نشریه کاربرد شیمی در محیط زیست
پیاپی 9 (زمستان 1390)

Heterocycles play a vital role in pharmacological, agricultural and synthetic fields [1]. Particularly these compounds are important because of the wide variety of physiological activities associated with this class of substances [2]. The paramount importance of heterocycles in nature product chemistry and pharmacology constantly drive the search for new methods for the construction of heterocyclic unit viz., isoxazoles and pyrazoles [2]. Isoxazole derivatives are interesting objects for synthesis in the search for various sorts of biological activity and exhibit a wide array of biological activities and many of them have found application in therapy [2]. The immunosuppressive or anti-inflammatory properties are most characteristic among that group of compounds [2] Isoxazoles possess interesting medicinal properties and have some industrial utility [3]. This research work describes the synthesis of new compound of isoxazole family. First 2-bromobenzaldehyde was transformed to 2-bromobenzaldoxime by using NH2OH in pyridine. The in situ generated nitriloxide from reaction between and NaOCl was reacted with propargylalcohol to produce 3-(2- bromophenyl)-5-hydroxymethyl isoxazole in a cycloaddition procedure. The required nitro derivative of the synthesized isoxazole was obtained from nitration of with mixture of nitric acid and sulphuric acid in high yield. The structure of all the synthesized compounds was characterized and confirmed by FT-IR and NMR spectroscopy techniques.

Water is necessary for the life and its important role in the survival of animal and plants are well-informed for everybody. We should responsible for the agents that impact on the quality of drinking water supply. Corrosion of water supply pipelines is one of the major concerns in the management of water distribution and treatment facilities and cause health problems and increases the cost of system maintenance. In this way many of researchers have investigated the methods of determining water potential in the decomposition of water supply installations. Some of the water distribution parts in Tabriz were selected in coordination with water and wastewater company branch in Azarbayjan shargi. Water samples were collected according with procedures issued in water and wastewater analyzing standard methods to determine the corrosion potential of water. The results of water samples analysis shows that average of pH, sulfate, carbonate, chloride, TDS and turbidity were 7.9, 25.9, 0, 149, 529, 1.1, mg/l respectively. Inspection of water distribution network indicated that most of pipelines are made from cast iron and in some reign constructed with polyethylene. Chemical properties of the water were the major reason in the corrosion of water supply network system related to lower level of water hardness. Langelier Saturation index (LSI) was rarely about precipitation range and scaling is occurring in the pipelines. Water scaling causes the corrosion of ducts and an introduction to the beginning of water related health problems due to infiltration of exterior polluted water into the water network. With practical policies it is possible to overcome on this problem and reduce of the water scaling in the Tabriz water distribution system. With proper management principals it is possible to dissolve water quality problems in Tabriz.

Molecularly imprinted polymers are cross linked polymers have selectivity around shape, structure, kind and number of templates molecules. These polymers show stability in different range of pH, temperature and organic solvents. As These polymers application we can mention to their usage as steady solid phase in liquid chromatography, electro chromatography, solid phase extraction and micro solid phase extraction.

The main reason of air pollution in industrial areas such as petrochemical complexes and refineries in Iran is because of improper combustion of fuel in the refinery and petrochemical burners. The most common method for increasing the thermal efficiency of burners is pre-heating of entrance fuel and oxidant of burner. But the main drawback of this method is increasing maximum flame temperature and thus increasing air pollutant emissions. Considering the obvious hazard of nitrous oxides and carbon monoxide in environmental pollution, finding ways to reduce emissions of harmful gases and studying the performance of industrial equipment is important and working on that with proper design and each zone temperature control, redundancy can be harnessed to produce toxic gases. In this study by using computational fluid dynamics of burners the effect of pre-heating the incoming air to a sample burner which is used in refineries has been studied and aims is reaching to answer of this question: Preheating action with regard to environmental pollution is working properly or not. Results by comparing the concentration of species such as CO and NOx are evaluated.

The present work is focused on the catalytic removal of 4-chloro-2-nitrophenol,using catalyst. The used catalyst was zinc oxide. Removal experimental was carried out to optimize the amount of catalyst, effect of 4-chloro-2- nitrophenol concentration, contact time and effect of pH using UV-visible Spectrophotometer technique. The removal rate was strongly influenced by the pH, initial concentrations of 4-chloro-2 nitrophenol and catalyst. The maximum degradation achieved at pH=4, 0.1 g of ZnO and 2mg/L of 4-chloro-2 nitrophenol concentration. The Maximum 38% removal achieved at this conditions. A pseudo second-order kinetic model resulted in the best fit (R2 = 0.985).

The TiO2/UV/O3 process has been employed to remove 4-nitroPhenol (4-NP) and compare to UV/O3, TiO2/O3, TiO2/UV/O2, TiO2 and O3. The deterioration viabilities of all these processes were tested in aqueous solutions. The effects of ozone and catalyst dosage and PH conditions of 4-nitroPhenol(4-NP) solution on the advanced oxidation process (AOP) were investigated. Results showed that the TiO2/UV/O3 is the most efficient process for complete mineralization of 4- nitroPhenol since the combination of photo catalytic oxidation with ozone has a synergistic effect. The relative intensity of DMPO-•OH follows the order of O3 < TiO2 /O3 < UV/O3 < TiO /UV/O2 < TiO2/UV/O3. In TiO2/UV/O3 process, the ozone and catalyst dosage are found to have a significant impact on the process efficiency whereas initial PH has relatively less effect. 4-nitroPhenol is absolutely oxidized to when the ozone dosage in the range of 5-18 mg/min, or the catalyst dosage ranging from 0.2 to 0.5 g/L. 4- nitroPhenol would be further oxidized to ions if the ozone dosage exceeds 24 mg/min, or the catalyst dosage exceeds 2.0g/L.

Typical way to effectively manage the safety risk analysis tools to reduce the risk of accidents will be but the chances never goes some events, the algorithmic approach to quantitative assessment of risk and reduce the risk of accidents due to where it is cost-effective gives And economic analysis, resource optimization is required. The purpose of this study, modeling and risk assessment of emissions of chlorine in water treatment plants to protect people and the environment from the toxic substance is stored. In order to model this process, water treatment plants, located in between Jalalyeh Fatemi Square and Fatemi Square in Tehran is one of the jobs in the city, has been studied.

Reaction of 1,3-dimethyl pyrimidine-(1H,3H,5H)-2,4,6-trione (1,3-dimethyl barbituric acid) with cyanogen bromide and aromatic dialdehydes in the presence of N-methyl Morpholine leads to the selective and efficient formation of a novel class of bifunctionalized linkaged heterocyclic stable bis-spiro[furo[2,3 d]pyrimidine-6,5'- pyrimidine]2,2',4,4',6'(3H,3'H,5H)-pentaones which are dimeric forms of barbiturate (uracil and thiouracil derivatives) at the range of 0°C to ambient temperature. Structure elucidation was carried out by 1H NMR, 13C NMR and FT-IR spectroscopy. A proposed mechanism was discussed for the formation of products.