WO2008096371A1

WO2008096371A1 - Isoindolinone pigments and a method of manufacturing.

Info

Publication number: WO2008096371A1
Application number: PCT/IN2008/000070
Authority: WO
Inventors: Satyanarayan Racherla; Chitale Rajendra Shashidhar; Diwate Balasaheb Bajirao
Original assignee: Sudarshan Chemical Industries Ltd.
Priority date: 2007-02-05
Filing date: 2008-02-05
Publication date: 2008-08-14

Abstract

An isoindolinone pigment having hexachlorobenzene (HCB) content less than 10 ppm and a method of manfacturing.

Description

ISOINDOLINONE PIGMENTS AND A METHOD OF MANUFACTURING

Field of the invention

This invention relates to Isoindolinone Pigments.

Particularly this invention relates to an intermediate tetra chloro cyano methyl benzoate (TCCMB) for the manufacture of Isoindolinone pigment.

This invention also relates to an improved process for manufacture of isoindolinone pigment and its intermediates with Low HCB.

Background of the invention:

Pigments appear the colors they are because they selectively reflect and absorb certain wavelengths of light. Pigments are classified as follows:

1) Organic: Organic pigments contain carbon, hydrogen, oxygen and nitrogen and are metal free.

2) Inorganic: Inorganic pigments contain metals in the form of their salts such as oxides, sulfides or silicates.

3) Synthetic: Many pigments are chemically synthesized by man. 4) Naturally occurring: Such as Siennas and Umbers.

Isoindolinone pigments are classified as organic pigment. Isoindolinone pigments are chemically related to the azo methine type. Having a chlorine group imparts insolubility and promotes light fastness in a molecule. It can readily be seen that these pigments have excellent solvent resistance and heat stability making them ideal for plastics and high quality paint systems, including automotive, decorative paints and tinting system.

There are, commercially known, three Isoindolinone pigments which are Pigment yellow 110, Pigment yellow 109, and Orange 61. Isoindolinone pigments are typically manufactured from tetrachloro phthalic anhydride (herein after called TCPA). A key intermediate tetrachloro cyano methyl benzoate (herein after called TCCMB) for the manufacturing of isoindolinone pigment is prepared from TCPA. TCCMB is reacted with an alkyl alcohol containing an earth metal alkoxide, typically sodium methoxide, to form a dialkoxy compound. The alkoxy compound is reacted with aromatic diamines to form pigment yellow 110, pigment yellow 109, and pigment orange 61.

TCPA itself is manufactured from phthalic anhydride which is reacted with halogen to obtain tetrachloro phthalic anhydride (TCPA). One of the uncontrolled side reactions in the manufacturing process, is the formation of hexachlorobenzene (herein after called HCB) as a result of cleavage of anhydride linkage, resulting in the halogenation of all the six positions of benzene moiety and formation of HCB.

HCB is a chlorinated hydrocarbon. HCB is an animal carcinogen and is considered to be a probable human carcinogen. HCB has been classified by the International Agency for Research on Cancer (IARC) as a Group 2B carcinogen (the agent is possibly carcinogenic to humans). HCB is very toxic to aquatic organisms and may cause long term adverse effects in the aquatic environment. Therefore, release of HCB into waterways is strictly avoided. In the known processes for manufacture of isoindolinone pigments and particularly manufacture of the intermediate TCCMB there is no known method whereby TCCMB containing less than 100 ppm of HCB can be achieved. Therefore, there is a need for the manufacture of isoindolinone pigment wherein the HCB content of the TCCMB intermediate and therefore the HCB content of the final pigment is less than 10 ppm.

Objects-

An object of the present invention is to provide an Isoindolinone pigment with low hexachlorobenzene content.

Yet another object of the present invention is to provide an Isoindolinone pigment intermediate namely tetrachloro cyano methyl benzoate with low hexachlorobenzene content.

