Patent ID: 8188205

Claim:
A process for producing unsubstituted or R-substituted poly(trimethylene carbonate)glycols, comprising contacting unsubstituted or R-substituted trimethylene carbonate with a catalyst in the presence of one or more solvents at a temperature of about 40 to about 120 degrees Celsius, to form a reaction mixture, the reaction mixture comprising unsubstituted or R-substituted poly(1,3-propanediol carbonate)diol oligomers, wherein the catalyst consists essentially of a hydrotalcite catalyst; and the reaction is represented by the equation; wherein n=2-100; R is substituent independently selected from the group consisting of H, C 1 -C 20 alkyl, C 3 -C 20 cyclic alkyl, C 5 -C 25 aryl, C 6 -C 20 alkaryl, and C 6 -C 20 arylalkyl, and each R substituent can optionally form a cyclic structural group with adjacent R substituents; the hydrotalcite catalyst is of formula Mg 2x Al 2 (OH) 4x+4 CO 3 .nH 2 O, wherein n represents the number of water molecules associated with the magnesium aluminum compound an integer of 1 to 4 and x=3.