The Experts below are selected from a list of 8700 Experts worldwide ranked by ideXlab platform
Jin-xian Wang - One of the best experts on this subject based on the ideXlab platform.
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mild and efficient barbier allylation reaction mediated by Magnesium Powder under solvent free conditions
Tetrahedron, 2011Co-Authors: Shunxi Li, Jin-xian WangAbstract:Abstract A novel and highly efficient synthesis of homoallylic alcohols is achieved by the allylation of carbonyl compounds using Magnesium Powder as mediator under solvent-free conditions. A series of aldehydes and ketones are converted to the corresponding homoallylic alcohols, the yields of the reaction is considerably high (85–98%). The procedure is environment benign, operationally simple and easy to scale up at room temperature.
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Solvent-Free, One-Pot ConjugateAddition of Benzyl Bromides to β-Nitro-alkenesMediated by Magnesium Powder
Synthesis, 2009Co-Authors: Wei Shi, Jin-xian WangAbstract:A convenient and efficient methodology for conjugate addition of benzyl bromides to beta-nitrostyrenes mediated by Magnesium Powder in one pot under solvent-free conditions at 0 degrees C has been developed. Advantages of this method are excellent yields, short reaction times, operational simplicity, and avoidance of the use of organic solvents.
Saswati Chakraborty - One of the best experts on this subject based on the ideXlab platform.
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chemical denitrification of water by zero valent Magnesium Powder
Journal of Hazardous Materials, 2006Co-Authors: Manish Kumar, Saswati ChakrabortyAbstract:Abstract A laboratory-scale study was conducted in batch mode to investigate the feasibility of using zero-valent Magnesium (Mg 0 ), for removal of nitrate from aqueous solution. Reaction pH, dose of Mg 0 , initial nitrate concentration and temperature were considered variable parameters during the study. Strong acidic condition enhanced nitrate reduction and in absence of external proton addition, reaction pH increased rapidly above ten and insignificant nitrate removal (7–16%) was achieved. At Mg 0 :NO 3 − –N molar ratio of 5.8 and controlled reaction pH of 2, 84% denitrification efficiency was achieved (initial NO 3 − –N 50 mg/L) under ambient temperature and pressure and total nitrogen removal was 70% with 3.2% and 10% conversion of initial NO 3 − –N to NO 2 − –N and NH 4 + –N, respectively. The reaction was first order with respect to nitrate concentration. Nitrate removal rate decreased with solution pH and increased linearly with Mg 0 dose. Nitrate removal was coupled with 96–100% removal of dissolved oxygen and 85–90% generation of soluble Mg 2+ ion. An activation energy ( E a ) of nitrate reduction over the temperature range of 10–50 °C was observed as 17.7 kJ mol −1 .
Li Gang - One of the best experts on this subject based on the ideXlab platform.
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Ignition behavior of Magnesium Powder layers on a plate heated at constant temperature.
Journal of hazardous materials, 2012Co-Authors: Yuan Chunmiao, Li Chang, Huang Dezheng, Li GangAbstract:The minimum temperature at which dust layers or deposits ignite is considered to be very important in industries where smoldering fires could occur. Experiments were conducted on the self-ignition behavior of Magnesium Powder layers. The estimated effective thermal conductivity k for modeling is 0.17 W m(-1)K(-1). The minimum ignition temperature (MIT) of Magnesium Powder layers for four different particle sizes: 6, 47, 104 and 173 μm, are also determined in these experiments. A model was developed describing temperature distribution and its change over time while considering the melting and boiling of Magnesium Powder. Parameter analysis shown that increasing particle size from 6 to 173 μm increased MIT from 710 to 760 K, and increased thickness of the dust layer led to a decreased MIT. The calculation termination time more than 5000 s didn't significantly impact MIT. Comparing predicted and experimental data showed satisfactory agreement for MIT of Magnesium Powder layers at various particle sizes. According to the ignition process of Magnesium Powder layer, a meaningful definition for the most sensitive ignition position (MSIP) was proposed and should be taken into consideration when preventing smoldering fires induced by hot plates.
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Ignition temperature of Magnesium Powder clouds: a theoretical model.
Journal of Hazardous Materials, 2012Co-Authors: Yuan Chunmiao, Li Gang, Li Chang, Zhang PeihongAbstract:Minimum ignition temperature of dust clouds (MIT-DC) is an important consideration when adopting explosion prevention measures. This paper presents a model for determining minimum ignition temperature for a Magnesium Powder cloud under conditions simulating a Godbert–Greenwald (GG) furnace. The model is based on heterogeneous oxidation of metal particles and Newton's law of motion, while correlating particle size, dust concentration, and dust dispersion pressure with MIT-DC. The model predicted values in close agreement with experimental data and is especially useful in predicting temperature and velocity change as particles pass through the furnace tube.
