Process for the production of low molecular weight polyoxyalkylene polyols

Patent metadata

Field	Value
Publication number	US-9879114-B2
Application number	US-201514978079-A
Country	US
Kind code	B2
Filing date	Dec 22, 2015
Priority date	Dec 22, 2015
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

This invention relates to a semi-batch process for producing low molecular weight polyoxyalkylene polyols. These polyoxyalkylene polyols are characterized by hydroxyl numbers of from 200 to 500. In accordance with the invention, the first alkylene oxide block used to activate the DMC catalyst comprises from 50% to 100% by weight of propylene oxide and from 0% to 50% by weight of ethylene oxide; and the second alkylene oxide block comprises from 50% to 100% by weight of propylene oxide and from 0% to 50% by weight of ethylene oxide. A continuously added starter is present. Optionally, a third alkylene oxide block can be added. The addition of the second alkylene oxide block and of the third alkylene oxide block when present is completed with a space time yield of greater than or equal to 250 kg/m 3 /hr.

First claim

What is claimed is:

1. A semi-batch process for the production of low molecular weight polyoxyalkylene polyols which have hydroxyl numbers of from 200 to 500, comprising:
(1) establishing a mixture of a double metal cyanide catalyst and an initial starter in a reactor;
(2) activating said double metal cyanide catalyst with a first alkylene oxide block that comprises from 50% to 100% by weight of propylene oxide and 0% to 50% by weight of ethylene oxide, wherein the sum of the % by weight of propylene oxide and the % by weight of ethylene oxide totals 100% by weight of said first alkylene oxide block;
(3) adding a second alkylene oxide block into the reactor, wherein said second alkylene oxide block comprises from 50% to 100% by weight of propylene oxide and 0% to 50% by weight of ethylene oxide, wherein the sum of the % by weight of propylene oxide and the % by weight of ethylene oxide totals 100% by weight of said second alkylene oxide block;
(4) continuously introducing one or more starters into the reactor;
(5) optionally, adding a third alkylene oxide block into the reactor, wherein said third alkylene oxide block comprises from 95% to 100% by weight of propylene oxide and from 5% to 0% by weight of ethylene oxide, wherein the sum of the % by weight of propylene oxide and the % by weight of ethylene oxide totals 100% by weight of the third alkylene oxide block;
(6) oxyalkylating the starters to form the low molecular weight polyoxyalkylene polyols;
and
(7) completing the addition of the second alkylene oxide block which was started in (3), and, when present, of the third alkylene oxide block, with a space time yield of greater than or equal to 250 kg/m 3 /hr.

2. The process of claim 1 , wherein said third alkylene oxide block is present and the content of ethylene oxide in said first alkylene oxide block and in said second alkylene oxide block is greater than the content of ethylene oxide in said third alkylene oxide block.

3. The process of claim 1 , wherein the ethylene oxide feed when present is stopped when the total alkylene oxide added in step (3) ranges from 10 to 20% of the total alkylene oxide added to the entire process and the process is completed with 100% propylene oxide.

4. The process of claim 1 , wherein at least one of said first alkylene oxide block and said second alkylene oxide block comprises a minimum of 5% by weight of ethylene oxide.

5. The process of claim 1 , wherein said second alkylene oxide block comprises from 50 to 95% by weight of propylene oxide and from 5 to 50% by weight of ethylene oxide, and the sum of the % by weight of propylene oxide and the % by weight of ethylene oxide totals 100% by weight of said second alkylene oxide block.

6. The process of claim 1 , wherein the ratio of continuous starter to said alkylene oxides is instantaneously within the range of 0.15 to 0.40.

7. The process of claim 1 , wherein steps (3) and (4) are conducted simultaneously.

8. The process of claim 1 , wherein said third alkylene oxide block is present and steps (4) and (5) are conducted simultaneously.

9. The process of claim 1 , wherein the composition of the second alkylene oxide block is the same as that of the first alkylene oxide block.

10. The process of claim 1 , wherein after the pressure decreases following the continuous introduction of one or more starters (S c ), a third alkylene oxide block having a different composition than the first and second alkylene oxide blocks is added.

11. The process of claim 1 , wherein said first alkylene oxide block and said second alkylene oxide block both comprise 100% of propylene oxide.

12. The process of claim 1 , wherein said first alkylene oxide block comprises a mixture of propylene oxide to ethylene oxide in a weight ratio of 95:5 to 80:20, and said second alkylene oxide block has the same propylene oxide to ethylene oxide weight ratio until at least 10% of the oxide feed, based on target amount of oxide required, is completed.

13. The process of claim 1 , wherein said initial starter comprises a heel from a previous product.

14. The process of claim 1 , wherein the addition of the second and third alkylene oxide block is completed with a space time yield of greater than or equal to 275 kg/m 3 /hr.

Assignees

• Covestro Llc

Inventors

• Reese Jack R
• Bowles Phillip E
• Browne Edward P

Classifications

• B01J37/26 Primary

  Fluorinating · CPC title

• C07C41/09

  by dehydration of compounds containing hydroxy groups · CPC title

• C08G65/2696

  characterised by the process or apparatus used · CPC title

• C08G65/10 Primary

  characterised by the catalysts used · CPC title

• C08G65/2639

  the other compounds containing elements other than oxygen, nitrogen or sulfur · CPC title