A process for producing a polycarbonate polyol by ester-interchange
reaction of a dialkyl, diaryl or alkylene carbonate and a polyhydroxy
compound, wherein the dialkyl, diaryl or alkylene carbonate is purified by
adsorption treatment with an adsorbent prior to use in the reaction. A
process for producing a polycarbonate polyol which comprises
ester-interchange reaction of a dialkyl or diaryl carbonate and a
polyhydroxy compound in the presence of a catalyst, wherein the proportion
of the polyhydroxy compound to the dialkyl or diaryl carbonate is 1.01 to
1.30 times its stoichiometrical amount, and the amount of the catalyst is
0.0001 to 0.5% by weight, calculated as metal, based on the dialkyl or
diaryl carbonate. Also provided is a process for producing a polycarbonate
polyol by ester-interchange reaction of a dialkyl, diaryl or alkylene
carbonate and a polyhydroxy compound in the presence of a catalyst in an
amount, as metal, of 0.0001 to 0.5% by weight based on the dialkyl, diaryl
or alkylene carbonate, which comprises a first step of reacting the
dialkyl, diaryl or alkylene carbonate with the polyhydroxy compound, a
second step of treating the resulting product with water at 60 to
300.degree. C. to inactivate the catalyst, and a third step of removing
water.