Dimethylsulphoxide Complexes of Vanadium(III)

Dimethylsulphaxide(DMSO) compkxsalts of vanadium(IIl) with theemfrincalformulae VCI,. 6DMSOand VBr,. 6DMSO were synthesized and investigated. The observed infra-red band positions of the v(S.O) stretch indicate that the ligand is coordinated to ·vanadium ion via oxygen. Far-infra-l-ed spectra lead to the conclusion that no-1U of the halide ions are eoen·dinated to the metal ion. Diffuse reflectance spectra are consistent with vanadium in an octahedral environment. Accordingly, the chlarideand bromide salts areformulated as [V(DMSO)jCI, and [V[DMSOljBrp respectivel

Adsorption enhancement of Pb(II) Ion in the presence of Nicotinic Acid during Cyclic Voltammetry.

The solution phase voltammetry employed in the study of metal ion interaction with a selected ligand. Voltammetry behaviours of lead (II) ion in the presence of ligand with N-heterocycle compounds, such as nicotinic acid (pyridine-3-carboxylic acid) were being studied using cyclic voltammetry (CV) on a hanging dropping mercury electrode (HDME). Assessment of the chemical and physical conditions that may favour optimum current enhancement was done by studying the effect of varying pH, concentration of metal ion and scan rate. It was found that in presence nicotinic acid (NA) result in a shift in peak potential (Ep) and peak current (Ip) in the determination of Pb(II). The addition of 1 x 10-2 M nicotinic acid in 0.1 M potassium chloride at pH 4.0 and scan rate of 100 mV/s in CV was required for optimum current enhancement to be observed by about 4.9 fold and 1.6 fold in oxidation and reduction current of Pb(II) respectively. Based on chronocoulometry and chronoamperometry technique the diffusion for Pb(II) were estimated by 9.18 x 10-6 cm2/s and 5.0 μc/cm2 respectively. The procedure was successfully applied to the simultaneous determination of Pb(II) ion in some real samples

Novel manganese(II) - based deep eutectic solvents: synthesis and physical properties analysis

Type IV deep eutectic solvent (DES) involves the formation of metal-based eutectics from metal salts or metal salt hydrate in combination with various hydrogen-bond donors (HBDs) such as urea, ethylene glycol or acetamide. In current study, two distinguished approaches were used to synthesize potential DESs, given as the direct heating and the evaporating methods. Successful synthesized DESs were subjected for physical properties characterization by Fourier Transform Infrared (FTIR) Spectroscopy, thermal stability, viscosity, and conductivity analyses. Five novel manganese (II)-based DESs were successfully synthesized as reported in this study. Data obtained indicated that the MnCl2·4H2O·acetamide DES exhibits the lowest freezing point (27.5 °C), highest thermal stability (193 °C point of dehydration), lowest viscosity (ŋ = 112.8 cP) and the highest conductivity (0.12723 mS/cm). The findings obtained reveal the characteristics, nature or features of synthesized DESs as potential industrial solvents

Synthesis of ferric-manganese doped tungstated zirconia nanoparticles as heterogeneous solid superacid catalyst for biodiesel production from waste cooking oil

The solid superacid catalyst ferric-manganese doped tungstated zirconia (FMWZ) nanoparticles was prepared by impregnation reaction followed by calcination at 600°C for 3 hr and had been characterized by X-ray diffraction (XRD), thermal gravimetric analysis (TGA), temperature programmed desorption of NH3 (TPD-NH3), X-ray fluorescence (XRF), transmission electron microscopy (TEM), and Brunner-Emmett-Teller (BET) surface area measurement. The transesterification reaction was used to determine the optimum conditions of methanolysis of waste cooking oil with FMWZ nanoparticles as heterogeneous solid superacid catalyst. The reactions variables such as reaction temperatures, catalyst loading, molar ratio of methanol/oil and reusability were also assessed which effects the waste cooking oil methyl esters (WCOME’s) production yield. The catalyst was reused ten times without any loss in activity and maximum yield of 96% was achieved at the optimized conditions of reaction temperature of 200°C; stirring speed of 600 rpm, 1:25 molar ratio of oil to alcohol and 4% w/w catalyst loading. The fuel properties of the WCOME’s were discussed in light of ASTM D6751 biodiesel standard

