Process for the preparation of polyether polyols

A process for the preparation of polyether polyols comprising reacting one or more alkylene oxides with one or more starter compounds containing active hydrogen atoms, in the presence of metal compounds corresponding to the formula (I):

• (X)nM(E—R—E′I)m (I)
• wherein:
• X:
• represents a halide, thiolate, sulfinate, sulfonate, sulfate, amide, or carboxylate group;
• M:
• represents a metal from Group 13 of the periodic Table of the elements;
• E:
• represents oxygen, sulfur, selenium, or NR1 or PR1;
• wherein:
• R1:
• represents a hydrogen atom or a C1-C20 hydrocarbon radical which may be alkyl or aryl;
• R:
• represent a C1-C30 hydrocarbon bridge which may be an alkylene, an arylene or an aralkylene bridge, wherein R can form a ring with R1;
• E′:
• represents a hydrogen atom, a C1-C20 hydrocarbon radical which may be alkyl or aryl, OR2, NR2R3, halogen, SR2 or PR2R3;
• wherein:
• R2 and R3:
• may be the same or different, and each independently represents a hydrogen atom, or a C1-C10 hydrocarbon radical which may be alkyl, aryl or aralkyl, and wherein R2 can form one or more rings with R3 or R, and/or R3 can form one or more rings with R or R2, and/or two or more ERE′ units can form one or more rings,
• n:
• represents 1 or 2,
• m:
• equals (3−n),
• and
• I:
• represents an integer from 1 to 10.