Patent ID: 7247699

Claim:
A process for purifying a crude polyether, comprising contacting a crude polyether obtained by addition polymerizing an active hydrogen-containing compound with an alkylene oxide compound in the presence of an alkali metal-containing basic catalyst to an adsorbent comprising a synthesized hydrous magnesium silicate compound which satisfies the following requirements (1) to (5) in order to reduce the alkali metal content of the crude polyether: (1) it is represented by the following formula I: (CaO) x .(MgO) y .(Al 2 O 3 ) z .SiO 2 .mH 2 O I wherein x, y, z and m satisfy the following ranges: x<y, z<y, 0≦x≦0.1, 0.06≦y≦0.6, 0≦z≦0.1 and 0.1≦m≦1.5, (2) it is amorphous according to the analysis of its powder method X-ray diffraction diagram, (3) it has a BET specific surface area of 100 to 400 m 2 /g, (4) it has an alkali metal content of 0.1 wt % or less, and (5) it has an average particle diameter of 2 to 60 μm.