Abstract: A gas-liquid reactor includes a cylindrical vessel containing a liquid with a head space defined above the liquid surface, a submerged jet nozzle positioned on the vessel axis for injecting liquid and gas upwardly into the vessel, and at least two free jet nozzles positioned at the top of the vessel in the head space for injecting a liquid jet downwardly into the liquid in the vessel such that gas in the head space is entrained into the liquid jet and mixed into the liquid in the vessel. The reactor is provided with a cylindrical guide tube coaxial with the vessel sidewall and terminating below the liquid surface for directing circulation. A baffle system directs reactive gas rising from the liquid surface to the head space for entrainment in the liquid jet and directs reacted gas rising from the liquid surface to a vent. Diffuser tubes extend downwardly from each of the free jet nozzles into the liquid for delivering the gas-liquid mixture into the lower portion of the vessel outside the guide tube.