Regular Article

Pressure-induced phase transition of 1,4-dioxane: From twisted-boat- to chair conformer

College of Physics, Jilin University, Changchun 130012, P.R. China

^a e-mail: mzhou@jlu.edu.cn
^b e-mail: whb2477@jlu.edu.cn

Received: 30 December 2019
Received in final form: 16 April 2020
Published online: 16 June 2020

Abstract

1,4-dioxane presents promising application in the field of organic synthesis. To discover the structural and phase information of 1,4-dioxane under pressure, in-situ high-pressure Raman measurement of 1,4-dioxane is carried out up to 15 GPa. At around 0.5 GPa, 1,4-dioxane undergoes a liquid–solid phase transition from liquid phase to a new high-pressure phase I. The evolution of Raman spectra in the region of 350–650 cm⁻¹ suggests that 1,4-dioxane is transformed from twisted-boat conformer to chair conformer. When the pressure increases to about 8 GPa, 1,4-dioxane undergoes a solid–solid phase transition to another new high-pressure phase II. This study, for the first time, comprehensively analyzes the conformational transformation of 1,4-dioxane in the solid phase and provides a new experimental strategy to identify conformational isomers.