US3968159A
Expired / Lapsed
US
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Process for preparing azomethines
Assignee: Monsanto Co
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Filing: 1974-05-23
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Granted: 1976-07-06
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Expires: 1994-05-23
Abstract
Abstract Azomethines are prepared by reacting under carbon monoxide pressure an aromatic or heterocyclic aldehyde and an aromatic or heterocyclic nitro compound in the presence of a tertiary amine and Group VIII metal carbonyl. Exemplary is the preparation of benzylidene-aniline by reaction of benzaldehyde and nitrobenzene in the presence of pyridine and Rh 6 (CO) 16 at 170°C and 150 atmospheres.
Inventors
- 👤 Abul F. M. Iqbal
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 14:00
CPC Classifications
C; C07; C07C; C07C249/00; C07C249/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
134 words
A process for the preparation of aromatic or heterocyclic azomethines which consists essentially of reacting under carbon monoxide pressure of 50 to about 500 atmospheres and a temperature of 50°-250°C, an aromatic or heterocyclic aldehyde, and an aromatic or heterocyclic nitro compound in the presence of a solvent containing a compound selected from the group consisting of basic tertiary amines and basic tertiary amides, and of a catalyst selected from the group consisting of [Rh(CO) 2 Cl] 2 , [Rh(OCOCH 3 ) 2 ] 2 Rh 4 (CO) 12 , Rh 6 (CO) 16 , RhCl[(C 6 H 5 ) 3 P] 3 , RhO 2 , Rh 2 O 3 , Rh(OH) 3 and RhCl 3 the molar ratio of said catalyst relative to the said nitro compound being from 1:100 to 1:50,000.
Claim 2
Dependent Claim
134 words
A process for the preparation of aromatic or heterocyclic azomethines which consists essentially of reacting under carbon monoxide pressure of 50 to about 500 atmospheres and a temperature of 50°-250°C, an aromatic or heterocyclic aldehyde, and an aromatic or heterocyclic nitro compound in the presence of a solvent containing a compound selected from the group consisting of basic tertiary amines and basic tertiary amides, and of a catalyst selected from the group consisting of [Rh(CO) 2 Cl] 2 , [Rh(OCOCH 3 ) 2 ] 2 Rh 4 (CO) 12 , Rh 6 (CO) 16 , RhCl[(C 6 H 5 ) 3 P] 3 , RhO 2 , Rh 2 O 3 , Rh(OH) 3 and RhCl 3 the molar ratio of said catalyst relative to the said nitro compound being from 1:100 to 1:50,000.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the catalyst is selected from the group consisting of Rh 6 (CO) 16 and Rh 4 (CO) 12 .
Claim 4
Dependent Claim
10 words
The process of claim 1 wherein the solvent is pyridine.
Claim 5
Dependent Claim
25 words
The process of claim 1 wherein the solvent is a tertiary amine having a dissociation constant in aqueous solution of at least pKa = 10.
Claim 6
Dependent Claim
63 words
A process for the preparation of aromatic azomethines which comprises reacting under carbon monoxide pressure of 50 to about 500 atmospheres, and a temperature of 50°-250°C, benzaldehyde and a nitrobenzene in the presence of pyridine as a solvent, and of hexarhodium hexadecacarbonyl as a catalyst, which catalyst is present in the molar ratio relative to the said nitrobenzene of 1:100 to about 1:50,000.
Claim 7
Dependent Claim
63 words
A process for the preparation of aromatic azomethines which comprises reacting under carbon monoxide pressure of 50 to about 500 atmospheres, and a temperature of 50°-250°C, benzaldehyde and a nitrobenzene in the presence of pyridine as a solvent, and of hexarhodium hexadecacarbonyl as a catalyst, which catalyst is present in the molar ratio relative to the said nitrobenzene of 1:100 to about 1:50,000.
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) | 1979-07-06 | 1980-01-05 | 1980-07-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-06 | 1984-01-05 | 1984-07-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-06 | 1988-01-05 | 1988-07-06 | $7700.00 | Window Closed / Lapsed |