Technology for the Production of Styrene Oxide via Non-chlorine Route

The preparation of epoxides from alkenes using a combination of transition metal salt, an inorganic promoter and an organic additive has been discussed.

The epoxidation process uses hydrogen peroxide (50%) as an environmentally safe oxidant under biphasic aqueous system (pH=~7) under mechanically stirred condition at 10-300C. In this process an extremely small quantity of simple Mn salt is used as a catalyst with environmentally safe water-soluble organic promoter in combination with small amount of sodium bicarbonate as inorganic promoter.

• Good isolated yields of epoxides are achievable with inexpensive reagents under mild reaction conditions.
• Organic ligand based metal complexes are not required for the activation of hydrogen peroxide and alkenes under the reaction conditions used in the present invention.
• Only smaller quantity of commercial LR grade transition metal salt is required to carry the reaction to completion at 1 Kg scale.
• Under certain reaction conditions the epoxidation reaction of alkene gave high conversion and selectivity even in absence of a transition metal salt.
• Inorganic salts and organic compounds used to activate hydrogen peroxide are inexpensive and of commercial grade.
• Under the defined reaction conditions the organic solvent is not required for most of the liquid alkenes.
• Epoxidation reactions are run in air (no prior oxygen free conditions are required).
• Final work up protocol at higher scale (at 1 Kg scale) does not require solvent extraction as water insoluble epoxides form a separate layer and thus can be physically separated.
• Using the present invention high level of conversion and selectivity was achieved within reasonable time period that makes the process viable for industrial application.
• Reaction rates are significantly faster than reported so far with these alkenes using hydrogen peroxide as oxidant.