CA1072117A - Process for the preparation of acetoacetylaryl-amides - Google Patents

Abstract

PROCESS FOR THE PREPARATION OF ACETOACETYLARYL-AMIDES

ABSTRACT OF THE DISCLOSURE
Acetoacetylarylamides are obtained in high yield and excellent purity by reacting a small excess of diketene with an aqueous suspension or emulsion of the arylamine at a temperature which is sufficiently high that the product is obtained in a non-solid form, i.e. in a solution or emulsion.

Description

~o7zll7 Acetoacetylarylamides are coupling components for azo pigments~ and for this application field, high purity degrees are required, since less pure products result in pigments of poor fastness.
Acetoacetylarylamides having the necessary purity may be obtained according to United States Patent Specification No. 3,304,328. This process requires the arylamine and the diketene to be introduced slowly into the re-actor in such a manner that any concentration of one component is prevented.
Furthermore, the amount of water and a minimum agitating power are indicated as~being essential~ Moreover, the temperature of the reaction should not ex-10 ceed 50 C and preferably be in a range of from 20 C to 30C.
The present invention provides a process for the preparation of anacetoacetylarylamide-which comprises reacting an excess of diketene with an arylamine which is aniline, ~m;nodiphenyl or naphthylamine unsubstituted or :` ~
substituted by halogen, lower alkyl, lower alkoxy or amino in a reaction medium which is water or an aqueous solution of acetic acid of up to 60% by weight of acetic acid at a temperature at which the product is obtained in solution or as an emulsion.
The process temperature may attain a limit of 100 C. Depending on the basicity of the arylamine, an excess of diketene of from àbout 3 to about 15, preferably from 3 to 5, mol % is used.
A preferred embodiment of this invention comprises carrying out the reaction in the presence of a solubilizer. Since commercial-grade diketene contains acetic anhydride as impurity, acetic acid is advantageously used as solubilizer. Preferably, acetic acid of about 15 to about 60, especially 25 to 50 % by weight is used as reaction medium; the

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' ~072~7 concentration of the acetic acid depending above all on the solubility of the reaction product. This embodiment of the invention allows to maintain the product in solution during the reaction, while without or with a too low concentration of the acetic acid the product is present in the form of an aqueous emulsion.
The two reactants may be added simultaneously; care has to be taken that amine and diketene are fed in in a constant molar ratio of, for example, 1:1.03 or 1:1.05. This operation mode requires corresponding precision measuring devices, for example rotameters or dose pumps, and it is of course expensive, especially when solid arylamines are used. A considerably simpler and cheaper method is the following: the arylamine, suspended or emulsified in the reaction medium, is introduced into the reactor, and diketene is added rapidly with agitation. Since the acetic anhydride contained as impurity in commercial diketene may also react with the aromatic amine, the diketene is preferably added as quickly as technically possible (that is, all at a time), in order to adjust the diketene excess very rapidly and thus to prevent the side reaction of the arylamine with the acetic anhydride. The diketene may also be introduced first and the amine suspension or emulsion be added sub-sequently, although this operation mode cannot be recommended generally.
Since the reaction is exothermal, it is advantageous in many cases to cool the batch at the start of the reaction and then to control the temp- -erature by dosing accordingly the reactants added (if they are introduced together) or optionally by further cooling. The starting temperature is maintained ;

