Williams-Seton L, Davey R J, Lieberman H F, Pritchard R G
Colloids, Crystals and Interfaces Group, Department of Chemical Engineering, UMIST, Manchester M60 1QD, UK.
J Pharm Sci. 2000 Mar;89(3):346-54. doi: 10.1002/(SICI)1520-6017(200003)89:3<346::AID-JPS6>3.0.CO;2-I.
The variation in physical properties of crystals grown in the presence of additives or impurities have previously been attributed to lattice disorder developed during crystallization. Adipic acid crystallized in the presence of a variety of stereochemically related impurities typifies such behavior with disorder manifest in variations of dissolution rates and enthalpies of solution and fusion. In this case the most extreme habit, produced by the presence of added monoalkanoic acids, is a rounded dumbbell that was suggested previously to be a twinned crystal. In this contribution such crystals are fully characterized both through their external morphology and by means of single crystal X-ray diffraction. These techniques show that these particles are not twinned but rather are disordered single crystals comprising a small number of slightly misaligned domains. The interaction between additive and substrate is modeled and new additives selected that induce the formation of true mechanical twins in adipic acid.
先前认为，在添加剂或杂质存在的情况下生长的晶体，其物理性质的变化归因于结晶过程中产生的晶格无序。在各种立体化学相关杂质存在的情况下结晶的己二酸就是这种行为的典型例子，无序表现为溶解速率以及溶解和熔融焓的变化。在这种情况下，由添加的单链烷酸的存在所产生的最极端晶习是圆形哑铃状，之前有人认为它是孪晶。在本论文中，通过其外部形态和单晶X射线衍射对这类晶体进行了全面表征。这些技术表明，这些颗粒不是孪晶，而是由少量轻微错位的畴组成的无序单晶。对添加剂与底物之间的相互作用进行了建模，并选择了新的添加剂来诱导己二酸中真正机械孪晶的形成。
