US5079383A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of condensing n-phenyl carbamates
Assignee: GETA GESELLSCHAFT fur ENERGIETECHNIK und -ANWENDUNG MBH
•
Filing: 1990-07-25
•
Granted: 1992-01-07
•
Expires: 2010-07-25
Abstract
Abstract A process for producing 4,4'-diphenylmethane dicarbamates through one-stage condensation by reacting N-phenyl carbamates with a methylenating agent in presence of a zinc halide, as a catalyst. 4,4'-diphenylmethane dicarbamates can be produced with high selectivity and in high yield.
Inventors
- 👤 Fujihisa Matsunaga
- 👤 Mitsuki Yasuhara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:10
CPC Classifications
C; C07; C07C; C07C271/00; C07C271/06; C07C271/40; C07C271/42; C07C269/00; C07C269/06; C07C271/08; C07C271/26; C07C271/28
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
34 words
A method of preparing a 4,4'-diphenylmethane dicarbamate, which comprises condensing a methylenating agent with 2 to 20 moles of an N-phenylcarbamate per mole of the methylenating agent in the presence of a zinc halide.
Claim 2
Independent Claim
34 words
A method of preparing a 4,4'-diphenylmethane dicarbamate, which comprises condensing a methylenating agent with 2 to 20 moles of an N-phenylcarbamate per mole of the methylenating agent in the presence of a zinc halide.
Claim 3
Dependent Claim
11 words
A method according to claim 1 which uses an organic solvent.
Claim 4
Dependent Claim
25 words
A method according to claim 1 or 2 wherein said zinc halide is used in an amount of 0.1-10 moles per mole of the N-phenylcarbamate.
Claim 5
Dependent Claim
25 words
A method according to claim 1 wherein said zinc halide is zinc chloride (ZnCl 2 ), zinc bromide (ZnBr 2 ) or a mixture thereof.
Claim 6
Independent Claim
23 words
A method of preparing 4,4'-diphenylmethane dicarbamates, which comprises condensing an N-phenyl carbamate with a methylenating agent int he presence of a zinc halide.
Claim 7
Independent Claim
23 words
A method of preparing 4,4'-diphenylmethane dicarbamates, which comprises condensing an N-phenyl carbamate with a methylenating agent int he presence of a zinc halide.
Claim 8
Dependent Claim
143 words
A method according to claim 1 wherein the N-phenyl carbamate is represented by the following general formula: ##STR4## where R is a C 1 -C 4 substituted or unsubstituted alkyl, a C 5 -C 9 cycloalkyl or aralkyl, a phenyl group having at least a C 1 -C 4 straight-chain or branched alkyl group on the benzene ring thereof; R' is a hydrogen atom, a C 1 -C 4 alkyl group, a halogen atom, a nitro group, a cyano group, a C 1 -C 4 alkoxy group, and an aralkyl or phenyl group having at least a C 1 -C 4 straight-chain or branched alkyl group on the benzene ring thereof, provided that R' is bonded to the urethane group in the ortho- or meta-position; and n is an integer of 0-4, provided that when n≧2, R' may be the same or different.
Claim 9
Dependent Claim
98 words
A method according to claim 6 wherein the N-phenyl carbamate represented by the general formula is selected from methyl N-phenylcarbamate, ethyl N-phenylcarbamate, n-propyl N-phenylcarbamate, isopropyl N-phenylcarbamate, n-butyl N-phenylcarbamate, isobutyl N-phenylcarbamate, tert-butyl N-phenylcarbamate, pentyl N-phenylcarbamate, hexyl N-phenylcarbamate, cyclohexyl N-phenylcarbamate, methyl N-o- or m-tolylcarbamate, ethyl N-o- or m-tolylcarbamate, propyl N-o- or m-tolyl carbamate, or isomers thereof, butyl N-o- or m-tolylcarbamate, or isomers thereof, methyl N-o- or m-chlorophenylcarbamate, ethyl N-o- or m-chlorophenylcarbamate, propyl N-o- or m-chlorophenylcarbamate, or isomers thereof, butyl N-o- or m-chlorophenylcarbamate, or isomers thereof, methyl N-2,6-dimethylphenylcarbamate, ethyl N-2,6-dimethylphenylcarbamate, propyl N-2,6-dimethylphenylcarbamate, or isomers thereof, or butyl N-2,6-dimethylphenylcarbamate, or isomers thereof.
Claim 10
Dependent Claim
35 words
A method according to claim 1 wherein the methylating agent is selected from the group consisting of formalin paraformaldehyde, trioxane, tetraoxane, a lower alkoxymethane, a diacycloxymethane having a lower carboxy group and a mixture thereof.
References Cited (Backward Citations)
US2946768A
Cited
US4699994A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-01-06 | 1995-07-08 | 1996-01-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-01-06 | 1999-07-08 | 2000-01-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-01-06 | 2003-07-08 | 2004-01-07 | $7700.00 | Window Closed / Lapsed |