Ethylene oxide prodn - in reactor tubes coated with phosphorus -nickel alloy

Ethylene oxide is produced more selectively and corrosion of the plant is prevented by subjecting ethylene to gaseous phase oxidation in the presence of a Ag catalyst and in reaction tubes coated with Ni-P alloy. In an example, 300 g. NiSO4, 400 g Na hypophosphite, 200 g. Na acetate and 200 g. monoethanolamine are dissolved in 12 l. pure water and the pH is adjusted to 5.0 with HCl. Then 2.5 cm dia. and 750 cm long steel tubes are washed with 3-5% aq. HCl, are degreased and again washed with HCl. The tubes are then coated internally by circulating through them the plating soln. for 30 min. at 90 degrees C to the b.pt. of the soln. The tubes then have a 10 mu Ni-P film and are charged with the usual Ag catalyst. Then a gaseous mixture contg. 4-5 vol.% ethylene, 6 vol.% oxygen and balance N2, CO2 and water is passed through the reaction tubes at 250 degrees C and 15 kg/cm2 pressure. Ethylene oxide free of aldehydes is obtd. and the degree of conversion is 30% and selectivity 71.9%.