The aminolytic depolymerization of PET bottle waste with ethanolamine by conventional heating and microwave irradiation heating method was attempted with heterogeneous, recyclable acid catalysts such as beta zeolite (SiO2/ AlO2= 15 Na- form) and montmorillonite KSF. The pure product bis-(2-hydroxyethyl) terephthalamide (BHETA) of aminolysis was obtained in good yield (85- 88%). The BHETA, thus obtained, was subjected to cyclization reaction by heating with polyphosphoric acid as well as by chlorination (using phosphoryl chloride), bromination (using red phosphorous and liquid bromine) and nitration (conc. HNO3 + conc. H2SO4) followed by conventional and microwave irradiation heating in N,N- dimethyl formamide/ potassium carbonate solution. The product so obtained was 2, 2’-(1,4-phenylene)–bis-(2-oxazoline) (PBO), which has applications in polymer synthesis as a chain extender/ chain coupling agent or a cross linker. The productswere analyzed by FTIR, DSC, Mass and NMR (1H and 13C NMR).
A microwave-assisted method was developed for the synthesis of aldol adducts using RuCl3.nH2O-BINAP as an efficient catalyst. Important advantages of this technology include environmentally benign condition, highly accelerated rate of the reaction with an improvement in the chemoselectivity and quality of the products.
A new analytical approach was proposed to monitor the reaction between epoxidized soybean oil and diethylene glycol in the presence of ZnCl2 as an epoxide ring opening catalyst for microwave assisted synthesis of polyol. Infrared spectra of the products were used as the input data, being processed by multivariate curve resolution – alternating least squares (MCR-ALS) for quantitative monitoring. The data obtained in different MW powers were analyzed by MCR factor analysis coupled with ALS optimization procedure. Standard deviation of residuals for experimental data and the variance explained at the optimum condition (r2) were 0.135 and 97.24% respectively.
Novel 4-(1-(4-(4-(4-aminophenyl)-1H-pyrazol-1-yl)-6-(4-(diethylamino)phenyl)-1,3,5-triazin-2-yl)-1H-pyrazol-4-yl)benzenamine fluorescent dye was synthesized by multistep synthesis from cyanuric chloride and phenyl acetonitrile. It has absorption at 360 nm with single emission at 497 nm having fairly good quantum yield (0.379). The intermediates and the dye were characterized by FT-IR, 1H NMR, 13C NMR and Mass spectral analysis. Its utility as biocompatible fluorescent dye was explained by conjugation with bovine serum albumin. The method is based on direct fluorescence detection of fluorophore labelled protein before and after conjugation. Purified fluorescent conjugates were subsequently analyzed by fluorimetry. The analysis showed that the tested conjugation reaction yielded fluorescent conjugates of the dye through carbodiimide chemistry.
In this study, flooring grade epoxy/nanoSiO2 nanocomposites were prepared by in-situ polymerization method. Nano silica was treated by coupling agent in order to surface treating and introducing of reactive functional groups to achieving adequate bonding between polar inorganic nano particles and epoxy organic polymer. ?-Aminopropyltriethoxysilane (Amino A-100) was used as an effective and commercially available coupling agent and nano silica treated in acetone media. SEM observations of cured samples revealed that the nano silica was completely dispersed into polymer matrix into nanoscale particles. Thermal and physical properties of prepared samples were investigated and data showed improvements in physical and mechanical properties of the flooring samples in comparison with unfilled resin.
An efficient and practical, three-component one-pot condensation reaction between 1, 2-phenylenediamine, 2-mercaptoacetic acid and aromatic aldehydes in ionic liquids have been reported for the synthesis of 1-aryl-1H, 3H-thiazolo [3, 4-a] benzimidazoles derivatives in excellent yields.
A simple and economic synthesis of 3,4-dihydropyrimidin-2(1H)-ones using pyridinium triflate as catalyst under microwave condition was attempted with an easy work-up protocol. Further tetrazolo [1,5-a] pyrimidine-6-carboxylates were synthesized by three-component coupling reaction of B-ketoesters with a mixture of aromatic aldehyde and 5-aminotetrazole. The products were well characterized with IR, NMR (1H and 13C NMR) and mass spectrometry.
In this paper complexation reaction between Yb3+ and Human serum albumin is examined using isothermal titration calorimetry (ITC). The extended solvation model was used to reproduce the enthalpies of HAS+Yb3+ interactions over the whole range of Yb3+ concentrations. The binding parameters recovered from this model were attributed to the structural change of HSA. The results show that Yb3+ ions bind to HSA with three equivalent affinity sites. It was found that in the high concentrations of the ytterbium ions, the HSA structure was destabilized.
The interaction of Jack Bean Urease with cobalt (II) ion was studied by Isothermal Titration Calorimetry (ITC) at 300 K and 310 K in 30 mM Tris buffer, pH=7. The stability of the enzyme increases due to its binding with cobalt ions. The extended solvation model was used to reproduce the heats of Co2++JBU interaction. It was found that there is a set of 12 equivalent and noninteracting binding sites for Co2+ ions. The association equilibrium constant and the molar enthalpy of binding are 4260.76M-1, -16.5 kJmol-1 at 300 K and 3438M-1, -16 kJmol-1 at 310 K, respectively.
A series of novel metal complexes containing metal atoms such as Zn, Co, Cu, Cd, Ni, Mg and Sn have been synthesized from 3-(1,3-benzoxazol-2-yl)naphthalen-2-ol. The synthesized ligand was well characterized by IR, 1H-NMR and mass spectrometry. The electrochemical properties were studied by cyclic voltammetric analysis. The synthesized complexes are fluorescent and absorb in the range of 317 to 323 nm while emit in the range of 371 to 416 nm with good quantum yield. All metal complexes show significant in vitro antibacterial activity against E. coli and S. aureus strains and in vitro antifungal activity against C. albicans and A. niger strains by using serial dilution method. The antibacterial activities were expressed as the minimum inhibitory concentration (MIC) in ?g/mL.