US3750735A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Removal of water from liquid mixtures containing formaldehyde using a porous polymeric membrane
Assignee: Monsanto Co
•
Filing: 1972-01-19
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Granted: 1973-08-07
•
Expires: 1992-01-19
Abstract
Abstract Process for the separation of water from mixtures of water and organic or inorganic compounds, soluble in water, by contacting the mixtures against a nitrogen-containing polymeric membrane, and withdrawing at the other side of the membrane a mixture having a higher concentration of water.
Inventors
- 👤 R Chiang
- 👤 E Perry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 15:54
CPC Classifications
C; C07; C07D; C07D309/00; C07D309/34; C07D309/36; C07D309/40; B; B01; B01D; B01D61/00; B01D61/36; B01D61/362; B01D71/00; B01D71/06; B01D71/40; B01D71/42; B01D71/421; B01D71/76; B01D71/82; C07C; C07C29/00; C07C29/74; C07C29/76; C07C45/00; C07C45/78; C07C45/786; Y; Y10; Y10S; Y10S159/00; Y10S159/27
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
15 words
Process as in claim 1 in which the feed mixture comprises water, formaldehyde and methanol.
Claim 2
Dependent Claim
85 words
Process for the separation of water from feed mixtures comprising water and formaldehyde which comprises contacting the aforesaid mixture against one side of a membrane, said membrane comprising a copolymer of acrylonitrile and styrene sulfonate, and withdrawing, at the second side, a vaporous mixture having a higher concentration of water than the aforesaid feed mixture, with the mixture at the second side being maintained at a pressure which is greater than atmospheric, but is less than the pressure at the feed side of the membrane.
Claim 3
Dependent Claim
81 words
Process for the separation of water from feed mixtures comprising water and formaldehyde which comprises contacting the aforesaid mixture against one side of a membrane, said membrane comprising a copolymer of acrylonitrile, and styrene sulfonate, and withdrawing, at the second side, a vaporous mixture having a higher concentration of water than the aforesaid feed mixture, with the mixture at the said second side being maintained at a pressure less than atmospheric, but less than the pressure at the side feed side.
Claim 4
Dependent Claim
86 words
Process for the separation of water from feed mixtures comprising water and formaldehyde which comprises contacting the aforesaid mixture against one side of a membrane, said membrane comprising a copolymer of acrylonitrile and styrene sulfonate, and withdrawing, at the second side, a vaporous mixture having a higher concentration of water than the aforesaid feed mixture, with the mixture at the second side being maintained at a pressure less than atmospheric, and the pressure at the side feed side being maintained at a pressure greater than atmospheric.
Claim 5
Dependent Claim
23 words
Process as in claim 5 in which the said second side is maintained at a vacuum of from 0.3 to 759 mm. Hg.
References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |