US4014914A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates
Assignee: BASF SE
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Filing: 1974-10-25
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Granted: 1977-03-29
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Expires: 1994-10-25
Abstract
Abstract Production of 4,4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates by the phosgenation of pure 4,4'-diaminodiphenylmethane and a mixture of diamines and polyamines. 4,4'-Diaminodiphenylmethane is obtained by distillation of the mixture of products obtained from the reaction of aniline with formaldehyde and crystallization of the distillate from a solvent. The combined distillation residue and mother liquor from the crystallization form the mixture for reaction with phosgene to produce a mixture of diisocyanates and polyiisocyanates. This process produces a highly pure 4,4'-diphenylmethane diisocyanate which is particularly suitable for the production of polyurethanes serving as intermediates in the manufacture of rigid foams or as glue.
Inventors
- 👤 Hans Joachim Pistor
- 👤 Herwig Hoffmann
- 👤 Hans-Ingo Joschek
- 👤 Gotthilf Wenner
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:23
CPC Classifications
C; C08; C08G; C08G18/00; C08G18/06; C08G18/70; C08G18/72; C08G18/74; C08G18/76; C08G18/7657; C08G18/7664; C07; C07C; C07C263/00; C07C263/10
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
155 words
A process for the manufacture of 4.4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates which consists essentially of a. condensing aniline with formaldehyde in a molar ratio of from 2:1 to 6:1 in the presence of a strong aqueous mineral acid at temperatures of 10° to 90°C at the start of the reaction rising to temperatures ranging from 80° to 150°C as condensation proceeds; b. neutralizing the reaction mixture on completion of condensation; c. distilling off from the mixture obtained after neutralization all or a portion of the diamines; d. recovering substantially pure 4,4'-diaminodiphenylmethane from the mixture of separated diamines by crystallization from a solvent; e. combining the distillation residue from step (c) and the mother liquor from step (d); f. reacting the substantially pure 4,4'-diaminodiphenylmethane with phosgene to form 4,4'-diphenylmethane diisocyanate; and g. reacting the mixture from step (e) containing diamines and polyamines with phosgene to form a mixture of diisocyanates and polyisocyanates.
Claim 2
Dependent Claim
155 words
A process for the manufacture of 4.4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates which consists essentially of a. condensing aniline with formaldehyde in a molar ratio of from 2:1 to 6:1 in the presence of a strong aqueous mineral acid at temperatures of 10° to 90°C at the start of the reaction rising to temperatures ranging from 80° to 150°C as condensation proceeds; b. neutralizing the reaction mixture on completion of condensation; c. distilling off from the mixture obtained after neutralization all or a portion of the diamines; d. recovering substantially pure 4,4'-diaminodiphenylmethane from the mixture of separated diamines by crystallization from a solvent; e. combining the distillation residue from step (c) and the mother liquor from step (d); f. reacting the substantially pure 4,4'-diaminodiphenylmethane with phosgene to form 4,4'-diphenylmethane diisocyanate; and g. reacting the mixture from step (e) containing diamines and polyamines with phosgene to form a mixture of diisocyanates and polyisocyanates.
Claim 3
Dependent Claim
24 words
A process as set forth in claim 1 wherein about 40 to 90% by weight of the diamines are distilled off in step (c).
Claim 4
Dependent Claim
40 words
A process as set forth in claim 1 wherein the solvent used in step (c) is an aromatic compound having one or two rings and one or two chlorine atoms or an aromatic compound having one or two methyl groups.
Claim 5
Dependent Claim
17 words
A process as set forth in claim 1 wherein the solvent used in step (c) is chlorobenzene.
Claim 6
Dependent Claim
33 words
A process as set forth in claim 1 wherein the mineral acid is hydrochloric acid and wherein the amount of said acid is from 0.02 to 0.3 mole for each mole of aniline.
Claim 7
Dependent Claim
38 words
A process as set forth in claim 1 wherein the temperature in step (a) at the start of the reaction is from 10° to 30°C and wherein the temperature rises to from 80° to 140°C as condensation proceeds.
References Cited (Backward Citations)
US3542871A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-03-28 | 1980-09-27 | 1981-03-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-28 | 1984-09-27 | 1985-03-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-28 | 1988-09-27 | 1989-03-29 | $7700.00 | Window Closed / Lapsed |