Bi(OTf)3 or Bi(TFA)3 catalyzed efficient, regio- and chemoselectively synthesis of beta-hydroxy thioethers from aryl disulfides in the presence of zinc powder

Chemical gas sensors were studied long ago and nowadays, for the advantageous role they provide to the environment, health condition monitoring and protection. The recent studies focus on the semiconductors sensing abilities, especially of non toxic and low cost compounds. The present work describes the steps to elaborate and perform a chemical sensor using intrinsic and doped semiconductor zinc oxide. First, we synthesized pure oxide using zinc powder, then, two other samples were established where we introduced the same doping percentage of Al and Sn respectively. Using low cost spray pyrolysis, and respecting the same conditions of preparation. The obtained samples were then characterized by X Ray Diffraction (XRD) that revealed the hexagonal wurzite structure and higher crystallite density towards the direction (002), besides the appearance of the vibration modes related to zinc oxide, confirmed by Raman spectroscopy. SEM spectroscopy showed that the surface morphology is ideal for oxidizing/reduction reactions, due to the porous structure and the low grain sizes, especially observed for the sample Sn doped ZnO. The gas testing confirms these predictions showing that the highest response is related to Sn doped ZnO compared to ZnO and followed by Al doped ZnO. The films exhibited responses towards: CO, acetone, methanol, H2, ammonia and NO2. The concentrations were varied from 10 to 500 ppm and the working temperatures from 250 to 500°C, the optimal working temperatures were 350 and 400 °C. Sn doped ZnO showed a high response towards H2 gas target, with a sensitivity reaching 200 at 500 ppm, for 400 °C.

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ChemInform Abstract: Frequency Effect of Ultrasound on Debromination of Stilbenedibromides with Zinc Powder.

ChemInform ◽

10.1002/chin.199847044 ◽

2010 ◽

Vol 29 (47) ◽

pp. no-no

Author(s):

M. ATOBE ◽

Y. KADO ◽

T. NONAKA

Keyword(s):

Zinc Powder ◽

Frequency Effect

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Zinc Powder as an Effective Reducing Reagent during Liquid-Phase Oxidation of Benzene to Phenol Using Molecular Oxygen over V-Substituted Heteropoly Acid Catalysts

Industrial & Engineering Chemistry Research ◽

10.1021/ie060743e ◽

2006 ◽

Vol 45 (22) ◽

pp. 7444-7450 ◽

Cited By ~ 31

Author(s):

Shingo Sumimoto ◽

Chiaki Tanaka ◽

Sho-ta Yamaguchi ◽

Yuichi Ichihashi ◽

Satoru Nishiyama ◽

...

Keyword(s):

Liquid Phase ◽

Molecular Oxygen ◽

Heteropoly Acid ◽

Zinc Powder ◽

Liquid Phase Oxidation ◽

Acid Catalysts ◽

Phase Oxidation ◽

Oxidation Of Benzene

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Consideration on Thermal Decomposition of Calcium Hydroxide Pellets for Energy Storage

Journal of Solar Energy Engineering ◽

10.1115/1.3268314 ◽

1989 ◽

Vol 111 (3) ◽

pp. 245-250 ◽

Cited By ~ 7

Author(s):

I. Fujii ◽

K. Tsuchiya ◽

Y. Shikakura ◽

M. S. Murthy

Keyword(s):

Heat Transfer ◽

Thermal Decomposition ◽

Calcium Hydroxide ◽

Thermal Stresses ◽

Zinc Powder ◽

Solar Thermal Energy ◽

Mechanism Of Decomposition ◽

Effect Of Additives ◽

Nucleation Sites ◽

Reversible Chemical Reaction

The reversible chemical reaction of Ca(OH)2/CaO appears to be attractive for storage of solar thermal energy, in view of the nonpolluting and nontoxic nature of the reactants. This paper presents some data on thermal decomposition of calcium hydroxide pellets along with its additives of aluminum, aluminum hydroxide, zinc, and copper. The addition of aluminum and zinc powder enhanced the rate of decomposition considerably at 450° C, but copper had no effect. Considerations on the effect of additives are also discussed in some detail, though their effects are not established with certainty. There is some evidence that heat transfer into the pellet, and the number of potential nucleation sites due to thermal stresses, influence the kinetics and mechanism of decomposition.

