Reducing molecular weight distribution of polyether glycols by short-path distillation
US5282929A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1992 |
| Grant date | Feb 1, 1994 |
| Priority date | — |
| Expiry date | Sep 15, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S159/16
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Polyether glycols, especially poly(tetramethylene ether) glycol (PTMEG) having a narrow molecular weight distribution of about 1.90 to 2.07, or dispersity of 1.50 to 1.90, are made by a process wherein the low molecular weight fraction in unit operations using at least one short-path distillation evaporator. In these units, PTMEG is subjected to temperatures in the range of 150.degree.-190.degree.C. with the hold-up time varying between 10-200 seconds. The required vacuum to force the separation of the low molecular weight PTMEG varies between 0.001 mm and 1.0 mbar. PTMEG residue from the distillation unit is also characterized by its low water content and low concentration of oligomeric cyclic ethers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.