Study by infrared spectrometry of furan adsorbed on sodium chloride: experimental evidence of a new condensed phase

Abstract

Analysis of the infrared spectra has led to the determination of the mechanism of fixation of the furan molecules adsorbed on NaCl and their orientation on the crystal surface. No modification of the infrared spectra has been found at the temperatures of the liquid-solid or solid I-solid II phase transitions. By increasing the pressure of furan vapour in the cell, the formation of a new condensed phase (NPC) showing the same structure as the adsorbed phase is observed. When the adsorbed and solid II phases are simultaneously obtained, the latter is spontaneously transformed into the NPC phase. It is deduced that the interaction energy between the molecules of the NPC phase is more important than the lattice energy of solid II.