Determination of Violet Covasol as a cosmetic dye in water samples by a CPE-Scanometry method

The trace amounts of Violet Covasol as a cosmetic dye was determined by an efficient cloud point extraction-Scanometry(CPE-Scanometry) method. This method has many advantages such as novelty,facility, high speed, sensitivity, low cost and safety. The method is based on the CPE of an analyte from an aqueous solution, diluting the extracted surfactant-rich phase with ethanol, transferring to Plexiglas~cell and scanning of the cells containing the analyte solution with a scanner and measuring the RGB parameters with software written in visual basic(VB 6) media. Parameters impacting the extraction efficiency such as p H of the system, the concentration of surfactant, equilibration temperature and time were optimized. Detection limit(DL), relative standard deviation(RSD) and linear range for the proposed method are 0.026, 0.71 and 0.16–6.6 μg m L ~(-1)respectively. The method was successfully applied for the determination of Violet Covasol dye in several water samples, including a water sample containing the dye as a tracer(to investigate subsurface water movement).     

Oil sand deformation under cyclic loading of ultra-class mobile mining equipment

The strain softening of oil sand in the underfoot, due to the loading action of large mobile mining equipment such as trucks and shovels, yields a highly unstable condition for the operation of this ultra-class equipment. High maintenance costs as a result of truck and shovel frame failures are a frequent result of this instability. With the advent of ever larger units as mining operations move towards in-pit extractive technologies, some of these units are now approaching 2800 tons GVW. The ultra class units are able to operate year round, the interactions with the ground conditions have become an integral concern in selection of these units.The scaling approach and multi cycle convergent value approximation allows operations personnel to predict the degree of ground deformation for large mobile mining equipment. Thus enabling the decision of whether to operate equipment in a given soft ground location to be made.A full-scale field test was performed to study the ground stiffness behaviour during ground loading by ultra-class mobile mining equipment. The test involved a P&H 4100 BOSS ultra class shovel, which was tested with respect to its loading and ground response on high-grade oil sand. The field test mimicked real conditions while operating a shovel. This test was the first attempt to measure the stiffness of the oil sand environment by using in-place pressure cells and displacement-measurement tools.The model’s average error for deformation prediction for the shovel underfoot test was approximately 5%. The mining-induced confinement during the plate load test and equipment activities using the elastic model using Boussinesq’s approach was estimated. The Boussinesq’s approach provides a reasonable match between the field shovel test and the model’s outcome.     

H5IO6/KI: A New Combination Reagent for Iodination of Aromatic Amines,and Trimethylsilylation of Alcohols and Phenols through in situ Generation of Iodine under Mild Conditions

A simple method for the in situ generation of iodine using H₅IO₆/KI has been developed, and its application in silylation of OH group and iodination of aromatic amines is described.     

Piperazinediium,Zr(IV) and Ce(IV) pyridine-2,6-dicarboxylates: Syntheses,characterizations, crystal structures, ab initio HF,DFT calculations and solution studies

The novel title compounds, (pipzH₂)_1.5(pydcH)₃·3.7H₂O, 1, (pipzH₂)[Zr(pydc)₃]·8H₂O, 2 and (pipzH₂)[Ce(pydc)₃]·8H₂O, 3 in which pydcH₂ is pyridine-2,6-dicarboxylic acid and pipz is piperazine were obtained in aqueous solution. The compounds were characterized by IR, ¹H NMR and ¹³C NMR spectroscopy, elemental analyses, and X-ray crystallography. Compound 1 is resulted from proton transfer between pydcH₂ and pipz. However, compounds 2 and 3 are resulted from complexation of 1 and corresponding metallic salts. Both compounds 2 and 3 contain three pyridine-2,6-dicarboxylate species as tridentate ligands, one piperazinediium as counter ion, and eight-uncoordinated water molecules in the asymmetric unit. In both structures each M(IV) is coordinated in a distorted tricapped trigonal prism geometry by three nitrogen and six oxygen atoms of carboxylate groups of three (pydc)²⁻ fragments. In the crystal structures of 1, 2 and 3, extensive O–H···O, N–H···O and C–H···O hydrogen bonds as well as electrostatic forces, C–H···π, C–O···π and π–π stacking play important roles in stabilizing structures. The geometrical parameters of the [M(pydc)₃]²⁻ anionic complexes, where M = Ce(IV), Zr(IV) have been optimized with the B3LYP method of density functional theory (DFT) and ab initio Hartree–Fock (HF) methods for comparison. In addition, we have studied the structures of (pydc)²⁻ anion and its mono and doubly protonated forms, (pydcH)⁻ and pydcH₂. The electronic properties of the anionic complexes and ligands have been investigated based on the natural bond orbital (NBO) analysis at the B3LYP method which verifies that the synergistic effect has been occurred in the title complexes. In solution study of 2, the stoichiometry and stability constant of complexation of pipz, pydc, pydc–pipz proton transfer system and Zr(IV) ion in aqueous solution were investigated by potentiometric method.     

