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.... 

γ-Alumina is used to catalyze the Cannizzaro reaction in the absence of any base under microwave irradiation in high yields. In the case of terephthalaldehyde the reaction is carried out with high selectivity  

The glucose-based ligand, N-salicylidene-d-glucosamine (Sal-d-glsmN), was readily obtained by reaction of salicylaldehyde (Hsal) with the d-glucosamine hydrochloride. Ligand Sal-d-glsmN was found to be an efficient ligand in the palladium-catalyzed Suzuki and Heck C-C coupling reactions in aqueous medium under aerobic condition. It was found that the use of Sal-d-glsmN/Pd(OAc) 2 system as a catalyst, aryl halides undergo Suzuki and Heck cross-couplings, respectively, with arylboronic acids and olefins to give the desired products in moderate to excellent yields  

An efficient and one-pot synthesis of thiopyrano[2,3-b]indole derivatives via Hetero Diels-Alder reaction of α,β-Unsaturated thio-oxindoles with electron poor acetylenes and Cyclic Dienophiles is described. In the proposed method the reaction is performed under neutral and one-pot reaction conditions, and also the substances can be mixed without any activation or modification and without using any catalysts  

Hetero-Diels–Alder reactions of [60]fullerene with α,β-unsaturated thio-oxindoles (3a, 3b, 3c), prepared from thio-oxindole 1 and heteroaromatic aldehydes (2a, 2b, 2c), to generate tetrahydrothiopyrano[2,3-b]indole [60]fullerene cycloadducts (5a, 5b, 5c) under thermal or microwave irradiation were described. The yields were improved, and the reaction time was decreased by conducting the reaction under microwave irradiation. © 2016 Wiley Periodicals, Inc  

The first example of a heterogeneous catalytically active system for Buchwald–Hartwig and Ullmann homocoupling of unactivated aryl halides (fluorobenzene) is presented. The novel magnetic heterogeneous palladium catalyst was synthesized by immobilization of palladium ions onto an aminopyridine-functionalized Fe3O4. The catalyst was fully characterized by FTIR spectroscopy, temperature-programmed reduction, thermogravimetric analysis, CHN elemental analysis, transmission electron microscopy, field-emission scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray spectroscopy, and atomic absorption spectroscopy. By using this catalyst system, various types of primary and... 

An efficient catalyst-free one-pot three-component reaction was developed for the synthesis of a new family of N- A nd S-containing spirocyclic compounds. Various derivatives of spirobenzimidazolidine containing an indole scaffold were synthesized for the first time in a modestly toxic solvent and under mild reaction conditions. The reaction times were of the order of several minutes, and all the products were obtained in moderate to high yields (overall yields 58-80%). © Georg Thieme Verlag Stuttgart New York  

Microwave induced Cannizzaro reaction, which was performed in presence of neutral γ-alumina as a polymeric catalyst, was discussed. Cannizzaro reaction was carried out on alumina surface and other unknown products were also obtained. Solvent extraction method was utilized to isolate mild and selective benzyl alcohol and carboxylic acids  

An efficient synthesis of polysubstituted thiophene derivatives is achieved via the multicomponent reaction of β-ketodithioesters, α-haloketones, and cyclohexylisocyanide in aqueous medium  

The kinetics of the enzymic reaction of penicillin G acylase from a mutant of Escherichia coli ATCC 11105 in forward and reverse directions were studied and the kinetic constants determined. Results show that the enzyme is inhibited by excess substrate, penicillin G (Pen G), and by both products. The non-competitive inhibition by 6-aminopenicillanic acid (6-APA) and competitive inhibition by phenylacetic acid were observed for the ordered uni bi deacylation reaction in the forward direction. The optimum pH value for the reverse acylation reaction was 5.7. The bi uni mechanism for the reverse reaction was investigated and the inhibitory effects of the substrates, 6-APA and phenyl acetic acid,... 

