Kinetics and mechanism insights into the heterogeneous methylation of nitroguanidine with aqueous methylamine

Abstract

This study investigated the kinetics and mechanism of the heterogeneous methylation of nitroguanidine with aqueous methylamine. The experiments were conducted in the temperature range of 303–318 K. To eliminate the effect of external diffusion, sufficient agitation was provided. Additionally, a shrinking core model and a dissolution model were developed to research the effects of dissolution, internal diffusion, and chemical reaction. The kinetic parameters of these models were fitted using experimental data, and the calculated results were compared with experimental data to assess the model’s applicability. The developed model was used to study the influence of the initial concentration of methylamine and particle diameter of nitroguanidine on the reaction. This work presents a case for the kinetic modeling of solid-liquid reactions considering non-constant liquid reactant concentrations, aiming to optimize the overall process efficiency of organic solid-liquid phase reactions.