Classical and Advanced Chemical Sciences
Two new schiff bases (E)-(4-chlorophenyl)-(4-chlorobenzylidene)acetohydrazide and (E)-(4-chlorophenyl)-(1-methoxynaphthalen-2- ylmethylene)acetohydrazide and their metal complexes were synthesized. All of the synthesized imines and their metal complexes were characterized and screened for antimicrobial activity.
Keywords: Imines, metal complexes & microbial activity
Nanosized coordination polymers of Co(II), Ni(II), Cu(II) and Cd(II) of mixed ligand derived from 5-(3-pyridyl)-1,3,4-oxadiazole-2-thiole (POZT) and 2-aminothiazole (AZ) were synthesized. The compounds were characterized by elemental analysis, IR and electronic spectral studies. Thermogravimetry (TG), derivative thermogravimetry (DTG) and differential thermal analysis (DTA) have been used to study the thermal decomposition steps of the compounds and to calculate the thermodynamic parameters of the nanosized metal coordination polymers. The kinetic parameters have been calculated making use of the Coats-Redfern and Horowitz-Metzger equations. The scanning electron microscope SEM photographs and particle size calculations from the powder XRD data indicate the nano-sized nature of four compounds prepared under ultrasonic irradiation (average size 23-60 nm). The antimicrobial activity of the synthesized compounds was tested against six fungal and five bacterial strains. The majority of compounds were effective against the tested microbes.
Keywords: Coordination polymers; nanoparticles; SEM; XRD; thermal studies
A new mefenamic acid derivative, (4-amino-5-(2-(2,3-dimethylphenyl)aminophenyl)-1,2,4-triazole-3-thion (L), has been synthesized and characterized by spectroscopic and elemental analysis. The ligand (L) has been used as a chelating agent to prepare complexes of Co(ІІ), Ni(П), Cu(П), Zn(II) and Cd(II) ions. The structure of the complexes, in solid state, has been suggested. The theoretical treatment of the complexes, in the gas phase, has been studied using the Hyperchem-8 program for the molecular mechanics and semi-empirical calculations. The heat of formation (ΔHf○) and binding energy (ΔEb) for the ligand and their complexes were calculated by PM3 method. The electrostatic potential of the ligand (L) has been calculated to investigate the reactive sites of the molecule. Photostabilization of PVC film in air was investigated in the absence and presence of the ligand L and theirs complexes by accelerated weathering tester. It was found that various indices values increased with irradiation time and this increase depend on the type of additives.
Keywords: Triazole; photochemistry; mefenamic acid metal complexes; UV light; photostabilization; semi-empirical calculations
Materials and Environmental Chemistry
The purple pigment that is used in colouring molten glass and porcelain known as Purple of Cassius discovered in the 17th century was found by Richard Zsigmondy in 1897 to consist of nano gold with stannic oxide. The preparation of this material involves gold being dissolved in aqua regia, then reacted with a solution of tin(II) chloride. The tin(II) chloride reduces the dissolved gold to elemental gold supported on tin dioxide to give a purple precipitate which is thermally stable and is used as a pigment to give purple colour to glass and porcelain.
Keywords: Zsigmondy; Stannous chloride; Aqua Regia; Swedish chemists; Thomas Graham; Ultramicroscope
Industrial and Engineering Chemistry, Biotechnology
The possibility of gold extraction from the concentrate obtained by secondary enrichment of flotation tails of Madneuli gold-containing barite-polymetallic ore has been studied. Such concentrate contains the gold in the mineral in finely-impregnated form and is considered as difficult-to-process material. It was shown that by the use of Fe2(SO4)3 as an oxidizer in thiourea acidic solution, the concentrate preliminary milling and roasting at 400 0C is necessary for the 90 % extraction of gold. By electrochemical method, the 90 % extraction is reached at the system “soft” oxidation in the conditions of Red/Ox potential of 0.4 V in temperature range of 25-35 0C.
Keywords: Electrochemical processing; gold-containing ores; flotation tails; barite-polymetallic
The aim of work is process optimization of a milling plant in order to minimize sucrose loss with final bagasse as another option. The experiment was carried out with design expert software. By identifying main factors i.e. imbibitions of water and hydraulic pressure effect on response variable i. e percentage sucrose in bagasse, it was applied to the process optimization in order to get the optimum process condition in which the sucrose loss is minimum. This is achieved at maximum imbibitions of water (62.6 m3 h-1) and maximum hydraulic pressure (110 kg cm-2). Under these optimum conditions, the minimum sucrose in bagasse is 3.4 % unit. This results in sucrose saving of 0.04 ton h-1.
Keywords: Boiling, crystallizer, economical, Massecuite, purity
Theoretical and Computational Chemistry
Previous tribochemical studies showed that the high activation energy of reactions between solids covered by mechanical energy has not exclusively be thermally origined as that had been adopted formerly. For studying of tribochemical elemental effects, some theoretical considerations of combination atomic force microscope (AFM) and scanning tunneling microscope (STM) techniques using one dual tip cantilever have been discussed to develop a solid baseto make experimental setup called Tandem Nanoscope.
Keywords: tribochemistry, nanoscope, SPM, AFM, STM
The notion of spatial-energy parameter (P-parameter) is introduced based on the modified Lagrangian equation for relative motion of two interacting material points, and is a complex characteristic of important atomic values responsible for interatomic interactions and having the direct connection with electron density inside an atom. Wave properties of P-parameter are found, its wave equation having a formal analogy with the equation of -function is given. With the help of P-parameter technique, numerous calculations of exchange structural interactions have been performed and the applicability of the model for the evaluation of the intensity of fundamental interactions has been demonstrated. Initial theses of quark screw model are also discussed.
Keywords: Lagrangian equations; wave functions; spatial-energy parameter; electron density; elementary particles; quarks