Classical chemical sciences
The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton’s LDR and LDRS equations. The rate of oxidation of metaand para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation of para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a rate-determining hydride transfer from the aldehyde to the protonated BPSP has been proposed.
Keywords:Permanganate, kinetics, correlation analysis, mechanism, oxidation
Water/n-propanol/sodium dodecyl sulfate/allylbenzene micellar systems were formulated. The ratio (w/w) of n-propanol/surfactant equals 2/1. The extent of the micellar region as function of temperature was determined. The micellar systems were characterized by the volumetric parameters, density, excess volume, ultrasonic velocity and isentropic compressibility. The micellar densities increase with the increase in the water volume fraction. Excess volumes of the sodium dodecyl sulfate decrease for water volume fraction below 0.3, stabilize for water volume fractions between 0.2 and 0.5 then increase for water volume fraction above 0.5. Excess volumes of the studied micellar systems increase with temperature. Ultrasonic velocities increase with the increase in water volume fraction up to 0.8 then decrease. Ultrasonic velocities increase with temperature for water volume fractions below 0.8 and increase for water volume fractions above 0.8. Isentropic compressibilities decrease with the water volume fraction up to 0.8 then increase. Isentropic compressibilities increase with temperature for water volume fractions below 0.8 and decrease for water volume fractions above 0.8. Structural transitions from water-in-oil to bicontineous to oil-in-water occur along the micellar phase. The particle hydrodynamic diameter of the oil-in-water micellar systems was found to decrease with temperature. In the diluted region nanoemulsion systems were observed.
Keywords:phase behavior, ultrasonic velocity, density, isentropic compressibility, hydrodynamic diameter
Materials and environmental chemistry
Tabas coalfield is one of the most important coalfields in Central Iran. The area is located in the central desert of Iran, very far from any inhabited areas. Mazino is the largest thermal coal deposit in Tabas coalfield. Coal-bearing strata in Tabas coalfield (as well as in Mazino deposit) are within the Middle Jurassic formations. This sedimentation has been developed in alluvial plain and coastal environment in Tabas coalfield. The coal-bearing sediments mainly consist of sandstone, shale, siltstone, and carbonatic rocks. Several coal seams with different thickness are interbedded with these sediments. Petrographic observations have shown that coals of the Mazino deposit are mainly anthracite to semi-anthracite and dominated by macerals of the vitrinite group; amounts of inertinite macerals are relatively very low. The dominant mineral phases of these coals are pyrite, siderite, calcite, gypsum, illite, and clays. The Mazino coals have high ash (average of 27.78%), low volatile matter (average of 5.2%), and high sulphur (average of 2.62%) content, and high calorific value with average of 22.94 MJ/Kg. The chemical composition shows that the Mazino coals range from semi-anthracite to anthracite (thermal coal), which are suitable as power-plant fuels with low chemical hazards to environment in the area.
Keywords:Coal composition, Tabas coalfield, Central Iran
Many researchers have studied aggregation of microgel particles; however, the majority of these studies have been limited to singlecomponent system in which homoaggregation is observed. On the other hand, less attention has been given to multi-component systems whereby heteroaggregation is seen. As such, heteroaggregation is not only important in various applications but is interesting from a fundamental point of view. In such a way, aggregation is driven not only by attractive electrostatic interactions, but also the presence of repulsive forces. Therefore this review discussed on the theoretical background, external effects on heteroaggregation and their potential applications.
Keywords:homoaggregation, heteroaggregation, particles, microgels, external effects
Textile industry is the largest number compared to other industries in Tamil Nadu. In spite of the continuous efforts to prevent water pollution from these industries, solving of the high total dissolved solids (5000-10000 mg L-1) in the effluent is not yet successfully done. India, being the tropical country, solar radiation is available in plenty during most of the year, enables the industries to use the solar evaporation ponds as a simple and economical treatment system. An experimental textile effluent evaporation tank made by natural black colored stone is developed. It showed excellent results of evaporation utilizing solar energy. The usage of overall pond depth of 17.5 cm and an initial liquid depth ranging from 5 cm to 15 cm depending upon the season with a salt removal period ranging from 5 to 6 days will make the solar evaporation pond an effective system for the recovery of the dissolved salts. Data have been collected, allowing us to know the mean evaporation to be expected in the region of Tamil Nadu, India. A solar wastewater treatment system is proposed for textile industry from this, which leads to possible recycling of chemicals and water by using solar evaporation. Calculation shows that the proposed system is quite competitive with conventional coagulation in the range of small textile effluent treatment installations.
Keywords:Effluent Treatment, Effluent, dyestuff, solar evaporation, zero liquid discharge
The inhibition efficiency (IE) of various concentrations of a TSC- Zn2+ system in controlling corrosion of mild steel immersed in well water was evaluated by a weight-loss study. The formulation consisting of 50 ppm of TSC and 25 ppm of Zn2+ showed 70% inhibition efficiency. A synergistic effect was noticed between trisodium citrate - Zn2+ system. In the presence of Zn2+ TSC has excellent inhibition efficiency. Polarization studies reveal that TSC - Zn2+ function as a mixed inhibitor. AC impedance spectra suggest that a protective film is formed on the metal surface. FTIR spectra reveal that the protective film consists of Fe2+ - TSC complex and Zn(OH)2. SEM micrographs and AFM reveals that a protective film is formed on the metal surface
Keywords:Corrosion inhibition, Carbon steel; Trisodium citrate; Synergistic effect
Waste materials such as coal fly ash generated from power plant in India and environmental threat causing plant such as Prosopis juliflora has been converted into a cheap potential adsorbent. This has been characterized and utilized for the removal of chromium, lead, zinc and copper from synthetic and actual wastewater. The sorption efficiency decreases with increase in pH. Adsorption of chromium, lead, copper and zinc on Coal Fly ash (CFA) and Prosopis Juliflora Carbon (PJC) individually and 50:50 mixture of CFA and PJC follows the Freundlich adsorption isotherm and these have been used to obtain the thermodynamic parameters of the process. The sorption capacity of these adsorbents for the heavy metal removal is found to be better alternative comparable to other low cost adsorbents.
Keywords:Adsorption, heavy metal, fly ash, effluent treatment
Industrial and engineering chemistry
Using n-butenes and water as feedstocks and molecular sieves as catalysts, effects of the reaction temperature, the reaction pressure, the weight hour space velocity (WHSV), and the ratio of water to n-butenes on the conversion of n-butenes were studied. The experimental results showed that the optimal reaction temperature, the pressure, the WHSV, and the ratio of water to n-butenes were 180 °C, 8.0 MPa, 0.2 h-1, and 8, respectively; the single conversion of n-butenes and the selectivity of 2-butanol formation were found to be 35.52% and 99%, respectively.
Keywords:sec-butanol; molecular sieve; synthesis; n-butenes; reaction condition
Resources and utilization of C2 compounds in China has been reviewed. Transformations of bioethanol feedstock into ethylene, acetylene and ethylene feedstocks into chloroethylene, and ethylene feedstock into ethylene oxide have been discussed, and effects of these processes on the energy utilization and environmental damage have been evaluated. The viewpoints of economic or social benefits have also been discussed.
Keywords:economic benefits; C2 utilization; ethylene production from bioethanol; chloroethylene production
The contribution of shale oil as raw material to the mineral oil processing industry has been increased due to the worldwide energy demand. This review article discusses the principles of shale oil processing using rotary dry distillation boilers and the practical applicability of shale oil. The complete utilization of oil shale sources results in good economic and social benefits.
Keywords:oil shale; shale oil; utilization; overview; processing, recovery of rare earth metals