CA2037714A1 - Process for the production of n,n'-bis-(3-aminophenyl)-ureas - Google Patents
Process for the production of n,n'-bis-(3-aminophenyl)-ureasInfo
- Publication number
- CA2037714A1 CA2037714A1 CA002037714A CA2037714A CA2037714A1 CA 2037714 A1 CA2037714 A1 CA 2037714A1 CA 002037714 A CA002037714 A CA 002037714A CA 2037714 A CA2037714 A CA 2037714A CA 2037714 A1 CA2037714 A1 CA 2037714A1
- Authority
- CA
- Canada
- Prior art keywords
- urea
- ureas
- bis
- aminophenyl
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C273/00—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups
- C07C273/18—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas
- C07C273/1854—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas by reactions not involving the formation of the N-C(O)-N- moiety
- C07C273/1863—Preparation of urea or its derivatives, i.e. compounds containing any of the groups, the nitrogen atoms not being part of nitro or nitroso groups of substituted ureas by reactions not involving the formation of the N-C(O)-N- moiety from urea
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
Mo3548 LeA 27,610 A PROCESS FOR THE PRODUCTION OF
N,N'-BIS-(3-AMINOPHENYL)-UREAS
ABSTRACT OF THE INVENTION
Disclosed herein is a process for preparing an N,N'-bis-(3-aminophenyl)-urea by reacting an alkyl-substituted m-phenylenediamines with urea in water, as solvent.
Le A 27 610
N,N'-BIS-(3-AMINOPHENYL)-UREAS
ABSTRACT OF THE INVENTION
Disclosed herein is a process for preparing an N,N'-bis-(3-aminophenyl)-urea by reacting an alkyl-substituted m-phenylenediamines with urea in water, as solvent.
Le A 27 610
Description
Mo3548 LeA 27,610 A PROCESS FOR THE PRODUCTION OF
N~N'-BIS-~3-AMINOPHENYL~-UREAS
BACKGROUND OF THE INYEN~ION
Field of the Invention : This ~nvention relates to a simple prooess for the product;on of N,N'-bis-(3-aminophenyl)-ureas which is based on the reaction of alkyl-substituted m-phenylenediamines with urea in water as solvent. More specifically, the invention relates to the process for the product~on of N,N'-~is-(3-aminophenyl)-ureas corresponding to general formula (I3 which may optionally contain small quantities of oligomeric ureas corresponding to general for~ula (II~
R R
\ O
~ NH-C-NH
R
/ NH-c-NH ~ [ NH-C-NH \ ~ ~NH2 NH2 R P~
_ _ n (II) wherein R is a linear or branched alkyl group containing 1 to 6 carbon atoms which may be ln the 2-, 4- and/or 6-positio...
Le A 27 610 ,.,1... ~
~ 3 Brief Descr;ption of the Prior Art : It is known that diaminodiphenyl ureas can be synthesked by phosgenation of corresponding nitroanilines to form dinitrodiphenyl urea and subsequent catalytic reduction to ~orm the diam;ne, cf. for example the synthesis of III described by I.L. Khemel nitskaya et al in ~h. Obsh. Khim 30 (2) (1960), page 6025 and the synthesis of the N,N'-bis-~5-amino-2-methylphenyl)-urea IV
described by W.R. Turner and L.M. Werbel in J. Med. Chem. 28 (1985), page 1738.
p ~ NH-C-NH ~
H3C ~ I CH3 (III) -, NH C^NH ~
(IV) ~H2 N~2 Apart from the generally poor yields of the synthesis, the main disadvantage thereof lies in the reduction step which is ~ost-intensive.
For the production of dia~inodiphenyl ureas such as N,N'-bis-~4-amino-phenyl~-urea, another two-step synthesis is the reaction of N-acetyl-p-phenylenediamine with urea, followed by saponification of the protec$ive acetyl group, which is described by H. Schiff and A. Ostrogovick in Liebigs Ann., 293, Mo3548 r J; 1"' '~ 'J
N~N'-BIS-~3-AMINOPHENYL~-UREAS
BACKGROUND OF THE INYEN~ION
Field of the Invention : This ~nvention relates to a simple prooess for the product;on of N,N'-bis-(3-aminophenyl)-ureas which is based on the reaction of alkyl-substituted m-phenylenediamines with urea in water as solvent. More specifically, the invention relates to the process for the product~on of N,N'-~is-(3-aminophenyl)-ureas corresponding to general formula (I3 which may optionally contain small quantities of oligomeric ureas corresponding to general for~ula (II~
R R
\ O
~ NH-C-NH
R
/ NH-c-NH ~ [ NH-C-NH \ ~ ~NH2 NH2 R P~
_ _ n (II) wherein R is a linear or branched alkyl group containing 1 to 6 carbon atoms which may be ln the 2-, 4- and/or 6-positio...
