Simple,Efficient, and Applicable Route for Synthesis of 2-Aryl(Heteroaryl)-Benzimidazoles at Room Temperature Using Copper Nanoparticles on Activated Carbon as a Reusable Heterogeneous Catalyst

Abstract  

A series of 2-(hetero)arylbenzimidazoles were synthesized by the catalytic condensation of (hetero)aryl aldehydes with 1,2-phenylenediamine derivatives at room temperature in the presence of air as the oxidant. Copper nanoparticles on charcoal was employed as an efficient and mild catalyst for this methodology.     

Emotional ANN (EANN) and Wavelet-ANN (WANN) Approaches for Markovian and Seasonal Based Modeling of Rainfall-Runoff Process

The hydrological time series have three principle components (autoregressive, seasonality and trend) and the performance of the models is strongly related to the nature of these components. The current research examines the accuracy of two Artificial Neural Network (ANN) based approaches for rainfall-runoff (r-r) modeling of two catchments with different geomorphological conditions at monthly and daily time scales. The techniques proposed here are hybrid wavelet-ANN (WANN) model, as a multi-resolution forecasting tool and Emotional Artificial Neural Network (EANN) (a new generation of ANN based models) which serves artificial emotional factors as well as classic bias and weights parameters. The obtained results for monthly modeling show that WANN could perform better than the simple feed forward neural network (FFNN) model up to 40% and 35% in terms of verification and training efficiency criteria due to significant seasonality involved in the monthly time series of the process. On the other hand, the obtained results for daily modeling via FFNN and EANN, both as Markovian models, indicates the superiority of EANN over FFNN because of EANN capability to better learning of extraordinary and extreme conditions of the process in the training phase.     

Catalytic Friedel–Crafts Acylation and Benzoylation of Aromatic Compounds Using Activated Hematite as a Novel Heterogeneous Catalyst

Catalytic Friedel–Crafts acylation of benzene and unactivated benzenes such as chlorobenzene and nitrobenzene have been successfully carried out using activated hematite (α‐Fe₂O₃) as a new, heterogeneous and green catalyst. Sonication of neat α‐Fe₂O₃ in a water bath under air atmosphere at room temperature followed by heating at 200 °C, dramatically increase the activity of α‐Fe₂O₃. With the catalyst loading as low as 5.0 mol%, a wide variety of benzene derivatives were easily converted into the corresponding acylated products in a clean and high‐yielding acylation reaction. It was found that the activated α‐Fe₂O₃ could be efficiently recycled and reused several times by simple washing with ethyl acetate, this cannot be attained with most of the traditional catalysts.     

Analysis of the Possible Cracking and Damages of Tunnel Lining Segments during Installing Stage

Soil Mechanics and Foundation Engineering - Tunnel lining segments can crack or sustain fractures at different stages. It will then affect the stability and structure of the tunnel construction...     

Application of some recently synthesized 9, 10-anthraquinone derivatives as new class of ionophores responsive to lead (II) ion

Lead-selective solvent polymeric membrane electrodes, based on some recently synthesized 9, 10-anthraquinone derivatives, are described. The electrode exhibits a good Nernstian response for Pb (II) ions over a wide concentration range of 1.0/spl times/10/sup -6/-1.0/spl times/10/sup -2/ M with a slope of 28.9 mV decade/sup -1/. The potential-pH profile of membrane based on 1-hydroxy-2-({2-[2-(2-hydroxyethoxy)ethoxy]ethoxy}methyl)anthra-9, 10-quinone (A/sub 3/) demonstrated a lack of H/sup +/ interference within a wide pH range (1.5-6.8). The detection limit is 6.7/spl times/10/sup -7/ M. The developed sensor has a very short response time (2.0 s), and it can be used as a working electrode in a flow injection system. The lifetime of the proposed sensor is 120 days (without any considerable divergence in potentials) with good reproducibility (SD=/spl plusmn/0.1 mV). The proposed sensor revealed good selectivity for Pb (II) over a wide variety of other metal ions. It can be used as an indicator electrode in the potentiometric titration of lead ions, with EDTA, oxalate, chromate, and hydroxide ions, and in direct determination of lead in a wastewater sample.     

Development of a specific and highly sensitive optical chemical sensor for determination of Hg(II) based on a new synthesized ionophore

A novel optode for determination of Hg(II) ions is developed based on immobilization of a recently synthesized ionophore, 7-(1H-imidazol-1-ylmethyl)-5,6,7,8,9,10-hexahydro-2H-1,13,4,7,10 benzodioxatriaza cyclopentadecine-3,11(4H,12H)-dione, in a PVC membrane. Dioctyl sebacate was used as a plasticizer, sodium tetraphenylborate as an anionic additive and ETH5294 as a chromoionophore. The response of the optode was based on the complexation of Hg(II) with the ionophore in the membrane phase, resulting an ion exchange process between Hg(II) in the sample solution and H⁺ in the membrane. The effects of pH and amounts of the ionophore, chromoionophore, ionic additive and type of plasticizer on the optode response were investigated. The selectivity of the optode was studied in the present of several cations. The optode has a linear response to Hg(II) in the range of 7.2 × 10^? 13–4.7 × 10^? 4 mol L^? 1 with detection limit of 0.18 pmol L^? 1. The optode was successfully applied to the determination of Hg(II) in real samples.     

One-Pot Three-Component Synthesis of 2,4,5-Triaryl-1H-imidazoles Using Mn2+ Complex of [7-Hydroxy-4-methyl-8-coumarinyl] Glycine as a Heterogeneous Catalyst

Catalysis Letters - A highly efficient and simple synthesis of 2,4,5-trisubstituted imidazoles has been developed using highly reusable support‐free Mn2+complex of...     

A Z-Number Valued Regression Model and Its Application

Regression analysis is widely used for modeling of real-world processes in various fields. It should be noted that information relevant to real-world processes is characterized by imprecision and partial reliability. This involves combination of fuzzy and probabilistic uncertainties. Prof.. L. Zadeh introduced the concept of a Z-number as a formal construct for dealing with such information. The present stateof-the-art of regression analysis under Z-number valued information is very scarce. In this paper we consider a Z-number valued multiple regression analysis and its application to a real-world decisionmaking problem. The obtained results show applicability of the proposed approach.