Solubility and Nucleation of Methyl Stearate as a Function of Crystallization Environment
Solubility and Nucleation of Methyl Stearate as a Function of Crystallization Environment
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DOI：
10.1021/acs.energyfuels.7b03212
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发表时间：
2018-03-01
期刊：
影响因子：
5.3
通讯作者：
Lewtas, Ken
中科院分区：
文献类型：
--
作者：
Camacho, Diana M.;Roberts, Kevin J.;Lewtas, Ken
硬脂酸甲酯从过饱和十二烷，煤油和甲苯溶液的结晶研究揭示了强有力的证据，溶剂的选择影响溶解度和成核行为。甲苯、煤油和十二烷的溶质溶解度分别低于理想值，表现出最接近理想值的行为，后者与最高溶剂化一致。使用Kashchiev-Borissova-Hammond-Roberts（KBHR）模型的多热结晶研究[Kashchiev等人，J. Phys. Chem. B 2010，114，5441; Kashchiev等人，J. Cryst. Growth 2010，312，698; Camacho等人CrystEngComm 2014，16，974]揭示了一个渐进成核（PN）机制与微晶界面张力对于十二烷、煤油和甲苯，γ（eff）值分别在0.94和1.55 mJ/m2之间、1.21和1.91 mJ/m2之间以及1.18和1.88 mJ/m2之间。临界过冷度下的成核速率介于4.56 × 10（16）和1.79 × 10（17）个核/mL.s之间，最高速率与煤油溶液中的结晶有关。十二烷的等过饱和成核速率最高，为2.39 × 10 ~（17）~ 3.63 × 10 ~（18）核/mL. s。在甲苯中的成核似乎是阻碍其相对较高的界面张力，这是与成核速率约一个数量级小于十二烷获得的。
Crystallization studies of methyl stearate from supersaturated dodecane, kerosene, and toluene solutions reveal strong evidence that solvent choice influences solubility and nucleation behavior. Solute solubility is less than ideal with toluene, kerosene, and dodecane, respectively, exhibiting the closest behavior to ideality, the latter consistent with the highest solvation. Polythermal crystallization studies using the Kashchiev-Borissova-Hammond-Roberts (KBHR) model [Kashchiev et al. J. Phys. Chem. B 2010, 114, 5441; Kashchiev et al. J. Cryst. Growth 2010, 312, 698; Camacho et al. CrystEngComm 2014, 16, 974] reveal a progressive nucleation (PN) mechanism with crystallite interfacial tension (gamma(eff)) values between 0.94 and 1.55 mJ/m(2), between 1.21 and 1.91 mJ/m(2), and between 1.18 and 1.88 mJ/m(2) for dodecane, kerosene, and toluene, respectively. Nucleation rates at the critical undercooling lie between 4.56 x 10(16) and 1.79 X 10(17) nuclei/mL.s, with the highest rates associated with crystallization from kerosene solutions. Iso-supersaturation nucleation rates are the highest for dodecane ranging from 2.39 X 10(17) to 3.63 X 10(18) nuclei/mL.s. Nucleation in toluene appears to be hindered by its relatively higher interfacial tension, which is associated with nucleation rates about an order of magnitude less than those obtained for dodecane.