Title of Invention	A PROCESS FOR THE PREPARATION OF FLOWABLE ACETOACETARYLAMIDES
Abstract	The invention describes novel process for preparing acetoacetarylamides which are flowable and more soluble in water. Diketene is reacted with aromatic amines in the presence of solubility promotors at a temperature of 500 C to 1000 C. Acetoacetarylamide produced is separated from the aqueous reaction medium and is cooled and solidified.

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in which R is one or more substituents from the series alkyl, alkoxy or halogen. Acetoacetarylamides are important starting materials for the preparation of coloured pigments, but are also used for the preparation of agrochemical active ingredients (Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. 15, p. 71). The preparation of acetoacetarylamides has been known for some time and is based on the reaction of diketene with corresponding aromatic amines in a variety of organic and aqueous solvents and solvent mixtures (Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. 15, p. 71). The process is usually carried out batchwise in water or aqueous solutions. Accordingly, DE-A 25 19 036 discloses the preparation of various acetoacetarylamides by simultaneous metered addition of diketene and corresponding aromatic amine in the presence of water or aqueous solutions. The resulting acetoacetarylamide is cooled in the reaction mixture and left to crystallize out. Centrifugation and drying give the acetoacetarylamides in good yield and high purity. Furthermore, EP-A 0 648 738 discloses a continuous process for the preparation of acetoacetarylamides. This involves continuously reacting diketene with the aromatic amine in a water/alcohol mixture with the reaction mixture having as long a residence time as possible in the reactor. The resulting acetoacetarylamide is' isolated by crystallization of the product stream discharged from » I^Tf^|Seactor. The acetoacetarylamide prepared by the classic process satisfies all requirements in terms of quality and purity. It has, however, been found that for further processing, e.g. for pigment preparation, which usually involves the dissolution of the acetoacetarylides in aqueous alkalis, the finely crystalline powder form is more of a disadvantage. Thus, in addition to the undesired formation of dust, the slow dissolution rate in aqueous alkalis is somewhat unsatisfactory. The object of the invention was consequently to prepare acetoacetarylamides in a form which does not have the said disadvantages. Moreover, the object of the invention was to provide an economic process which permits acetoacetarylamide preparation at a relatively low cost. The object was achieved according to the invention by the acetoacetarylamides in the form and with the properties according to Patent Claim 1. The acetoacetarylamides are defined by the general formula in which R is hydrogen or one or more substituents from the series alkyl, alkoxy or halogen, are a solidified melt in a form which can be used in industry and is easy to handle, and have a water content between 5% by weight and 15% by weight. An alkyl group is expediently taken to mean a Ci_4-alkyl group, namely methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, t-butyl. A preferred alkyl is methyl. The alkoxy group has meanings corresponding to the alkyl group. Here too, preference is given to methoxy. Halogen represents fluorine, chlorine, bromine or iodine, preferably chlorine. R is particularly preferably an arylamide radical of aniline, o-anisidine, o-toluidine, m-xylidine, o-chloroaniline, 2,4-dimethoxyaniline, 4-isopropyl- aniline, 4-ethoxyaniline, 2,5-dimethoxyaniline or 4-chloro-2,S-dimethoxyaniline. The term "form which can be used in industry and is easy to handle" includes those application forms which can be obtained from a solidified melt using methods customary in the expert field. Nonexhausted examples include: pastilles, flakes, tablets or prills. The dimension and size of said application forms is dependent on said pastilling, flaking, tabletting or prilling processes and can vary within a wide range. The novel acetoacetarylides also have improved flowability compared with an acetoacetarylide according to the prior art. The bulk density of the novel acetoacetarylides is expediently in the range from 0.3 kg/1 to 0.8 kg/1, preferably in the range from 