Thermochemistry of hydrogen bonding of linear and cyclic amides in proton acceptors media

•Enthalpies of solution were measured of amides in 10 proton acceptor solvents.•Enthalpies of NH⋯B hydrogen bonds were calculated for amides with proton acceptors.•Hydrogen bond enthalpies of linear and cyclic amides are differed.

In present work thermochemistry of hydrogen bond formation of linear (acetamide (АА), N-methylacetamide (NMA), N,N-dimethylacetamide (DMAA)) and cyclic amides (2-pyrrolidone (Py), N-methyl-2-pyrrolidone (MPY)) in the medium of proton acceptors (B) was studied. Enthalpies of solution of amides in nitriles, ketones, esters, ethers and amines were measured at 298.15 and infinite dilution conditions. Enthalpies of hydrogen bonding of studied solutes with proton acceptor solvents were determined on the basis of experimental data. It was shown that proton donor properties of 2-pyrrolidone are more pronounced than linear amides. Enthalpies of hydrogen bonding of acetamide in proton acceptors are twice more than N-methylacetamide due to formation of 1:2 complexes.

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