Impact of malonic acid on the segregation of glycine polymorphs – Analytical assisted molecular approach

Abstract

Proton dissociation assisted negative polarity of malonic acid molecules admist glycine zwitterions leads to orgination of γ nucleation in the solution. Alteration in the nucleation behaviour and segregation of glycine polymorphs in the presence of malonic acid over a wide range of concentrations has been investigated both by experimental and analytical approaches. Complete changeover in the nucleation behaviour from 100% α to 100% γ is observed at the critical concentration of the additive. Shifting in the overall charge environment of the system towards cationic in the presence of malonic acid favours the nucleation of γ through induced charge compensation in the solution. Tuning of merohedral twinning in γ nucleation by the additive concentration has been well revealed in the present work. CNT based analytical approach employed elucidates well the experimental observations through the estimated interfacial energy, volume excess free energy, critical radius, activation energy barrier and nucleation rates of α and γ polymorphs. Structural affirmation of the nucleated polymorphs was carried out by powder x-ray diffraction.

Nucleation of amino acid‐rich crystals on the surface of dried scallop (Chlamys farreri) during storage: formation mechanism and influence of environmental relative humidity

“…The diffraction peaks at 12.68° and 18.52° were assigned to Tau as in good agreement with the reported patterns (Momma et al ., ). The characteristic diffraction peaks for α‐ and γ‐glycine were reported at 29.5° and 25.4° (Devi & Srinivasan, ). In another study of glycine crystal growth in the solution of zinc acetate dehydrate, the position of the peaks of α‐glycine crystal was found to be at 29.67°, while at 25.3° for γ‐glycine.…”

Separation and nucleation kinetics of l-menthol polymorph through a swift cooling crystallization process

“…6. The interfacial energy can be calculated using experimentally determined values of induction time based on nucleation theory, 27,31–39 where τ is the induction period of l -menthol solution with respect to temperature T , B is a constant determined by the graph plotting against ln τ and the intercept of straight line on y -axis gives the value of ln B , V is the molar volume of the crystal, N A is the Avogadro's number and R is a gas constant.…”