Neutralization of deactivated polymerization catalyst using phosphoric or phosphonic acid salts
View Patent ↗A process for deactivating an active catalyst species in an olefin polymer stream exiting a polymerization reactor and neutralizing catalyst residues, as well as reducing corrosion, plugging or fouling of olefin production and recovery equipment and imparting antioxidative properties to an olefin polymer comprising adding a catalyst deactivator and an alkaline earth metal salt of a phosphoric- or phosphonic acid to an olefin polymer stream exiting a polymerization reactor, each in a quantity at least sufficient to deactivate active catalytic species in the polymer stream and neutralize catalyst residues, respectively, and subsequently recovering the resulting polymer product.
1. A process for deactivating an active catalyst species in an olefin polymer stream exiting a polymerization reactor and neutralizing catalyst residues and imparting antioxidative properties to an olefin polymer comprising adding a catalyst deactivator and an alkaline earth metal salt of a phosphoric- or phosphonic acid to an olefin polymer stream exiting a polymerization reactor, each in a quantity at least sufficient to deactivate active catalytic species in the polymer stream and neutralize catalyst residues, respectively, and subsequently recovering the resulting polymer product;
wherein the phosphoric- or phosphonic acid salt corresponds to the formula:
wherein,
R 1 is a divalent oxygen or hydrocarbylene group;
R 2 is C 1-4 alkyl;
R 3 , individually each occurrence, is C 1-20 alkyl;
X is oxygen or sulfur; and
M is an alkaline earth metal cation.
2. A process for reducing corrosion, plugging or fouling of olefin production and recovery equipment while deactivating active catalyst species in an olefin polymer stream exiting a polymerization reactor and neutralizing catalyst residues, said process comprising adding to the olefin polymer stream a catalyst deactivator and an alkaline earth metal salt of a phosphoric- or phosphonic acid and subsequently recovering the resulting polymer product;
wherein the phosphoric- or phosphonic acid salt corresponds to the formula:
wherein,
R 1 is a divalent oxygen or hydrocarbylene group;
R 2 is C 1-4 alkyl;
R 3 , individually each occurrence, is C 1-20 alkyl;
X is oxygen or sulfur; and
M is an alkaline earth metal cation.
3. A process according to any one of claim 1 or 2 , wherein the deactivating agent and alkaline earth metal salt of a phosphoric- or phosphonic acid are combined prior to addition to the olefin polymer stream, and thereafter said combination is mixed with the olefin polymer stream.
4. The process according to any one of claims 1 - 3 wherein calcium bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl) methyl)ethylphosphonate) is added to the polymer stream.
5. The process according to any one of claims 1 - 3 wherein the olefin polymer is a homopolymer of ethylene or propylene or a copolymer of ethylene with one or more C 3-10 α-olefins prepared by use of a transition metal containing catalyst composition.
6. The process according to any one of claims 1 - 3 wherein the catalyst composition comprises halogen, a transition metal of Groups 3 - 6 of the Periodic Table of Elements, and optionally magnesium and/or an alkoxide; and an organoaluminum cocatalyst.
7. The process according to any one of claims 1 - 3 wherein an aqueous solution containing from 0.1 to 60percent phosphoric- or phosphonic acid salt is employed as the catalyst deactivator and neutralizer.
8. The process according to any one of claims 1 - 3 wherein the polymer stream, catalyst deactivator and alkaline earth metal salt are mixed by passing through one or more static mixing elements prior to recovery of the polymer.
9. The process according to any one of claims 1 - 3 wherein the polymer is recovered by devolatilization.