Lubricant treatments for free-radical polymerizations

Patent metadata

Field	Value
Publication number	US-11078441-B2
Application number	US-201716332579-A
Country	US
Kind code	B2
Filing date	Sep 19, 2017
Priority date	Sep 28, 2016
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

A process to prepare an ethylene-based polymer, said process comprising polymerizing a mixture comprising ethylene, at a pressure greater than, or equal to, 100 MPa, in the presence of at least one free-radical initiator; and in a reactor system comprising at least one reactor and at least one Hyper-compressor, and wherein at least one oil formulation, optionally comprising one or more lubrication agents, is added to the Hyper-compressor; and wherein at least one of the following steps takes place: A) thermally treating the one or more lubrication agents, in an oxygen-free atmosphere, to achieve a peroxide level ≤10 ppm, based on the weight of the lubrication agent(s), and then adding said agent(s) to the oil formulation, prior to adding the oil formulation to the Hyper-compressor; or B) thermally treating the oil formulation, in an oxygen-free atmosphere, to achieve a peroxide level ≤10 ppm, based on the weight of the oil formulation, prior to adding the oil formulation to the Hyper-compressor; C) a combination of A and B.

First claim

The invention claimed is:

1. A process to prepare an ethylene-based polymer, said process comprising polymerizing a mixture comprising ethylene, at a pressure greater than, or equal to, 100 MPa, in the presence of at least one free-radical initiator; and in a reactor system comprising at least one reactor and at least one Hyper-compressor;
wherein at least one oil formulation, optionally comprising one or more lubrication agents, is added to the Hyper-compressor if a peroxide level of the at least one oil formulation, the at least one lubrication agent, or both the at least one oil formulation and the at least one lubrication agent ≤10 ppm; and wherein at least one of the following steps takes place if the peroxide level >10 ppm before adding the at least one oil formulation to the Hyper-compressor:
A) thermally treating the one or more lubrication agents, in an oxygen-free atmosphere, at from 50° C. to 200° C. for from 1 hour to 24 hours, to achieve a peroxide level ≤10 ppm, based on the weight of the lubrication agent(s), and then adding said agent(s) to the oil formulation, prior to adding the oil formulation to the Hyper-compressor;
B) thermally treating the oil formulation, in an oxygen-free atmosphere, at from 50° C. to 200° C. for from 1 hour to 24 hours, to achieve a peroxide level ≤10 ppm, based on the weight of the oil formulation, prior to adding the oil formulation to the Hyper-compressor; or
C) a combination of A and B; and

the Hyper-compressor does not contain, when the one or more oil formulation is present, a compound selected from the following compounds i) through iv):

wherein, for Compound 1, R1, R2, R3, R4, R5, R6, R7 and R8 are each independently selected from H, an alkyl, or an alkoxy;

wherein, for Compound 2, R1 is selected from OH or O—R, wherein R is alkyl; and R2, R3, R4 and R5 are each independently selected from H, an alkyl, or an alkoxy;

wherein, for Compound 3, R1, R2, R4 and R5 are each independently selected from H, an alkyl, or an alkoxy; and R3 is selected from H or an alkyl; or
iv) a combination of two or more of Compounds 1 through 3.

2. The process of claim 1 , wherein the at least one reactor is a tubular reactor.

3. The process of claim 1 , wherein the oil formulation comprises greater than, or equal to, 70.0 wt % oil, based on the weight of the oil formulation.

4. The process of claim 1 , wherein the oil formulation is injected at one or more injection points into the Hyper-compressor.

5. The process of claim 1 , wherein the ethylene-based polymer is an ethylene homopolymer.

Assignees

• Dow Global Technologies Llc

Inventors

• Ewart Sean W
• Munjal Sarat
• Sun Kefu

Classifications

• C10M175/0025 Primary

  by thermal processes · CPC title

• C08F2/002

  Scale prevention in a polymerisation reactor or its auxiliary parts · CPC title

• C10M2219/108

  Phenothiazine · CPC title

• Y02P30/40

  Ethylene production · CPC title

• C10N2040/30

  Refrigerators lubricants {or compressors lubricants} · CPC title