US4035291A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for separating aqueous formaldehyde mixtures
Assignee: Monsanto Co
•
Filing: 1976-01-05
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Granted: 1977-07-12
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Expires: 1996-01-05
Abstract
Abstract Process for the separation of water from mixtures of water and formaldehyde by contacting the mixtures against an organic polymeric membrane, and withdrawing at the other side of the membrane a mixture having a higher concentration of water.
Inventors
- 👤 Robert Chiang
- 👤 Eli Perry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:29
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/36; B01D61/362; B01D71/00; B01D71/06; B01D71/76; B01D71/82; B01J; B01J47/00; B01J47/12; C; C07; C07C; C07C45/00; C07C45/78; C07C45/786; B01D2325/00; B01D2325/14
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
73 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 comprising a copolymer of non-nitrogen containing monomer and a copolymerizable sulfonate-substituted monomer and withdrawing, at second side, a vaporous mixture having a higher concentration of water than the aforesaid feed mixture, with the mixture at second side being maintained at a lower chemical potential than the feed side.
Claim 2
Dependent Claim
73 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 comprising a copolymer of non-nitrogen containing monomer and a copolymerizable sulfonate-substituted monomer and withdrawing, at second side, a vaporous mixture having a higher concentration of water than the aforesaid feed mixture, with the mixture at second side being maintained at a lower chemical potential than the feed side.
Claim 3
Dependent Claim
84 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 comprising a copolymer of a non-nitrogen-containing monomer and a copolymerizable sulfonate-substituted monomer 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, but less than the pressure at the feed side of the membrane.
Claim 4
Dependent Claim
84 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 comprising a copolymer of a non-nitrogen-containing monomer and a copolymerizable sulfonate-substituted monomer 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, but less than the pressure at the feed side of the membrane.
Claim 5
Dependent Claim
15 words
Process as in claim 1 in which the feed mixture comprises water, formaldehyde and methanol.
Claim 6
Dependent Claim
20 words
Process as in claim 1 in which the said membrane comprises a copolymer of a non-nitrogen-containing monomer and alkyl sulfonate.
Claim 7
Dependent Claim
20 words
Process as in claim 1 in which the said membrane comprises a copolymer of a non-nitrogen-containing monomer and vinyl sulfonate.
Claim 8
Dependent Claim
25 words
Process as in claim 1 in which the said membrane comprises a non-nitrogen-containing polymer which has as pendant groups along the polymer chain a sulfonate.
Claim 9
Dependent Claim
24 words
Process as in claim 1 in which the said membrane polymer contains groups whose model compounds have pK values of from 0.1 to 3.
Claim 10
Dependent Claim
20 words
Process as in claim 1 in which said membrane comprises a copolymer of a non-nitrogen-containing monomer and alkylene sulfonic acid.
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) | 1980-07-11 | 1981-01-10 | 1981-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-07-11 | 1985-01-10 | 1985-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-07-11 | 1989-01-10 | 1989-07-12 | $7700.00 | Window Closed / Lapsed |