0.5 kg/1 to 0.7 kg/1. The specified term water content can also mean a content of any mixture of water with an additional solubility promoter, which may originate from the reaction, such as, for example, an aliphatic carboxylic acid such as acetic acid, ketones such as acetone or ethyl methyl ketone, Ci-C4-alcohols or glycols such as ethylene glycol. The novel acetoacetarylides have a reduced characteristic melting point compared with the dried product. The novel acetoacetarylides dissolve in a 0.5 N sodium hydroxide solution at 20°C in from approximately half to one third of the time required by a dried acetoacetarylide prepared according to the prior art. Preferred acetoacetarylides with their characteristic properties are: acetoacetanilide, water content expediently from 5% by weight to 15% by weight, preferably from 9% by weight to 11% by weight; melting point expediently from 50°C to 70°C, preferably from 57°C to 62°C/ solubility in 500 ml of 0.5 N NaOH, 60 g pastilles having a diameter of 0.6 cm in from 10 to 20 minutes. o-Acetoacetanisidide, water content expediently from 3% by weight to 12% by weight, preferably from 6% by weight to 9% by weight; melting point expediently from 60°C to 80°C, preferably from 72°C to 75°C, solubility in 500 ml of 0.5 N of NaOH, 60 g pastilles having a diameter of 0.6 cm in from 10 to 20 minutes, o-Acetoacetotoluidide, water content expediently from 5% by weight to 15% by weight, preferably from 8% by weight to 12% by weight; melting point expediently from 80°C to 100°C, preferably from 82°C to 94°C, solubility in 700 ml of 0.5 N NaOH, 60 g pastilles having a diameter of 0.6 cm in from 10 to 20 minutes. m-Acetoacetoxylidide, water content expediently from 3% ^by weight to 12% by weight, preferably from 4% by weight" to 8% by weight; melting point expediently from 65°C to 85°C, preferably from 68°C to 73°C, solubility in 700 ml of 0.5 N NaOH, 60 g pastilles having a diameter of 0.6 cm in from 10 to 20 minutes. o-Acetoacetochloroanilide, water content expediently from 3% by weight to 12% by weight, preferably from 5% by weight to 8% by weight; melting point expediently from 75°C to 95°C, preferably from 89°C to 93°C; solubility in 500 ml of 0.5 N NaOH, 60 g pastilles having a diameter of 0.6 cm in from 10 to 20 minutes. The preparation of the novel acetoacetarylides initially takes place in a known manner by reaction of diketene with the corresponding aromatic amine in the presence of water or aqueous solutions of water with a suitable solubility promoter such as, for example, acetic acid. According to the present invention, the reaction is carried out such that the resulting acetoacetarylide is produced as a melt, the melt is removed from the reaction medium after the reaction is complete at the reaction temperature, and, after cooling, is converted into the form which can be used in industry and is easy to handle. 'me preparation can either be carried out batchwise, for example in a classic stirred apparatus, or continuously, for example in a tubular reactor. The reaction is preferably carried out continuously in a tubular reactor. It is particularly preferable to meter diketene and the corresponding aromatic aniline into a tubular reactor simultaneously to recirculated mother liquor such that the reaction temperature is maintained at from SCC to 100°C. The mother liquor expediently comprises at least 80% by weight of water, and is preferably exclusively water. After the reaction, in accordance with the preferred process at from 50°C to 100°C, the aqueous mother liquor is removed and returned to the tubular reactor. The acetoacetarylide melt, which has a temperature of from 50°C to 100°C, is then solidified by cooling and converted into the form which can be used in industry and is easy to handle. This can be carried out using, for example, drum coolers customary in the expert field, which are provided with a flaking device, with belt coolers, which are provided with a flaking device, or belt pastilling machines. Accordingly the present invention provides a process for the preparation of flowable acetoacetarylamides of the general formula in which R is hydrogen, Ci-4 alkyl group, a Ci-4 alkoxy group, or halogen comprising reacting diketene with an aromatic amine such as herein described in the presence of water or aqueous solutions of known solubility promotors while maintaining the