4-hydroxyquinolinones 7 were applied as 1,3-dinucleophiles in the reaction with Baylis-Hillman adduct acetates 6 to synthesize, in high yields of 75-92%, novel 2H-pyrano[3,2-c]quinoline-2,5(6H)-diones which are present in a number of biologically active compounds. The reaction was carried out under different conditions to achieve the optimum ones. The results indicated that acetonitrile as solvent and K2CO3 as base, under reflux conditions, were the optimum conditions. The reaction times are short and the experimental procedure is straightforward  

A simple bidentate ligand, 2-(2′-hydroxyphenyl)-5,6-dihydro-1,3- oxazine, was readily prepared with a two-step synthesis. Two novel complexes of Pd(II) and Cu(II) with this (N,O) oxazine ligand have been prepared and the molecular structures of these complexes have been confirmed by X-ray structure analysis, NMR, IR and UV-Vis spectroscopy. These complexes efficiently catalyze the Heck reaction of aryl halides with olefins at 120 °C in 8 h. The reaction conditions for the Heck coupling of iodobenzene with styrene was optimized by varying the amount of the catalyst, reaction temperature, solvent and exogenous base  

An efficient one-pot synthesis of functionalized trisubstituted thiophenes via the reaction of 3-morpholino-3-thioxopropanenitrile, cyclohexyl isocyanide and -haloketones is reported. This method provides a straightforward route to a variety of highly substituted thiophenes not easily accessible by conventional methods  

Owing to the inherent incompatibility with water, cyanation of aryl halides may be the most challenging category of palladium-catalyzed coupling reactions. The major challenges are attributed to the catalyst deactivation by the soluble cyanide (CN−) ions and desirable conversions only could be obtained by employing toxic organic solvents. The current minireview highlights mechanistic insights and breakthrough achievements for this reaction in the aqueous media  

In this work, we report the synthesis of silver decamolybdate, Ag6Mo10O33, nanostructure by a simple mechanochemical process followed by calcination treatment using acetamide as driving agent. Morphological study by scanning electron microscopy (SEM) images revealed bundles of rods grown closely together with an average diameter of 92 nm for Ag6Mo10O33 sample. Ni-substituted Ag6Mo10O33 compound was prepared via introducing nickel cation to precursor system in mechanical milling step. The particle size decreased to 87 nm by incorporating nickel units in substituted polymolybdate. It was concluded that the suitable selection of reagents can direct solid phase reaction towards producing... 

Cell lysis is the most important first step for molecular biology and diagnostic testing. Recently, microfluidic systems have attracted considerable attention due to advantages associated with automation, integration and miniaturization, especially in resource-limited settings. In this work, novel centrifugal microfluidic platforms with new configurations for chemical cell lysis are presented. The developed systems employ passive form of pneumatic and inertial forces for effective mixing of lysis reagents and cell samples as well as precise fluidic control. Characterizations of the developed Lab-on-a-Discs (LoaDs) have been conducted with dyed deionized (DI) waters and white blood cells... 

The importance of the gas-to-liquid process is increasing due to growing demand for a high quality, less expensive, and cleaner fuel. Faujasite zeolites, e.g,. zeolites type X and Y, are well-known catalysts in the petrochemical industry. Faujasitic supports (mainly X zeolites) were prepared via hydrothermal synthesis with different Si/Al ratios from pure chemical materials and fly ash as a source of silicon. A high quantity of cobalt oxides was deposited on supports by varying samples Si/Al ratios during the zeolite preparation procedure. Using fly ash in synthesizing the zeolitic support resulted in a A-X zeolite material with a very high cation exchange capability and final cobalt... 

TmBa2_xPrxCu3O7+δ and LuBa2_xPrxCu3O7+δ samples with 0.0 < x ≤ 1.0 have been prepared by a solid-state reaction technique. The occurrence of the orthorhombic to tetragonal phase transition, increasing of oxygen content with the increase of Pr doping, and the existence of solubility limit in both systems confirm the correct substitution of Pr at Ba sites. The solubility limit for Pr in the Lu-based samples is less than 0.7, which is less than x = 0.90 for the Tm-based samples. The Tc depression versus doping content in both systems shows that depression of superconductivity by Pr at Ba sites is mostly due to the hole-filling/localization effects. Also, in the Tm-based system, the... 

A mathematical model is presented to simulate the multiple heterogeneous reactions with complex set of physicochemical and thermal phenomena in a moving bed of porous pellets. This model is based on both heat and mass transfer phenomena of gaseous species in a porous medium including chemical reactions at interfaces whose areas vary during the conversion. This model accounts for both the exothermic and endothermic reactions which can be equimolar or nonequimolar. Furthermore it considers simultaneously the reactions in the nonisothermal transient condition. A powerful technique based upon finite volume fully implicit approach has been implemented to solve the complicated governing equations...