Study of Disorder in Different Phases of Tetratriacontane and a Binary Alkane Mixture, Using Vibrational Spectroscopy

• Published in: The journal of physical chemistry. B Vol. 111; no. 7; pp. 1604 - 1609
• Main Authors: Wickramarachchi, P. A. Suranga R, Spells, Stephen J, de Silva, D. Sujeewa M
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 22.02.2007
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp066207h

Raman spectroscopy has been used to investigate the monoclinic crystal → rotator → melt phase transitions in n-C34H70, for both real-time heating and cooling runs. Changes in band intensity and frequency in the CH2 bending, CH2 twisting, skeletal C−C stretching, and CH3 rocking regions revealed both transitions, particularly when using band components related to gauche bonds. In the room temperature infrared spectrum, the CH2 rocking−twisting and CH2 wagging progressions were observed and indexed for n-C34H70 and a 2:1 (w/w) mixture of C34H70 and C36D74. This led to best estimates for the all-trans crystal core in both cases of 33 to 34 carbon atoms, indicating that the core corresponds to almost the whole of the C34H70 molecule.