1. Lubricating and Waxy Esters. VI. Effect of Symmetry about Ester on Crystallization of Linear Monoester Isomers
- Author
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Suresh S. Narine, Shaojun Li, and Laziz Bouzidi
- Subjects
crystal structure ,Phase transition ,crystallization ,Physics and Astronomy (miscellaneous) ,General Mathematics ,jojoba-like wax esters ,02 engineering and technology ,Crystal structure ,010402 general chemistry ,01 natural sciences ,polymorphism ,law.invention ,Differential scanning calorimetry ,law ,Computer Science (miscellaneous) ,Crystallization ,Alkyl ,symmetry ,chemistry.chemical_classification ,lcsh:Mathematics ,Transition temperature ,lcsh:QA1-939 ,021001 nanoscience & nanotechnology ,X-ray diffraction ,0104 chemical sciences ,terminal double bond ,Crystallography ,Polymorphism (materials science) ,chemistry ,Chemistry (miscellaneous) ,X-ray crystallography ,differential scanning calorimetry ,0210 nano-technology - Abstract
The crystal structure development of jojoba-like esters incorporating either 1-decenoic acid and/or 1-decenol, namely octadec-9-enyl dec-9-enoate (JLE-281), and its isomer dec-9-enyl oleate (JLE-282) was investigated to reveal the effect of symmetry about the ester group on crystallization of aliphatic fatty monoesters. The phase transformation path was investigated with temperature-time resolved X-ray diffraction during stepped isothermal crystallization, and while cooling from the melt at a fixed rate. Startling differences in phase behavior were uncovered between the isomers. When stepped isothermals were used, selective extinctions occurred at a transition temperature for JLE-281 but not for JLE-282. The extinctions, which are due to dramatic changes in the electronic density of certain families of planes, indicate a phase transition attributed to a brusque rearrangement of the oxygen atoms in the crystal subcell. The phase transition did not occur when the JLEs were cooled continuously. The crucial role played by the position of the alkyl chain and its orientation relative to the easy rotation site of the C–O bond in the phase trajectories of the JLEs was particularly highlighted.
- Published
- 2014