Yet another object of the present invention is to provide a method for manufacturing an Isoindolinone pigment or its intermediates, which increases the product yield.

Further, another object of the present invention is to provide a method for manufacturing an Isoindolinone pigment or its intermediates, which is economical.

Still further, another object of the present invention is to provide a method for manufacturing an Isoindolinone pigment or its intermediates, which is environment friendly. Summary of the invention-

In accordance with this invention provided an isoindolinone pigment, with HCB content lower than 10 ppm; and a method for manufacture of Tetra chloro cyano methyl benzoate (TCCMB), an intermediate for manufacture of isoindolinone pigment comprises the following steps:

1) An isoindolinone pigment having hexachlorobenzene (HCB) content less than 10 ppm.

2) An isoindolinone pigment is claimed in claim 1 wherein the pigment is Yellow 110.

3) An isoindolinone pigment is claimed in claim 1 wherein the pigment is Yellow 109.

4) An isoindolinone pigment is claimed in claim 1 wherein the pigment is Orange 61.

5) An intermediate compound for the isoindolinone pigment as claimed in claim 1 said compound being Tetra chloro cyano methyl benzoate (TCCMB) having HCB content less than 10 ppm.

6) A method of manufacturing isoindolinone pigment as claimed in any one of claims 1 to 5 comprising the following steps:

a) further chlorinating tetrachlorophthalic anhydride (TCPA) by reacting with chlorinating agent at an elevated temperature and distilling out the chlorinating agent to obtain a chlorinated clear solution containing tetrachloro phthaloyl chloride (TCPC), unreacted chlorinating agent.

b) adding a first organic solvent to the chlorinated clear solution under stirring and washing the mixture of first organic solvent and chlorinated clear solution by adding water at temperature below 1O⁰C with stirring to form a biphasic mixture;

c) allowing the biphasic mixture obtained in step (b) to obtain a first organic phase and a first aqueous phase;

d) decanting the first aqueous phase obtained in step (c) containing water, traces of chlorinating agent;

e) washing the first organic phase obtained in step (c) with water at least once to obtain a clear solution containing tetrachloro phthaloyl chloride (TCPC), hexachlorobezene (HCB), and some quantity of water;

f) ammoniating the clear solution by drop wise addition to liquor ammonia solution and gradually heating to obtain a hazy reaction mass containing ammonium salt of tetrachloro cyano benzoic acid (TCCBA) and traces of hexachlorobenzene (HCB);

g) filtering the hazy reaction mass to obtain a wet cake comprise ammonium salt of tetrachloro cyano benzoic acid (TCCBA); h) washing the wet cake obtained in step (g) with a second organic solvent to obtain a washed wet cake comprising ammonium salt of tetrachloro cyano benzoic acid (TCCBA);

i) adding hot water at temperature above 80⁰C to the washed wet cake obtained in step (h) and further addition of a second organic solvent while stirring to obtain a second biphasic mixture comprising a second organic phase containing xylene and traces of HCB, and a second aqueous phase containing ammonium salt of tetrachloro cyano benzoic acid (TCCBA);

j) separating the second organic phase from the second biphasic mixture obtained in step (i) and cooling the second aqueous phase below 1O⁰C to obtain precipitated white crystals of ammonium salt of TCCBA;

k) filtering and drying the precipitated white crystals of ammonium salt of TCCBA obtained in step (J) to obtain dried crystal mass of ammonium salt of TCCBA;

1) esterifying the dried crystal mass with an alkylating agent in presence of a polar aprotic solvent to obtain a clear solution containing of tetrachloro cyano methyl benzoate;

m) quenching the clear solution obtained in step (1) in water to obtain white crystals of tetrachloro cyano methyl benzoate (TCCMB); and

n) converting those crystals of TCCMB having HCB content less than 10 ppm to form an Isoindolinone pigment; 7) A method of manufacturing isoindolinone pigment wherein the elevated temperature is about 125°C to about 130⁰C.

