The results of the study of stationary (equilibrium) and non-stationary (non-equilibrium) patterns of chemical reactions within the framework of ideal (the law of acting masses) and non-ideal kinetics . are presented. It is shown that reactions described by simple models of imperfect kinetics can exhibit any complex behavior. Models of non-ideal kinetics can describe the complex behavior of chemical reactions and significantly reduce the threshold of occurrence of "complex from simple". Examples of analysis of reaction models characterized by various critical phenomena (multiplicity of stationary states and various forms of its manifestation) are given. The above material is a continuation of the monograph: Koltsov N. and . , Fedotov V. X. "Invariants and Reverse Problems of Chemical Kinetics" . Cheboksary: Chuvash Edition. Uncategorized, 2022. 240 s. For researchers, graduate students, university teachers and students specializing in the field of chemical kinetics and mathematical modeling of physical and chemical processes .