Table 5.

Hydrogen bonding enthalpies of N-methylbutyrolactam, N-methylvalerolactam, N-methylcaprolactam in proton donor solvents (S), (kJ·mol⁻¹, T= 298.15 K, P = 0.1 MPa) ^a.

Solvent (S)	N-methylbutyrolactam	N-methylvalerolactam	N-methylcaprolactam
Dichloromethane	−4.9	−4.5	−3.9
Chloroform	−17.7	−17.8	−16.3

^a Standard uncertainties u are u(T) = 0.01 K, u(p) = 10 kPa.