Wydział Chemii

Władysław Wrzeszcz

Paweł Tomza

Michał Kwaśniewicz

Sylwester Mazurek

Roman Szostak

Mirosław A. Czarnecki

2016

RSC Advances

6

37195-37202

10.1039/C6RA04595B

Naukowa

Angielski

Artykuł

This paper reports ATR-IR and NIR spectroscopic studies on microheterogeneity in binary mixtures of
methanol with five short chain aliphatic alcohols: ethanol, 1-propanol, 2-propanol, tert-butanol and
cyclopentanol. The inhomogeneity distribution of molecules in the mixtures was characterized by MIR/
NIR excess absorption spectra, two-dimensional correlation approach, and chemometric methods. The
experimental data were compared and discussed with the theoretical calculations of homo- and
heteroclusters of different size and composition. The results obtained in the present work allow us to
infer that all studied mixtures deviate from the ideal and the largest effect appears at equimolar mixture.
At this composition about 50% of molecules are involved in the mixed clusters. In the entire range of
compositions in the mixtures coexist the clusters of pure alcohols and heteroclusters with an average
mole ratio of 1 : 1. Only in methanol/tert-butanol mixture was observed an additional tert-butanol-rich
cluster with an average methanol : tert-butanol mole ratio between 1 : 3 and 1 : 4. The excess absorption
and two-dimensional correlation spectra reveals that methanol/ethanol mixture is the closest to the
ideal one, while the largest degree of non-ideality was observed for methanol/tert-butanol mixture. The
extent of deviation from the ideal mixture increases with an increase in the chain length and the order of
the alcohol. These trends are correlated with decreasing degree of self-association of the alcohol.

CC-BY

http://dx.doi.org/10.1039/C6RA04595B

https://www.rsc.org/