Sharif Digital Repository

Glycerin (glycerol) is a co-product of biodiesel production that is widely produced and is available at a low cost. To date, various applications have been investigated and introduced for biodiesel glycerin. In this study, a number of valuable products were produced using biodiesel glycerin and formic acid as the main reactants. Allyl alcohol is one of the valuable chemicals produced from glycerin monoformate. Efficient production of this product requires successful completion of the first section of the reaction, which is an equilibrium reaction. The highest feasible yield achieved was about 83% (based on the consumption of formic acid) at 120-140°C without the addition of any catalysts.... 

Glycerin (glycerol) is a co-product of biodiesel production that is widely produced and is available at a low cost. To date, various applications have been investigated and introduced for biodiesel glycerin. In this study, a number of valuable products were produced using biodiesel glycerin and formic acid as the main reactants. Allyl alcohol is one of the valuable chemicals produced from glycerin monoformate. Efficient production of this product requires successful completion of the first section of the reaction, which is an equilibrium reaction. The highest feasible yield achieved was about 83% (based on the consumption of formic acid) at 120-140°C without the addition of any catalysts.... 

Artificial Immune System algorithms use antibodies which fully specify the solution of an optimization, learning, or pattern recognition problem. By being restricted to fully specified antibodies, an AIS algorithm can not make use of schemata or classes of partial solutions. This paper presents a symbiotic artificial immune system (SymbAIS) algorithm which is an extension of CLONALG algorithm. It uses partially specified antibodies and gradually builds up building blocks of suitable sub-antibodies. The algorithm is compared with CLONALG on multimodal function optimization and combinatorial optimization problems and it is shown that it can solve problems that CLONALG is unable to solve.... 

The synthesis of a series of benzoxazocines has been achieved in good yields by tandem C-alkylation and intramolecular O-alkylation of 1,3-dicarbonyl compounds with quinolinium salts. This is a novel example of the synthesis of eight-membered rings via a tandem process, which provides a method for the synthesis of medium-ring heterocycles  

An efficient and simple method for the reduction of aldehydes, ketones and acid chlorides has been accomplished by using NaBH4-solid LiClO 4 in mild conditions at ambient temperature with complete chemoselectivity in reduction of α,β-unsaturated aldehydes and ketones. The reaction is fast with high yield and simple workup. Copyright © Taylor & Francis, Inc  

The Taguchi method, a robust experimental design for optimization, was used for the synthesis of a superabsorbent hydrogel network using γ-rays as an initiator, energy source and crosslinker at the same time. Nine different samples of superabsorbent hydrogels were prepared in various conditions from kappa-carrageenan (κC) and acrylamide by γ-irradiation at room temperature. Considering the results of nine trials and according to analysis of variance (ANOVA), a new experimental condition with the concentrations of κC and acrylamide 1.5 g and 0.028 mol (2 g in total volume of 50 mL H2O), respectively, as well as γ-ray at the optimum total dose (7 kGy) was proposed. After preparing the desired... 

Highly efficient one-pot reactions of amines and carbon disulfide with α,β-unsaturated compounds were carried out in water under a mild and green procedure with high yields. © 2006 American Chemical Society  

Water dispersed magnetic nanoparticles (DMNPs) of γ-Fe 2O3 represent a simple and green catalyst for the rapid three-component synthesis of tetrahydro-4H-chromene and hexahydroquinoline carboxylate skeletons via single-pot domino Knoevenagel-Michael-cyclization reactions  

A novel class of substituted quinazolines were prepared in good yields by a one-pot three-component reaction of isocyanides with adducts of anilines and tri- or dichloroacetonitrile, followed by intramolecular C-H activation, catalyzed by copper(I) iodide with l -proline as a ligand in acetonitrile at room temperature. © 2017 Georg Thieme Verlag Stuttgart .New York-Synlett  

A computational code, based on the genetic algorithm and MCNPX version 2.6 code was developed and used to investigate the effects of some important parameters of HPGe detector (such as Al cap thickness, dead-layer thickness and Ge hole size) on optimum dimensions of marinelli beaker. In addition, the effects of detector material on optimal beaker dimensions were also investigated. Finally, the optimized beaker dimensions at various beaker volumes (300, 500, 700, 1000 and 1500 cm3) were determined for some conventional Ge detectors with different crystal sizes (16 sizes). These sets of data then were used to drive mathematical formulas (obtained by best fitting to data sets). The results... 

In this study, an enzymatic pathway has been developed to replicate the Calvin Cycle by creating the individual steps of the carbon cycle in a bioreactor. The technology known as “artificial photosynthesis” converts CO2 emissions into a variety of intermediates that serve as precursors to high-value products. CO2, light, water, and electricity were used as feedstock. An electrochemical reactor was also studied for the regeneration of active NADH operating at constant electrode potential. Initially, a batch electrochemical reactor containing 80 mL of 0.2 mM NAD+ in Tris-buffer (pH 7.40) was used to evaluate the electrode material operating at normal temperature and pressure. The results... 