8) A method of manufacturing isoindolinone pigment the said chlorinated clear solution is heated for the period of 10 to 12 hours under stirring at atmospheric pressure.

9) A method of manufacturing isoindolinone pigment wherein the said chlorinating agent is typically phosphorous pentachloride.

10) A method of manufacturing isoindolinone pigment wherein the said first organic solvent is from the group of non-polar aprotic solvent.

11) A method of manufacturing isoindolinone pigment wherein the said first organic solvent is typically xylene.

12) A method of manufacturing isoindolinone pigment stirred for 10 minutes after addition of the first organic solvent.

13) A method of manufacturing isoindolinone pigment wherein the pH of the solution after washing is 4 to 7.

14) A method of manufacturing isoindolinone pigment wherein the addition of the clear solution to liquor ammonia solution drop wise is at the rate of 10 to 15 ml per minute. 15) A method of manufacturing isoindolinone pigment wherein the concentration of said liquor ammonia solution is 20 to 30% and molar ratio is about 1:4 to about 1 :12.

16) A method of manufacturing isoindolinone pigment wherein the reaction temperature is maintained between about 4°C to about 6⁰C during addition of the clear solution to liquor ammonia solution and the reaction mixture is allowed stand for the period of 60 minutes.

17) A method of manufacturing isoindolinone pigment wherein the white curd like slurry is heated gradually to a temperature between about 85⁰C to about 87°C and stirred for the period of 4 hours.

18) A method of manufacturing isoindolinone pigment wherein the said first organic solvent is selected from the group of non-polar aprotic solvent.

19) A method of manufacturing isoindolinone pigment typically the said second organic solvent is xylene.

20) A method of manufacturing isoindolinone pigment wherein the second biphasic mixture stirred for the period of 30 minutes at temperature above 80⁰C.

21) A method of manufacturing isoindolinone pigment wherein recovered and recycled the separated second organic phase. 22) A method of manufacturing isoindolinone pigment wherein the precipitated white crystals of ammonium salt of TCCBA filtered by Buchner funnel with filter paper.

23) A method of manufacturing isoindolinone pigment wherein the precipitated white crystals of ammonium salt of TCCBA dried at temperature above 100⁰C.

24) A method of manufacturing isoindolinone pigment the dried crystal mass is added in the polar aprotic solvent at temperature about 40⁰C to about 42°C.

25) A method of manufacturing isoindolinone pigment the alkylating agent is added in mixture of polar aprotic solvent and dried crystal mass at temperature about 40⁰C to about 42°C.

26) A method of manufacturing isoindolinone pigment the said polar aprotic solvent is selected from group dimethyl formamide (DMF), dimethyl sulfoxide, and hexamethylphosphorotriamide.

27) A method of manufacturing isoindolinone pigment the said polar aprotic solvent is typically dimethylformamide.

28) A method of manufacturing isoindolinone pigment the said alkylating agent selected from the Ci to C₄ compounds.

29) A method of manufacturing isoindolinone pigment the used alkylating agent is typically dimethyl sulfate (DMS). Detailed description of the invention

Tetrachlorophthalic anhydride (TCPA) and chlorinating agent PCl₅ were mixed together in the round bottom flask provided with stirring arrangement and refluxed condenser. The mixture was gradually heated under stirring to melt the solid. The reaction mixture was maintained at temperature in the range of 125 to 130⁰C for period of 12 hours. A clear solution containing TCPC was left in the flask and unreacted POCl₃ was separated by distillation. Xylene was added in the flask containing TCPC solution because TCPC is dissolved in organic solvent. Xylene and TCPC solution were stirred for 10 minutes; then cold water at 1O⁰C was added for phase separation and the mixture was again stirred. The mass of liquid in flask is separated in two layers i.e. aqueous layer at the top and organic layer at the bottom by phase separation. The organic layer containing TCPC, HCB and some quantity of water was treated with water 4 times quantity with water. After washing, the pH of the solution was found to be 4.8.

