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Search Results: 1 - 10 of 126 matches for " Chlorination "
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A New Facile Route to Chlorination of Alcohols via Lewis Acid AlCl3  [PDF]
Hengchang Ma, Zhikang Bao, Lianhua Bai, Wei Cao
International Journal of Organic Chemistry (IJOC) , 2012, DOI: 10.4236/ijoc.2012.21004
Abstract: Halogenated aluminates AlCl3, applied as efficient chlorination reagent for hydroxyl groups of substitution alcohols is described. Primary and secondary benzylic alcohols could be transformed into corresponding aromatic halides with almost complete conversion and unique selectivity. As chlorination reagent, AlCl3 has an incomparable advantage over others, such as low material cost, commercial availability as well as convenient product isolation.
Disinfection Water Wells and Sterilization  [PDF]
Mehaysen Ahmed Mahasneh
Computational Water, Energy, and Environmental Engineering (CWEEE) , 2016, DOI: 10.4236/cweee.2016.52004
Abstract: Disinfection is an important step in ensuring that water is safe to drink. Well disinfection is used to inactivate or control bacteria populations in a well and the distribution system. Disinfection is the inactivation or destruction of pathogenic organisms through the disruption of the organisms’ normal life processes. The objective of this work is to clean and/or disinfect entire borehole to prepare wells for pump installation. The last water sample was collected after the well disinfec-tion on that time. The results of water chemical analysis are presented in Tables 2-4, and there was nothing found against the specification requirements. After a reaction time of approximately 12 h, the well was cleaned from the sterilization solution by airlifting until chlorine concentration in the water reached 0 mg/l. Then through analyzing the test for samples of water after disinfection and sterilization the wells showed the Iron Bacteria were not seen and the Bacteria Species/Anaerobic Bacteria were absent.
Levels of Trihalomethanes in Stored Water from High and Fundamental Schools: Comparison between Two Temporal Data Sets  [PDF]
Ricardo Andreola, Anny Rosi Mannigel, Graciene de Souza Bido, Thaise Moser Teixeira, Edison Schmidt Filho, Jussara Ricardo de Oliveira, André Ribeiro da Costa, Rebecca Manesco Paix?o
Journal of Water Resource and Protection (JWARP) , 2018, DOI: 10.4236/jwarp.2018.106032
Abstract: Epidemiological studies have been investigating the relationship between chlorination byproducts exposure and cancer. Studies showed the incidence of colon, rectum and bladder cancer in laboratory animals when halogenated byproducts were administered to them, such as trihalomethanes. Based on this fact, in this work, two data sets of water quality parameters were analyzed with focus on total trihalomethanes (THMt). These two data sets are from two different time periods (one in 2014 and other in 2017). All the samples were collected in the same months, in both data sets. The samples were taken from its same corresponding sampling points in both periods of time. Trihalomethanes (THMs) are undesired byproducts of chlorination and its formation occurs when the chlorine used in water treatment reacts with natural organic matter, which is present in natural waters, during the disinfection process. The aim of this research was to investigate the THMs levels in storage water from the chlorination performed by the Water Treatment Station (WTS) of the Maringá-Parana-Brazil; also, to compare the results obtained with the maximum allowable values (MAVs) established by the Consolidation Resolution n.05/2017, current law of water quality in Brazil. Water samples were collected in eight high and fundamental schools of Maringá-Paraná-Brazil and analyzed through the gas chromatography method by the use of mass spectrometry detector with purge-and-trap concentrator (GC-MS) for THM. Furthermore, parameters such as pH and residual chlorine were analyzed following the methodology proposed by the Standard Methods for the Examination of Water and Wastewater. The study results to THMt show that the maximum value of 21.5 μg/L obtained is within the MAV of 100 μg/L. Chloroform was the compound with higher concentrations in all samples in THMt analysis. Results of residual chlorine and pH also are within the MAVs. Studies like this are important to continuous monitoring of the water quality distributed to population.
Effect of Roasting Temperature for Copper Leaching of Sulfide Concentrate by Combined Methods  [PDF]
Lkhamtogmid Nyamjargal, Ganbat Batdemberel, Gunchin Burmaa, Dashdendev Burmaa
Open Journal of Applied Sciences (OJAppS) , 2018, DOI: 10.4236/ojapps.2018.812044
Abstract: This study was undertaken to develop a cost-effective method of copper leaching in sulfide concentrate involving minerals as chalcopyrite and pyrite. The combined methods involving low temperature roasting of sulfide copper minerals with potassium chlorides without the formation of sulfurous gases and their evolution into the atmosphere is suggested. The effect of experi-mental parameters such as a roasting temperature and time has been pre-sented and discussed in detail. This study was carried out in the roasting temperature range 400°C - 600°C and roasting time ranges 1 - 4 h with potas-sium chloride. The obtained cake is leached by an aqueous sulfuric acid 60 g/l concentrated at pH = 2 - 2.5 and 4 h. The concentrate, a roasting cake and after leaching solid residue were analyzed by chemical analysis, XRD and SEM-EDX. At temperature ranges 450°C - 550°C and 3 h of roasting, the pro-cess is activated. The recovery of copper into the solution at optimal roasting condition (500°C, roasting time 3 h) is 93.2%. The advantage of the devel-oped method is that, it not requires high roasting temperature and the use of autoclave for leaching. The method gives possibility to leach the concentrate at room temperature and atmospheric pressure, which gives possibility to reduce cost of the process.
