Flow reactor vessels and reactor systems

A process for forming a sulfide compound, the process comprising:

• (i) introducing a fluid comprising a mercaptan compound and a compound having a carbon-carbon double bond into a flow reactor vessel, the flow reactor vessel comprising:
• (a) a reaction chamber comprising a reactor wall, an inlet for the fluid, and an outlet;
• (b) a tube positioned within the reaction chamber, a flow path for the fluid including a region between an outer surface of the tube and an inner surface of the reactor wall;
• and
• (c) an electromagnetic radiation source enclosed within the tube, the electromagnetic radiation source configured to deliver electromagnetic radiation into the fluid in the flow path;
• wherein an average linear distance between the outer surface of the tube and the inner surface of the reactor wall is less than or equal to 10 cm;
• (ii) exposing the fluid to the electromagnetic radiation within the reaction chamber to form the sulfide compound;
• and
• (iii) discharging a composition comprising the sulfide compound from the reaction chamber via the outlet;
• wherein the fluid in the flow path has a volumetric flow rate from 12 to 120 gallons/min and a Reynolds number of at least 10,000.