Catalyst system for high-cis polybutadiene
A catalyst system suitable for use in the production of high cis polybutadiene is disclosed. The catalyst system includes a cobalt salt of the formula CoA x?, where A is a monovalent or divalent anion and x is 1 or 2; an alkyl aluminum chloride compound of the structure R 2 AlCl, where R is an alkyl group containing 2-8 carbon atoms; a trialkyl aluminum compound of the formula R 3 Al, where R is an alkyl group containing 2-8 carbon atoms; and a catalytic amount of water.
1. A catalyst system suitable for use in the production of high cis polybutadiene, comprising:
cobalt neodecanoate;
alkyl aluminum chloride selected from ethylaluminum sesquichloride and a compound of the structure R 2 AlCl where R is an alkyl group containing 2-8 carbon atoms;
trialkyl aluminum compound of the formula R 3 Al, where R is an alkyl group containing 2-8 carbon atoms; and
water,
wherein the cobalt neodecanoate is present in an amount such that the molar ratio of Co to Al is from 1:75 to 1:150.
2. The catalyst system of claim 1 wherein the alkyl aluminum chloride compound is ethylaluminum sesquichloride and the trialkyl aluminum compound is trioctylaluminum.
3. The catalyst system of claim 2 further comprising a ternary alkyl amine or a ternary aryl amine.
4. The catalyst system of claim 2 wherein the ethylaluminum sesquichloride and trioctyl aluminum are present in an amount such that the concentration of Al is in the range of from 0.002 to 0.004 moles per liter.
5. The catalyst system of claim 1 wherein the water is present in an amount of 0.1 to 0.8 moles per mole of the alkyl aluminum chloride compound.
6. The catalyst system of claim 3 wherein the ternary alkyl amine or ternary aryl amine is triethanolamine or triethylamine.
7. The catalyst system of claim 3 wherein the ternary alkyl amine or ternary aryl amine present in an amount such that the molar ratio of Co to N in the system is in the range of from 1:1 to 1:3.
8. A catalyst system suitable for use in the production of high cis polybutadiene, comprising the product of mixture of:
a) cobalt neodecanoate;
b) ethylaluminum sesquichloride;
c) trioctyl aluminum; and
d) water,
wherein ethylaluminum sesquichloride and trioctyl aluminum are added in such an amount that the concentration of Al is in the range of from 0.002 to 0.004 moles per liter, and the cobalt neodecanoate is present in an amount such that the molar ratio of Co to Al is in the range of 1:75 to 1:150.
9. The catalyst system of claim 8 further comprising a ternary alkyl amine in an amount such that the molar ratio of Co to N in the system is in the range of from 1:1 to 1:3.
10. A process for producing polybutadiene having a high cis content comprising contacting a feed comprising 1,3-butadiene, butene and cyclohexane with a catalyst system to polymerize the 1,3-butadiene, wherein the catalyst system comprises:
a) a cobalt neodecanoate;
b) alkyl aluminum chloride selected from ethylaluminum sesquichloride and a compound of the structure R 2 AlCl where R is an alkyl group containing 2-8 carbon atoms;
c) trialkyl aluminum compound of the formula R 3 Al, where R is an alkyl group containing 2-8 carbon atoms; and
d) water,
wherein the cobalt neodecanoate is present in an amount such that the ratio of Co to Al is from 1:75 to 1:150.
11. The process of claim 10 wherein the feed additionally contains benzene.
12. The process of claim 11 wherein the feed comprises 20 percent by weight 1,3-butadiene and 55 percent by weight butene.
13. The process of claim 12 wherein the catalyst system further comprises a ternary alkyl amine or a ternary aryl amine.
14. The process of claim 13 wherein the alkyl aluminum chloride compound is ethylaluminum sesquichloride; the trialkyl aluminum compound is trioctyl aluminum; and wherein ethylaluminum sesquichloride and trioctyl aluminum are added in such an amount that the concentration of Al is in the range of from 0.002 to 0.004 moles per liter, and wherein the ternary alkyl amine or ternary aryl amine is triethanolamine or triethylamine added in such amount so that the molar ratio of Cobalt to nitrogen is the range of 1:1 to 1:3.
15. The catalyst system of claim 2 wherein the ethylaluminum sesquichloride and trioctyl aluminum are reacted together prior to combining with the other elements.