US4137054A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Purification of formaldehyde by separation
Assignee: Asahi Kasei Corp
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Filing: 1977-01-17
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Granted: 1979-01-30
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Expires: 1997-01-17
Abstract
Abstract A mixture containing formaldehyde and water is separated effectively by contacting with adsorbents of specific type A zeolites containing exchanged cations of the elements from Group IA (4) to (6) or Group IIA (6) or mixture thereof of the Periodic Table of Elements.
Inventors
- 👤 Tetsuya Miyake
- 👤 Kunihiko Takeda
- 👤 Naoki Miyata
- 👤 Tatsushi Saeki
- 👤 Maomi Seko
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 12:55
CPC Classifications
C; C07; C07C; C07C45/00; C07C45/78; C07C45/79; Y; Y10; Y10S; Y10S95/00; Y10S95/90; Y10S95/902
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
97 words
A process for purification of formaldehyde by separation, which comprises contacting a mixture containing formaldehyde and water with an adsorbent selected from the group consisting of type A synthetic zeolites wherein the exchangeable cations contain at least one of the Group IA, from the fourth to the sixth period, and Group IIA, the sixth period, of the Periodic Table of Elements thereby selectively to adsorb water on said adsorber and to leave a stream enriched in formaldehyde, said zeolite having been pretreated with a treating agent selected from the group consisting of phosphoric acid and salts thereof.
Claim 2
Dependent Claim
97 words
A process for purification of formaldehyde by separation, which comprises contacting a mixture containing formaldehyde and water with an adsorbent selected from the group consisting of type A synthetic zeolites wherein the exchangeable cations contain at least one of the Group IA, from the fourth to the sixth period, and Group IIA, the sixth period, of the Periodic Table of Elements thereby selectively to adsorb water on said adsorber and to leave a stream enriched in formaldehyde, said zeolite having been pretreated with a treating agent selected from the group consisting of phosphoric acid and salts thereof.
Claim 3
Dependent Claim
29 words
A process as in claim 1, wherein the exchangeable cations in the type A synthetic zeolite are composed of 90 wt.% or more of potassium ions or barium ions.
Claim 4
Dependent Claim
29 words
A process as in claim 1, wherein the exchangeable cations in the type A synthetic zeolite are composed of 90 wt.% or more of barium, or barium and potassium.
Claim 5
Dependent Claim
13 words
A process as in claim 1, wherein the treating agent is phosphoric acid.
Claim 6
Dependent Claim
49 words
A process as in claim 1, wherein the type A synthetic zeolite is produced by replacing the type A synthetic zeolite in hydrogen form with cations of the Group IA, from the fourth to the sixth period, or Group IIA, the sixth period, of the Periodic Table of Elements.
Claim 7
Dependent Claim
15 words
A procwess as in claim 1, wherein the mixture containing formaldehyde and water is gaseous.
Claim 8
Dependent Claim
30 words
A process as in claim 1, wherein the mixture containing formaldehyde and water further contains other substances composed principally of methyl alcohol, formic acid, methyl formate, methylal and carbon dioxide.
Claim 9
Dependent Claim
23 words
A process as in claim 1, wherein the ratio by weight of formaldehyde to water is in the range from 0.25 to 120.0.
Claim 10
Dependent Claim
23 words
A process as in claim 1, wherein the mixture of formaldehyde and water is formaldehyde with water content of 500 ppm or less.
Claim 11
Dependent Claim
31 words
A process as in claim 1, wherein the adsorbents are packed in a development column and in the adsorbents on consumption of a part of adsorption capacity are subjected to regeneration.
Claim 12
Dependent Claim
27 words
A process as in claim 10, wherein a part of the components eluted from the adsorbents is recovered and the remainder thereof is recycled to the column.
Claim 13
Dependent Claim
33 words
A process as in claim 1, wherein the adsorbents are packed in plural columns provided in parallel to each other, and separation is operated continuously by switching from one column to another, successively.
Claim 14
Dependent Claim
75 words
A process as in claim 1, wherein separation is operated by use of plural columns packed with the adsorbents and connected in series in a closed recycle system, by forming an adsorption zone of formaldehyde and water and displacing said zone through said plural columns, and recovering a stream enriched in formaldehyde from the forefront portion of said adsorption zone and a stream enriched in water from the rear-end portion of said adsorption zone, respectively.
Claim 15
Dependent Claim
27 words
A process as in claim 13, wherein fresh feed of a mixture containing formaldehyde and water is charged supplementarily to the central portion of the adsorption zone.
Claim 16
Dependent Claim
30 words
A process as in claim 11, wherein the adsorbents are shaped in particles with sizes from 20 to 400 mesh or in pellets with sizes from 1/2 to 1/32 inch.
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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) | 1982-01-29 | 1982-07-31 | 1983-01-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-01-29 | 1986-07-31 | 1987-01-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-01-29 | 1990-07-31 | 1991-01-30 | $7700.00 | Window Closed / Lapsed |