Polymorphism and structural mechanism of the phase transformation of phenyl carbamate (PC).
Crystallization experiments with phenyl carbamate as a hydrogen-bond donor with crown ethers have led to the discovery of three unknown polymorphs of phenyl carbamate. In this contribution, we characterize the phenyl carbamate polymorphs by a variety of methods including variable temperature powder X-ray diffraction (PXRD), vibrational spectroscopy (infrared and Raman), calorimetry (DSC) and optical microscopy (HSM). The phase transformation from form I to form II is rapid by both solution-mediated and solid state transformation processes. Through comparison of the two structures of form I and form II it is possible to propose a mechanism for the transformation.
Wishkerman
Sara
S
Department of Chemistry, Ben-Gurion University of the Negev, P.O. Box 653 Beer Sheva, 84105, Israel.
Bernstein
Joel
J