Continuous preparation of low unsaturation polyoxyalkylene polyether polyols with continuous additon of starter
US5689012A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 1996 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Jul 18, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G65/2696
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A continuous process for the preparation of polyoxyalkylene polyethers using DMC catalysts as the polyoxyalkylation catalyst employs continuous addition of alkylene oxide in conjunction with continuous addition of starter and catalyst to a continuous oxyalkylation reactor. Despite the continuous introduction of starter, the molecular weight distribution of the polyether product is quite narrow, as indicated by the exceptionally low polydispersity of the product. The presence of low molecular weight species during the majority of the polyoxyalkylation also substantially eliminates extremely high molecular weight fractions having molecular weights greater than 100,000 Da, again without appreciably broadening molecular weight distribution. By withdrawing intermediate molecular weight polyether product or diverting a portion of the end product to prepare a catalyst/starter mixture, rapid and sustained reaction rates can be achieved while employing low molecular weight starters. Continuous build ratios in excess of 0.98 can be achieved.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.