γ-氨基丁酸晶体成核动力学、晶体生长及热力学性质研究

Investigation on the Nucleation Kinetics,Growth and Thermal Properties of γ-aminobutyric Acid Crystal

本文研究了γ-氨基丁酸的热力学及成核动力学性质。对γ-氨酪酸晶体的热力学性质进行研究,γ-氨基丁酸的差示扫描量热研究表明:γ-氨基丁酸的熔点为190.6℃,熔化焓为-343.4 J/g。测定了不同温度下γ-氨基丁酸在水中的溶解度及不同过饱和度下的诱导期。结果表明:γ-氨基丁酸的诱导期随着过饱和度的增加而降低。通过经典成核理论计算了固-液表面张力、成核自由能和临界成核半径。

In this paper, the nucleation kinetics and thermal properties of γ-aminobutyric acid which is the chief inhibitory neurotransmitter in the mammalian central nervous system were investigated. The grown crystals have also been subjected to thermal studies. The DSC studies showed that the sample started to melt at 190.6 ℃ with high melting enthalpy of -343.4 J/g. The solubility of γ-aminobutyric acid was estimated at different temperatures in water. The induction period was measured for the different supersaturation ratios. The study revealed that the induction period of γ-aminobutyric acid decreased as the supersaturation increasing. The metastable zone width of γ-aminobutyric acid was measured by polythermal method. Interfacial tension has been estimated by the experimentally determined induction period values. Nucleation parameters, such as the radius of critical nucleus and the Gibbs free energy barrier, have also been investigated based on classical nucleation theory. The relationship between high melting enthalpy of γ-aminobutyric acid and its structure was also explained.