Process for selective oxidation of olefins to epoxides

Abstract

A process for the selective oxidation of olefins to epoxides comprising the step of contacting the olefin (propylene) with an oxidant (hydrogen peroxide) in the presence of a Lewis acid oxidation catalyst (MTO), organic base (pyridine or its N-oxide), in a solvent system comprising an organic water-miscible solvent (methanol); and adding a pressurizing gas (nitrogen) to increase the pressure, whereby olefin is further dissolved in organic solvent system to increase the selectivity and yield of the desired epoxide (propylene oxide).

Description

Background technique Industrial-scale epoxidation of olefins, such as propylene to propylene oxide ("PO"), is one of the most challenging chemistries. Propylene oxide is primarily used in the production of propylene glycol and polyesters, and is a starting material for polyurethanes, unsaturated resins, and other products. The industry produces over 4.5 million tons of propylene oxide annually using the chlorohydrins or Halcon process. In the chlorohydrin method, propylene is reacted with chlorine and water to produce 1-chloro-2-propanol and HCl, which is then treated with base to produce propylene oxide and the salt. For every pound of propylene oxide produced, two pounds of salt are consumed. This method consumes large amounts of chlorine and lime, which are eventually transformed into useless and environmentally polluting waste. The Halcon, or hydroperoxide method, produces an organic peroxide and undergoes epoxidation in the presence of a transition metal catalyst, res...

AI Technical Summary

Problems solved by technology

However, this method is problematic because the catalyst deactivates rapidly and high temperatures are required to regenerate the catalyst

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