The paper presents thermodynamic analysis of equilibrium and quasi-equilibrium of multicomponent systems for different technological types of pyrolysis of hydrocarbons, boron gasification, synthesis of titanium diboride TiB2. The objects of thermodynamic modeling were the C-H-N, B-H-N, Ti-O-C- B-H-N, Ti-B-H-N, Ti-B-Cl-H-N systems. TiB2 forms through boriding titanium by borohydrides in the temperature range of 2300-3500 K. A 100% yield of titanium diboride in the Ti-B-H-N and Ti-B- O-C-H-N systems is possible at stoichiometric ratios Ti: B = 1: 2, O: C = 2: 2 and a 6-fold excess of hydrogen (B: H = 2:12). A 100% yield of titanium diboride in the Ti-B-Cl-H-N system is achieved at a stoichiometric ratio Ti-B and an excess of hydrogen (Cl: H = 1: 9).