Le A 27 610 ,.,1... ~
~ 3 Brief Descr;ption of the Prior Art : It is known that diaminodiphenyl ureas can be synthesked by phosgenation of corresponding nitroanilines to form dinitrodiphenyl urea and subsequent catalytic reduction to ~orm the diam;ne, cf. for example the synthesis of III described by I.L. Khemel nitskaya et al in ~h. Obsh. Khim 30 (2) (1960), page 6025 and the synthesis of the N,N'-bis-~5-amino-2-methylphenyl)-urea IV
described by W.R. Turner and L.M. Werbel in J. Med. Chem. 28 (1985), page 1738.
p ~ NH-C-NH ~
H3C ~ I CH3 (III) -, NH C^NH ~
(IV) ~H2 N~2 Apart from the generally poor yields of the synthesis, the main disadvantage thereof lies in the reduction step which is ~ost-intensive.
For the production of dia~inodiphenyl ureas such as N,N'-bis-~4-amino-phenyl~-urea, another two-step synthesis is the reaction of N-acetyl-p-phenylenediamine with urea, followed by saponification of the protec$ive acetyl group, which is described by H. Schiff and A. Ostrogovick in Liebigs Ann., 293, Mo3548 r J; 1"' '~ 'J
18g6, pages 371 et seq. The disadvantage of this synthesis is that monoacetylated diam;nes, which are generally not easy to produce, have to be used as starting components.
Special p-phenylenediamines9 in which the reactivity of an NH2 group is greatly reduced by suitable o-substituents, can be directly reacted with phssgene to form the corresponding aminocarbanilides. Suitable diamines are, for example, ~,S-diaminosulfonic acid (DRP 140613, Frl. 11, 1292) or 2,6-dichloro-p-phenylenediamine (~RP 268658, Frl. 11 164) Under the conditions in question, other phenylenediamines almost exclusively yield polyureas which are totally unsuitable as reactive chain-extending agents.
US-PS 1,617,847 relates to the production of N,N'-bis-(4-aminophenyl~-ureas by re~ction of p-phenylenediamine and alkyl-substituted p phenylened;amines with urea in bulk or in inert solvents, such as for example o-dichlorobenzene.
US-PS 2,503,797 des~ribes reaction of p-phenylenediamines with urea in a~ueous solution However, it is specifically pointed out and demonstrated by examples therein that high yields of the corresponding low-oligomer m-phenylenediamines are only obtained when 4 equivalents sulfuric acid are added.
For working up, the sulfuric acid salt of the urea which is precipitated has to be converted with BaC12 into the corresponding chlor~de from which the free base can then be obtained.
To sum up, it may be said that all hitherto known processes are either expensi~e or are only suitable for special diamines, or only lead to the desired low molecular weight ureas with p-substituted phenylenediamines as starting compounds.
The problem addressed by the present invention was to provide a simple synth~sis for ureas based on ortho-alkyl substituted m-phenylenediamines.
Mo3548 SUMMARY OF_THE INVENTION
In accordance with the foregoing, the present invention enco~passes a process for the production of an N,N'-bis-(3-aminophenyl)-urea correspondir,g to yeneral formula (I) R NII-C-NH
wherein R is a linear or branched alkyl group containing 1 to 6 carbon atoms which is in the 2-, 4- and/or 6i-position, comprising reacting a corresponding phenylenediamine with urea in a molar ratio greater than 2:1, in water as a solvent.
The diaminodiphenyl ureas obtained by the process according to the invention may be used in solid or dissolved forms as chain-extending agents for the production of polyurethane polyurea elastomers or pure polyurea elastomers.
The diaminodiphenyl ureas according to the inYention may also be used, ~or example, as coupling components for diazo dyes, as a catalyst ~or epo~y and phenolic resins and for other reactions known per se involv;ng amines, such as amide or imide formation and the like.
