Solvent Effects on Hydrogen Bonding Between Ethanol and Acrylic Esters

Abstract

The association between ethanol and acrylic esters (methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate and butyl methacrylate) in non-polar solvents, viz. n-hexane, carbon tetrachloride and benzene has been investigated by means of FTIR spectroscopy. The formation constants of 1:1 complexes have been calculated using Nash’s method. The values of the formation constant and the Gibbs energy vary with ester chain length, which suggests that the strengths of the intermolecular O–H···O=C bonds are dependent on alkyl group of the acrylic ester and the results show that the proton accepting ability of acrylic esters is in the order methyl methacrylate < ethyl methacrylate < butyl methacrylate and methyl acrylate < ethyl acrylate < butyl acrylate. The results also show a significant dependence of the association constant upon the solvents used. The solvent effect on the hydrogen bond equilibria is discussed in terms of specific interaction between the solute and solvent.