SCANDIUM CATALYST SYSTEM AND PROCESS FOR PRODUCING ETHYLENE/BUTADIENE COPOLYMER
A process for producing an ethylene-butadiene copolymer includes copolymerizing butadiene with ethylene in the presence of a catalyst system. The catalyst system includes tris[(trimethylsilyl)methyl]scandium and an aluminum-containing activator.
1 . A process for producing an ethylene-butadiene copolymer comprising:
copolymerizing butadiene with ethylene in the presence of a catalyst system comprising:
tris[(trimethylsilyl)methyl]scandium; and
an aluminum-containing activator.
2 . The process of claim 1 , wherein the catalyst system further comprises:
a borate coactivator.
3 . The process of claim 2 , wherein the borate coactivator comprises a salt of tetrakis(3,5-bis(trifluoromethyl)phenyl)borate and/or a salt of tetrakis(pentafluorophenyl)borate.
4 . The process of claim 1 , wherein the aluminum-containing activator is an aluminoxane activator.
5 . The process of claim 4 , wherein the aluminoxane activator is a modified aluminoxane activator.
6 . The process of claim 4 , wherein the aluminoxane activator is a methylaluminoxane activator.
7 . The process of claim 6 , wherein the methylaluminoxane activator is a modified methylaluminoxane activator.
8 . The process of claim 1 , wherein the aluminum-containing activator comprises MMAO-12.
9 . The process of claim 1 , wherein the aluminum-containing activator comprises a trialkyl aluminum activator; and wherein the catalyst system further comprises:
a borate coactivator.
10 . The process of claim 9 , wherein the trialkyl aluminum activator comprises triisobutylaluminum.
11 . The process of claim 9 , wherein the borate coactivator comprises a salt of tetrakis(3,5-bis(trifluoromethyl)phenyl)borate.
12 . The process of claim 9 , wherein the borate coactivator comprises a salt of tetrakis(pentafluorophenyl)borate.
13 . The process of claim 1 , wherein a molar ratio of the aluminum-containing activator to tris[(trimethylsilyl)methyl]scandium is in a range of about 20 to about 1000.
14 . The process of claim 1 , further comprising:
quenching a reaction product of the copolymerization.
15 . The process of claim 14 , further comprising:
drying the quenched reaction product.
16 . The process of claim 14 , wherein the reaction product is quenched with a quenching composition comprising isopropanol and butylated hydroxytoluene.
17 . A process for producing an ethylene-butadiene copolymer comprising:
providing a first composition comprising butadiene and ethylene to a reactor;
providing a second composition comprising tris[(trimethylsilyl)methyl]scandium and a first aliquot of an aluminum-containing activator to the reactor; and
copolymerizing butadiene with ethylene.
18 . The process of claim 17 , wherein the first composition further comprises a second aliquot of the aluminum-containing activator.
19 . The process of claim 17 , further comprising:
quenching a reaction product of the copolymerization; and
drying the quenched reaction product.
20 . The process of claim 17 , wherein
(a) the aluminum-containing activator comprises a modified aluminoxane activator; or
(b) the aluminum-containing activator comprises a trialkyl aluminum activator and at least one of the first composition and the second composition further comprises a borate coactivator.