Acetazolamide polymorphism: a case of hybridization induced polymorphism?

2016 ◽  
Vol 52 (34) ◽  
pp. 5820-5823 ◽  
Author(s):  
Sounak Sarkar ◽  
Mysore S. Pavan ◽  
Suryanarayan Cherukuvada ◽  
Tayur N. Guru Row
Keyword(s):  
Aqueous Solution ◽  
Slow Cooling ◽  
Theoretical Investigations ◽  
Unusual Phenomenon ◽  
Kinetic Form

The unusual phenomenon of the formation of the kinetic form as against the thermodynamic form upon slow cooling of boiling aqueous solution in the case of diuretic drug acetazolamide is rationalized in terms of “hybridization induced polymorphism” based on extensive experimental and theoretical investigations.

Experimental and Theoretical Investigations of Condensation and Disproportionation of Mn(bpy)Cl3(H2O) in Aqueous Solution

1999 ◽  
Vol 38 (1) ◽  
pp. 4-11 ◽  
Author(s):  
Christian Philouze ◽  
Marc Henry ◽  
Nathalie Auger ◽  
Daniel Vignier ◽  
Monique Lance ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Theoretical Investigations

scholarly journals Theoretical investigations on hydrogen peroxide decomposition in aquo

2018 ◽  
Vol 20 (38) ◽  
pp. 24992-24999 ◽  
Author(s):  
Takao Tsuneda ◽  
Tetsuya Taketsugu
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Oh Radical ◽  
Iron Ions ◽  
Hydrogen Bond Network ◽  
Iron Ion ◽  
Hydrogen Peroxide Decomposition ◽  
Peroxide Decomposition ◽  
Theoretical Investigations ◽  
Bond Network

Hydrogen peroxide (H2O2) decomposition mechanisms in the absence and presence of iron ions in aqueous solution, which contain no OH radical formation, are theoretically determined. H2O2 decomposition in the presence of iron ions is driven by electron transfer to the iron ion and proceeds by hydrogen transfers in the hydrogen bond network around H2O2.

Avoiding Ethanol Presence in DNA Samples Enhances the Performance of Ultraviolet Resonance Raman Spectroscopy Analysis

2016 ◽  
Vol 71 (1) ◽  
pp. 152-155 ◽  
Author(s):  
Francesca Cammisuli ◽  
Lorella Pascolo ◽  
Marcello Morgutti ◽  
Alessandro Gessini ◽  
Claudio Masciovecchio ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Dna Isolation ◽  
Resonance Raman Spectroscopy ◽  
Spectroscopy Analysis ◽  
Chemical Reagent ◽  
Slow Cooling ◽  
Simple Method ◽  
Ultraviolet Resonance Raman ◽  
Essential Chemical ◽  
Cooling Procedure

Ethanol is an essential chemical reagent in DNA preparation as its use increases the yield of extraction. All methodologies for DNA isolation involve the use of ethanol in order to prevent DNA dissolution in water and to optimize the binding of DNA to chromatographic membranes. In this note, we show how the presence of ethanol traces in DNA aqueous solution affects ultraviolet Raman spectra, leading to possible misinterpretations. We report a simple method to remove the ethanol Raman features from the spectra, based on heating the DNA sample at 80 ℃, followed by a slow cooling procedure.

Structures Formed by Cryoprotective Agents Used in Freezc-Etching

1971 ◽  
Vol 29 ◽  
pp. 448-449
Author(s):  
G. G. Cocks ◽  
C. E. Cluthe
Keyword(s):  
Aqueous Solution ◽  
Polyethylene Oxide ◽  
Liquid Nitrogen Temperature ◽  
Ice Crystals ◽  
Etching Technique ◽  
Structural Constituent ◽  
Cryoprotective Agents ◽  
Quick Freezing ◽  
Freeze Etching ◽  
Fractured Surface

The freeze etching technique is potentially useful for examining dilute solutions or suspensions of macromolecular materials. Quick freezing of aqueous solutions in Freon or propane at or near liquid nitrogen temperature produces relatively large ice crystals and these crystals may damage the structures to be examined. Cryoprotective agents may reduce damage to the specimem, hut their use often results in the formation of a different set of specimem artifacts.In a study of the structure of polyethylene oxide gels glycerol and sucrose were used as cryoprotective agents. The experiments reported here show some of the structures which can appear when these cryoprotective agents are used.Figure 1 shows a fractured surface of a frozen 25% aqueous solution of sucrose. The branches of dendritic ice crystals surrounded hy ice-sucrose eutectic can be seen. When this fractured surface is etched the ice in the dendrites sublimes giving the type of structure shown in Figure 2. The ice-sucrose eutectic etches much more slowly. It is the smooth continuous structural constituent surrounding the branches of the dendrites.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

TEM observation of iron oxide pillars in montmorillonite

1990 ◽  
Vol 48 (4) ◽  
pp. 882-883
Author(s):  
H. Mori ◽  
Y. Murata ◽  
H. Yoneyama ◽  
H. Fujita
Keyword(s):  
Aqueous Solution ◽  
Iron Oxide ◽  
Fine Particles ◽  
Aqueous Suspension ◽  
Volume Ratio ◽  
Exchange Capacity ◽  
Nano Composites ◽  
Pillared Montmorillonite ◽  
Topographic Features ◽  
Transmission Electron

Recently, a new sort of nano-composites has been prepared by incorporating such fine particles as metal oxide microcrystallites and organic polymers into the interlayer space of montmorillonite. Owing to their extremely large specific surface area, the nano-composites are finding wide application[1∼3]. However, the topographic features of the microstructures have not been elucidated as yet In the present work, the microstructures of iron oxide-pillared montmorillonite have been investigated by high-resolution transmission electron microscopy.Iron oxide-pillared montmorillonite was prepared through the procedure essentially the same as that reported by Yamanaka et al. Firstly, 0.125 M aqueous solution of trinuclear acetato-hydroxo iron(III) nitrate, [Fe3(OCOCH3)7 OH.2H2O]NO3, was prepared and then the solution was mixed with an aqueous suspension of 1 wt% clay by continuously stirring at 308 K. The final volume ratio of the latter aqueous solution to the former was 0.4. The clay used was sodium montmorillonite (Kunimine Industrial Co.), having a cation exchange capacity of 100 mequiv/100g. The montmorillonite in the mixed suspension was then centrifuged, followed by washing with deionized water. The washed samples were spread on glass plates, air dried, and then annealed at 673 K for 72 ks in air. The resultant film products were approximately 20 μm in thickness and brown in color.

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