| abstract |
The invention relates to a process for preparing a polyether polyol comprising: continuously feeding into a reactor which contains a composite metal cyanide complex catalyst and (i) a poly (oxyalkylene) polyol or (ii) a polyether polyol obtainable by the process according to the invention: (a) ethylene oxide, (b) a substituted alkylene oxide, (c) optionally a starter compound having a hydroxyl functionality of from 1 to 8, wherein the weight ratio of the total amount of ethylene oxide fed to the total amount of the substituted alkylene oxide fed is of from 50:50 to 95:5, and wherein the ethylene oxide concentration is below 13,000 parts per million by weight (ppmw) per minute during continuously feeding ethylene oxide, wherein the ethylene oxide concentration is defined as the weight of ethylene oxide in the reactor based on the total weight of the reactor contents. |