The autoclave reactor is a small cylindrical reactor, built to withstand high pressures, and used to evaluate the kinetics of high-temperature, high-pressure reactions and the production of small quantities of specialty chemicals. The autoclave is usually a heterogeneous batch reactor mainly used for high-pressure kinetic studies. The autoclave is typically a solid catalyzed gas–liquid reaction system. The autoclave operating conditions vary over a wide range from 120°C and 40 psi to well over 450°C and 600 psi.