US4143072A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the purification of polyethers using a tubular coil evaporator
Assignee: Bayer AG
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Filing: 1978-04-27
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Granted: 1979-03-06
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Expires: 1998-04-27
Abstract
Abstract This invention relates to a process for the removal of troublesome secondary products, particularly small quantities of water, solvents, low molecular weight glycols, and pungent-smelling substances, from polyethers by means of a tubular coil evaporator.
Inventors
- 👤 Hartmut Hetzel
- 👤 Pramod Gupta
- 👤 Hans-Joachim Sandhagen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:10
CPC Classifications
C; C08; C08G; C08G65/00; C08G65/02; C08G65/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
128 words
A process for the purification of crude polyethers, comprising introducing crude polyether into a heated tubular coil evaporator together with from 1 to 20%, by weight, of steam, a pressure of from 5 to 200 mbars being applied to the end of the tubular coil evaporator and, at the same time, the heating of the tubular coil evaporator being regulated in such a way that the polyether temperature in the evaporator is from 100° to 220° C., the rate of flow of the vapor mixture, based on the cross-sectional area of the tube through which it flows, being between 40 m/s and the speed of sound; separating the pure polyether from the vapor phase which contains the added steam and the volatile impurities; and recovering the purified polyether.
Claim 2
Dependent Claim
128 words
A process for the purification of crude polyethers, comprising introducing crude polyether into a heated tubular coil evaporator together with from 1 to 20%, by weight, of steam, a pressure of from 5 to 200 mbars being applied to the end of the tubular coil evaporator and, at the same time, the heating of the tubular coil evaporator being regulated in such a way that the polyether temperature in the evaporator is from 100° to 220° C., the rate of flow of the vapor mixture, based on the cross-sectional area of the tube through which it flows, being between 40 m/s and the speed of sound; separating the pure polyether from the vapor phase which contains the added steam and the volatile impurities; and recovering the purified polyether.
Claim 3
Dependent Claim
16 words
The process of claim 1 wherein from 2 to 8% by weight of steam is used.
Claim 4
Dependent Claim
16 words
The process of claim 1 wherein from 2.5 to 5% by weight of steam is used.
Claim 5
Dependent Claim
18 words
The process of claim 1 wherein said pressure applied to the end of the evaporator is 20-80 mbars.
Claim 6
Dependent Claim
15 words
The process of claim 1 wherein the polyether temperature is from 130° to 170° C.
Claim 7
Dependent Claim
46 words
The process of claim 1 wherein the polyethers used are based on ethylene oxide and/or propylene oxide and contain from 1 to 5 hydroxyl groups, have a molecular weight of from 750 to 15,000 and have a viscosity at 100° C. of from 10 to 800cP.
Claim 8
Dependent Claim
37 words
The process of claim 6 wherein the polyether contains from 2 to 3 hydroxyl groups, has a molecular weight of from 2000 to 6000 and has a viscosity at 100° C. of from 50 to 200 cP.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1982-03-05 | 1982-09-04 | 1983-03-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-03-05 | 1986-09-04 | 1987-03-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-03-05 | 1990-09-04 | 1991-03-06 | $7700.00 | Window Closed / Lapsed |