Among nanomaterials the considerable interest is represented by nanoporous materials . These materials are a basis for aerogels. The open structure of pores in aerogel can be used for creation of high-porous matrixes for materials with high nonlinearities, and also for development of the sensors based on methods of laser spectroscopy. Temperature of phase transition in pores usually is described by Laplace's equation, but for a pore size less than 8-10 nm temperature predicted by the Laplace equation differs from temperature received by experiments .
The purpose of this work is the explanation of difference between temperature of phase transition of liquid substance in a nanoporous materials and a massive sample; obtaining the generalization of the equation of Laplace for a case of a nanopores and a comparison with existing experimental data.