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首页> 外文期刊>Chemistry and Physics of Lipids >The binary phase behavior of 1,3-dilauroyl-2-stearoyl-sn-glycerol and 1,2-dilauroyl-3-stearoyl-sn-glycerol
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The binary phase behavior of 1,3-dilauroyl-2-stearoyl-sn-glycerol and 1,2-dilauroyl-3-stearoyl-sn-glycerol

机译：1,3-二茂铁基-2-硬脂酰基-sn-甘油和1,2-二茂铁基-3-硬脂酰基-sn-甘油的二元相行为

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The binary phase behavior of purified 1,3-dilauroyl-2-stearoyl-sn-glycerol (LSL) and 1,2-dilauroyl-3-stearoyl-sn-glycerol (LLS) was investigated at a slow (0.1 °C/min) and a relatively fast (3.0 °C/min) cooling rate in terms of melting and crystallization, polymorphism, solid fat content (SFC), hardness and microstructure. Much of the behavior of the system is explained by its polymorphism and the influence of thermal processing. The α-form and the β-form of a double chain length structure were detected in the mixtures cooled at 3.0 °C/min, whereas only the β-form was detected in those cooled at 0.1 °C/min. X-ray diffraction data as well as thermodynamic data propose that the most stable phases are promoted by the symmetrical LSL. The measured trends in structural characteristics, thermal properties, SFC, relative hardness and microstructure delimit three groups of mixtures which imply a competition between the stabilizing effect of LSL and disordering introduced by kinetic effects: (a) LLS-rich mixtures with LSL molar fractions (XLSL) less than 0.3, (b) mixtures with XLSL clustered around 0.5 and (c) LSL-rich mixtures with XLSL =0.7. The balance between ordering and kinetic effects determines the polymorphism of the mixtures, which in turn determines the behavior of the LSL/LLS system. The kinetic phase diagram of the LSL/LLS binary system constructed using heating differential scanning calorimetry thermograms displayed a singularity at the 0.5LSL molar fraction which delimits two distinct behaviors: eutectic behavior in one region and monotectic behavior in the other. The molecular interactions, as depicted by a nonideality parameter of mixing obtained from a thermodynamic model based on the Hildebrand equation, suggests an almost ideal mixing behavior and a moderate tendency to the formation of unlike-pairs in the liquid state.
机译：在慢速（0.1°C / min）下研究了纯化的1,3-二茂铁基-2-硬脂酰基-sn-甘油（LSL）和1,2-二茂铁基-3-硬脂酰基-sn-甘油（LLS）的二元相行为）和相对较快的（3.0°C / min）冷却速度，包括熔融和结晶，多态性，固体脂肪含量（SFC），硬度和微结构。该系统的许多行为由其多态性和热处理的影响来解释。在以3.0°C / min冷却的混合物中检测到双链长结构的α-型和β-形式，而在以0.1°C / min冷却的混合物中仅检测到β-型。 X射线衍射数据以及热力学数据表明，对称的LSL促进了最稳定的相。测得的结构特征，热性能，SFC，相对硬度和微观结构的趋势界定了三类混合物，这暗示了LSL的稳定作用和动力学效应引起的无序之间的竞争：（a）具有LSL摩尔分数的富含LLS的混合物（ XLSL）小于0.3，（b）XLSL的混合物聚集在0.5左右，（c）XLSL = 0.7的富含LSL的混合物。有序和动力学效应之间的平衡决定了混合物的多态性，而后者又决定了LSL / LLS系统的行为。使用热差示扫描量热法热分析图构建的LSL / LLS二元系统的动力学相图在0.5LSL摩尔分数下显示出奇异性，这界定了两种不同的行为：一个区域的共晶行为和另一区域的单晶行为。如从基于Hildebrand方程的热力学模型获得的混合的非理想参数所描绘的，分子相互作用表明了几乎理想的混合行为和中等的液态异对形成趋势。

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