The organic layer containing TCPC solution in the form of xylene layer was added drop by drop in a three necked round bottom flask containing liquor ammonia with concentration was about 25 to 30% at molar ratio about 1 :4 to 1 :12. This addition is exothermic reaction and to avoid the loss of ammonia maintained at a temperature below 5⁰C. The time taken for addition was 63 minutes. The flask was placed in an ice bath containing brine solution at temperature between -2°C to -4⁰C. The reaction mixture was allowed to stand for 60 minutes in the cold bath. The temperature was periodically checked to ensure that the temperature of the reaction mixture did not exceed 5⁰C. Then the flask was removed from the bath and the temperature was slowly raised up to 5O⁰C in 1 hour time. The flask was further gradually heated to 85⁰C and stirred at this temperature for 4 hours. A hazy reaction mass was obtained. This mass was filtered in a Buchner funnel containing filter paper. Wet cake obtained was washed with xylene. Xylene washed cake was dissolved in hot water at 80⁰C to form a clear solution; to this solution, xylene was added to lead phase change. Washing of ammonium salt is also important to remove maximum HCB from final product by dissolving wet cake of ammonium salt of TCCBA in hot water and use of organic solvent for complete extraction of HCB. The reaction solution was stirred for 30 minutes at 80⁰C and phase separation was seen in the flask in which the organic layer was at the top. Xylene layer was sent for recycling and the aqueous layer containing ammonium salt of TCCBA was transferred to an ice bath at 5°C. Ammonium salt of TCCBA were precipitated as white shiny crystals. These crystals were separated by filtration wet cake of ammonium salt of TCCBA was obtained. This material was dried in tray dryer at 100⁰C for 8 hours.

The polar aprotic solvent dimethylformamide (DMF) at 40⁰C was taken in a three necked round bottom flask and the crystals of ammonium salt of TCCBA obtained above were added under stirring. To this slurry the alkylating agent dimethyl sulfate (DMS) were added at 40⁰C. The resultant mixture was allowed to mature for 3 hours. A clear solution containing tetra chloro cyano methyl benzoate (TCCMB) in the solvent system containing DMF and mono methyl ammonium sulfate was formed. This solution was quenched in water. White crystals of TCCMB having purity 99.9% and melting point of 84.8⁰C were obtained. The HCB content was measured on gas chromatogram make Varian GC CP 3800 and was found to be 7 ppm. The resultant tetra chloro cyano methyl benzoate (TCCMB) converted to isoindolinone pigment with hexachlorobenzene (HCB) content less than 10 ppm.

Isoindolinone pigment was prepared by reacting the TCCMB with alkylating agent selected from the group of Ci to C₄ compounds, preferably dimethyl sulfate in presence of alcohol selected from the group of Ci to C₄ compounds, preferably methanol to form methoxy compound intermediate; further treated with aromatic diamine p-phenylene diamine (PPDA), 2,6 diamino toluene, and 4,4 diamino azo benzene-2- methyl to form pigment yellow- 110, pigment yellow- 109 and pigment orange-61 respectively.

The crude pigment disperses in this media. The water immiscible solvents typically acting as accelerants. The dispersion mass is filtered, dried and pulverized to a particulate pigment with the significant particle size having surface area in the range of 24 to 58 sq.mtr.per gm. The solvent is recovered by steam distillation.

Using this process, it was found that the tetra chloro cyano methyl benzoate so obtained had a hexachlorobenzene level below 10 ppm having purity greater than 99 %.

