Elena B. Quantum-chemical analysis of clusterization of amines, thioalcohols and cis-monoenic acids at water/air interface.

In the work results of quantum-chemical calculations of entalpy, entropy and Gibbs energy of formation and clusterization of amins, thioalcohols and cis-monoenic carbon acids on a water/air interface within the framework of semiempiric method of PM3 have been held. Spontaneous clusterization of thioalcohols starts at length of hydrocarbon radical in 14-15 atoms of carbon, amins - at 18-19, cis-monoenic acids - at 17-19. Calculated parameters conform with proper experimental well. The values of thermodynamics parameters of clusterization of monoenic acids do not rely on position of double bond in a radical, except for its extreme position, when the number of intermolecular H-H bonds changes. Five types of intermolecular interactions between СН2-groups were defined. It is shown, that "a"-type of such interactions describes experimental data the best. The "Simple" method of preliminary estimation of thermodynamics parameters of clusterization of surface-active compounds on the surface was offered, it reproduces the thermodynamics parameters of clusterization, got within the framework of additive scheme, and proper experimental parameters well.