Two aspects of the invention are particularly ~ignifican~.
The process gives ureas of low molecular weight which are suitable as chain-extending agents. Also, the percentage content of monomeric starting amine in the ureas is reduced as far as possible in order to eliminate any risk to health in the handling of the product and the well-known adverse effect of Mo3548 7 ~
free, aromatic low molecular weight-mines on the light stability and color stability of the plastics produced therewith.
~ETAILED DESCRIPTION OF THE INVENTION
It was surprising to find that, under the special reaction conditions descr;bed in deta;l hereinafter, m-phenylenediamines can be reacted with urea in aqueous solution to form good to very good yields of low-oligomer diamincdiphenyl ureas. More specifically, it was surprising to find that the reaction of ortho-alkyl substituted m-phenylenedtamines with urea in water as solvent, ln a molar ratio of phenylenediamine to urea greater than 2:1 solves the problems set forth above.
Accordingly, the present ;nvention relates to a process for the production of N,N'-bis-(3-aminophenyl)-ureas corresponding to general formula tI) R R
~ NH-C-NH
NH2 N~l2 in which R is a linear or branched alkyl group containing 1 to 6 carbon atoms which may be in the 2-, 4- and/or 6-positinn, characterized 1n that the corresponding phenylenediamines are reacted with urea in a molar ratio greater than ~:1 in water as solvent.
The process of the invention is described in detail as ~ollows. Generally, the corresponding phenylenediamines such as l-alkyl-2,4-diaminobenzenes, for example tolylene-2,4-Mc3548 " ~, J 1:. ... ,!`
diamine, can be used in the process of the invention. Suitablecompounds may be used either individually or even in combination with one another. Water is used as solvent.
The m-phenylenediamine and urea are used in a molar ratio greater than 2:1, preferably in a molar ratio greater than 10:1 and more preferably in a molar ratio greater than 3:1 to 5:1.
If molar ratios of less than or equal to 2:1 are used~ products having inadequate NH values, l.e. highly pre-extended ureas, are obtained. In the particularly preferred range, products having NH values approaching the theoretical are obtained.
Although an increase in ~he molar ratio is possible in principle, this does not lead to any improvement in the product and, in addition, does not make good economic sense.
The m-phenylenediamines are dissolved in the water in quantities of 20 to 200 parts by weight, preferably in quantities of 40 to 150 parts by weight and more preferably in quantities of 80 to 120 parts by weight per 100 parts by weight solvent. If the concentr~tion is excessively increased, the reaction mixture becomes increasingly more difficult to stir on account of the precipitating product. In addition, the product contains considerable quantities of entra;ned starting amine which can only be removed by expensive purifying steps. In the preferred concentration range, NH values approaching the theoretical are obtained. The urea is added to the solution of the amine in water in the described molar ratio and the reaction mixture is stirred at temperatures of 60 to 100C, preferably under reflux.
The precipitated product is filtered off and washed with water to remove residual quantities of starting amine. It is of advantage in this regard to add water before filtration and to carry out the filtration step in a steamheated nutsch filter to prevent the residual am;ne from precipitating at low tPmperatures. For the same reasons, it is also of advantage to wash the product with hot water. The excess starting amine Plo3548 ~? ~ ~''~iig~ ',3 .';~, recoverable from the mother liquor may be reused without further purification.
After drying, the desired urea is obtained in an excellent yield in the form of a finely crystalline solid which, depending on the concentration ratios selected, has NH values which are greater than 270 mg KOH/g ~theoretical 416 mg KOH/g~
and preferably greater than 360 mg KOH/g, the content of free monomeric starting amine being less than 1% by weight and preferably less 0.5% by weight.
The following Examples are intended to illustrate the process according to the invention without limiting it in any way (percentages are by we;ght, unless otherwise stated).
EXAMPLES
ExamDle 1 366 g (3 mol) 2,4-tolylened;amine (2,4-TDA) and 60 9 (1 mol) urea (molar ratio of 2,4-TDA to urea 3:1) were dissolved in 400 ml water. The reaction solution was stirred under reflux for 20 hours. 1,000 ml water were then added and the reaction mixture was refluxed for another 30 minutes.
After filtration in a steam-heated nutsch filter, the residue was washed twice with 300 ml hot (90C) water. The product was then freed from adhering water in a vacuum drying cabinet.
