Applied Chemistry

The resin SHMF has been synthesized by the condensation of salicylicacid and hexamethylenediamine with formaldehyde and hydrochloric acid as catalyst. Thermal degradation curve has been discussed which shows four decomposition steps and detailed thermal degradation studies of the resin have been carried out to ascertain its thermal stability. Sharp–Wentworth and Freeman–Carroll methods have been used to calculate activation energies and thermal stability. The activation energy (Ea) calculated by using the Sharp–Wentworth (17.86 kJ/mol) has been found to be in good agreement with that calculated by Freeman–Carroll (18.96 kJ/mol) method. Thermodynamic parameters such as free energy change (?F), entropy change (?S), apparent entropy change (S*) and frequency factor (Z) have also been evaluated on the basis of the data of Freeman–Carroll method. The order of reaction (n) is found out to be 0.99. Electrical conductivity measurements have been also conceded to ascertain the semiconducting nature of the resin.

The synthesis of non-electrolyte mixed-ligand complexes of the general formula [M(Hdmg)B], Ni(II), Hdmg=dimethylgloximato monoanion, B=2-aminophenol(2-aph), diethylamine (dea) or malonic acid (MOH) has been synthesized and characterized. However theoretical calculations were carried out to obtain the geometric and thermodynamic parameters, vibrational and electronic parameters, dipole moments and HOMO-LUMO band gaps of the complex with different substituents. These properties were obtained using the PM3 and DFT with B3LYP at 6-31G* level. Comparisons were made on the calculated bond length, bond angle, dihedrals and vibrational frequencies and it was observed that the calculated data are in good agreement with experimental data.

In the present study, we report a theoretical study on molecular structure, electronic and thermodynamical properties of 2-amino-1,3-benzothiazole tautomers by using density functional theory (DFT) methods employing B3LYP exchange correlation with different basis;6-311,6-311++, and 6-311++G(d,p) basis set. The Synchronous Transit-Guided Quasi-Newton (STQN) method was used to locate the transition structures. The reactants and products were fully optimized at the DFT level of theory using 6-311++G (d,P) basis set in gas phase and the equilibrium constant and rate of reaction were calculated. Global descriptors such as ionization energy (I), electron affinity (EA), molecular hardness (?), chemical potential (?), electrophilicity (?), and frontier molecular energy gaps (?Eg) were determined and used to identify the differences in the reactivity of reactant and product. The bond lengths of transition state were lie between the reactant and product. From the values of ?, ? and ? suggested that product is more energetically stable and less reactive, that reactant is more electronegative than the product and reactant is a good electrophile and product is a good nucleophile.

In the present student, Sudan Orange G (SOG) [4-(Phenylazo)resorcinol] derivatives have been studied at Density Functional theory (TD-DFT) at B3LYP level of theory with 6-31G(d) basis set. Different substituent groups were introduced in different position to investigate their effects on the electronic and optical properties. The HOMO and LUMO energies and the energy gap (Egap) between HOMO and LUMO of the studied dyes were calculated. The light harvesting efficiency (LHE), the open-circuit voltage (Voc) and injection driving force (?Ginject) which are the key parameters related to the solar cell efficiency (?) were computed. The LHE values for the dyes are in different ranges and that all the dyes will give different photocurrent. The D6 dye has highest oscillator strength value 1.1263 and the LHE value is 0.925235. So the D6 dye has more efficiency than other studied dyes. Based on the values, the meta substituent dyes are better sensitizers compare to other dyes.

The elastic properties of mantle minerals are important for the interpretation of the structure and composition of the lower mantle and also in seismic studies. The elastic properties of minerals depend on its composition, crystal structure, temperature and the level of defect. In the present work we have calculated the elastic parameters such as bulk modulus, shear modulus, seismic velocities, and Debye temperatures of some garnets such as Pyrope garnet (Mg3Al2Si3O12) and Grossular garnet (Ca3Al2Si3O12) at different temperature ranges by using Hill's averaging method and other methods of thermodynamics.