Example 1 a) 315 gm of TCPA( HCB content more than 100 ppm) and 345 gm (1.5 MR) PC15 were mixed together in the round bottom flask provided with stirring arrangement and refluxed condenser, The mixture was gradually heated under stirring to melt the solid. The reaction mixture was maintained at temperature in the range of 125 to 130⁰C for period of 12 hours. A clear solution containing TCPC was left in the flask and POCl₃ was separated by distillation. 600 ml of xylene was added in the flask containing TCPC solution. Xylene and TCPC solution were stirred for 10 minutes; then 500 ml of cold water at 10⁰C was added and the mixture was again stirred. The mass of liquid in flask is separated in two layers i.e. aqueous layer at the top and organic layer at the bottom by phase separation. The organic layer containing TCPC, HCB and some quantity of water was treated with water 4 times quantity of water being 1000 ml each time. After washing, the pH of the solution was found to be 4.8

352 gm of TCPC solution obtained in step 1 (a) in the form of organic (xylene) layer was added drop by drop in a three necked round bottom flask containing 633 gm 25% liquor ammonia at molar ratio Jj9. Maintained at a temperature of 4.8°C. The flask was placed in an ice bath containing brine solution at temperature between -2°C to -4°C. The reaction mixture was allowed to stand for 60 minutes in the cold bath. The temperature was periodically checked to ensure that the temperature of the reaction mixture did not exceed 5⁰C. Then the flask was removed from the bath and the temperature was slowly raised up to 50⁰C in 1 hour time. The flask was further gradually heated to 85°C and stirred at this temperature for 4 hours. A hazy reaction mass was obtained. This mass was filtered in a Buchner funnel containing filter paper. Wet cake obtained was washed with 200 ml xylene. Xylene washed cake was dissolved in hot water at 80⁰C to form a clear solution; to this solution, 100 ml of xylene was added. The reaction solution was stirred for 30 minutes at 80⁰C and phase separation was seen in the flask in which the organic layer was at the top. Xylene layer was sent for recycling and the aqueous layer was transferred to an ice bath at 5⁰C. Ammonium salt of TCCBA were precipitated as white shiny crystals. These crystals were separated by filtration. 286 gm of ammonium salt of TCCBA was obtained. This material was dried in tray dryer at 100⁰C for 8 hours.

1000 ml of DMF at 40⁰C was taken in a three necked round bottom flask and the crystals of ammonium salt of TCCBA obtained above were added under stirring. To this slurry 163 gm of DMS were added at 40⁰C. The resultant mixture was allowed to mature for 3 hours. A clear solution containing tetra chloro cyano methyl benzoate (TCCMB) in the solvent system containing DMF and mono methyl ammonium sulfate was formed. This solution was quenched in water. White crystals of TCCMB was 225 gm having purity 99.9% having melting point of 84.8°C were obtained. The HCB content was measured on gas chromatogram make Varian GC CP 3800 and was found to be 7 ppm.

Example 2

The process as per the Example 1 step(a) and (b) was repeated using ortho dichlorobenzene (ODCB) as the organic solvent instead of xylene. The resultant white crystals of TCCMB was 210 gm having purity 99.8% and melting point of 84.6°C were obtained. The HCB content was measured on gas chromatogram and was found to be 9 ppm. Example 3

The process as per the Example 1 step(a) and (b) was carried out using benzene as the organic solvent instead of xylene. The resultant white crystals of TCCMB was 230 gm having purity 99.9% having melting point of 84.7⁰C was obtained. The HCB content was measured on gas chromatogram and was found to be 6 ppm.

Example 4

The process as per the Example 1 step(a) and (b) was carried out using toluene as the organic solvent instead of xylene. The resultant white crystals of TCCMB was 228 gm having purity 99.7% having melting point of 84.9°C was obtained. The HCB content was measured on gas chromatogram and was found to be 8 ppm.

Example 5

The process was carried out as per the Example 1 upto step (a). On step (b), 1 liter of ethyl alcohol was used as organic solvent instead of dimethyl formamide (DMF). The resultant white crystals of TCCMB was 205 gm having purity 95.0% having melting point of 84.5°C was obtained. The HCB content was measured on gas chromatogram and was found to be 7 ppm.

