Tubular reactor, process for conducting liquid/liquid multiphase reactions in a tubular reactor, and a process for ring-nitrating aromatic compounds in a tubular reactor

A process for conducting a multiphase liquid/liquid reaction, comprising

• (1) introducing a stream of a multiphase liquid reaction mixture into an inlet end of a tubular reactor having a sequence of short static mixing elements separated by coalescing zones, wherein
• (a) the length of each coalescing zone is selected together with a flow rate of the reaction mixture such that as said reaction mixture passes through said coalescing zone, droplets of at least one liquid phase of the multiphase reaction mixture coalesce and at least partially phase separate from at least one other liquid phase of said reaction mixture, forming a topmost portion of said reaction mixture rich in one phase and a bottommost portion of said reaction mixture poor in said one phase, and
• (b) when said reaction mixture passes from a coalescing zone through a static mixer element, said topmost and bottommost portions of said reaction mixture are sheared and blended to redisperse the coalesced droplets as smaller droplets in said at least one other liquid phase,
• (2) passing said reaction mixture under reaction conditions through said tubular reactor, and
• (3) withdrawing a stream containing a desired reaction product from an outlet end of the tubular reactor.