In this article, an effect of ultrasound on chemical reactions is reviewed. The sonochemical reaction proceeds at a hot spot produced by cavitation of bubble, i. e., creation and collapse of a bubble in liquid. Temperature and pressure at the hot spot exceed 5000 K and 100 MPa, respectively, therefore, pyrolysis of solvent can occur. We present experimental technique and our recent results of sonochemical decomposition of organic liquids and synthesis of C60 from liquid benzene.