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107Z~7 preferably in a range of from -10 to about +20C~ in order to avoid a too high final temperature.
The ratio of reaction medium to reactants is not critical in the process of the invention and may be varied within a wide range. Advantageous-ly, operations are carried out in the presence of a minimum amount of reaction medium. Since the reaction product is not in solid state, mechanical inter-mixing and thus agitating power questions are not important. Furthermore, the reaction proceeds so rapidly at the temperatures in accordance with this invention, which are preferably in a range of from 60 to 90 C, that it is com-plete immediately or shortly after the addition of the total diketene. Agita-tion therefore needs not be continued then, or only for a few minutes.
` Interesting as starting materials for the preparation of pigments are the following arylamines: aniline and its derivatives, for example lower alkylanilines such as toluidine or xylidine~ halogenated derivatives such as chloro-aniline or 5-chloro-2-toluidine, lower alkoxy derivatives such as an-isidines~ phenetidines or dimethoxy-anilines, multinuclear products such as aminodiphenyl or naphthyl~m;nes, furthermore aryl diamines such as phenylene diamine~ benzidine and its derivatives such as dianisidine, dimethyl-benzidines or dichlorobenzidines.
It is advantageous to decrease the te~mperature of the reaction m;Y-ture as soon as possible after the reaction is ' :' ~o7Z~7 complete to a value where the final product is in solid state. Advantageous-ly, the mixture is cooled to about 40 - 50C, which cooling can be easily obtained within 15 to 20 minutes by evaporation cooling. Subsequently, the temperature may be further decreased by external cooling, for example by means of brine.
On cooling, the reaction product crystallizes with a purity degree of at least 99 %. The products are transparently soluble in cold sodium hydroxide solution. The yields are generally above 90 %, often in the range of from 94 to about 98 %.
The mother liquor which may contain arylamine not completely reacted can be reused for further reactions. It may be recycled several times, in many cases more than 20 times.
The crystallized reaction product can be separated in known manner by filtration or centrifugation. After washing with water, the products may be directly processed or dried according to known methods.
The following examples illustrate the invention, all percentages being by weight. In each case, commercial-grade diketene having a purity degree of 96 % by weight was used. Cooling was effected by evaporation cooling to about 40 C, and subsequently by means of water and brine to about 5 to 10C.
E X A M P L E 1:
Acetoacetylanilide a) 800 kg of aniline and 780 kg of diketene are added simultaneously and in a constant ratio within 60 minutes to 3000 kg of water being agitated.
During the reaction, cooling is ensured in such a manner that the temperature ~-in the vessel rises from 20 to 63 C. Immediately after having added the total of both reactants, the reaction mixture is cooled to 40 C. At this temperature~ the mother liquor is examined for small amounts of non-reacted - . -. .

"` ~o72~7 aniline. In case such amounts are detected, a further 5 to 10 kg of diketene are added. After further cooling, the batch is agitated for 2 hours at 5 C.
The product is centrifuged and washed with water. Acetoacetylanilide is obtained in the form of a white, crystallized powder with a yield of 96 %.
The dried product has a purity degree of 99.3 % and a melting point of 84 -85C. A sample of 1 g dissolves completely in 10 g of 5 % sodium hydroxide solution, giving a clear and colorless solution.
b) 760 kg of diketene are added within 90 seconds and with agitation to a mixture of 1500 kg of water, 1500 kg of ice and 800 kg of aniline, which causes the temperature to rise from 0 to 65 C. Immediately after the addition of the diketene, the mixture is cooled. The work-up is as des-- cribed in Example la). Acetoacetylanilide is obtained with a yield of 95.3 %.
~ The product dissolves in 5 % sodium hydroxide solution, giving a transparent ,:
and colorless solution. The dried product has a melting point of 84 C.
E X A M P L E 2:
Acetoacetyl-p-phenetidide 660 kg of diketene are added within 5 minutes and with agitation to an emulsion of 4000 kg of water and 1000 kg of p-phenetidine cooled to 15 C.
The temperature thus rises to 77 - 80 C. 5 minutes after the addition of diketene is complete, the mixture is cooled to 5 C. Immediately thereafter, - the product is centrifuged and washed with water. Acetoacetyl-p-phenetidide is obtained with a yield of 94 %. The dried product has a melting point of 105 - 106 C. The product dissolves in 5 % sodium hydroxide solution, giving a transparent solution which has a slightly yellow color.
E X A M P L E 3:
Acetoacetyl-o-toluidide - 920 kg of diketene are added within 4 minutes and with agitation to a mixture of 3200 kg of water and 1080 kg of o-toluidine cooled to 0 C, which .

