Abstract: In a regulated process wherein propylene is reacted with tertiary butyl hydroperoxide in solution in tertiary butyl alcohol to produce propylene oxide and tertiary butyl alcohol in a reactor system comprising a first isothermal segment comprising a plurality of at least four sequentially interconnected internally cooled reactors, and a second adiabatic segment,an initial feed mixture is continuously charged to the first reactor, comprising propylene and a recycle stream composed of about 25 to about 75 wt.

Abstract: In reacting tertiary butyl hydroperoxide in solution in tertiary butyl alcohol with propylene to produce propylene oxide and tertiary butyl alcohol in a reactor system comprising a first isothermal segment and a second adiabatic segment about 60 to 80 wt % of the tertiary butyl hydroperoxide is converted in the isothermal segment to provide an intermediate reaction mixture, a recycle stream comprising about 25 to 100 wt. % of the combined weight of the propylene and the tertiary butyl alcohol solution is removed from the intermediate reaction mixture and recycled to the first isothermal segment and the remainder of the intermediate reaction mixture is passed through the adiabatic segment where an additional 20 to 40 wt. % of the tertiary butyl hydroperoxide is converted.