Yield: 213 9 (79%, based on the urea used) NH value (HClO4/glacial acetic acid) 369 mg KOH/g Residual 2,4-TDA content (HPLC): 0.353~ by weight.
ComParison Example (from US-PS 2,503,797) ` 54 Parts by weight 1,3-diaminobenzene were dissolved while stirring in 110 parts by volume 38.6% sulfuric acid. The temperature of the solution rose to 65-70C. After the add;tion of l9 parts by weight urea, the reaction mixture was boiled under reflux for 32 hours. 120 Parts by weight water were then added. The precipitated product was filtered off and washed with 200 parts by weight cold water. The sulfuric acid salt thus obtained may be converted into the free base by standard methods. It is of advantage to convert the salt into Mo3548 ~' ' C`t ,~1 ~ ,. ; ;.
-~-the corresponding ehloride with BaC12 before recovery of the base.
No details of yield or analytical data are provided in the Comparison Example. From the above examples, however, one skilled in the art can appreciate the advantages of the claimed process.
Although the invention hàs been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that 10 . variation can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo3548
Special p-phenylenediamines9 in which the reactivity of an NH2 group is greatly reduced by suitable o-substituents, can be directly reacted with phssgene to form the corresponding aminocarbanilides. Suitable diamines are, for example, ~,S-diaminosulfonic acid (DRP 140613, Frl. 11, 1292) or 2,6-dichloro-p-phenylenediamine (~RP 268658, Frl. 11 164) Under the conditions in question, other phenylenediamines almost exclusively yield polyureas which are totally unsuitable as reactive chain-extending agents.
US-PS 1,617,847 relates to the production of N,N'-bis-(4-aminophenyl~-ureas by re~ction of p-phenylenediamine and alkyl-substituted p phenylened;amines with urea in bulk or in inert solvents, such as for example o-dichlorobenzene.
US-PS 2,503,797 des~ribes reaction of p-phenylenediamines with urea in a~ueous solution However, it is specifically pointed out and demonstrated by examples therein that high yields of the corresponding low-oligomer m-phenylenediamines are only obtained when 4 equivalents sulfuric acid are added.
For working up, the sulfuric acid salt of the urea which is precipitated has to be converted with BaC12 into the corresponding chlor~de from which the free base can then be obtained.
To sum up, it may be said that all hitherto known processes are either expensi~e or are only suitable for special diamines, or only lead to the desired low molecular weight ureas with p-substituted phenylenediamines as starting compounds.
The problem addressed by the present invention was to provide a simple synth~sis for ureas based on ortho-alkyl substituted m-phenylenediamines.
Mo3548 SUMMARY OF_THE INVENTION
In accordance with the foregoing, the present invention enco~passes a process for the production of an N,N'-bis-(3-aminophenyl)-urea correspondir,g to yeneral formula (I) R NII-C-NH
wherein R is a linear or branched alkyl group containing 1 to 6 carbon atoms which is in the 2-, 4- and/or 6i-position, comprising reacting a corresponding phenylenediamine with urea in a molar ratio greater than 2:1, in water as a solvent.
The diaminodiphenyl ureas obtained by the process according to the invention may be used in solid or dissolved forms as chain-extending agents for the production of polyurethane polyurea elastomers or pure polyurea elastomers.
The diaminodiphenyl ureas according to the inYention may also be used, ~or example, as coupling components for diazo dyes, as a catalyst ~or epo~y and phenolic resins and for other reactions known per se involv;ng amines, such as amide or imide formation and the like.
Two aspects of the invention are particularly ~ignifican~.
The process gives ureas of low molecular weight which are suitable as chain-extending agents. Also, the percentage content of monomeric starting amine in the ureas is reduced as far as possible in order to eliminate any risk to health in the handling of the product and the well-known adverse effect of Mo3548 7 ~
free, aromatic low molecular weight-mines on the light stability and color stability of the plastics produced therewith.
~ETAILED DESCRIPTION OF THE INVENTION
It was surprising to find that, under the special reaction conditions descr;bed in deta;l hereinafter, m-phenylenediamines can be reacted with urea in aqueous solution to form good to very good yields of low-oligomer diamincdiphenyl ureas. More specifically, it was surprising to find that the reaction of ortho-alkyl substituted m-phenylenedtamines with urea in water as solvent, ln a molar ratio of phenylenediamine to urea greater than 2:1 solves the problems set forth above.
