High-Pressure Study of the Vibrational Properties and Chemical Reaction of N-Vinyl-2-pyrrolidinone by Raman Spectroscopy

Abstract

The vibrational properties and chemical stability of N-vinyl-2-pyrrolidinone (NVP) were studied by Raman measurements under high pressure up to 28.5 GPa. When the pressure exceeded 0.4 GPa, NVP crystallized and the volume collapsed so significantly that the pressure around the sample dropped to 0.1 GPa. During the subsequent pressurization, when the pressure reached about 2.6 GPa, the abrupt changes in the Raman modes indicate the occurrence of a phase transition. Then, the continuous compression induced the irreversible chemical reaction beyond 15.0 GPa. The newly generated sp3 Raman modes in the product indicate the formation of carbon chains. This study revealed the polymerization process of NVP by adjusting only pressure, which is very useful for the related chemical synthesis.

High‐pressure‐induced phase transition and amorphization of xylitol by Raman spectroscopy

“…[3,12,[14][15][16] The changes in the structure, chemical information, and phase transition behavior can be demonstrated by the relationship between environmental changes and wavenumbers. [17][18][19] Moreover, the spot diameter of the laser from Raman is on the micron scale, which is appropriate for testing high-pressure samples at small sizes.…”