| abstract |
The present invention relates to a process for treating a mixture of impure ethylene oxide and of water in a ratio by weight of ethylene oxide to water of 0.1/1 to 4/1, comprising aldehyde impurities, formaldehyde and acetaldehyde, in order to obtain a purified ethylene oxide essentially free of water and of the aldehyde impurities. The process comprises (1) conveying the mixture to a first fractionation region Z1, while a liquid stream Ll comprising at least 98 % by weight of water and a portion of the aldehyde impurities is withdrawn at the bottom of Z1, and a gas stream G1 comprising more than 99 % by weight of ethylene oxide with residual amounts of water and of the aldehyde impurities is withdrawn at the top of Z1, and (2) conveying the gas stream G1 to a second fractionation region Z2, while a liquid stream L2 comprising a mixture of ethylene oxide, of water and of the aldehyde impurity(ies) is withdrawn at the bottom of Z2, a liquid stream L3 is withdrawn as a side stream from the region Z2 and is conveyed to the region Zl, and a gas stream G2 comprising the purified ethylene oxide is withdrawn at the top of Z2. The process is particularly suitable when it is combined with a process for the manufacture of ethylene oxide by gas-phase catalytic oxidation of ethylene by molecular oxygen. |