Production of biodiesel from mixed waste vegetable oils using Ferric hydrogen sulphate as an effective reusable heterogeneous solid acid catalyst

Biodiesel production by simultaneous esterification and transesterification of waste oil with methanol has been studied in a heterogeneous system using solid ferric hydrogen sulphate [Fe (HSO4)3] acid catalyst. The catalyst was prepared by displacement reaction followed by calcination at 400 °C for 3 h. The prepared catalyst was characterized using X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), Brunner-Emmett-Teller surface area measurement (BET), thermal gravimetric analyzer (TGA) and temperature-programmed desorption of NH3 (TPD - NH3). Furthermore, the dependence of the conversion of mixed waste oil on the reactions variables such as the molar ratio of methanol/oil, the amount of catalysts used, reaction temperatures, reusability were also investigated. The catalyst was reused many times with slight loss in activity and the maximum yield of 94.5% was achieved at the optimized conditions of reaction temperature of 205 °C; stirring speed of 350 rpm, 1:15 molar ratio of oil to alcohol and 1% w/w catalyst loading

Tetra­ethyl­ammonium l-tartarate dihydrate

In the crystal structure of the title compound, C8H20N+·C4H5O6 −·2H2O, the ions and water mol­ecules are linked via O—H⋯O and C—H⋯O hydrogen bonds, forming a two-dimensional network parallel to (001)

Tetra­ethyl­ammonium l-malate 1.36-hydrate

The asymmetric unit of the title compound, C8H20N+·C4H5O5 −·1.36H2O, contains two independent ion pairs, with similar conformations, and three water mol­ecules of crystallization, one water mol­ecule haing a site-occupancy factor of 0.721 (5). Intra­molecular O—H⋯O hydrogen bonds, involving the hydr­oxy groups and an O atom of each carboxyl­ate anion, generate five-membered rings involving S(5) ring motifs. In the crystal structure, mol­ecules are linked together by water mol­ecules through four-membered O—H⋯O—H⋯O—H inter­actions to form one-dimensional infinite chains along the a axis. Since the mol­ecules are also linked into one-dimensional infinite chains along the b axis, mol­ecular sheets parallel to the (001) plane are created. Overall, the crystal structure is stabilized by two intra­molecular O—H⋯O hydrogen bonds, nine inter­molecular O—H⋯O and ten C—H⋯O hydrogen bonds

Structure, vibrational and electronic spectra, and bonding in trans-diaquabis(oxalato)vanadate(III) complex salts, A[V(ox)2(H2O)2]·xH2O (A = Cs, K, or NH3Me), and the X-ray crystal structure of the potassium salt (x= 3)

The X-ray crystal structure of potassium diaquabis(oxalato)vanadate(III), K[V(ox)₂(H₂0)2].3H₂0, has been determined [monoclinic, space group P2/c, with unit-cell parameters a = 7.971 (4), b = 5.691 (2), c = 14.167(5) A, β = 108.97(3)", and Z = 2]. The structure has been refined to an R value of 0.032 using 560 independent reflections. In comparison with the corresponding Cs⁺ and NH₃Me⁺ salts, the K⁺ salt exhibits a significantly longer bond distance for axially co-ordinated water and this is manifested in band shifts of 500-1 000 cm ⁻¹ in the visible region. For all three salts vibrational spectra and single-crystal polarised electronic spectra are reported together with assignments. Analysis of the ligand-field spectra is presented in terms of the angular overlap model. It is shown that the band shifts occurring in the electronic spectrum of the K⁺ salt can be reproduced by a reduction in the cr-bonding capacity of the co-ordinated water together with a slight increase in the c bonding of the oxalate ligand, both of which areconsistent with structural differences existing between the K⁺ and the other two salts. Significant anisotropy exists in the metal- oxalate IT interaction with the in-plane contribution relatively small. In addition, anomalous temperature-dependent bands resulting from vibronic coupling with internal O-H stretching vibrations are present in the electronic spectra of both the Cs⁺and NH₂Me⁺ salt