Patent US4490557A successfully refreshed from Google Patents.
US4490557A
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Ethylidene bisformamide, its preparation and use in preparing poly(vinylamine) and salts thereof
Assignee: Dynapol Corp
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Filing: 1981-11-05
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Granted: 1984-12-25
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Expires: 2001-11-05
Abstract
Abstract Ethylidene bisformamide is prepared by reacting, at elevated temperatures, dry acetaldehyde and formamide in the presence of an acidic catalyst and an ammonia scavenger such as acetic anhydride. The bisformamide is recovered as a bottoms products of high speed low residence time distillation techniques, e.g., wiped film evaporation. The resulting ethylidene bisformamide may be cracked to N-vinylformamide, which monomer is useful in the preparation of active polymers and copolymers, including poly(vinylformamide) which can be hydrolyzed to poly(vinylamine) salts by contact with acid. These amine salts can then be converted to the free amines, which are precursors of polymeric dyes and pharmaceuticals.
Inventors
- 👤 Daniel J. Dawson
- 👤 Kenneth M. Otteson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 09:50
CPC Classifications
C; C07; C07C; C07C233/00
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
67 words
A process for preparing ethylidene bisformamide which comprises contacting a liquid admixture comprising formamide, acetaldehyde, and an ammonia scavenger with a catalytic amount of an acidic catalyst at a temperature greater than 50° C. and under conditions sufficient to thereby form an ethylidene bisformamide reaction product, separating said reaction product from the catalyst and recovering from it ethylidene bisformamide using a low residence time-high surface area evaporator.
Claim 2
Dependent Claim
67 words
A process for preparing ethylidene bisformamide which comprises contacting a liquid admixture comprising formamide, acetaldehyde, and an ammonia scavenger with a catalytic amount of an acidic catalyst at a temperature greater than 50° C. and under conditions sufficient to thereby form an ethylidene bisformamide reaction product, separating said reaction product from the catalyst and recovering from it ethylidene bisformamide using a low residence time-high surface area evaporator.
Claim 3
Dependent Claim
12 words
The process of claim 1 wherein said ammonia scavenger is acetic anhydride.
Claim 4
Dependent Claim
13 words
The process of claim 2 wherein said catalyst is solid cation exchange resin.
Claim 5
Dependent Claim
26 words
The process of claim 3 wherein said liquid admixture is substantially water-free and contains acetaldehyde and formamide in the molar ratio of 1:2 to 1:6 inclusive.
Claim 6
Dependent Claim
18 words
The process of claim 4 wherein said temperature is in the range of from 50° to 100° C.
Claim 7
Dependent Claim
16 words
The process of claim 5 wherein said cation exchange resin is a protonated sulfonated divinylbenzene-crosslinked polystyrene.
Claim 8
Dependent Claim
76 words
A process for preparing ethylidene bisformamide which comprises contacting a substantially water-free liquid admixture comprising formamide, acetaldehyde and acetic anhydride with a catalytic amount of a solid cation exchange resin catalyst for a period of 0.50 hours to 24 hours inclusive at a temperature of from 50° C. to 120° C. thereby forming an ethylidene bisformamide--containing reaction product, separating said reaction product from said catalyst, and recovering the ethylidene bisformamide by using a wiped film evaporator.
Claim 9
Dependent Claim
76 words
A process for preparing ethylidene bisformamide which comprises contacting a substantially water-free liquid admixture comprising formamide, acetaldehyde and acetic anhydride with a catalytic amount of a solid cation exchange resin catalyst for a period of 0.50 hours to 24 hours inclusive at a temperature of from 50° C. to 120° C. thereby forming an ethylidene bisformamide--containing reaction product, separating said reaction product from said catalyst, and recovering the ethylidene bisformamide by using a wiped film evaporator.
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) | 1987-12-25 | 1988-06-25 | 1988-12-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-25 | 1992-06-25 | 1992-12-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-25 | 1996-06-25 | 1996-12-25 | $7700.00 | Window Closed / Lapsed |