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1072~17 causes the temperature to raise to 82C. The mixture is cooled with water in such a manner that this temperature is not exceeded. Immediately after the addition of the diketene, the mixture is cooled to 40C, at which temp-erature a further 10 kg of diketene are added, and the mixture is cooled then to S C. The product is centrifuged and washed with water. Acetoacetyl-o-toluidide is obtained with a yield of 93 %. The dried product has a purity - degree of 99.5 % and a melting point of 103 - 105 C. The product dissolves in 5 % sodium hydroxide solution, giving a transparent and colorless solution.
E X A M P L E 4:
Acetoacetyl-2,5-dimethoxyanilide 610 kg of diketene are added within 60 minutes and with agitation to a mixture of 3500 kg of water, 15 kg of 40 % sodium bisulfite solution and 1000 kg of 2,5-dimethoxyaniline cooled to 15 C. By cooling, it is ensured that the temperature does not exceed 55C. 15 minutes after the addition of the diketene is complete, the mixture is cooled. The product is centrifuged and washed with water. Acetoacetyl-2,5-dimethoxyanilide is obtained with a i yield of 94 %. The dried product has a purity degree of 99.2 % and a melting point of 72 - 74C. It is a light brown, crystalli~ed powder which dissolves in 5 % sodium hydroxide solution, giving a transparent solution which has a brownish color.
E X A M P L E 5:
Acetoacetyl-p-anisidide 600 kg of diketene are added within 25 minutes and with agitation to a mixture of 2400 kg of water, 800 kg of glacial acetic acid, 15 kg of 40 % sodium bisulfite solution and 800 kg of p-anisidine cooled to 25C.
Cooling is adjusted in such a manner that after the addition of the diketene, the temperature rises to 70C. The reaction is allowed to proceed for a further 15 minutes, and subsequently, the mixture is diluted with 500 kg of . . .

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L~7Z~7 water. A further 10 kg of diketene are added, and the mixture i8 then cool-ed to 10C. After 2 hours, the product is centrifuged and washed with water.
Acetoacetyl-p-anisidide is obtained with a yield of 92 %. The dried product has a purity degree of more than 99 % and a melting point of 115 - 116C. It dissolves in 5 % sodium hydroxide solution, giving a transparent solution.

Acetoacetyl-m-xylidide a) 978 kg of m-xylidine and 750 kg of diketene are added simultaneously and in a constant ratio within 60 minutes to 3500 kg of 40 % acetic acid which is being agitated. The temperature is adjusted by cooling in such a manner that it rises from 22 to 60C during the reaction. After having added the two reactants, the mixture is cooled to 5C, and agitation is continued for 2 hours at this temperature. The product is centrifuged and washed for a first time with 30 % acetic acid, and for a second and third time with water.
- Acetoacetyl-m-xylidide is obtained with a yield of 94 %. The dried product has a purity degree of 99.6 % and a melting point of 91 C. It dissolves in 5 % sodium hydroxide solution, giving a transparent and colorless solution.
The mother liquor and the first washing liquor are joined and adjusted to a content of 40 % acetic acid by means of glacial acetic acid.
This mother liquor is reused as reaction medium for the following batch, and - it may be recycled more than 15 times. The above yield is calculated on a mean value of 15 batches.
b) 700 kg of diketene are added within 20 minutes and with agitation to a mixture of 3500 kg of 40 % acetic acid and 900 kg of m-xylidine cooled to 0 C, which addition causes the temperature to rise to 65 C. 2 minutes after the addition of the diketene, the mixture is cooled to 5 C and agitation is con-tinued at this temperature for another 2 hours. The work-up is as in Example 6 a). Colorless, crystallized acetoacetyl-m-xylidide is obtained with a yield '. ~
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~072117 of 94 %. The dried product has a purity degree of 99.5 % and a melting point of 91 C, and it dissolves in 5 % sodium hydroxide solution giving a trans-parent and colorless solution.
E X A M P L E 7:
Acetoacetyl-o-chloro-anilide a) 460 kg of diketene and 606 kg of o-chloroaniline are added simultaneously and in a constant ratio within 2 minutes and with agitation to 4000 kg of 40 % acetic acid cooled to 0C. When the temperature has risen to 20 C, a further 460 kg of diketene and 606 kg of o-chloroaniline are added under the same conditions within 40 minutes. The cooling is adjusted in such a manner that the temperature is 65 C at the end of the reaction. Agitation is con-tinued for a further 20 minutes, the mixture is cooled to 5C, and this temperature is maintained for 2 hours. The product is centrifuged and washed for a first time with 30 % acetic acid, and for a second and third time with water. Colorless, crystallized acetoacetyl-o-chloro-anilide is obtained with a 94 % yield. The dried product has a purity degree of 99.4 % and a melting point of 104C, and it dissolves in 5 % sodium hydroxide solution, giving a transparent and colorless solution.
The mother liquor and the first washing liquor are combined and worked up as indicated in Example 6a), and it may be reused more than 20 times.
b) 600 kg of diketene are added within 4 minutes and with agitation to a mixture of 4000 kg of 40 % acetic acid and 1213 kg of o-chloro-aniline cooled to -5 C. Subsequently, the feed of diketene is slowed down to 500 kg/h, so that further 320 kg of diketene are fed in in less than 40 minutes. When the temperature has attained 20 C, cooling is adjusted in such a manner that the . final temperature is 65C. Cooling and work-up are then as indicated in . .
Example 7a), and yield and quality of the acetoacetyl-o-chloro-anilide are .: _g _ --; ' , ~ ~
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` ~072117 also the same as indicated above.
E X A M P L E 8:
Acetoacetyl-5-chloro-2-toluidide 740 kg of diketene are added within 30 minutes and with agitation to a mixture of 4000 kg of 40 % acetic acid and 1000 kg of 5-chloro-2-toluidine cooled to 5C. When the temperature has attained 20 C, cooling is adjusted in such a manner that the temperature is 65 C at the end of the reaction. The work-up is the same as in Example 7. Colorless, crystallized acetoacetyl-S-chloro-2-toluidide is obtained with an average yield of 95 %.
; 10 The dried product has a purity degree of 99.6 %, a melting point of 103C
; and it dissolves in 5 % sodium hydroxide solution giving a transparent and colorless solution. The mother liquor may be reused up to 10 times.
E X A M P L E 9:
Bis-acetoacetyl-o-dianisidide 600 kg of diketene are added within 30 minutes and with agitation to a mixture of 2000 kg of water, 1600 kg of glacial acetic acid and 700 kg of o-dianisidine cooled to 0 C. The cooling is adjusted in such a manner that the temperature has attained 55 C at the end of the reaction. The reaction is allowed to continue for a further 10 minutes, and then the mixture is cooled to 10 C. The product is filtered, and washed for a first time with 30 % acetic acid, and for a second and third time with water. Bis-acetoacetyl-o-dianisidide is obtained with a 93 % yield. The dried product has a melting point of 167 - 169C and dissolves in sodium hydroxide solution, giving a transparent dark red solution. Mother liquor and first washing liquor are combined and adjusted to a 45 % acetic acid content by means of glacial acetic acid. This mother liquor may be reused more than 15 times.

