添加剂对氨基酸晶体生长的影响

氨基酸大多生长为针状或片状晶习，存在堆密度低、流动性差等问题，严重影响产品后加工处理过程。因此，实现氨基酸晶习的定向调控具有重要意义。添加剂对氨基酸晶习调控直接有效，广泛应用于工业生产中。本文主要从抑制和促进晶体生长两个角度，综述了添加剂对氨基酸晶体生长的作用机理。添加剂对晶体生长的抑制机理主要有两点：一是添加剂分子吸附到晶面上，阻碍溶质分子的扩散和聚集；二是添加剂分子嵌入晶格并占据生长位点。而添加剂促进晶体生长的机理为：添加剂加快了溶质分子在晶体表面的聚集速度、使晶体表面粗糙化和降低了溶剂层脱除能垒。最后，针对添加剂对氨基酸晶体生长影响的研究，从晶体工程的角度提出了通过分子模拟设计的添加剂定向控制氨基酸晶体生长，从而调控晶习的展望。

The regulation mechanism of additives on the amino acid crystal growth

Most of the amino acids grow in needle-like or sheet-like crystal habit, which have problems such as low bulk density and poor fluidity, and seriously affect the post-processing process of the product. Therefore, it is of great significance to control the crystal habit of amino acids. Additives are directly effective in regulating the crystal habit of amino acids and are widely used in industrial production. In this paper, the mechanism of additives on the growth of amino acid crystals is reviewed from the perspectives of inhibiting or promoting crystal growth. There are two main mechanisms for the inhibition of crystal growth by additives: one is that the additive molecules are adsorbed on the crystal surface, which hinders the diffusion and aggregation of solute molecules, the other is that the additive molecules are embedded in the crystal lattice and occupy growth sites. The mechanism of additive promoting crystal growth is that the additive accelerates the aggregation rate of solute molecules on the crystal surface, roughens the crystal surface and reduces the energy barrier removal of the solvent layer. Finally, we propose the prospect of directionally regulating the amino acid crystal growth through molecular design of additives from the perspective of crystal engineering.