Processes for producing polytrimethylene ether glycol and copolymers thereof
View Patent ↗Processes for producing polytrimethylene ether glycol and copolymers thereof are provided wherein, by condensing and recycling at least a portion of the vapor phase produced as the reaction progresses, the yield loss and polymer color are reduced.
1. A process for producing a reaction product, comprising:
a) polymerizing reactants comprising 1,3-propanediol, oligomers of 1,3-propanediol, poly-1,3-propanediol, or a mixture thereof, in the presence of at least one polycondensation catalyst in a vessel to produce a reaction product whereby a vapor phase comprising water and reactants is produced as the polymerization proceeds;
b) condensing and collecting at least a portion of the vapor phase at a temperature sufficient to form a condensate comprising water and reactants; and
c) recycling at least a portion of the condensate to the vessel; wherein the condensate comprises water and reactants, and wherein the process is characterized by a reactant loss and wherein the reactant loss is less than about 5% by weight over the course of the polymerization and wherein the reaction product has color less than about 200 APHA.
2. The process of claim 1 wherein the reactants further comprise a comonomer diol.
3. The process of claim 1 wherein the 1,3 propanediol is biologically-derived 1,3-propanediol.
4. The process of claim 1 wherein the 1,3 propanediol is chemically-derived 1,3-propanediol.
5. The process of claim 1 wherein the polycondensation catalyst is an acid.
6. The process of claim 1 wherein the polycondensation catalyst is sulfuric acid.
7. The process of claim 1 wherein the polycondensation catalyst is 1,1,2,2-tetrafluoroethanesulfonic acid or trifluoromethanesulfonic acid.
8. The process of claim 1 wherein the condensing of the vapor phase is carried out at a temperature of less than about 110° C.
9. The process of claim 8 wherein the condensing of the vapor phase is carried out for an initial time at a temperature of at least about 80° C. and at a second time at a temperature of at least about 60° C.
10. The process of claim 1 further comprising recycling about 50% to about 90% of the condensate to the reaction vessel.
11. The process of claim 1 wherein the reactant loss is less than about 3%.
12. The process of claim 1 wherein the condensate comprises at least about 50 weight percent water.
13. The process of claim 1 wherein the condensate comprises at least about 70 weight percent water.
14. The process of claim 1 wherein the reaction product comprises a homopolymer.
15. The process of claim 1 wherein the reaction product has a molecular weight of at least about 1000 g/mol.
16. The process of claim 1 wherein the color is less than about 100 APHA.
17. The process of claim 1 wherein the color is less than about 50 APHA.