Crystallization of s-carboxymethyl-cysteine for its optical resolutic

从工业应用的角度研究了s-羧甲基半胱氨酸（l-SCMC）在氯化钠存在下的过饱和溶液中的结晶现象。特别是采用间歇结晶器悬浮晶种的方法，重点讨论了细粉在l-SCMC晶种上的粘附现象及其二次成核现象。在这些测试中，标记的晶种也被悬浮，并且还观察到在晶体表面上发现的细粒群体，获得以下结果。1）悬浮在过饱和溶液中的细粒群体在间歇操作的初始阶段几乎恒定。在籽晶表面上，几乎没有发现细小颗粒，但是粘附在籽晶上的细小颗粒的数量随着籽晶生长周期的增加而增加。在这些条件下，人口是不同的过饱和度和罚款的l-SCMC。通过对种子表面粘附的观察，建立了粘附微粒的模型，并从理论上解释了悬浮微粒的聚集率与粘附率之间的线性关系。当晶种被细小颗粒覆盖的表面积达到50%左右时，粘附的细小颗粒量与生长周期的关系曲线偏离理论曲线。2）观察到d-SCMC粘附在晶种表面的量。在l-SCMC晶种上出现d-SCMC微粒的初期，d-SCMC微粒的粘附量随运行时间的四次方增加。在种子表面观察到d-SCMC后1.5 h，在悬浮细颗粒中观察到d-SCMC。在此基础上，提出了d-SCMC的异相成核模型，认为微细颗粒悬浮在工业结晶器的过饱和溶液中，影响晶体的生长速度和质量。在研究结晶器生产所需晶体的优化设计时，细小颗粒对生长晶体的粘附现象是一个重要问题。

Crystallization phenomena of l-SCMC(s-carboxymethyl-cysteine)in supersaturated solution of dl-SCMC in the presence of sodium chloride was studied from the point of view of industrial purpose. Especially, sticking phonomena of fines on l-SCMC seed crystal and secondary nucleation by it were focused and discussed by suspended seed crystal in a batch crystallizer. In these tests, the marked seed crystal was also suspended and populations of fines found on a crystal surface were also observed, following results were obtained.1)Population of fines suspended in supersaturated solution were almost constant for initial period of batch operation. On a surface of seed crystal, fines were hardly found, but population of fines stuck on seed increased with increase of growth period of seed crystal. On these conditions, population were different by degree of supersaturation and fines were of l-SCMC. From the observation of seed surface rharked, behavior of stuck fines were modeled, and linear correlation between population rate of suspended fines and sticking rate of fines, observed were explained theoretically. When surface area of seed crystal covered by fines became about fifty percents, plots between amount of stuck fines and growing period, became deviated from theoretical line.2)Amount of d-SCMC stuck on crystal surface were observed. For initial period that fines of d-SCMC appeared on l-SCMC seed, amount of stuck d-SCMC fines increased with fourth power of operating period. After 1.5 h after d-SCMC was observed on seed surface, d-SCMC was observed in the suspended fines. From this results, heterogeneous nucleation model of d-SCMC was proposed.Fines are generally considered to be suspended in a supersaturated solution in an industrial crystallizer and affect on growth rate and quality of product crystal. When optimum design for produce of desired crystal in a crystallizer is studied, sticking phenomena of fines on growing crystal is considered important.