Highly Selective Perchlorate Membrane Electrode Based on Cobalt(III) Schiff Base as a Neutral Carrier

A highly selective poly(vinyl chloride) (PVC) membrane electrode based on Co(III)-Schiff base [Co(5-NO2- Salen)(PBu3)]ClO4•H2O (where 5-NO2-SalenH＝bis(5-nitrosalycilaldehyde)ethylenediamine) as a new carrier for construction of perchlorate-selective electrode by incorporating the membrane ingredients on the surface of a graphite electrodes has been reported. The proposed electrode possesses a very wide Nernestian potential linear range to perchlorate from 1.0×10－6 to 5.0×10－1 mol•L－1 with a slope of (59.4±0.9) mV per decade of perchlorate concentration with a low detection limit of 5.0×10－7 mol•L－1 and good perchlorate selectivity over the wide variety of other anions. The developed electrode has an especially fast response (＜5 s) and a wide pH independent range (3.0—12.0) in comparison with recent reported electrodes and can be used for at least 2 months without any considerable divergence in their potential response. This electrode was used for the determination of perchlorate in river water, drinking water, sludgy water and human urine with satisfactory results without complicated and time consuming pretreatment.     

A highly efficient and ecofriendly procedure for tetrahydropyranylation of alcohols and phenols in the presence of in-situ generated I2 under heterogeneous and neutral conditions

Abstract  Molecular iodine generated in situ from Fe(NO₃)₃·9H₂O/NaI acts as a highly efficient catalyst for tetrahydropyranylation of various alcohols and phenols with 3,4-dihydro-2H-pyran in almost quantitative yields. The reaction occurs rapidly in dichloromethane at room temperature, and use of toxic molecular iodine is avoided. Graphical Abstract        

Cloud point extraction-preconcentration and flame atomic absorption spectrometric determination of low levels of zinc in water and blood serum samples

A simple, sensitive and selective flotation method is described for the preconcentration and atomic absorption spectrometric determination of zinc ion in water and blood samples. At a solution pH of 5.2, 4-(2-pyridylazo-resorcinol) and Triton X-114 were used as hydrophobic ligand and non-ionic surfactant, respectively. The chemical variables affecting the preconcentration process were optimized. Under the optimized experimental conditions, the selective preconcentration and determination of as low zinc concentration as 6.5 μg L⁻¹ can be made. The proposed method was successfully applied to the preconcentration and low-level determination of zinc in different water and blood serum samples.      

Efficient Synthesis of β‐Acetamido Ketones and Esters Using Aluminum Chloride as an Inexpensive and Green Catalyst

Aluminum chloride (AlCl₃) efficiently catalyzes one‐pot multicomponent condensation of enolizable ketones or alkyl acetoacetates with aldehydes, acetonitrile and acetyl chloride to afford β‐acetamido ketone or ester derivatives in high to excellent yields and in relatively short reaction times. Moreover, by this synthetic method, some novel β‐acetamido ketones and esters (i.e. one complex structure) are prepared.     

Design of ionic liquid 3-methyl-1-sulfonic acid imidazolium nitrate as reagent for the nitration of aromatic compounds by in situ generation of NO(2) in acidic media

3-Methyl-1-sulfonic acid imidazolium nitrate ([Msim]NO(3)) as a new Br?nsted acidic ionic liquid and nitrating agent was prepared and used for the efficient nitration of aromatic compounds (even aniline derivatives). The dramatic effect of this reagent by in situ generation of nitrogen dioxide as a radical on aromatic compounds to give nitroarenes has been studied.     

Solvent‐Free Synthesis of Some New PolyAromatic Hydrocarbons by Diels‐Alder Reaction of Tetracyclone

Diels‐Alder reactions of tetracyclone with various dienophiles under solvent free conditions were studied. In the case of cyclic dienophiles that exhibit more steric hindrance, decarbonylation of [4+2] adducts were carried out.