Accordingly, the present ;nvention relates to a process for the production of N,N'-bis-(3-aminophenyl)-ureas corresponding to general formula tI) R R
~ NH-C-NH
NH2 N~l2 in which R is a linear or branched alkyl group containing 1 to 6 carbon atoms which may be in the 2-, 4- and/or 6-positinn, characterized 1n that the corresponding phenylenediamines are reacted with urea in a molar ratio greater than ~:1 in water as solvent.
The process of the invention is described in detail as ~ollows. Generally, the corresponding phenylenediamines such as l-alkyl-2,4-diaminobenzenes, for example tolylene-2,4-Mc3548 " ~, J 1:. ... ,!`
diamine, can be used in the process of the invention. Suitablecompounds may be used either individually or even in combination with one another. Water is used as solvent.
The m-phenylenediamine and urea are used in a molar ratio greater than 2:1, preferably in a molar ratio greater than 10:1 and more preferably in a molar ratio greater than 3:1 to 5:1.
If molar ratios of less than or equal to 2:1 are used~ products having inadequate NH values, l.e. highly pre-extended ureas, are obtained. In the particularly preferred range, products having NH values approaching the theoretical are obtained.
Although an increase in ~he molar ratio is possible in principle, this does not lead to any improvement in the product and, in addition, does not make good economic sense.
The m-phenylenediamines are dissolved in the water in quantities of 20 to 200 parts by weight, preferably in quantities of 40 to 150 parts by weight and more preferably in quantities of 80 to 120 parts by weight per 100 parts by weight solvent. If the concentr~tion is excessively increased, the reaction mixture becomes increasingly more difficult to stir on account of the precipitating product. In addition, the product contains considerable quantities of entra;ned starting amine which can only be removed by expensive purifying steps. In the preferred concentration range, NH values approaching the theoretical are obtained. The urea is added to the solution of the amine in water in the described molar ratio and the reaction mixture is stirred at temperatures of 60 to 100C, preferably under reflux.
The precipitated product is filtered off and washed with water to remove residual quantities of starting amine. It is of advantage in this regard to add water before filtration and to carry out the filtration step in a steamheated nutsch filter to prevent the residual am;ne from precipitating at low tPmperatures. For the same reasons, it is also of advantage to wash the product with hot water. The excess starting amine Plo3548 ~? ~ ~''~iig~ ',3 .';~, recoverable from the mother liquor may be reused without further purification.
After drying, the desired urea is obtained in an excellent yield in the form of a finely crystalline solid which, depending on the concentration ratios selected, has NH values which are greater than 270 mg KOH/g ~theoretical 416 mg KOH/g~
and preferably greater than 360 mg KOH/g, the content of free monomeric starting amine being less than 1% by weight and preferably less 0.5% by weight.
The following Examples are intended to illustrate the process according to the invention without limiting it in any way (percentages are by we;ght, unless otherwise stated).
EXAMPLES
ExamDle 1 366 g (3 mol) 2,4-tolylened;amine (2,4-TDA) and 60 9 (1 mol) urea (molar ratio of 2,4-TDA to urea 3:1) were dissolved in 400 ml water. The reaction solution was stirred under reflux for 20 hours. 1,000 ml water were then added and the reaction mixture was refluxed for another 30 minutes.
After filtration in a steam-heated nutsch filter, the residue was washed twice with 300 ml hot (90C) water. The product was then freed from adhering water in a vacuum drying cabinet.
Yield: 213 9 (79%, based on the urea used) NH value (HClO4/glacial acetic acid) 369 mg KOH/g Residual 2,4-TDA content (HPLC): 0.353~ by weight.
ComParison Example (from US-PS 2,503,797) ` 54 Parts by weight 1,3-diaminobenzene were dissolved while stirring in 110 parts by volume 38.6% sulfuric acid. The temperature of the solution rose to 65-70C. After the add;tion of l9 parts by weight urea, the reaction mixture was boiled under reflux for 32 hours. 120 Parts by weight water were then added. The precipitated product was filtered off and washed with 200 parts by weight cold water. The sulfuric acid salt thus obtained may be converted into the free base by standard methods. It is of advantage to convert the salt into Mo3548 ~' ' C`t ,~1 ~ ,. ; ;.