The validity of equation-of-state (EOS) of geophysical minerals is very important for various scientific fields including geophysics, material science and high-pressure physics. In the present work we have calculated pressure , isothermal bulk modulus , first pressure derivative of isothermal bulk modulus and second order pressure derivative of isothermal bulk modulus in terms of for MgO and Al2O3, using different equation of state. Using the values of these parameters we have computed the values of Gruneisen parameter ( ) corresponding to different values of V/V0 and graphs are plotted for Gruneisen parameter ( ) vs. v/v0 for MgO and Al2O3. From these plots it is clear that the Brennan-Stacey and Shanker EOS is compatible both low and high compression ranges for calculating Gruniesen parameter where as Vinet EOS is not compatible for calculating the Gruniesen parameter at low compression ranges.

Ultrasonic velocities and densities of the binary liquid mixtures of o-chlorophenol with o-xylene, p-xylene and o-chlorotoulene have been measured over the entire composition range of mole fractions at a temperature range from 303.15 to 318.15 K with an interval of 5 K. The theoretical values of ultrasonic velocity were evaluated by using Nomoto (NOM), Impedance (IMP), Van Deal and Vangeel (VDV), Junjie (JUN), Rao’s specific velocity (RAO) models. The results were discussed in terms of non-ideality in the mixtures, molecular interaction parameter, Relative deviation ? and Chi-square (?2) test for the goodness of the fit is applied to understand the applicability of these theories to the present systems.

Ultrasonic velocities, viscosities and densities of binary liquid mixtures containing dimethyl carbonate and cresols (ortho, meta and para) have been measured at temperatures T= (303.15, 308.15, 313.15 and 318.15) K over the entire mole fraction range of dimethyl carbonate. The theoretical values of ultrasonic velocity were evaluated using Nomoto’s relation (UNR), impedance relation (UIR), ideal mixing relation (UIMR), Jungie’s relation (UJR), and Rao’s specific velocity relation(UR).The molecular interaction parameter (?) has been evaluated from the values of experimental and theoretical velocities. The experimental data of viscosity is used to test the applicability of semi empirical relations of various viscosity models like Grunberg–Nissan, Katti–Chaudhri, Heric–Brewer and Hind et al. for the systems studied. On the basis of the values of interaction parameters (d) of these viscosity models and interaction parameter (?) obtained from various velocity models ,the nature of molecular interactions between the components of mixtures have been explained.

Chemical industries are continuously faced with increasing challenges of safety requirements in plant design and operation. Consequently, more and more attention has been focused on developing greener, safer and efficient chemical processes employing process intensifying methodologies and equipment. While engineered safety devices can be added on to a plant as risk mitigation measures, safety is most reliably ensured by developing inherently safer techniques. This paper reviewed some of the process intensification approaches that could be utilized by chemical industries to improve inherent safety in plant design and operation protocols. Although the potentials of the techniques described in this review for intensification of chemical processing have already been proven in the laboratories, however their application on the industrial scale still presents a difficult challenge.

The physiochemical properties of the leaf extract of four Nigeria medicinal plants were investigated in order to ascertain their level of safety for human consumption. The results obtained from the analysis show a range of temperature 25.50 + 0.003 , 26.00+0.0020C, as against 30.000C obtained for the water used for the extraction, pH range 5.50+0.003 - 8.0+0.002. All the other extracts showed greenish coloration except Eremomastex polysperman extract that appears bluish purple. Electrical conductivity 24.00+0.012-145.20+ 0.053uscm-1. Suspended solid ranged between 1.60+0.001-3.60+0.008, dissolved solid 12.00+0.003-98.20+0.005, titratable alkalinity and acidity ranged 25.34+0.003-500.00+0.0012 and 40.44+0.005-900.00+0.128mg/l respectively. Biochemical oxygen demand BOD and dissolved oxygen DO values ranged 118.00+0.008-360.00+0.025 and 1.26+0.007-1.50+0.008 respectively. Total hardness ranged from 31.61+0.012 to 48.00+0.015. Finally sulphate, nitrate and chlorides values ranged within 2.10+0.003-24.20+0.004, 2.10+0.005-4.32+0.005 and 30.74+0.025-309.41+0.043 (mg/l). Respectively. The extraction of these leaves in water has strongly altered the entire physiochemical parameter of drinkable water. These variations does not show any definite correlation. However when compared with the WHO permissible level despite the variations over 85% of the values were within the permissible limits. Thus these extract may not pose any danger with respect to physicochemical properties except for acidity. Thus one may apply caution when consuming these extract.