51604-53-6Relevant articles and documents
Crystallization and polymorphism of 1,3-acyl-palmitoyl-rac-glycerols
Craven, R. John,Lencki, Robert W.
experimental part, p. 1113 - 1123 (2011/11/07)
Crystallization and melting behavior, small-angle X-ray scattering, X-ray powder diffraction and infra-red absorbance were measured for nine 1,3-acyl-palmitoyl-rac-glycerols (1,3-acetoyl-, -butyroyl-, -hexanoyl-, -octanoyl-, -decanoyl-, -lauroyl, -myristoyl- and -oleoyl-palmitoyl-rac-glycerol and 1,3-dipalmitoyl-glycerol). All but one of the prepared 1,3-diacylglycerols (1,3-DAG) were β-stable with 1,3-acetoyl-palmitoyl-rac-glycerol being the exception (β-stable). Small-angle X-ray scattering indicates that molecules in β-tending diacid 1,3-DAG adopt a herringbone-type configuration similar to monoacid 1,3-DAG. In this configuration acyl chains of the same length associate and regular chain-end matching between terminal methyl groups delineate lamellae. In contrast, molecules in crystalline 1,3-acetoyl-palmitoyl- rac-glycerol are oriented similar to those of 1(3)-monoacylglycerol. Interestingly, DSC curves indicate five of the nine diacid compounds have meta-stable forms-suggesting these forms are quite common for diacid 1,3-DAG. Meta-stable forms are observed in the melting curve when the difference in length between acyl chains is large (1,3-acetoyl-, -butyroyl- and -hexanoyl-palmitoyl-rac-glycerol), and in the crystallization curve when the difference is moderate (1,3-decanoyl- and -lauroyl-palmitoyl-rac-glycerol).