Example 6

The process was carried out as per the Example 1 upto step (a). On step (b), 1 liter of methyl alcohol was used as organic solvent instead of dimethyl formamide (DMF). The resultant white crystals of TCCMB was 204 gm having purity 96.0% having melting point of 84.6°C was obtained. The HCB content was measured on gas chromatogram and was found to be 6 ppm.

Example 7

Pigment Yellow-110 was prepared by reacting 40 gm of TCCMB with

32.9 gm of sodium methoxide lye in presence of 400 gm of methanol

(MeOH) The resultant dimethoxy intermediate was treated with 8.17 gm ofp-phenylene diamine (PPDA) to form 35 gm of pigment yellow-110.

The particulate pigment with surface area 26 to 56 sq.mtr per gm. is formed

Example 8

Pigment Yellow- 109 was prepared by reacting 40 gm of TCCMB with 32.9 gm of sodium methoxide lye in presence of 400 gm of methanol (MeOH) The resultant dimethoxy intermediate was treated with 8.25 gm of 2,6 diamino toluene to form 33 gm of pigment yellow- 109 which was isolated by filtration. The particulate pigment with surface area 24 sq.mtr per gm. is formed

Example 9

Pigment Orange-61 was prepared by reacting 40 gm of TCCMB with 32.9 gm of sodium methoxide lye in presence of 400 gm of methanol (MeOH) The resultant dimethoxy intermediate was treated with 15.12 gm of 4,4 diamino azo benzene-2- methyl to form 38.9 gm of pigment orange-61. The particulate pigment with surface area 58 sq.mtr per gm. is formed

Claims

Claims:

1) An isoindolinone pigment having hexachlorobenzene (HCB) content less than lO ppm.

6) A method of manufacturing isoindolinone pigment as claimed in any one of claims 1 to 5 comprising the following steps: a) further chlorinating tetrachlorophthalic anhydride (TCPA) by reacting with chlorinating agent at an elevated temperature and distilling out the chlorinating agent to obtain a chlorinated clear solution containing tetrachloro phthaloyl chloride (TCPC), unreacted chlorinating agent. b) adding a first organic solvent to the chlorinated clear solution under stirring and washing the mixture of first organic solvent and chlorinated clear solution by adding water at temperature below 10⁰C with stirring to form a biphasic mixture; c) allowing the biphasic mixture obtained in step (b) to obtain a first organic phase and a first aqueous phase; d) decanting the first aqueous phase obtained in step (c) containing water, traces of chlorinating agent; e) washing the first organic phase obtained in step (c) with water at least once to obtain a clear solution containing tetrachloro phthaloyl chloride (TCPC), hexachlorobezene (HCB), and some quantity of water; f) ammoniating the clear solution by drop wise addition to liquor ammonia solution and gradually heating to obtain a hazy reaction mass containing ammonium salt of tetrachloro cyano benzoic acid (TCCBA) and traces of hexachlorobenzene (HCB); g) filtering the hazy reaction mass to obtain a wet cake comprise ammonium salt of tetrachloro cyano benzoic acid (TCCBA); h) washing the wet cake obtained in step (g) with a second organic solvent to obtain a washed wet cake comprise ammonium salt of tetrachloro cyano benzoic acid (TCCBA); i) adding hot water at temperature above 80⁰C to the washed wet cake obtained in step (h) and further addition of a second organic solvent while stirring to obtain a second biphasic mixture comprising a second organic phase containing xylene and traces of HCB, and a second aqueous phase containing ammonium salt of tetrachloro cyano benzoic acid (TCCBA); j) separating the second organic phase from the second biphasic mixture obtained in step (i) and cooling the second aqueous phase below 10⁰C to obtain precipitated white crystals of ammonium salt of TCCBA; k) filtering and drying the precipitated white crystals of ammonium salt of

TCCBA obtained in step (j) to obtain dried crystal mass of ammonium salt of

TCCBA;

1) esterifying the dried crystal mass with an alkylating agent in presence of a polar aprotic solvent to obtain a clear solution containing of tetrachloro cyano methyl benzoate; m) quenching the clear solution obtained in step (1) in water to obtain white crystals of tetrachloro cyano methyl benzoate (TCCMB); and n) converting those crystals of TCCMB having HCB content less than 10 ppm to form an Isoindolinone pigment;

7) A method of manufacturing isoindolinone pigment as claimed in claim 6 (a) wherein the elevated temperature is about 125°C to about 130⁰C.

