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Introduction Natural zeolites are the framework aluminosilicates with rather large amount of water molecules inside cavities and channels, up to 20% by weight [ 1 – 3 ]. Thermal dehydration of zeolites is usually accompanied
Introduction The dehydration of Portland cement paste plays an important role in the concrete structure explosive spalling at fire. Calcium silicate hydrate (CSH) and calcium hydroxide (CH) are the main hydration phases which
nesosilicate is observed when dehydrated hydration products contact with water [ 9 – 12 ]. With such a possibility, surface cementitious properties of coarse fly ash were improved by dehydration and rehydration processes, meanwhile the un-burnt carbon is
decomposes approximately between 450 and 550 °C, calcium carbonate approximately between 700 and 900 °C, while the crystallisation water of the hydration products disappears gradually between 100 and 1,000 °C. It is considered that the total dehydration of
dehydration/desolvation, hydration/solvation or polymorphic transformation of API in the manufacturing process, leading to the changes in solid-state physicochemical properties and bioavailability of APIs [ 3 – 7 ]. Thus, an analytical study for the
Abstract
A model developed for the estimation of the diffusion coefficient based on Fickian diffusion is applied to the dehydration of a Coober Pedy white play of colour (precious) opal using thermogravimetric analysis (TG). The model was originally applied to bulk and powdered opal (opal with no bulk). In this paper the opal was graded prior to TG analysis. The diffusion coefficient was calculated and is reported up to the critical point of water.
aid of acid catalysts, can be further converted into furfural by dehydration. The dehydration reaction has several side reactions such as isomerization, condensation and polymerization [ 2 ]. Furfural is widely used as an intermediate for the
Thermal dehydrations
Calcium copper acetate hexahydrate and calcium cadmium acetate hexahydrate
Abstract
The behaviour of thermal dehydrations of isomorphous complexes of calcium copper acetate hexahydrate, CaCu(CH3CO2)4·6H2O and calcium cadmium acetate hexahydrate, CaCd(CH3CO2)4· 6H2O was studied by means of thermal analyses and X-ray structural analysis. The enthalpy changes for the dehydration of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 315±9.7 and 295±8.0 kJ mol−1, respectively. The DSC curves of the dehydrations indicated that the seemingly simple dehydrations are more complex than they appear at first sight. Apparent activation energies for the dehydrations of CaCu(CH3CO2)4·6H2O and CaCd(CH3CO2)4·6H2O were 85.7±7.4 and 87.9±12.5 kJ mol−1, respectively.
For the aluminum compound, the first mass loss occurred only between 30 and 110 °C (TG) due to dehydration, with a loss of 1.76%, corresponding to the endothermic peak (91 °C) in the DSC curve. After dehydration, between 191 and 638 °C, the thermal
Preparation of the Ca–diclofenac complex in solid state
Study of the thermal behavior of the dehydration, transition phase and decomposition
stages of dehydration, transition phase, and the first and second stages of thermal decomposition. Besides this, an investigation with two mass samples was carried out, in order to determine the effect of changing the experimental variables as well as the