materials leads to the generation of electrostatic charges. Most energetic materials are non-conductive, easily accumulate charge and are highly sensitive to Electrostatic discharge (ESD) ignition. To reduce the risk aroused by ESD ignition hazard in the processing and handling of energetic materials, antistatic modifications are necessary. In this study, to reduce the accumulation of static charge, synthetic polyaniline additive has been used by slurry, water-evaporation, solvent evaporation and physical mixture methods. Among the studied samples, the composition containing 5% by weight of polyaniline by the slurry method were studied by electrostatic charging test setup to investigate and to measure the production and accumulation of static charge. In this evaluation, the amount of reduction of static charge accumulation in Cyclotetramethylene Tetranitramie (HMX) and Pentaerythritol Tetranitrate (PETN) explosives, using polyaniline, was very significant, from -3,600 and -5,400 nC/kg to 0 nC/kg, respectively. so that in both explosive compounds, the charge accumulation was reduced nearly 100%.

In this work, facile and efficient procedures were described for the synthesis of 4,7-dihydro[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamides via three-component reaction of aryl aldehyde, acetoacetanilide and 3-amino-1,2,4-triazole. The reactions were performed using p-toluenesulfonic acid monohydrate in refluxing EtOH or trityl chloride under solvent-free conditions at 80 ºC. Comparison of the results shows that both organic catalysts are effective for the synthesis of these fused heterocyclic compounds. Some advantages of these methods are short reaction times, good to excellent yields and easy to operate. Additionally, all products were obtained through simple filtration and no need for column chromatography or tedious work-up, which is an important factor to reduce environmental pollutions.

Steam reforming of methanol over nanocatalysts and nanocomposites is one of the promising methods for hydrogen production which is attracted by scientists. It is important to note that the precursor can play a major role in the preparation of these materials. In this research, CuO/ZnO/Al2O3 nanocomposite with different alumina precursors of boehmite and aluminum nitrate was prepared via urea-nitrate combustion method. The physiochemical properties of nanocomposites were assessed by XRD, BET, FESEM, EDX and FTIR techniques. The catalytic performance of the synthesized samples in steam reforming of methanol was investigated. The XRD results showed that lower crystals size for nanocomposite synthesized with aluminum nitrate and FESEM images confirmed better dispersion on the surface of this sample. BET analysis showed higher surface area for catalyst synthesized with boehmite. The catalytic performance tests in steam reforming of methanol illustrated slightly higher methanol conversion for the sample with aluminum nitrate source while the boehmite derived sample performed much better in less CO formation. The boehmite sample was also stable for 480 min in the SRM reaction.