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Temperature Evolution of Cluster Structures in Ethanol

DOI: 10.1155/2013/473294

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Abstract:

The dependence of FTIR spectrum of pure ethanol on the temperature was investigated. The measurements were performed for frozen (the minimum temperature ?180°C) and liquid ethanol (the maximum temperature 40°C). All changes in IR spectrum of ethanol during gradual warming were detected and analyzed. On the bases of preset observations, the conclusions concerning the evolution of cluster structures in ethanol during transition from solid (frozen) state to liquid state were made. 1. Introduction The alcohols belong to the specific kind of species since their molecules can form hydrogen bonds and arrange in different structures named clusters. Numerous works were devoted to the investigation of these substances. Special attention was paid to the investigation of monohydric alcohols among which methanol [1–5] and ethanol [6–9] were the most popular as the simplest ones. The main competitive structures are ring and chainlike clusters. In the first type of clusters, all hydroxyl groups of alcohol molecules are H-bonded with neighboring molecule until the conditionally last molecule would bond with the first one. In chainlike structures, the last molecule is not bonded with the first one, thus leaving one hydroxyl group free. But the situation is still not obvious, and different authors postulate different sets of clusters that exist in liquid phase on the basis of different experimental and theoretical techniques [1–11]. Also the evolution of cluster structures during the change of ambient conditions has not been followed yet. In the first stage of such type of investigations, we decided to choose infrared spectroscopy as the experimental tool since any changes in clusters sizes and types may be clearly detected by IR spectrum. Ethanol was chosen as the object of investigation. 2. Methodology Registration of the presented spectra was performed in the laboratory of Fourier transform infrared absorption spectroscopy in the Faculty of Physics of Vilnius University, Lithuania. All spectra were recorded using Bruker’s FTIR-spectrometer VERTEX 70 equipped with LINKAM cryostat (model FTIR 600). The spectra were recorded in the spectral range from 750 to 4000?cm?1 and in temperature range from ?180 to 40°C. Liquid-N2-cooled mercury cadmium telluride (MCT) was used as a detector. Spectral resolution was set to 1?cm?1, and in order to increase signal-to-noise ratio, each spectrum was taken as an average of??128 scans. Liquid ethanol with purity greater than 99.9 from Fluka was used as received. In Figure 1, the registered FTIR spectra of ethanol at different

References

[1]  S. L. Boyd and R. J. Boyd, “A density functional study of methanol clusters,” Journal of Chemical Theory and Computation, vol. 3, no. 1, pp. 54–61, 2007.
[2]  I. Yu. Doroshenko, O. I. Lizengevych, V. E. Pogorelov, and L. I. Savransky, “Associates of methanol molecules: quantum-chemical calculations of structure and vibrational spectra,” Ukrainian Journal of Physics, vol. 49, no. 6, pp. 540–544, 2004.
[3]  R. Ludwig, “Isotopic quantum effects in liquid methanol,” ChemPhysChem, vol. 6, no. 7, pp. 1376–1380, 2005.
[4]  I. Bako, P. Jedlovzky, and G. Palinkas, “Molecular clusters in liquid methanol: a reverse Monte Carlo study,” Journal of Molecular Liquids, vol. 87, no. 2, pp. 243–254, 2000.
[5]  S. Kashtanov, A. Augustson, J. E. Rubensson et al., “Chemical and electronic structures of liquid methanol from X-ray emission spectroscopy and density functional theory,” Physical Review B, vol. 71, no. 10, pp. 1–8, 2005.
[6]  M. Tomsic and A. Jamnik, “Structural properties of pure simple alcohols from ethanol, propanol, butanol, pentanol, to hexanol: comparing Monte Carlo simulations with experimental SAXS data,” Journal of Physical Chemistry B, vol. 111, no. 7, pp. 1738–1751, 2007.
[7]  A. Vrhovsek, O. Gereben, A. Jamnik, and L. Pusztai, “Hydrogen bonding and molecular aggregates in liquid methanol, ethanol, and 1-propanol,” Journal of Physical Chemistry B, vol. 115, no. 46, pp. 13473–13488, 2011.
[8]  Y. J. Hu, H. B. Fu, and E. R. Bernstein, “Infrared plus vacuum ultraviolet spectroscopy of neutral and ionic ethanol monomers and clusters,” Journal of Chemical Physics, vol. 125, Article ID 154305, 2006.
[9]  C. J. Benmore and Y. L. Loh, “The structure of liquid ethanol: a neutron diffraction and molecular dynamics study,” Journal of Chemical Physics, vol. 112, no. 13, pp. 5877–5883, 2000.
[10]  J. Lehtola, M. Hakala, and K. H?m?l?inen, “Structure of liquid linear alcohols,” Journal of Physical Chemistry B, vol. 114, no. 19, pp. 6426–6436, 2010.
[11]  I. M. Svishchev and P. G. Kusalik, “Structure in liquid methanol from spatial distribution functions,” The Journal of Chemical Physics, vol. 100, no. 7, pp. 5165–5171, 1994.
[12]  G. A. Pitsevich, I. Y. Doroshenko, V. Y. Pogorelov, V. Shablinskas, and V. Balevichus, “Structure and vibrational spectra of gauche- and trans-conformers of ethanol: Nonempirical anharmonic calculations and FTIR spectra in argon matrices,” Low Temperature Physics, vol. 39, article 389, 2013.
[13]  N. P. G. Roeges, A Guide To the Complete Interpretation of the Infrared Spectra of Organic Structures, John Wiley & Sons, New York, NY, USA, 1994.
[14]  S. Coussan, Y. Bouteiller, J. P. Perchard, and W. Q. Zheng, “Rotational isomerism of ethanol and matrix isolation infrared spectroscopy,” Journal of Physical Chemistry A, vol. 102, no. 29, pp. 5789–5793, 1998.
[15]  A. J. Barnes and H. E. Hallam, “Infra-red cryogenic studies. Part 5. Ethanol and ethanol-d argon matrices,” Transactions of the Faraday Society, vol. 66, pp. 1932–1940, 1970.
[16]  J. R. Dunig, H. Deeb, I. D. Darkhalil, J. J. Klassen, T. K. Gounev, and A. Ganguly, “The r0 structural parameters, conformational stability, barriers to internal rotation, and vibrational assignments for trans and gauche ethanol,” Journal of Molecular Structure, vol. 985, no. 2-3, pp. 202–210, 2011.
[17]  G. Pitsevich, I. Doroshenko, V. Pogorelov, V. Shablinskas, V. Balevichus, and N. Kozlovskaya, “Nonempiric anharmonic computations of IR spectra of ethanol conformers in B3LYP/-pVQZ approximation (stretch-vibrations),” The American Journal of Chemistry, vol. 2, no. 4, pp. 218–227, 2012.

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