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Claims (15)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for the preparation of an acetoacetylarylamide which comprises reacting an excess of diketene with an arylamine which is aniline, aminodiphenyl or naphthylamine unsubstituted or substituted by halogen, lower alkyl, lower alkoxy or amino in a reaction medium which is water or an aqueous solution of acetic acid of up to 60% by weight of acetic acid at a tempera-ture at which the product is obtained in solution or as an emulsion.

2. A process as claimed in claim 1, wherein the excess of diketene is 3 to 15 mol percent.

3. A process as claimed in claim 1, wherein the excess of diketene is 3 to 5 mol percent.

4. A process as claimed in claim 1, wherein the arylamine is substitut-ed by one or two substituents which are the same or different and which are selected from chlorine, methyl, ethyl, methoxy, ethoxy and amino with the proviso that at most one substituent is amino.

5. A process as claimed in claim 4, wherein the amine is aniline, phenylene diamine, naphthylamine, aminodiphenyl or benzidine which amines are unsubstituted or substituted by one or two substituents which are the same or different selected from methyl, ethyl, methoxy, ethoxy and chlorine.

6. A process as claimed in claim 1, wherein the reaction temperature is below 100°C.

7. A process as claimed in claim 1, wherein the reaction temperature is 60 to 90°C.

8. A process as claimed in claim 1, wherein the reaction medium is aqueous 15 to 60 % by weight acetic acid.

9. A process as claimed in claim 8, wherein the acetic acid has a strength of 25 to 50 %.

10. A process as claimed in claim 8, wherein the reaction product is dissolved in said acetic acid.

11. A process as claimed in claim 1, wherein the reaction product is obtained as an aqueous emulsion.

12. A process as claimed in claim 1, wherein the amine and the diketene are simultaneously introduced.

13. A process as claimed in claim 1, wherein the diketene is added to the aqueous reaction system containing the amine as rapidly as possible.

14. A process as claimed in claim 1, wherein the temperature at the beginning of the reaction is -10 to +20°C.

15. A process as claimed in claim 1, wherein the product is crystalliz-ed by rapidly cooling the reaction medium.