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Ignition of Magnesium Powder Dust Layers at Constant Heated Plate
Journal of Northeastern University, 2011Co-Authors: Li GangAbstract:The ignition processes of four types of Magnesium Powder dust layers at constant heated plate were investigated.In this respect,main concerns are temperature distribution inside Magnesium Powder layers at precritical,critical,and postcritical temperature of hot plate.The results showed that the ignition of Magnesium dust layer would not occur at the maximum temperature of hot plate determined by standards GB/T 16430—1996 and IEC 61241-2-1—1994.The dust layer would come into a long-duration stable temperature after a short period of rising temperature.The critical temperature of hot plate and the ignition delay time increase with particle size.As the temperature of hot plate is larger than the critical one,the higher the temperature of hot plate is,the shorter the ignition delay time of dust layer is.
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experiment based fire and explosion risk analysis for Powdered Magnesium production methods
Journal of Loss Prevention in The Process Industries, 2008Co-Authors: Li Gang, Zhang Peihong, Yuan Chunmiao, Chen BaozhiAbstract:More than 100,000 tons of Powdered or granular Magnesium are produced annually in China in factories with high potential fire and explosion risk. The primary methods for Magnesium Powder production are reviewed in this paper. Fire risk analyses, based on minimum ignition energy (MIE) and minimum ignition temperature (MIT) test results for Magnesium Powder of different diameters, are provided for each method. Sparks caused by static electricity, mechanical friction, or impact are the most likely ignition sources for fine Magnesium Powder fires and explosions. However, MIT of Powdered Magnesium was much higher than that of organic or coal dust even for very fine Magnesium Powder. Magnesium Powder fires and explosion were not readily caused by hot surfaces. A two-stage combustion model was experimentally determined for a Magnesium dust layer.
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The Research on Explosion Mechanism and Protection Technology of Magnesium Powder
Industrial Safety and Environmental Protection, 2008Co-Authors: Li GangAbstract:There exists fire and explosion of Magnesium Powder in the process of its manufacture,transport,use and so on,so it is important to take effective protection measures to prevent and reduce Magnesium Powder explosion accidents.This paper firstly analyzes the Magnesium Powder explosion mechanism and then raises preventive and protective technologies of Magnesium Powder based on the conditions of Magnesium Powder explosion,using the explosion suppression methods for protective technologies and selecting 7150 or Powder as the explosion suppressant.Moreover some suggestions are provided correspondingly to offer references for Magnesium Powder explosion accident research.
Manish Kumar - One of the best experts on this subject based on the ideXlab platform.
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chemical denitrification of water by zero valent Magnesium Powder
Journal of Hazardous Materials, 2006Co-Authors: Manish Kumar, Saswati ChakrabortyAbstract:Abstract A laboratory-scale study was conducted in batch mode to investigate the feasibility of using zero-valent Magnesium (Mg 0 ), for removal of nitrate from aqueous solution. Reaction pH, dose of Mg 0 , initial nitrate concentration and temperature were considered variable parameters during the study. Strong acidic condition enhanced nitrate reduction and in absence of external proton addition, reaction pH increased rapidly above ten and insignificant nitrate removal (7–16%) was achieved. At Mg 0 :NO 3 − –N molar ratio of 5.8 and controlled reaction pH of 2, 84% denitrification efficiency was achieved (initial NO 3 − –N 50 mg/L) under ambient temperature and pressure and total nitrogen removal was 70% with 3.2% and 10% conversion of initial NO 3 − –N to NO 2 − –N and NH 4 + –N, respectively. The reaction was first order with respect to nitrate concentration. Nitrate removal rate decreased with solution pH and increased linearly with Mg 0 dose. Nitrate removal was coupled with 96–100% removal of dissolved oxygen and 85–90% generation of soluble Mg 2+ ion. An activation energy ( E a ) of nitrate reduction over the temperature range of 10–50 °C was observed as 17.7 kJ mol −1 .
Wei Shi - One of the best experts on this subject based on the ideXlab platform.
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Solvent-Free, One-Pot ConjugateAddition of Benzyl Bromides to β-Nitro-alkenesMediated by Magnesium Powder
Synthesis, 2009Co-Authors: Wei Shi, Jin-xian WangAbstract:A convenient and efficient methodology for conjugate addition of benzyl bromides to beta-nitrostyrenes mediated by Magnesium Powder in one pot under solvent-free conditions at 0 degrees C has been developed. Advantages of this method are excellent yields, short reaction times, operational simplicity, and avoidance of the use of organic solvents.
