Nucleation mechanism and kinetics from the analysis of polythermal crystallisation data: methyl stearate from kerosene solutions
Nucleation mechanism and kinetics from the analysis of polythermal crystallisation data: methyl stearate from kerosene solutions
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DOI：
10.1039/c3ce41098f
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发表时间：
2014-01-01
期刊：
影响因子：
3.1
通讯作者：
More, Iain
中科院分区：
文献类型：
--
作者：
Corzo, Diana M. Camacho;Borissova, Antonia;More, Iain
描述了一种评估溶液结晶机制和动力学的多热方法，并将其与最近提出的结晶临界过冷依赖于冷却速率的模型（D. Kashchiev， A. Borissova， R. B. Hammond， K. J. Roberts， J. Cryst）联系起来。中国农业科学，2010 (5):391 - 391；期刊。化学。生物医学工程学报，2010(5):591 - 596。这个第一性原理模型可以确定结晶参数，否则只能通过等温和多热方法的联合应用来获得。通过分析煤油溶液中硬脂酸甲酯结晶的实验数据，验证了该方法的有效性。煤油溶液的浓度为200至350 g l。分析表明，晶体界面张力值在1.64 ~ 1.79 mJ/m(2)之间，与溶液浓度无明显关系，与等温法得到的结果吻合较好。灵敏度分析得出的结论是，至少四种不同的冷却速率跨越至少一个数量级，并且在每种冷却速率下的结晶温度值至少重复五次是合适的。大量的补充材料提供了上述作者模型的数学描述，对该模型与经验Nyvlt模型之间关系的见解，以及对所使用的实验方法进行敏感性分析结果的进一步详细说明。
A polythermal methodology to assess the mechanisms and the kinetics of solution crystallisation is described and used in connection with a recently proposed model for the dependence of the critical undercooling for crystallisation on the cooling rate (D. Kashchiev, A. Borissova, R. B. Hammond, K. J. Roberts, J. Cryst. Growth, 312 (2010) 698-704; J. Phys. Chem. B, 114 (2010) 5441-5446). This first principles model allows determination of crystallisation parameters that could otherwise only be obtained by combined application of both the isothermal and the polythermal methods. The methodology is validated through analysis of experimental data measured for methyl stearate crystallising from kerosene solutions with concentrations from 200 to 350 g l(-1). The analysis reveals a progressive heterogeneous nucleation mechanism and crystallite interfacial tension values between 1.64 and 1.79 mJ/m(2) with no obvious dependence on the solution concentration, in good agreement with values derived by isothermal methods. Sensitivity analysis leads to the conclusion that a minimum of four different cooling rates spanning at least one order of magnitude together with at least five repeats for crystallisation temperature values at each cooling rate are appropriate. Extensive supplementary material provides a mathematical description of the above authors' model, insight into the relationship between this model and the empirical Nyvlt model, and further detail concerning the results of the sensitivity analysis carried out on the experimental methodology used.