A process of preparing alkylene oxides comprises steps of: (1) optionally contacting metal hydroxide or oxide with chlorine to form a metal hypochlorite solution; (2) contacting chlorine with a solution of a metal hypochlorite at a temperature below 60 °C, and a pH of less than 5.5, with sufficient micromixing to achieve a product hypochlorous acid in a yield of at least 80 mole percent based on hypochlorite; (3) separating at least a portion of the hypochlorous acid from an aqueous metal chloride solution thereof, hereinafter referred to as chloride brine, wherein the solution is sprayed as droplets having a volume median diameter of less than 500 micrometers into a vapor stream such that at least 30 mole percent of the hypochlorous acid is desorbed from a liquid phase into a vapor phase where hypochlorous acid and dichlorine monoxide are in equilibrium; (4) distilling the remaining liquid phase to obtain additional hypochlorous acid and dichlorine monoxide vapor; (5) absorbing the hypochlorous acid and dichlorine monoxide in low-chlorides water to produce a low-chlorides aqueous hypochlorous acid solution; (6) contacting the low-chlorides aqueous hypochlorous acid solution with an olefin in a continuous process using a continuous stirred tank reactor to maintain a uniform steady-state HOCl concentration in the reactor of 0.2 weight percent or less to form a corresponding olefin chlorohydrin; (7) optionally contacting the olefin chlorohydrin with a base to form a corresponding alkylene oxide and a salt solution; and (8) optionally separating the alkylene oxide from the salt solution; (9) optionally removing chlorates from the chloride brine from at least one of Steps 3 or 4 by contacting the chlorates with acid to convert the chlorates to chlorine; and (10) optionally recycling the chlorine to at least one of Steps 1 or 4. The process yields particularly high yields of the alkylene oxide without substantial production of by-products.