Patent US4268683A successfully refreshed from Google Patents.
US4268683A
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Preparation of carbamates from aromatic amines and organic carbonates
Assignee: Dow Chemical Co
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Filing: 1980-02-21
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Granted: 1981-05-19
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Expires: 2000-02-21
Abstract
Abstract Carbamates are prepared from organic cabonates and aromatic amines in the presence of zinc or tin salts of monovalent organic compounds having a pKa value of at least 2.8 such as zinc naphthenate and which are soluble at the reaction conditions.
Inventors
- 👤 Arthur E. Gurgiolo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:49
CPC Classifications
C; C07; C07C; C07C271/00; C07C271/06
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
116 words
In a process for preparing carbamates from an organic carbonate and an aromatic amine in the presence of catalytic quantities of a Lewis acid catalyst; the improvement which comprises employing as the Lewis acid catalyst, a zinc or divalent tin halide, zinc or divalent tin salt of a monovalent organic compound which has a pKa value of at least 2.8, a zinc or divalent tin salt of trifluoroacetic acid or a mixture of such catalysts and which is soluble in the reaction mixture at the reaction conditions employed; with the proviso that when a zinc or divalent tin salt of trifluoroacetic acid is employed as the only catalyst, the organic carbonate is a cyclic organic carbonate.
Claim 2
Dependent Claim
116 words
In a process for preparing carbamates from an organic carbonate and an aromatic amine in the presence of catalytic quantities of a Lewis acid catalyst; the improvement which comprises employing as the Lewis acid catalyst, a zinc or divalent tin halide, zinc or divalent tin salt of a monovalent organic compound which has a pKa value of at least 2.8, a zinc or divalent tin salt of trifluoroacetic acid or a mixture of such catalysts and which is soluble in the reaction mixture at the reaction conditions employed; with the proviso that when a zinc or divalent tin salt of trifluoroacetic acid is employed as the only catalyst, the organic carbonate is a cyclic organic carbonate.
Claim 3
Dependent Claim
30 words
The process of claim 1 wherein the compound has a pKa of from about 4 to about 10, the reaction temperature is from about 80° C. to about 300° C.
Claim 4
Dependent Claim
18 words
The process of claim 2 wherein the reaction temperature is from about 120° C. to about 250° C.
Claim 5
Dependent Claim
24 words
The process of claim 3 wherein the catalyst is a zinc salt and the temperature is from about 130° C. to about 200° C.
Claim 6
Dependent Claim
22 words
The process of claim 4 wherein the catalyst is selected from zinc naphthenate, zinc acetate, zinc propionate, zinc octoate or mixtures thereof.
Claim 7
Dependent Claim
20 words
The process of claim 1, 2, 3 or 4 wherein said catalyst is zinc carbonate, cobaltous acetylacetonate, or mixtures thereof.
Claim 8
Dependent Claim
40 words
The process of claim 1, 2, 3, 4 or 5 wherein said aromatic amine is aniline, 2,4-toluene diamine, 2,6-toluene diamine, methylene dianiline or mixtures thereof and said organic carbonate is dimethylcarbonate, diethylcarbonate, diphenylcarbonate, ethylene carbonate, propylene carbonate or mixtures thereof.
Claim 9
Dependent Claim
35 words
The process of claim 6 wherein said aromatic amine is aniline, 2,4-toluene diamine, 2,6-toluene diamine, methylene dianiline or mixtures thereof and said organic carbonate is dimethylcarbonate, diethylcarbonate, diphenylcarbonate, ethylene carbonate, propylene carbonate or mixtures thereof.
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) | 1984-05-18 | 1984-11-17 | 1985-05-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-05-18 | 1988-11-17 | 1989-05-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-05-18 | 1992-11-17 | 1993-05-19 | $7700.00 | Window Closed / Lapsed |