Process for depolymerization of a poly(C2-C4 alkylene terephthalate)
Provided is a process for depolymerization of a poly(C 2 -C 4 alkylene terephthalate), which comprises contacting a poly(C 2 -C 4 alkylene terephthalate) with methanol and a catalyst chosen from potassium carbonate, sodium carbonate, magnesium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, and triazabicyclodecene, at a temperature sufficient to effect said depolymerization. The process of the invention can be carried out a substantially lower temperature and requires less methanol than necessary for zinc acetate-catalyzed reactions, and is sufficiently robust to tolerate lower-quality poly(C 2 -C 4 alkylene terephthalate) scrap feeds.
1 . A process for methanolytic depolymerization of a poly(C 2 -C 4 alkylene terephthalate), which comprises contacting a poly(C 2 -C 4 alkylene terephthalate) with methanol and a catalyst chosen from magnesium methoxide, 1,8-diazabicyclo[5.4.0]undec-7-ene, and triazabicyclodecene, at a temperature sufficient to effect said depolymerization, wherein the temperature ranges from about 100° C. to about 180° C.
2 . The process of claim 1 , wherein the catalyst is magnesium methoxide.
3 . The process of claim 1 , wherein the catalyst is 1,8-diazabicyclo[5.4.0]undec-7-ene.
4 . The process of claim 1 , wherein the catalyst is triazabicyclodecene.
5 . The process of claim 1 , wherein the poly(C 2 -C 4 alkylene terephthalate) is poly(ethylene terephthalate).
6 . The process of claim 1 , wherein the poly(C 2 -C 4 alkylene terephthalate) is poly(propylene terephthalate).
7 . The process of claim 1 , wherein the poly(C 2 -C 4 alkylene terephthalate) is poly(butylene terephthalate).
8 . The process of claim 1 , further comprising the step of isolating dimethyl terephthalate formed therefrom.
9 . The process of claim 8 wherein the dimethyl terephthalate is isolated via distillation.