Two-Dimensional Correlation Analysis of Temperature-Dependent FT-IR Spectra of Oleic Acid

Unger, Miriam and Chaturvedi, Deepika and Mishra, Soni and Tandon, Poonam and Siesler, Heinz W (2013) Two-Dimensional Correlation Analysis of Temperature-Dependent FT-IR Spectra of Oleic Acid. In: SPECTROSCOPY LETTERS, 46 (1). pp. 21-27.

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Abstract

In the present study, variable temperature FT-IR spectroscopic investigations were used to characterize the spectral changes in oleic acid during heating oleic acid in the temperature range from -30 degrees;C to 22 degrees C. In order to extract more information about the spectral variations taking place during the phase transition process, 2D correlation spectroscopy (2DCOS) was employed for the stretching (C?O) and rocking (CH2) band of oleic acid. However, the interpretation of these spectral variations in the FT-IR spectra is not straightforward, because the absorption bands are heavily overlapped and change due to two processes: recrystallization of the ?-phase and melting of the oleic acid. Furthermore, the solid phase transition from the ?- to the a-phase was also observed between -4 degrees C and -2 degrees C. Thus, for a more detailed 2DCOS analysis, we have split up the spectral data set in the subsets recorded between -30 degrees C to -16 degrees C, -16 degrees C to 10 degrees C, and 10 degrees C to 22 degrees C. In the corresponding synchronous and asynchronous 2D correlation plots, absorption bands that are characteristic of the crystalline and amorphous regions of oleic acid were separated.

Item Type:	Journal Article
Publication:	SPECTROSCOPY LETTERS
Publisher:	TAYLOR & FRANCIS INC
Additional Information:	Copyright for this article belongs to TAYLOR & FRANCIS INC, USA
Keywords:	2DCOS;generalized 2D correlation spectroscopy;oleic acid;phase transition;variable-temperature FT-IR spectroscopy
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	05 Mar 2013 06:16
Last Modified:	05 Mar 2013 06:16
URI:	http://eprints.iisc.ac.in/id/eprint/45962

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