Multimers of 1-Propanol and their Heteromolecular Hydrogen Bonds with Ethyl Acetate: Fourier Transform Infrared Spectral Studies

Abstract

Fourier transform infrared spectral studies have been carried out on pure 1-propanol (PrOH), pure ethyl acetate (AcOEt), and 1:1 (ethyl acetate: 1-propanol), 1:2, 1:3, 2:1 and 3:1 binary solutions at room temperature. The broad hydroxyl stretching band of pure PrOH has been deconvoluted into six Gaussian profiles which have been assigned to the O–H stretching bands of monomer, open dimer (free and bonded O–H), closed trimer, closed tetramer and closed pentamer units with the aid of density functional theory frequency calculations. The carbonyl stretching bands of monomer and closed dimer of ethyl acetate have also been discussed. The classical and non-classical H-bond interactions of n-mers of 1-propanol with ethyl acetate monomer and dimer in the solutions have been investigated using the frequency shift of the hydrogen bond donor and acceptor bond stretching bands of PrOH and AcOEt. The concentration of PrOH/AcOEt-dependent PrOH n-mer-AcOEt complexation order has been analysed.