Propylene preliminary polymerization

Patent metadata

Field	Value
Publication number	US-12319756-B2
Application number	US-202217850489-A
Country	US
Kind code	B2
Filing date	Jun 27, 2022
Priority date	Jun 25, 2021
Publication date	Jun 3, 2025
Grant date	Jun 3, 2025

Abstract

A process for propylene preliminary polymerization in liquid phase that occurs in a continuous preliminary polymerization reactor may include feeding a propylene monomer and a Ziegler-Natta catalyst system having (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester, (b) a catalyst activator and optionally (c) an external donor, into the continuous preliminary polymerization reactor, wherein the feeding is carried out without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous preliminary polymerization reactor.

First claim

What is claimed:

1. A process for propylene bulk preliminary polymerization, comprising:
feeding propylene monomer and a Ziegler-Natta catalyst system comprising (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester and (b) a catalyst activator, into a continuous loop preliminary polymerization reactor that comprises a feeding apparatus connected thereto, configured to feed propylene monomer and the Ziegler-Natta catalyst system into the continuous loop preliminary polymerization reactor,
wherein the feeding apparatus is configured to carry out said feeding without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous loop preliminary polymerization reactor,
wherein the propylene monomer and the Ziegler-Natta catalyst system, when in the continuous loop preliminary polymerization reactor, are in a liquid medium that is passed through the continuous loop preliminary polymerization reactor, and
wherein the process is carried out in the absence of, and the liquid medium does not have, saturated hydrocarbon diluent.

2. The process of claim 1 , wherein the pro-catalyst is suspended in mineral oil, has total intrusion volume less than or equal to 1 mL/g, total pore area less than or equal to 10 m 2 /g, and apparent skeletal density 1.6 to 2.1 g/ml.

3. The process of claim 1 , wherein a molar ratio of aluminum to titanium (Al/Ti) in the pro-catalyst and catalyst activator is from about 50:1 to about 200:1.

4. The process of claim 1 , wherein the preliminary polymerization is carried out without feeding hydrogen, and fed monomer has hydrogen concentration of no more than 20 ppm.

5. The process of claim 1 , wherein the propylene/pro-catalyst mass feed ratio is in the range from 1 to 35 kg propylene per gram pro-catalyst.

6. The process of claim 1 , wherein an average residence time of the preliminary polymerization is from 3 to 5 minutes.

7. The process of claim 1 , wherein a temperature of the preliminary polymerization is from 0 to 10° C.

8. The process of claim 1 , wherein a preliminary polymerization rate is from 10 to 65 g PP/g Catalyst·min.

9. The process of claim 1 , wherein a preliminary polymerization rate is from 10 to 20 g PP/g Catalyst·min.

10. The process of claim 1 , wherein the preliminary polymerization reactor comprises a feeding zone having:
a maximum polymer concentration at least 58% lower than the maximum polymer concentration in the preliminary polymerization reactor;
a maximum Ziegler-Natta catalyst concentration at least 58% lower than the maximum Ziegler-Natta catalyst concentration in the preliminary polymerization reactor; and
a maximum temperature at least 47% lower than the maximum temperature in the preliminary polymerization reactor.

11. The process of claim 1 , wherein an inlet velocity of the pro-catalyst is between 2 to 5 m/s.

12. The process of claim 1 , wherein the feeding apparatus comprises a first feeding tube and a second feeding tube, the feeding is carried out by passing the propylene monomer through the first feeding tube, and by passing the pro-catalyst and catalyst activator through the second feeding tube, wherein the first feeding tube and the second feeding tube are separated by an inner tube wall.

13. The process of claim 12 , wherein the first feeding tube comprises grooves that are configured to increase turbulent flow of the propylene monomer through the first feeding tube.

14. The process of claim 12 , wherein the first feeding tube comprises grooves that are configured to increase turbulent flow of the propylene monomer through the first feeding tube, and wherein turbulent flow of the propylene monomer comprises a vortex flow.

15. The process of claim 1 , wherein the continuous loop preliminary polymerization reactor does not have an agitator.

16. The process of claim 12 , wherein the preliminary polymerization reactor comprises a feeding zone, wherein the each of the first feeding tube and the second feeding tube comprises an exit region, each exit region in fluid communication with the feeding zone, wherein the feeding zone of the preliminary polymerization reactor has:
a maximum polymer concentration at least 58% lower than the maximum polymer concentration in the preliminary polymerization reactor;
a maximum Ziegler-Natta catalyst concentration at least 58% lower than the maximum Ziegler-Natta catalyst concentration in the preliminary polymerization reactor; and
a maximum temperature at least 47% lower than the maximum temperature in the preliminary polymerization reactor.

17. A process for propylene bulk preliminary polymerization, comprising:
feeding propylene monomer and a Ziegler-Natta catalyst system comprising (a) a pro-catalyst having an internal electron donor comprising a substituted phenylene aromatic diester and (b) a catalyst activator, into a continuous stirred-tank preliminary polymerization reactor that comprises a feeding apparatus connected thereto, configured to feed propylene monomer and the Ziegler-Natta catalyst system into the continuous stirred-tank preliminary polymerization reactor,
wherein the feeding apparatus is configured to carry out said feeding without pre-contact of the pro-catalyst with the catalyst activator, and also without pre-contact of the catalyst activator with the propylene monomer before entering the continuous stirred-tank preliminary polymerization reactor,
wherein the propylene monomer and the Ziegler-Natta catalyst system, when in the continuous stirred-tank preliminary polymerization reactor, are in a liquid medium that is passed through the continuous stirred-tank preliminary polymerization reactor, and
wherein the process is carried out in the absence of, and the liquid medium does not have, saturated hydrocarbon diluent.

Assignees

• Braskem Sa

Inventors

• Martins Junior Olavo
• Pozzer Dihogenes Adriano
• Cavalli Élita
• Almeida Thiago Roberto
• Dawson Bryan

Classifications

• C08F4/654

  with magnesium or compounds thereof · CPC title

• C08F4/655

  with aluminium or compounds thereof · CPC title

• C08F2/02

  Polymerisation in bulk · CPC title

• C08F4/65912

  in combination with an organoaluminium compound · CPC title

• C08F2/01

  characterised by special features of the polymerisation apparatus used · CPC title