甘氨酸α-晶型定向转化为γ-晶型的影响因素研究

Study on the Factors Affecting the Directional Conversion of α-Glycine to γ-Glycine Crystal

α-晶型甘氨酸产品性质不稳定,易结块,而γ-晶型相对稳定。本文研究了α-晶型定向转化为γ-晶型的影响因素,湿度、添加剂以及溶剂种类等。研究发现湿度越大越有利于α-晶型的转化,存在一个临界转化湿度;盐类添加剂中,+1价金属离子有利于α-晶型的转化,在一定条件下均能转化为γ-晶型,阴离子和+2价金属离子均不会促进α-晶型的转化。溶剂种类对转化的结果表明中性溶液不利于α-晶型,在一定浓度的酸性或碱性溶液下,α-晶型也能定向转化为γ-晶型。

α-form glycine is not stable and easy to agglomerate, however γ-form glycine crystal structure is relatively stable. In this paper, the factors of humidity, additives and solvent types, affecting the orientation conversion of α-crystal form to γ-crystal form are studied. Results of humidity experiments show that higher humidity contributes to the transformation from α to γ form, also existed a critical humidity for transformation. In addition, salt additives experiments show that +1 valence metal ions are advantageous to the α-crystal shape transformation, under certain conditions can be converted into γ-crystal type, yet anion and +2 valence metal ions have little influence on the transformation process. Results of solvent type on the transformation show that neutral solution has little influence on the transformation, acid or alkaline solution under certain concentration forms the α-form convert to γ-form.