Abstract A numerical simulation of a non-isothermal gas–liquid absorption with chemical reaction on a spherical laminar film is presented. The mass and heat balances equations were solved with the orthogonal collocation method on finite elements. The simulation is in good accordance with published data on phosgene absorption in sodium hydroxide solution or water. If the contact time between gas and liquid is large, the sodium hydroxide in the film can be depleted and phosgene hydrolysis can occur. If the contact time is small, only the reaction between hydroxy anion and phosgene takes place. Furthermore, simulation results concerning the global behavior of non-isothermal gas–liquid absorption accompanied with a chemical reaction are given.