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Structure-Property Relationships of N,N′-Dinitroso-P-Phenylene-Bis (Hydroxylamine) Salts. Vulcanization of Nonhalogenated Elastomers

Rubber Chemistry and Technology ◽

10.5254/1.3539884 ◽

1962 ◽

Vol 35 (1) ◽

pp. 141-146 ◽

Cited By ~ 7

Author(s):

Rock F. Martel ◽

David E. Smith

Keyword(s):

Thermal Analysis ◽

Differential Thermal Analysis ◽

Silver Salt ◽

Crosslinking Agent ◽

Authentic Sample ◽

Zinc Powder ◽

Metallic Silver ◽

Crosslinking Reaction ◽

Oxides Of Nitrogen ◽

Structure Property

Abstract In a previous report the vulcanization activity of N,N′-dinitroso-p-phenylene-bis(hydroxylamine) salts in Neoprene WRT was discussed. The vulcanization was catalyzed by addition of stoichiometric amounts of aluminum or zinc powder (based upon percentage of allylic chloride), very possibly via the metal halide formed in situ. Natural rubber could not be vulcanized with these materials, however, differential thermal analysis indicated that amine-treated neoprene undergoes a crosslinking reaction at above normal curing temperatures. This evidence led us to propose that bisalkylation (α and/or β) at the allylic position is responsible for the formation of crosslinks. The mechanistic path is shown in Equations 1 and 2, and the analogy with the SN2′ activity of diamines in neoprene is quite apparent. The crosslinks III and/or IV are shown as the β form and one of the possible a structures. A number of structures for the α form have been proposed. The β structure has been known for some time. Our primary interest at this point was to extend the activity of N,N′-dinitroso-p-phenylene-bis(hydroxylamine) salts to elastomers which do not contain halogen. Any hope of achieving this goal depended, for the most part, upon whether or not certain of these materials would produce p-dinitrosobenzene, a known crosslinking agent, during the vulcanization cycle. The silver salt of phenylnitrosohydroxylamine, the monosubstituted counterpart of the bis(hydroxylamine) structure, decomposes readily to nitrosobenzene, nitric oxide and metallic silver. Accordingly, we prepared the di-silver salt of N,N′-dinitroso-p-phenylene-bis(hydroxylamine). The maximum rate of decomposition of this material was determined by differential thermal analysis, and occurred at 295° F. When 1.0 g of the di-silver salt was heated [see Reaction (3)] at 200° F for 2 hours, 0.3 g of a yellow solid sublimate was collected on a cold finger. The infrared spectrum of the yellow solid was identical with that of an authentic sample of p-dinitrosobenzene. Oxides of nitrogen were also visible in the reaction vapors (brown coloration).

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Spectrophotometric determination of nicradipine and isradipine in pharmaceutical formulations

Chemical Industry and Chemical Engineering Quarterly ◽

10.2298/ciceq0902069a ◽

2009 ◽

Vol 15 (2) ◽

pp. 69-76 ◽

Cited By ~ 1

Author(s):

S.M. Al-Ghannam ◽

A.M. Al-Olyan

Keyword(s):

Standard Deviation ◽

Detection Limit ◽

Reaction Pathway ◽

Pharmaceutical Preparations ◽

Pharmaceutical Formulations ◽

Molar Absorptivity ◽

Zinc Powder ◽

Conditional Stability ◽

Conditional Stability Constant

A sensitive spectrophotometric method was developed for the determination of some 1,4-dihydropyridine compounds namely, nicardipine and isradipine either in pure form or in pharmaceutical preparations. The method is based on the reduction of nicardipine and isradipine with zinc powder and calcium chloride followed by further reduction with sodium pentacyanoaminoferrate (II) to give violet and red products having the absorbance maximum at 546 and 539 nm with nicardipine and isradipine, respectively. Beer's law was obeyed over the concentration range 8.0-180 ?g/ml with the detection limit of 1.67 ?g/ml for nicardipine and 8.0-110 ?g/ml with the detection limit of 1.748 ?g/ml for isradipine. The analytical parameters and their effects on the reported methods were investigated. The molar absorptivity, quantization limit, standard deviation of intercept (Sa), standard deviation of slope (Sb) and standard deviation of the residuals (Sy/x) were calculated. The composition of the result compounds were found 1:1 for nicardipine and 1:2 for isradipine by Job's method and the conditional stability constant (Kf) and the free energy changes (?G) were calculated for compounds formed. The proposed method was applied successfully for the determination of nicardipine and isradipine in their dosage forms. The results obtained were in good agreement with those obtained using the reference or official methods. A proposal of the reaction pathway was presented.

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Characterizations of Zinc Oxynitride Powders Prepared Under Ammonia Gas Flow

International Journal of Modern Physics B ◽

10.1142/s0217979203019265 ◽

2003 ◽

Vol 17 (08n09) ◽

pp. 1523-1526 ◽

Cited By ~ 2

Author(s):

Takashi Sakamoto ◽

Ryoji Saki ◽

Toshihiro Moriga ◽

Kei Ichiro Murai ◽

Ichiro Nakabayashi

Keyword(s):

Band Gap ◽

Oxygen Content ◽

Lattice Constant ◽

Gas Flow ◽

Optical Band Gap ◽

Zinc Powder ◽

Ammonia Gas

The anti-bixbyite-type zinc oxynitrides Zn 3( N1-xOx ) 2-y could be prepared by directly nitriding zinc powder under ammonia gas flow. Oxygen content x and amount of anion deficiency y decreased with increasing nitriding period at [Formula: see text]. Zn 3( N0.91O0.09 )1.98 could be obtained after the 168 hours of nitridation at [Formula: see text]. Reduction of both x and y, especially x, enhanced the lattice constant and reduced optical band gap of the oxynitride.

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