Multisite heterogeneous catalyst, process for preparing the same and process for obtaining polyolefins using said catalyst

Patent metadata

Field	Value
Publication number	US-11014996-B2
Application number	US-201616097019-A
Country	US
Kind code	B2
Filing date	May 25, 2016
Priority date	Apr 27, 2016
Publication date	May 25, 2021
Grant date	May 25, 2021

Abstract

The instant invention relates to the use of titanium-based oxopolymers for preparing suitable catalysts for reactions of olefin polymerization and/or olefin and alpha-olefin copolymerization. The instant invention further discloses the synthesis of catalyst formulated from titanium-based oxopolymers, as well as its use for olefin polymerization and/or copolymerization reactions.

First claim

What is claimed is:

1. A multisite heterogeneous catalyst which is suitable for reactions of olefin polymerization and olefin and alpha-olefin copolymerization comprising a support and a titanium oxopolymer in its active composition, the latter being an organometallic chemical compound having an oligomeric structure and a chemical formula according to Equation 1:
(R a ) p M a (O—Ti—O) n M b (R b ) q    (1)

where: (O—Ti—O) is the monomeric unit of the oligomer formed by n units; R a and R b are alike or different substituents, and are a halogen an alkoxy group of linear or branched or cyclic or aromatic chain; M a and M b are alike or different and are transition metals of groups 4, 5 or 6 or, semi-metals of group 14 of the periodic table, wherein subindexes p and q of the substituents satisfy the coordination number of the respective M, and the polymerization level n is higher than or equal to 3, wherein the support is pre-treated with a Ziegler-Natta catalyst.

2. The multisite heterogeneous catalyst according to claim 1 , wherein the titanium oxopolymer is synthesized via a non-hydrolytic sol-gel route.

3. The multisite heterogeneous catalyst according to claim 2 , wherein the titanium oxopolymer produced through the chemical reaction of titanium (IV) chloride and titanium (IV) tetraalkoxide is catalyzed by a Lewis acid.

4. The multisite heterogeneous catalyst according to claim 3 , wherein the reaction proceeds according to the stoichiometric ratios of the reagents, according to Equation 2 below:
CT:TAT=(1.5−3):1  (2a)

TAT:CT=(1.5−3):1  (b)

where: CT indicates the titanium (IV) chloride precursor and TAT, titanium (IV) tetraalkoxide.

5. The multisite heterogeneous catalyst according to claim 1 , wherein the titanium oxopolymer is incorporated into the support through impregnation or precipitation technique.

6. The multisite heterogeneous catalyst according to claim 1 , wherein the support is magnesium chloride or silica.

7. A process for preparing the multisite heterogeneous catalyst according to claim 1 , comprising the incorporation of the titanium oxopolymer into a support through impregnation or precipitation, wherein the support is pre-treated with a Ziegler-Natta catalyst.

8. The process for preparing the multisite heterogeneous catalyst according to claim 7 , wherein the titanium oxopolymer is produced through the chemical reaction of titanium (IV) chloride and titanium (IV) tetraalkoxide, catalyzed by a Lewis acid at temperature of 90-150° C., for a total reaction time of 2-12 hours, in a closed reactor provided with agitation.

9. The process for preparing the multisite heterogeneous catalyst according to claim 7 , wherein the support (a) is magnesium chloride or silica, and (b) is treated by physical or chemical methods.

10. A process for obtaining polyolefins comprising a reaction of olefin polymerization and/or olefin and alpha-olefin copolymerization in the presence of a multisite heterogeneous catalyst, as defined in claim 1 .

11. The process for obtaining polyolefins according to claim 10 , wherein the multisite heterogeneous catalyst is combined with other catalytic compounds able to polymerize olefins and copolymerize olefins and alpha-olefins.

12. The process for preparing the multisite heterogeneous catalyst according to claim 9 , wherein the physical methods comprise calcination or grinding.

13. The process for preparing the multisite heterogeneous catalyst according to claim 9 , wherein the chemical methods comprise reaction with surface modifying agents or dissolution and reprecipitation.

14. The process for preparing the multisite heterogeneous catalyst according to claim 7 , wherein the oxopolymer is synthesized via sol-gel route.

Assignees

• Braskem Sa

Inventors

• Fisch Adriano Giraldi
• Cardoso Maila Noeli
• Brambilla Rodrigo

Classifications

• C08F4/642 Primary

  Component covered by group C08F4/64 with an organo-aluminium compound {(C08F4/64003 - C08F4/64196 take precedence)} · CPC title

• C08F4/6545

  and metals of C08F4/64 or compounds thereof · CPC title

• C08F4/64 Primary

  Titanium, zirconium, hafnium or compounds thereof · CPC title

• C08F4/16

  of silicon, germanium, tin, lead, titanium, zirconium or hafnium · CPC title

• C08F10/02 Primary

  Ethene · CPC title