| abstract |
Process for the preparation of monomeric dihydroxy terephthalate diester, which comprises: Forming a reaction mixture comprising a terephthalate polyester, an amidine organocatalyst and a glycol in an amount of 8 molar equivalents based on a total mole number of a repeating terephthalate unit in the terephthalate polyester, the glycol having 2 to 5 carbon atoms, which is in the Glycol is a co-catalyst; and Heating the reaction mixture to a temperature in the range of about 120 ° C to about 210 ° C to depolymerize the terephthalate polyester, thereby forming a terephthalate reaction product comprising a monomeric dihydroxy terephthalate diester in an amount greater than 90 percent by weight based on a total mole number of the terephthalate reaction product, and wherein the amidine organocatalyst is selected from the group consisting of 1,8-diazabicycloundec-7-ene (DBU), 1,5-diazabicyclo [4.3.0] non-5-ene (DBN), polymer-assisted DBU, polymer-assisted DBN and combinations thereof. |