Temperature and Methane Pressure Effects on the Spectral Characteristics of the Raman Bands of n-Butane in the Range 300–1100 cm–1.

Changes in the spectral characteristics of the vibrational bands of n-butane have been studied in the spectral range 300–1100 cm^–1 at a temperature varied from 285 to 365 K and a methane pressure varied in the range 2–40 atm. It was established that the enthalpy of the trans–gauche transition of n-butane in the gas phase is 657 ± 66 cal/mol. The methane pressure in the given range was found to have a negligible effect on the conformational equilibrium of n-butane. The impact of changes in the spectral characteristics of n‑butane on the accuracy of measuring the composition of natural gas using Raman spectroscopy was determined. [ABSTRACT FROM AUTHOR]