Solid state reaction of mixed powder compacts of succinic anhydride and paranitraniline

Solid State Reactions - Theoretical and Experimental Aspects

Abstract: (1984). Solid State Reactions - Theoretical and Experimental Aspects. Drug Development and Industrial Pharmacy: Vol. 10, No. 8-9, pp. 1175-1276.

Stability Aspects of Preformulation and Formulation of Solid Pharmaceuticals

Abstract: (1984). Stability Aspects of Preformulation and Formulation of Solid Pharmaceuticals. Drug Development and Industrial Pharmacy: Vol. 10, No. 8-9, pp. 1373-1412.

Acceleration of the addition reaction of succinic anhydride and p-nitroaniline in synthetic aluminium silicate

Abstract: Intact and heat-treated synthetic aluminum silicates (SAS) were used to investigate the change in crystalline properties and the solid-state reaction of succinic anhydride and p-nitroaniline mixed with SAS. Heat-treated SAS was obtained by heating at 850°C for 3 h. Pore volume and specific surface area of SAS heated at 120°C (SAS120) were much greater than those of SAS heated at 850°C (SAS850). From the powder X-ray diffraction measurement, it was found that the mixing of organic compounds with SAS caused changes in their crystalline state. The ability of SAS120 for changing organic components from crystal to amorphous state was greater than that of SAS850. Extreme acceleration of the addition reaction between succinic anhydride and p-nitroaniline was observed when mixed with SAS. The acceleration of the reaction can be explained in terms of the adsorption of organic molecules in the pores of SAS and the surface acidity of SAS.

Numerical Data for Some Commonly Used Solid State Reaction Equations

Abstract: Many solid state reactions can be represented by equations of the type F(α) =kt, where α is the fraction of material reacted in time, t. These equations can be expressed in the form F(α) =A(t/t0.5) where t0.5 is the time for 50% reaction and A is a calculable constant depending on the form of F(α). Numerical tables are given of F(α) in relation to α, and to (t/t0.5), for nine equations corresponding to reactions which are diffusion controlled, or are reaction-rate controlled, or obey first order kinetics, or follow the equations of Avrami and Erofe'ev. The application of the tables to the analysis of experimental data is described.

Kinetic Model for Solid‐State Reactions

Abstract: A model for solid‐solid or solid‐gas reactions between spherical particles and a fine powder or gas has been developed. The oxidation of uniformly sized nickel spheres has been shown to fit this model to 100% reaction. Previously reported models are inadequate because they do not meet the boundary conditions set down and because the volume of the product was assumed to equal that of one of the reactants. The inadequacy of earlier experimental results has been explained by the failure to experimentally meet the boundary conditions imposed.

Kinetics and Mechanism of the Reaction Between Zinc Oxide and Barium Carbonate

Abstract: The kinetics of reaction between BaCO3 and ZnO were studied using thermogravimetric analysis to monitor the percent reaction versus time. Solid state reaction models based on (a) product growth controlled by diffusion through a continuous product layer, (b) product growth controlled by phase boundary reactions, and (c) the concept of an order of reaction, were invalid for the reaction studied. The kinetics of the reaction were described by the kt=–ln (1 –x)⅔ nuclei growth equation. The defect nature of the zinc oxide studied was altered by doping with Li2O and Cr2O3. The activation energy for the reaction of BaCO3 and pure ZnO was 54.6 kcal/mole. The changes in activation energy with the type and amount of ZnO doping cannot be accounted for by the quasi-chemical theory of solids.