Dependence of kinetics of copper sulfate pentahydrate dehydration on water vapor pressure

1978 ◽  
Vol 26 (2) ◽  
pp. 173-178 ◽  
Author(s):  
N.Z. Lyakhov ◽  
A.P. Chupakhin ◽  
V.P. Isupov ◽  
V.V. Boldyrev
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Copper Sulfate ◽  
Water Vapor Pressure ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Kinetics Of

Thermal analysis and decomposition kinetics of the dehydration of copper sulfate pentahydrate

2018 ◽  
Vol 135 (5) ◽  
pp. 2697-2703 ◽  
Author(s):  
Long Cheng ◽  
Wen Li ◽  
Yifan Li ◽  
Yue Yang ◽  
Yanchun Li ◽  
...  
Keyword(s):  
Thermal Analysis ◽  
Copper Sulfate ◽  
Decomposition Kinetics ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Kinetics Of

Quantitation of crystallinity in substantially amorphous pharmaceuticals and study of crystallization kinetics by X-ray powder diffractometry

2000 ◽  
Vol 15 (1) ◽  
pp. 2-6 ◽  
Author(s):  
Rahul Surana ◽  
Raj Suryanarayanan
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Crystallization Kinetics ◽  
Water Vapor Pressure ◽  
Three Dimensional ◽  
Weight Percent ◽  
X Ray ◽  
Amorphous Pharmaceuticals ◽  
Integrated Intensities ◽  
Kinetics Of

The first object was to develop an X-ray diffractometric method for the detection and quantification of crystalline sucrose when it occurs as a mixture with amorphous sucrose. Standards consisting of amorphous sucrose physically mixed with 1 to 5 weight percent crystalline sucrose were prepared. The sum of the background subtracted integrated intensities of the 12.7°2θ (6.94 Å) and 13.1°2θ (6.73 Å) sucrose diffraction peaks were linearly related to the weight percent crystalline sucrose. The limits of detection and quantitation of crystalline sucrose were 0.9% and 1.8% w/w, respectively. The second object was to study the kinetics of crystallization of sucrose as a function of temperature (at 102, 105 and 110 °C under a water vapor pressure of 0 Torr) and water vapor pressure (17.4, 19.8 and 21.4 Torr at 27 °C). In all cases, the crystallization kinetics was best described by the Avrami-Erofe’ev model (three-dimensional nucleation).

THE EFFECT OF WATER VAPOR UPON THE DEHYDRATION OF CaSO4•2H2O

1964 ◽  
Vol 42 (4) ◽  
pp. 792-801 ◽  
Author(s):  
H. G. McAdie
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Vapor Pressures ◽  
Heat Of Solution ◽  
Temperature Dependent ◽  
Exponential Factor ◽  
Fixed Composition ◽  
Kinetics Of ◽  
Partial Water

Kinetics of the two-stage dehydration of CaSO4•2H2O have been examined under controlled water vapor pressures up to one atmosphere. For both stages water vapor initially accelerated the rate of dehydration and subsequently retarded it. Separate, temperature-dependent water vapor pressures were noted above which each stage could be suppressed.The hemihydrate was clearly defined either as a change in the rate of weight loss during dehydration or, at higher water vapor pressures, as a fixed composition. The heat of solution of the hemihydrate increased linearly with the partial water vapor pressure present during its formation, but was independent of the formation temperature over the range studied. Activation energy and pre-exponential factor for the dihydrate → hemihydrate process also increased linearly with water vapor pressure. Hemihydrates produced at the extremes of water vapor pressure corresponded to the α- and β-modifications, as defined thermodynamically, and the production of a hemihydrate series with properties varying linearly from one extreme to the other is discussed.

Kinetics of Absorption by Metals of Hydrogen From Water and Aqueous Solutions

CORROSION ◽  
1960 ◽  
Vol 16 (4) ◽  
pp. 198t-200t ◽  
Author(s):  
T. G. OWE BERG
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Initial Period ◽  
Water Vapor Pressure ◽  
Cube Root ◽  
Square Root ◽  
Linear Rate ◽  
Rate Law ◽  
Kinetics Of ◽  
Absorption Of Hydrogen

Abstract The kinetics of absorption of hydrogen in corrosion is treated on the basis of a mechanism previously proposed for the absorption of hydrogen from H2 gas. Rate formulae are derived and compared with experimental data. On certain simple assumptions, a parabolic or a cubic rate law is derived for an initial period, during which absorption of hydrogen occurs. This rate law is succeeded by a linear rate law when the metal is saturated with hydrogen. The rate in acid solutions is proportional to the square root or the cube root of the acid concentration. The rate in water vapor is proportional to the square root of the water vapor pressure or independent of the water vapor pressure. 3.8.4

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