-~-the corresponding ehloride with BaC12 before recovery of the base.
No details of yield or analytical data are provided in the Comparison Example. From the above examples, however, one skilled in the art can appreciate the advantages of the claimed process.
Although the invention hàs been described in detail in the foregoing for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that 10 . variation can be made therein by those skilled in the art without departing from the spirit and scope of the invention except as it may be limited by the claims.
Mo3548
Claims (7)
1. A process for the production of an N,N'-bis-(3-aminophenyl)-urea corresponding to general formula (I) (I) in which R is a linear or branched alkyl group containing 1 to 6 carbon atoms which is in the 2-, 4- and/or 6-position, comprising reacting a corresponding phenylenediamine with urea in a molar ratio greater than 2:1, in water as a solvent.
2. A process as claimed in Claim 1, characterized in that the molar ratio of m-phenylenediamine to urea is greater than 3:1.
3. A process as claimed in Claim 1 wherein the alkyl group is in the 4- and/or 6-position.
4. A process as claimed in Claims 2 wherein the alkyl group is in the 4- and/or 6-position.
5. A process as claimed in Claim 1 wherein the alkyl group is a methyl group.
6. A process as claimed in Claim 2 wherein the alkyl group is a methyl group.
7. An N,N'-bis-(3-aminophenyl)-urea corresponding to general formula (I) Mo3548 (I) in which R is a linear or branched alkyl group containing 1 to 6 carbon atoms which is in the 2-, 4- and/or 6-position, which is prepared by the process of claim 1.
Mo3548
Mo3548
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4011360.4 | 1990-04-07 | ||
| DE4011360A DE4011360A1 (en) | 1990-04-07 | 1990-04-07 | N,N'-bis:(3-amino phenyl)urea cpds. prodn. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2037714A1 true CA2037714A1 (en) | 1991-10-08 |
Family
ID=6404009
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002037714A Abandoned CA2037714A1 (en) | 1990-04-07 | 1991-03-07 | Process for the production of n,n'-bis-(3-aminophenyl)-ureas |
Country Status (7)
| Country | Link |
|---|---|
| EP (1) | EP0451599B1 (en) |
| JP (1) | JPH04234840A (en) |
| AT (1) | ATE98224T1 (en) |
| BR (1) | BR9101383A (en) |
| CA (1) | CA2037714A1 (en) |
| DE (2) | DE4011360A1 (en) |
| ES (1) | ES2060226T3 (en) |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1617847A (en) * | 1925-06-10 | 1927-02-15 | Ig Farbenindustrie Ag | Manufacture of diamino-diaryl-urea |
| US2503797A (en) * | 1946-11-18 | 1950-04-11 | Ciba Ltd | Process for the manufacture of diamino-diphenyl-ureas |
| DE3843410A1 (en) * | 1988-12-23 | 1990-07-05 | Bayer Ag | METHOD FOR PRODUCING N, N'-BIS (3-AMINOPHENYL) UREAS |
-
1990
- 1990-04-07 DE DE4011360A patent/DE4011360A1/en not_active Withdrawn
-
1991
- 1991-03-07 CA CA002037714A patent/CA2037714A1/en not_active Abandoned
- 1991-03-26 EP EP91104725A patent/EP0451599B1/en not_active Expired - Lifetime
- 1991-03-26 ES ES91104725T patent/ES2060226T3/en not_active Expired - Lifetime
- 1991-03-26 DE DE91104725T patent/DE59100680D1/en not_active Expired - Fee Related
- 1991-03-26 AT AT91104725T patent/ATE98224T1/en not_active IP Right Cessation
- 1991-04-05 BR BR919101383A patent/BR9101383A/en not_active Application Discontinuation
- 1991-04-05 JP JP3099842A patent/JPH04234840A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0451599A1 (en) | 1991-10-16 |
| ATE98224T1 (en) | 1993-12-15 |
| BR9101383A (en) | 1991-11-26 |
| DE59100680D1 (en) | 1994-01-20 |
| ES2060226T3 (en) | 1994-11-16 |
| EP0451599B1 (en) | 1993-12-08 |
| DE4011360A1 (en) | 1991-10-10 |
| JPH04234840A (en) | 1992-08-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FZDE | Discontinued |