The nucleus in solid state reactions: Towards a definition

Integrated Approach to Study the Dehydration Kinetics of Nitrofurantoin Monohydrate

“…With respect to solid‐state kinetics, these initial nuclei most probably represent the germ/growth nuclei. As a precursor of them, incipient nuclei, defined as a modified or somewhat activated site on the reactant, may not be accessible to experimental detection under most conditions 43. From each nuclei, the propagation of a dehydration reaction is visible along two directions, the a ‐axis and the b ‐axis.…”

A kinetic study of the dehydrations of the alums KCr(SO4)2. 12H2O and KAl(SO4)2. 12H2O

“…The present results will also be compared with behaviour characterized for other dehydrations (Galwey & Laverty 1990;Galwey 1992). Guarini & Dei (1983) demonstrated that, in addition to the alums mentioned above, orange peel texture is developed during the dehydrations of a number of other crystalline hydrates.…”

“…The vacuum apparatus was identical with that already described by Carr & Galwey (1986) and used for the previous dehydration studies of Li2S04.H 20 (Galwey et al 1990) and of lignite (Brady et al 1990). The pressure of product water vapour in the constant volume was recorded automatically at specified times from the output of a MKS 222B absolute pressure gauge (range 0-1500 N m-2, read with an accuracy of +0.1 N m-2).…”

“…Studies of the dehydrations of alums have contributed significantly towards the establishment of theoretical foundations for the rate expressions that are used in kinetic descriptions of solid state reactions (Brown et al 1980;Galwey et al 1981) and, in particular, the characterization of nucleation (Galwey & Laverty 1990) and growth ) processes. However, rate studies which investigated the reactions of this type that occur during the dehydrations of KCr(S04)2.12H20, KA1(S04)2.…”

A kinetic study of the thermal dehydration of calcium sulphite hemihydrate

“…Previous work has been concerned with the release of water from alums (1,2), lithium potassium tartrate monohydrate (3), lithium sulphate monohydrate (4), magnesium chloride dihydrate ( 3 , and lignite (brown coal) (6). Conclusions based on dehydration studies have contributed significantly to our theoretical understanding of solid state reactions generally (7)(8)(9)(10) and the reaction models developed have been applied to diverse chemical changes proceeding in varied crystalline reactants (7). In extending this approach we now report a study of the dehydration of CaSO, -1/2H20.…”