temperature of the reaction mixture at 50°C to 100°C to produce a melt of acetoacetaralyde, removing said melt from the reaction mixture which is solidified by cooling. Examples Exanrple 1: Preparation of acetoacetanilide (Conrparative Exas^le in accordance with DE-A 25 19 036) Water was introduced into a 1.5 1 bench stirrer and adjusted to a temperature of 20°C. The stirrer was then rendered inert using nitrogen. Using two pumps, 133 g of aniline and 124 g of diketene were metered in over the course of 10 minutes. The addition of aniline was delayed by about 30 sec. At the end of the metered addition, the reaction temperature increased to 65-70°C. The mixture was then allowed to react for a further 30 minutes, and the reaction temperature dropped to 60°C. Vacuum cooling (450 - 120 mbar) was used to cool the mixture to 40"C, and the liquid acetoacetanilide began to crystallize, as a result of which the temperature immediately rose to about 58 °C. The mixture was then cooled to 15°C. At 15°C, the solid product was centrifuged off, washed with 50 ml of water and dried at 50°C under reduced pressure for 12 h. This method gave acetoacetanilide having a content of >99.5% (with a residual moisture content of Example 2: Preparation of the solidified melt of acetoacetanilide (tubular reactor) In a tubular reactor (length 80 cm, diameter 10 cm), 1300 ml of water were circulated at 62°C, and 0.200 g/s of aniline and 0.190 g/s of diketene (5% by weight excess) were metered in simultaneously. After the reaction mixture had passed through the tubular reactor, it was left in a separating vessel thermostatted at 62 °C. The melt was then separated off from the aqueous phase. The aqueous phase was returned to the tubular reactor using a pump at a recirculation rate of 2250 ml/min. The melt which was separated off was immediately solidified and further processed according to Examples 4 to 6. This gave a melt having a water content of 11% by weight and a melting point of 62°C. Grinding the solidified melt and drying under reduced pressure for 12 h at 50°C led to a crystalline acetoacetanilide having a content of >99.5% by weight (with a residual moisture content of excess. Example 3: Preparation of the solidified melt of acetoacetanilide (bench stirrer) Water was introduced into a 1.5 1 bench stirrer and adjusted to a temperature of 20"C. The stirrer was then rendered inert using nitrogen. Using two pumps, 133 g of aniline and 124 g of diketene were metered in over the course of 10 minutes. The addition of aniline was delayed by about 30 sec. At the end of the metered addition the reaction temperature increased to 65-70°C. The mixture was then allowed to react for a further 30 minutes, and the reaction temperature dropped to 60°C. The melt was run off and cooled thoroughly. This gave a melt having a water content of 10% by weight and a melting point of 61.5°C. Grinding the solidified melt and drying under reduced pressure for 12 h at 50°C led to a crystalline acetoacetanilide having a content of >99.5% by weight (with a residual moisture content of Exan^le 4: Flaking the solidified melt of acetoacetauiilide using a drum cooler The melt prepared according to Example 3 was continually dropped, at a temperature of 60°C, onto a rotating metal roller which was cooled to 0°C using an external cooling circuit and had a smooth surface, a diameter of 30 cm and a rotation speed of 10 rpm, as a result of which it immediately solidified and, after a cooling stretch of 30 cm, was chipped off the roller using a knife. This gave white flakes having an average thickness of 0.08 mm and an average diameter of from 0.5 mm to 500 mm. 55.6 g of the resulting acetoacetanilide (moist, content of acetoacetanilide 89.5%, "water content 10%) dissolved completely at 20'C in 500 ml of a 0.5 M aqueous sodium hydroxide solution in about 15 minutes. Example 5: Flaking the solidified melt of acetoacetanilide using a belt cooler The melt prepared according to Example 3 was continually dropped, at a temperature of 60°C, onto a rotating metal belt, which was cooled to 0°C using an external cooling circuit and had a smooth surface, a width of 30 cm and a rotation speed of 10 m/min, as a result of which it immediately solidified and, after a cooling stretch of 4 m, was chipped off the belt cooler using a knife. This gave white flakes having an average thickness of 0.08 cm and