| Abstrakt: |
The experimental temperaturecomposition phase diagram of the binary system decanedioic acid C10H18O4dodecanedioic acid C12H22O4 was established by combining Xray powder diffraction XRD, differentialscanning calorimetry DSC, infrared spectroscopy IR, scanning electron microscopy SEM, and thermooptical microscopy TOM. Both compounds crystallize in the same ordered form, CP21c, which is the phase that melts in both cases. The Cform melts in C12H22O4earlier than in C10H18O4, in contrast to other unbranchedchain compounds alkanes, alkanols, and alkanoic acids in which the melting temperatures increase as the Catom number rises. Contrary to what might be expected, total solidstate miscibility is not observed. The C10H18O4C12H22O4binary system shows a complex phase diagram. At low temperatures, a new monoclinic form, CiP21c, stabilizes as a result of the disorder of composition in the mixed samples; two C+Ci domains appear. Upon heating, four solid–solid and seven solid–liquid domains appear related by eutectic and peritectic invariants. All the crystallographic forms observed are isostructural. [ABSTRACT FROM AUTHOR] |
Plný text