Kinetic analysis of isothermal, non-isothermal and catalysed thermal decomposition of malonic acid

Abstract

A comparative study of the isothermal and non-isothermal decompositions of malonic acid has been carried out using the gasometric technique at atmospheric pressure. Under isothermal conditions, the results indicate two different mechanisms. At lower operating temperatures the decomposition process is governed by first-order kinetics, while at higher ~temperatures it is controlled by the random nucleation Erofeev equation. Analysis of the non-isothermal TG curves proved the advantageous use of this technique. It provides quick and valid information about the the r~nal decomposition kinetics of malonic acid, both in the pure state and when catalysed by solid 12-molybdophosphoric acid and its bismuth salts. Via the applicability of a non-isothermal kihetic equation, it was demonstrated that the factor causing the enhancemen! effect of these catalysts is mainly electronic in nature.The kinetics of thermal decomposition of solids has attracted the interest of investigators under both isothermal and non-isothermal conditions. It has been reported [1,2] that the kinetic analysis of thermogravimetric data obtained under isothermal conditions is preferable, with the integral kinetic equationwhere ~ is the fraction of solid decomposed after time t, K is the constant rate, which is related with temperature by the Arrhenius equation

Accelerating Effect of Poly(vinylpyrrolidone) Matrix on Thermal Decomposition of Malonic Acid

“…Apparently, the accelerating action persists but its efficiency decreases; i.e., the acceleration is close to its saturation. Note that the aforementioned temperature depressions are comparable to those reported 58 for the thermal decomposition of MA catalyzed by molybdophosphoric acid and its bismuth salts.…”

“…On the other hand, the thermal decomposition of MA is of general interest because it represents a wide class of decarboxylation reactions. On heating, MA is well-known − to decompose forming acetic acid and carbon dioxide: Therefore, the results obtained on the effect of PVP on the thermal decomposition of MA should be of importance for understanding the thermal stability of various compounds containing the carboxylic group, including drugs.…”

Hydrophobic functional liquids based on trioctylphosphine oxide (TOPO) and carboxylic acids

“…3). [78][79][80][81][82][83] This decomposition pathway has recently been reported also in choline chloride:malonic acid eutectics. 84…”

A microwave molecular solution based approach towards high-κ-tantalum(v)oxide nanoparticles: synthesis, dielectric properties and electron paramagnetic resonance spectroscopic studies of their defect chemistry

“…S2, ESI †). According to earlier investigations by other groups, the decomposition of malonic acid proceeds by cleavage, yielding carbon dioxide and acetic acid, 22,23 whereas salts of malonic acid with alkali, alkaline earth or transition metals also lead to the formation of acetone and esters as by-products. 23,24 In the present investigation the tantalum complexes (1)-(3) lead to a plethora of gaseous products, those were obviously dependent on the nature of the alkoxylato moiety.…”