The synthesis of functionalized benzothiadiazine 1,1-dioxide derivatives was achieved through a novel three-component intramolecular C–H activation reaction of trichloroacetonitrile, benzenesulfonyl chloride, and various primary amines. This reaction was performed in the presence of catalytic copper(I) and L-proline as the ligand in tetrahydrofuran at room temperature. © 2018 Elsevier Ltd  

A headspace adsorptive microextraction technique was developed using a novel polyaniline-nylon-6 (PANI-N6) nanofiber sheet, fabricated by electrospinning. The homogeneity and the porosity of the prepared PANI-N6 sheet were studied using the scanning electron microscopy (SEM) and nanofibers diameters were found to be around 200nm. The novel nanofiber sheet was examined as an extracting medium to isolate some selected chlorobenzenes (CBs), as model compounds, from aquatic media. The extracted analytes were desorbed using μL-amounts of solvent and eventually an aliquot of extractant was injected into gas chromatography-mass spectrometry (GC-MS). Various parameters affecting the extraction and... 

Herein, functionalized spiro[indoline-3,5′-pyrazolo[1,2-a]pyridazine]-7′-carbonitrile containing two contiguous chiral stereocenters was efficiently synthesized in a satisfactory yield (up to 91% yield) and with excellent diastereoselectivity. We have reached this satisfactory yield by DABCO-catalyzed [3+3] annulation reactions of an isatin N,N′-cyclic azomethine imine 1,3-dipole with a Knoevenagel intermediate in dichloromethane (DCM) as solvent at ambient temperature; this was an entirely new strategy for creating one quaternary stereogenic center at the position-3 of an oxindole structure using an abnormal tandem Michael addition, N-cyclization, and a unique approach via the azomethine... 

Herein, functionalized spiro[indoline-3,5′-pyrazolo[1,2-a]pyridazine]-7′-carbonitrile containing two contiguous chiral stereocenters was efficiently synthesized in a satisfactory yield (up to 91% yield) and with excellent diastereoselectivity. We have reached this satisfactory yield by DABCO-catalyzed [3+3] annulation reactions of an isatin N,N′-cyclic azomethine imine 1,3-dipole with a Knoevenagel intermediate in dichloromethane (DCM) as solvent at ambient temperature; this was an entirely new strategy for creating one quaternary stereogenic center at the position-3 of an oxindole structure using an abnormal tandem Michael addition, N-cyclization, and a unique approach via the azomethine... 

Increasing energy demands for pollution-free and renewable energy technologies have stimulated intense research on the development of inexpensive, highly efficient, and stable non-noble metal electrocatalysts for oxygen evolution reaction (OER). In this study, a superior OER performance was achieved using a tri-metallic (Zn, Co, Ni) high-performance electrocatalyst. We successfully fabricated a peony-flower-like hierarchical ZnCo2O4 through an additive-free hydrothermal reaction followed by heat treatment. Then NiCo-LDH (layered double hydroxides) nano-flakes was electrodeposited on the ZnCo2O4/GCE surface to prepare NiCo-LDH/ZnCo2O4/GCE which was used as electrode for OER. The structure and... 

Herein, an efficient and sustainable one-pot, four-component access to rhodanine-oxindole derivatives is achieved by a reaction between primary amines, carbon disulfide, ethyl chloroacetate, and cyano-substituted alkenyl oxindoles. The reaction was conducted without any harsh conditions as well as exhausting workup in polyethylene glycol (PEG) as a green solvent at room temperature and delivered rhodanine-oxindole products in high yield. This publication is the first easy protocol to be reported for the rapid construction of new rhodanine-oxindole derivatives at room temperature without harsh conditions and via multicomponent reaction. © 2021 Taylor & Francis Group, LLC  

Some new 1,4-distyrylbenzene derivatives were synthesized by using immobilized palladium nanoparticles on silica-bonded N-propyl morpholine (PNP-SBNPM) as a heterogeneous catalyst. These one-pot reactions afforded a range of stereoselective, symmetrical (E)-1,4-distyrylbenzene derivatives with high yields (78-90%). The green catalyst system is recyclable and allows facile product isolation. The recycled catalyst could be reused six times without appreciable loss of catalytic activity  

A metal organic framework-polyaniline (MOF/PANI) nanocomposite was electrodeposited on a stainless steel wire and used as a solid phase microextraction (SPME) fiber coating. The electropolymerization process was carried out under a constant deposition potential and applied to the corresponding aqueous electrolyte containing aniline and MOF particles. The employment of MOFs with their large and small cages and 3-D structures in synthesizing a nanocomposite was assumed to be efficient constitutes to induce more non-smooth and porous structures, approved by scanning electron microscopy (SEM) images. Three different MOFs were incorporated to synthesize the desired nanocomposites and the... 

Introduction: In recent years, the use of cost-effective, multifunctional, environmentally friendly and simple prepared nanomaterials/nanoparticles have been emerged considerably. In this manner, different synthesizing methods were reported and optimized, but there is still lack of a comprehensive method with multifunctional properties. Materials and Methods: In this study, we aim to synthesis the copper oxide nanoparticles using Achillea millefolium leaf extracts for the first time. Catalytic activity was investigated by in situ azide alkyne cycloaddition click and also A3 coupling reaction, and optimized in terms of temperature, solvent, and time of the reaction. Furthermore, the...