Carbon dioxide as a catalyst quench agent in solution polymerization, and products made therefrom
A method for making a polymer, having the steps of (a) polymerizing one or more monomers in the presence of a solvent and a catalyst to form a reaction product; (b) removing an effluent from the reaction product, where the effluent comprises an active catalyst and one or more unreacted monomers; (c) combining a quench, comprising carbon dioxide, with the effluent to form a quenched polymer stream, having a carboxyl metal complex; and (d) recovering a polymer from the quenched polymer stream.
1. A method for making a polymer, comprising:
(a) polymerizing one or more monomers in the presence of a solvent and a catalyst to form a reaction product;
(b) removing an effluent from the reaction product, wherein the effluent comprises an active catalyst and one or more unreacted monomers;
(c) combining a quench, comprising carbon dioxide, with the effluent to form a quenched polymer stream comprising a carboxyl metal complex; and
(d) recovering a polymer from the quenched polymer stream.
2. The method of claim 1 , wherein the carboxyl metal complex is represented by the following complex,
wherein Hf is the catalyst and P is the reaction product.
3. The method of claim 1 , wherein the step (d) further comprises separating the quenched polymer stream into a polymer stream and a polymer recycle stream, wherein the polymer stream is separated from the polymer recycle stream to recover the polymer.
4. The method of claim 3 , further comprising contacting at least a portion of the polymer recycle stream with an adsorbent bed comprising at least two adsorbents to produce a treated recycle stream.
5. The method of claim 1 , wherein the one or more monomers comprises C 2 -C 40 α-olefins or one or more polyenes.
6. The method of claim 1 , wherein the one or more monomers comprise ethylene, propylene, and a diene.
7. The method of claim 4 , wherein the adsorbent bed comprises a molecular sieve and a hybrid zeolite in alumina.
8. The method of claim 4 , wherein the adsorbent bed further comprises at least one silica adsorbent.
9. The method of claim 7 , wherein the molecular sieve comprises material selected from the group consisting of zeolite X, zeolite Y, zeolite A, faujasite, mordenite, ferrierite, and combinations thereof.
10. The method of claim 1 , wherein the catalyst is represented by formula (I):
wherein:
J is a divalent bridging group comprising carbon, silicon, or both;
M is a group 4 transition metal;
each X is independently a univalent anionic ligand, or two Xs are joined together to form a metallocycle ring with M, or two Xs are joined to form a chelating ligand, a diene ligand, or an alkylidene ligand; and
each R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , and R 10 is independently selected from hydrogen, C 1 -C 10 substituted or unsubstituted alkyls.
11. The method of claim 10 , wherein R 6 and R 9 are each C 1 to C 4 alkyl; R 1 -R 4 , R 5 , R 7 , R 8 , and R 10 are each independently selected from methyl, ethyl, or hydrogen; M is hafnium; and each X is independently C 1 -C 3 alkyl or a halide.
12. The method of claim 10 , wherein any one or more of the pairs R 1 and R 2 , R 3 and R 4 , R 5 and R 6 , R 6 and R 7 , R 8 and R 9 , and R 9 and R 10 are bonded together to form a saturated or partially saturated cyclic ring structure.
13. The method of claim 1 , wherein the solvent is a liquid hydrocarbon.
14. The method of claim 1 , wherein the quench comprises the solvent.
15. The method of claim 1 , wherein the quench consists essentially of carbon dioxide and solvent.
16. The method of claim 1 , wherein the quench is free of water.
17. The method of claim 1 , wherein the quench is free of methanol.
18. The method of claim 1 , wherein the polymer has less than about 5% increase in Mooney viscosity (ML 1+4, 125° C.) compared to a comparative polymer prepared by the method of any preceding claim without adding the quench in step (c).