FORM-2
THE PATENT ACT, 1970
(39 of 1970)
'&
THE PATENT RULES, 2003
PROVISIONAL SPECIFICATION
(See section 10 and Rule 13)
ISOINDOLINONE PIGMENTS
SUDARSHAN CHEMICAL INDUSTRIES LIMITED An Indian Company
of 162, Wellesley Road, Pune-411 001,
Maharashtra, India
THE FOLLOWING SPECIFICATION DESCRIBES THE INVENTION

Field of the invention
This invention relates to Isoindolinone Pigments. In particular, this invention relates to the following pigments such as :
Yellow 109 (CAS No. 5045-40-9)
Yellow 110 (CAS No.5590-18-1)
Orange 61(CAS No.40716-47-0)
Background of the invention:
Isoindolinone pigments are typically manufactured from Tetrachlorophthalic anhydride (TCPA). Tetrachlorophthalic anhydride 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 (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.
Hexachlorobenzene is a.__ chlorinated hydrocarbon
Hexachlorobenzene is an animal carcinogen and is considered to be a probable human carcinogen. Hexachlorobenzene has been classified by the International Agency for Research on Cancer (IARC) as a Group 2B carcinogen (the agent is possibly carcinogenic to humans). Hexachlorobenzene 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.
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Hitherto, the HCB has been found in the TCPA of the order of over 1000 ppm and this HCB having carcinogenic properties remains in the final pigments. The pigments so produced are typically used for coloring of plastics and plastic products such as toys and containers, coatings and different types of inks.;
With newer and newer stringent regulations against use of carcinogenic substances coming into force, it has become necessary to eliminate carcinogenic substances like hexachlorobenzene from the pigments ab initio and therefore there is a need for pigments, including Isoindolinone pigments, having lower amounts of HCB.
An object of this invention is to provide Isoindolinone pigment with low Hexachlorobenzene.
The process envisaged in accordance with the present invention involves following steps:
1. TCPA is reacted with phosphorous pentachloride (PC15) at 120-160 °C for 10-20 hrs to form Tetrachloro phthaloyl chloride (TCPC)
2. TCPC is isolated by drowning the reaction mass in excess of chilled water (0-10 °C) and filtration typically under vacuum.
3. The wet cake residue is washed with chilled water until the pH of washed cake lies between 4 and 7.
4. TCPC is then reacted with an ammonical solution and in the presence of an organic water-immiscible solvent such as toluene, xylene, benzene, monochlorobenzene (MCB), o-
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dichlorobenzene and the like to form an ammonium salt of Tetrachlorocyano benzoic acid (TCCBA). This product is dried and methylated in the presence of methylating agent like
dimethyl sulfate! (DMS) 'and aprotic polar solvent; to form tetrachlorocyanomethyl benzoate (TCCMB).
5. The TCCMB so formed is drowned in water, filtered and further washed with water.
6. TCCMB is then reacted with an alkyl alcohol containing an earth metal alkoxide to form a dialkoxy compound. The alkoxy
compound is reacted with aromatic diamine like p-phenylene
diamine (PPD), 2,6-Diamino toluene! to form the crude pigment bis-4,5,6,7-tetrachloro- isoindolinone l-one-3-ylidene-phenylene diamine. 7. The crude pigment is filtered, washed and charged to water containing solvents typically toluene, xylene, benzene, MCB etc. at a pH of about 8-10, which acts as a dispersion media.
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 being below 25 u. The solvent is recovered by steam distillation.
Using this process, it was found that the Isoindolinone pigment so obtained had a hexachlorobenzene level below 50 ppm with yield of greater than 60 % based on Tetrachloro phthalic anhydride (TCPA).
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While considerable emphasis has been placed herein on the specific steps of the preferred embodiment, it will be appreciated that many alterations can be made and that many modifications can be made in the preferred embodiment without departing from the principles of the invention. These and other changes in the preferred embodiment as well as other embodiments of the invention will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.
Dated this 5th day of February 2007

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