Chlorination of isatins with trichloroisocyanuric acid
Silva, Bárbara V;Esteves, Pierre M;Pinto, Angelo C;
Journal of the Brazilian Chemical Society , 2011, DOI: 10.1590/S0103-50532011000200010
Abstract: isatin and its derivatives have been extensively reported in the literature as having range of potential pharmacological compounds. the sandmeyer method is the most widely used for isatin synthesis and furnishes different substituted isatins, usually with high yields. although efficient, the sandmeyer route has certain limitations, such as the formation of a mixture of regiosiomers and low yields depending on the type and position of the substituent. thus, overcome these limitations, it is preferable that some derivative isatins be obtained by alternative methods. this article has investigated the chlorination of isatin derivatives using trichloroisocyanuric acid [1,3,5-trichloro 1,3,5-triazine-2,4,6-(1h,3h,5h)-trione or tcca] at different reaction conditions.
A mild procedure for a,a-dichlorination of cyclic aryl ketones using commercial bleach
Quintiliano, Samir A. P.;Silva Jr., Luiz F.;
Journal of the Brazilian Chemical Society , 2007, DOI: 10.1590/S0103-50532007000600026
Abstract: a,a-dichloro-cyclic aryl ketones were obtained treating a methanolic solution of the corresponding ketone with commercial bleach at ambient conditions in yields varying from 61 to 92%. electron-donating and -withdrawing groups in the starting ketone are tolerated but the reaction appears to be sensitive to steric effects. moreover, five-, six-, and seven-membered aryl-cycloalkanones can be used as substrate.
GaAs chlorination study
Túnez,F. M.; Gonzalez,J.; Ruiz,M. del C.;
Latin American applied research , 2008,
Abstract: the compound gaas is at the present time an essential part of electronic devices. the recovery of elements from electronic wastes is fundamental for the metallurgic industries. in this work, the following reaction is investigated: gaas + 3cl2(g) → gacl3 + ascl3 with the aim of recovering constituent elements by chlorination, several variables were studied such as: chlorine partial pressure, in the range between 0.2 and 1 atm, by dilution with n2; and temperature of reaction, in the -29°c to 200°c range. the reagents used were gaas of analytical quality, chlorine and nitrogen gas of high purity. the reagents and products were analyzed by x-ray fluorescence (xrf), x-ray diffraction (xrd), scaming electronic microscopy (sem) and atomic absorption spectofotometry (aaes). the results show that the rate of chlorination did not change significantly with the temperature, but increased with the chlorine partial pressure. it was found that ascl3 was partially evaporated at temperatures above 20°c, while the gacl3 start to be evaporated at 100°c. these partial results show that chlorination is a selective and economic methodology for the recovery of gallium from electronic wastes.
GaAs chlorination study
F. M. Túnez,J. Gonzalez,M. del C. Ruiz
Latin American applied research , 2008,
Abstract: The compound GaAs is at the present time an essential part of electronic devices. The recovery of elements from electronic wastes is fundamental for the metallurgic industries. In this work, the following reaction is investigated: GaAs + 3Cl2(g) → GaCl3 + AsCl3 With the aim of recovering constituent elements by chlorination, several variables were studied such as: chlorine partial pressure, in the range between 0.2 and 1 atm, by dilution with N2; and temperature of reaction, in the -29°C to 200°C range. The reagents used were GaAs of analytical quality, chlorine and nitrogen gas of high purity. The reagents and products were analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), scaming electronic microscopy (SEM) and atomic absorption spectofotometry (AAES). The results show that the rate of chlorination did not change significantly with the temperature, but increased with the chlorine partial pressure. It was found that AsCl3 was partially evaporated at temperatures above 20°C, while the GaCl3 start to be evaporated at 100°C. These partial results show that chlorination is a selective and economic methodology for the recovery of gallium from electronic wastes.
Attacks of Asthma due to Chlorinized Water: Case Report
Murat Eyup Berdan,Ercan Gocgeldi,Sami Ozturk,Ali Kutlu
TAF Preventive Medicine Bulletin , 2008,
Abstract: The presence of a high prevalence of bronchial hyperresponsiveness and asthma-like symptoms in swimmers has been reported. But, attacks of asthma which is related to chlorinized water is rare. Chlorine, a strong oxidizing agent, is an important toxic gas that the swimmer can breath during swimming and a worker can exposed to chlorine while he or she was using water with chlorine at home. We describe a persistent increase in nonspecific bronchial hyperresponsiveness following chronic exposure to strong respiratory irritant with chlorinized water in two subjects with no past history of asthma or atopy. We conclude that airway hyperresponsiveness can develop or increase after chronic inhalation of high concentrations of irritants such as chlorinized water an indoor irritant factor and that these changes may be prolonged. [TAF Prev Med Bull. 2008; 7(1): 87-90]
Reviw Article:Organic Compound Resulting from Drinking Water Chiorination
H Pourmoghaddas
Journal of School of Public Health and Institute of Public Health Research , 2003,
Abstract: Organic chlorination by-products of drinking water have been considered public health issue and drinking water treatment problem since the 1974 reportng of the formation of chloroform and three other trihalomethanes (THMs) during chlorination. Much work has been accomplished since then to understand the factors influencing this formation and the treatment techniques to reduce the formation of chlorination by - products. Humic materials occure in surface waters, these naturally occuring organic compounds can serve as percursors to possible carcinogencs when fresh water supplies are subjected to chlorination for disinfection purposes. Over 780 compounds were formed by the reaction of chlorine with humic acids, which a large percentage are halogenated. The most commonly formed groups of these by-products are thrihalomethanes (4 compounds), Haloacetic Acids (9 compounds) and Haloacetonitrile (4 compounds). Total organic halogen (TOX) is an - easy method to determine the organic Halogen in water. GC and GC/MS methods are used to detrmine the chlorination by - products in water. In this review article the main chlorination by - products in drinking water, the factors which influences on the formation, the techniques in water treatment plants to reduce the concentration of chlorination by - products and the methods of determinations are discussed.
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