8) A method of manufacturing isoindolinone pigment as claimed in claim 6 (a) wherein the said chlorinated clear solution is heated for the period of 10 to 12 hours under stirring at atmospheric pressure.

9) A method of manufacturing isoindolinone pigment as claimed in claim 6 (a) wherein the said chlorinating agent is typically phosphorous pentachloride.

10) A method of manufacturing isoindolinone pigment as claimed in claim 6 (b) wherein the said first organic solvent is selected from the group of non-polar aprotic solvent.

H) A method of manufacturing isoindolinone pigment as claimed in claim 6 (b) wherein the said first organic solvent is typically xylene. 12) A method of manufacturing isoindolinone pigment as claimed in claim 6 (b) wherein after addition of the first organic solvent stirred for 10 minutes.

13) A method of manufacturing isoindolinone pigment as claimed in claim 6 (e) wherein the pH of the solution after washing is 4 to 7.

14) A method of manufacturing isoindolinone pigment as claimed in claim 6 (f) wherein the addition of the clear solution to liquor ammonia solution drop wise is at the rate of 10 to 15 ml per minute.

15) A method of manufacturing isoindolinone pigment as claimed in claim 6 (f) wherein the concentration of said liquor ammonia solution is 20 to 30% and molar ratio is about 1 :4 to about 1 :12.

16) A method of manufacturing isoindolinone pigment as claimed in claim 6 (f) wherein the reaction temperature is maintained between about 4°C to about 6°C during addition of the clear solution to liquor ammonia solution and the reaction mixture is allowed stand for the period of 60 minutes.

17) A method of manufacturing isoindolinone pigment as claimed in claim 6 (f) wherein the clear solution is heated gradually to a temperature between about 85°C to about 87°C and stirred for the period of 4 hours.

18) A method of manufacturing isoindolinone pigment as claimed in claim 6 (h) and (i) wherein the said first organic solvent is selected from the group of non- polar aprotic solvent. 19) A method of manufacturing isoindolinone pigment as claimed in claim 6 (h) and (i) wherein the said second organic solvent is xylene.

20) A method of manufacturing isoindolinone pigment as claimed in claim 6 (i) wherein the second biphasic mixture stirred for the period of 30 minutes at temperature above 80⁰C.

2I) A method of manufacturing isoindolinone pigment as claimed in claim 6 (j) wherein recovered and recycled the separated second organic phase.

22) A method of manufacturing isoindolinone pigment as claimed in claim 6 (k) wherein the precipitated white crystals of ammonium salt of TCCBA filtered by Buchner funnel with filter paper.

23) A method of manufacturing isoindolinone pigment as claimed in claim 6 (k) wherein the precipitated white crystals of ammonium salt of TCCBA dried at temperature above 100⁰C.

24) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the dried crystal mass is added in the polar aprotic solvent at temperature about 40⁰C to about 42⁰C.

25) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the alkylating agent is added in mixture of polar aprotic solvent and dried crystal mass at temperature about 40⁰C to about 42°C. 26) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the said polar aprotic solvent is selected from group dimethyl formamide (DMF), dimethyl sulfoxide, and hexamethylphosphorotriamide.

27) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the said polar aprotic solvent is typically dimethylformamide.

28) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the said alkylating agent selected from the Ci to C₄ compounds.

29) A method of manufacturing isoindolinone pigment as claimed in claim 6 (1) wherein the used alkylating agent is typically dimethyl sulfate (DMS).