an average diameter of from 0.5 mm to 500 mm. 55.6 g of the resulting acetoacetanilide (moist, content of acetoacetanilide 89.5%, water content 10%) dissolved completely at 20°C in 500 ml of a 0.5 M aqueous sodium hydroxide solution in about 17 minutes. Exeunple 6: Pastxlling the solidified melt of acetoacetanilide using a belt pastilling machine The melt prepared according to Example 3 was continually dropped, at a temperature of 60°C, using a device suitable for the preparation of pastilles, onto a rotating metal belt, which was cooled to 0°C by means of an external cooling circuit and had a smooth surface, a width of 30 cm and a rotation speed of 10 m/min, as a result of which it immediately solidified and, after a cooling stretch of 4 m, was removed from the belt. This gave white pastilles having an average thickness of 0.05 cm and an average diameter of 0.6 cm. 55.6 g of the resulting acetoacetanilide (moist,- ^content of acetoacetanilide 89.5%, water content 10%) dissolved completely at 20°C in 500 ml of a 0.5 M aqueous sodium hydroxide solution in about 17 minutes. Example 7: Preparation of the solidified melt of o-acetoacetanisidide Following the procedure as in Example 2, the corresponding reaction of diketene and o-anisidine gave a melt having a water content of 7% by weight and a melting point of 74°C, which was processed to give pastilles according to Example 6. 60 g of the resulting o-acetoacetanisidide (moist, o-acetoacetaniside content 91.8%, water content 8%) dissolved at 20°C in 500 ml of a 0.5 M aqueous sodium hydroxide solution in about 20 minutes. Example 8: Preparation of the solidified melt of o-acetoacetotoluidide Following the procedure as in Example 2, the corresponding reaction of diketene and o-totoluidine gave a melt having a water content of 10% by weight and a melting point of 85°C, which was processed to give pastilles according to Example 6. 60 g of the resulting o-acetoacetotoluidide (moist, o-acetoacetotoluidide content 89.6%, water content 10%) dissolved at 20°C in 700 ml of a 0.5 M aqueous sodium hydroxide solution in about 19 minutes. Example 9 Preparation of the solidified melt of m-acetoacetoxylidide As in Example 2, the corresponding reaction of diketenes and m-xylidine gave a melt having a water content of 7% by weight and a melting point of 74°C, which was processed to give pastilles according to Example 6. 60 g of 'the resulting m-acetoacetoxylidide (moist, m-acetoacetoxylidide content 92.5%, water content 7%) dissolved at 20"C in 700 ml of a 0.5 M aqueous sodium hydroxide solution in about 18 minutes. - ^ Example 10 Preparation of the solidified melt of o-acetoacetochloroanilide As in Example 2, the corresponding reaction of diketene and o-chloroaniline gave a melt having a water content of 7% by weight and a melting point of 90°C, which was processed to give pastilles according to Example 6. 60 g of the resulting o-acetoacetochloroanilide (moist, o-acetoacetochloroanilide content 92.7%, water content 7%) dissolved at 20°C in 500 ml of a 0.5 M aqueous sodium hydroxide solution in about 18 minutes. WE CLAIM: 1. A process for the preparation of flowable acetoacetarylamides of the general formula in which R is hydrogen, C1-4 alkyl group, a C1-4 alkoxy group, or halogen comprising reacting diketene with an aromatic amine such as herein described in the presence of water or aqueous solutions of known solubility promoters while maintaining the temperature of the reaction mixture at 50°C to 100°C to produce a melt of acetoacetaralyde, removing said melt from the reaction mixture which is solidified by cooling. 2. The process as claimed in claim 1, wherein said reaction of the said diketene with the said aromatic amine is carried out in a tubular reactor in the presence of an aqueous mother liquor containing at least 80% by weight of water, the said diketene and the said aromatic amine are metered simultaneously into said tubular reactor to recirculate the mother liquor while maintaining the reaction temperature at 50°C to 100°C, separating said mother liquor from the melt for recycling to said tubular reactor, cooling the melt to a temperature of O'C to 30°C to solidify the aceoacetary'lamide. 3. A process for the preparation of flowable acetoacetarylamides of the general formula substantially as herein described and exemplified.

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